85 km Long Reach PON System Using a Reflective SOA-EA Modulator and Distributed Raman Fiber Amplification

DEFF Research Database (Denmark)

Tafur Monroy, Idelfonso; Öhman, Filip; Yvind, Kresten

2006-01-01

We report on a bidirectional 85 km long reach PON system supported by distributed fiber Raman amplification with a record 7.5 Gb/s remote carrier modulated upstream signal by employing a reflective SOA-EA monolithically integrated circuit......We report on a bidirectional 85 km long reach PON system supported by distributed fiber Raman amplification with a record 7.5 Gb/s remote carrier modulated upstream signal by employing a reflective SOA-EA monolithically integrated circuit...

Information rates of next-generation long-haul optical fiber systems using coded modulation

NARCIS (Netherlands)

Liga, G.; Alvarado, A.; Agrell, E.; Bayvel, P.

2017-01-01

A comprehensive study of the coded performance of long-haul spectrally-efficient WDM optical fiber transmission systems with different coded modulation decoding structures is presented. Achievable information rates are derived for three different square QAM formats and the optimal format is

Fiber-optic perimeter security system based on WDM technology

Science.gov (United States)

Polyakov, Alexandre V.

2017-10-01

Intelligent underground fiber optic perimeter security system is presented. Their structure, operation, software and hardware with neural networks elements are described. System allows not only to establish the fact of violation of the perimeter, but also to locate violations. This is achieved through the use of WDM-technology division spectral information channels. As used quasi-distributed optoelectronic recirculation system as a discrete sensor. The principle of operation is based on registration of the recirculation period change in the closed optoelectronic circuit at different wavelengths under microstrain exposed optical fiber. As a result microstrain fiber having additional power loss in a fiber optical propagating pulse, which causes a time delay as a result of switching moments of the threshold device. To separate the signals generated by intruder noise and interference, the signal analyzer is used, based on the principle of a neural network. The system detects walking, running or crawling intruder, as well as undermining attempts to register under the perimeter line. These alarm systems can be used to protect the perimeters of facilities such as airports, nuclear reactors, power plants, warehouses, and other extended territory.

Optical chaos and hybrid WDM/TDM based large capacity quasi-distributed sensing network with real-time fiber fault monitoring.

Science.gov (United States)

Luo, Yiyang; Xia, Li; Xu, Zhilin; Yu, Can; Sun, Qizhen; Li, Wei; Huang, Di; Liu, Deming

2015-02-09

An optical chaos and hybrid wavelength division multiplexing/time division multiplexing (WDM/TDM) based large capacity quasi-distributed sensing network with real-time fiber fault monitoring is proposed. Chirped fiber Bragg grating (CFBG) intensity demodulation is adopted to improve the dynamic range of the measurements. Compared with the traditional sensing interrogation methods in time, radio frequency and optical wavelength domains, the measurand sensing and the precise locating of the proposed sensing network can be simultaneously interrogated by the relative amplitude change (RAC) and the time delay of the correlation peak in the cross-correlation spectrum. Assisted with the WDM/TDM technology, hundreds of sensing units could be potentially multiplexed in the multiple sensing fiber lines. Based on the proof-of-concept experiment for axial strain measurement with three sensing fiber lines, the strain sensitivity up to 0.14% RAC/με and the precise locating of the sensors are achieved. Significantly, real-time fiber fault monitoring in the three sensing fiber lines is also implemented with a spatial resolution of 2.8 cm.

Concurrent support of higher-layer protocols over WDM

NARCIS (Netherlands)

Theelen, B.D.; Voeten, J.P.M.; Putten, van der P.H.A.; Stevens, M.P.J.; Dorren, H.J.S.

2002-01-01

To satisfy the severe requirements involved in future communication networks, commercial and research interest in the applicability of wavelength division multiplexing (WDM) is growing. However, since WDM is merely concerned with transmitting bits over optical fibers, full advantage can only be

WDM-Coherent OCDMA over one single device based on short chip Super Structured Fiber Bragg Gratings.

Science.gov (United States)

Amaya, Waldimar; Pastor, Daniel; Baños, Rocio; Garcia-Munoz, Victor

2011-11-21

We theoretically propose and demonstrate experimentally a Coherent Direct Sequence OCDMA en/decoder for multi-channel WDM operation based on a single device. It presents a broadband spectral envelope and a periodic spectral pattern that can be employed for en/decoding multiple sub-bands simultaneously. Multi-channel operation is verified experimentally by means of Multi-Band Super Structured Fiber Bragg Gratings with binary phase encoded chips fabricated with 1mm inter-chip separation that provides 4x100 GHz ITU sub-band separation at 1.25 Gbps. The WDM-OCDMA system verification was carried out employing simultaneous encoding of four adjacent sub-bands and two different OCDMA codes. © 2011 Optical Society of America

Low-Complexity Tracking of Laser and Nonlinear Phase Noise in WDM Optical Fiber Systems

DEFF Research Database (Denmark)

Yankov, Metodi Plamenov; Fehenberger, Tobias; Barletta, Luca

2015-01-01

In this paper, the wavelength division multiplexed (WDM) fiber optic channel is considered. It is shown that for ideal distributed Raman amplification (IDRA), the Wiener process model is suitable for the non-linear phase noise due to cross phase modulation from neighboring channels. Based......, at the moderate received SNR region. The performance in these cases is close to the information rate achieved by the above mentioned trellis processing....

Konsep Dan Kinerja Dari Sistem Hybrid OCDMA/WDM Untuk Local Area Network

OpenAIRE

Nasaruddin, Nasaruddin

2011-01-01

Peningkatan kapasitas, distribusi bandwidth dan daya merupakan beberapa isu penting untuk aplikasi local area network (LAN). Saat ini, teknologi fiber optik sudah dapat mendukung jaringan akses dengan kecepatan tinggi untuk layanan multimedia diantaranya teknologi OCDMA dan WDM. Penambahan kapasitas transmisi LAN bisa dilakukan dengan penggabungan sistem transmisi OCDMA dengan WDM. Untuk itu, paper ini mengusulkan konsep dan kinerja dari sistem hybrid OCDMA/WDM. Sistem hybrid OCDMA/WDM ini be...

85 km long reach PON system using a reflective SOA-EA modulator and distributed Raman fiber amplification

NARCIS (Netherlands)

Tafur Monroy, I.; Öhman, F.; Yvind, K.; Kjaer, R.; Peucheret, C.; Koonen, A.M.J.; Jeppesen, P.

2006-01-01

We report on a bidirectional 85 km long reach PON system supported by distributed fiber Raman amplification with a record 7.5 Gb/s remote carrier modulated upstream signal by employing a reflective SOA-EA monolithically integrated circuit.

Comparison of WDM/Pulse-Position-Modulation (WDM/PPM) with Code/Pulse-Position-Swapping (C/PPS) Based on Wavelength/Time Codes

Energy Technology Data Exchange (ETDEWEB)

Mendez, A J; Hernandez, V J; Gagliardi, R M; Bennett, C V

2009-06-19

Pulse position modulation (PPM) signaling is favored in intensity modulated/direct detection (IM/DD) systems that have average power limitations. Combining PPM with WDM over a fiber link (WDM/PPM) enables multiple accessing and increases the link's throughput. Electronic bandwidth and synchronization advantages are further gained by mapping the time slots of PPM onto a code space, or code/pulse-position-swapping (C/PPS). The property of multiple bits per symbol typical of PPM can be combined with multiple accessing by using wavelength/time [W/T] codes in C/PPS. This paper compares the performance of WDM/PPM and C/PPS for equal wavelengths and bandwidth.

The Gain of Performance of Optical WDM Networks

Directory of Open Access Journals (Sweden)

Miroslav Bahleda

2008-01-01

Full Text Available We study the blocking probability and performance of single-fiber and multifiber optical networks with wavelength division multiplexing (WDM. We extend the well-known analytical blocking probability model by Barry and Humblet to the general model, which is proposed for both single-fiber and multifiber network paths with any kind of wavelength conversion (no, limited, or full wavelength conversion and for uniform and nonuniform link loads. We investigate the effect of the link load, wavelength conversion degree, and the number of wavelengths, fibers, and hops on blocking probability. We also extend the definition of the gain of wavelength conversion by Barry and Humblet to the gain of performance, which is fully general. Thanks to this definition and implementation of our model, we compare different WDM node architectures and present interesting results.

A Novel Reliable WDM-PON System

Science.gov (United States)

Chen, Benyang; Gan, Chaoqin; Qi, Yongqian; Xia, Lei

2011-12-01

In this paper, a reliable Wavelength-Division-Multiplexing Passive Optical Network (WDM-PON) system is proposed. It can provide the protection against both the feeder fiber failure and the distribution fiber failure. When the fiber failure occurs, the corresponding switches in the OLT and in the ONU can switch to the protection link without affecting the users in normal status. That is to say, the protection for one ONU is independent of the other ONUs.

Self-healing ring-based WDM-PON

Science.gov (United States)

Zhou, Yang; Gan, Chaoqin; Zhu, Long

2010-05-01

In this paper, a survivable ring-based wavelength-division-multiplexing (WDM)-passive optical network (PON) for fiber protection is proposed. Protections for feeder fiber and distributed fiber are independent in the scheme. Optical line terminal (OLT) and optical network units (ONUs) can automatically switch to protection link when fiber failure occurs. Protection distributed fiber is not required in the scheme. Cost-effective components are used in ONUs to minimize costs of network. A simulation study is performed to demonstrate the scheme. Its result shows good performance of upstream and downstream signals.

Performance comparison of a wdm pon with tdm pon at 10 gbps

International Nuclear Information System (INIS)

Usman, M.

2014-01-01

Recent developments in optical technologies have realized wavelength division multiplexed passive optical network (WDM PON) as a promising and a cost-effective solution for the next generation networks. Due to the intrinsic optical transparency and extremely high transmission capacity, WDM PON is considered more future oriented than conventional TDM PON. In this paper we compare an eight channel WDM PON with an eight channel TDM PON, both operating at 10 Gbps data rate. Network parameters like input laser power, optical fiber length and optical amplifier gain are varied and their impact on performance parameters i.e. Q-factor, BER, OSNR, Eye opening and Extinction ratio penalty is recorded. Results reveal that WDM PON exhibits superior performance than TDM PON in each case. (author)

Crosstalk in WDM communication networks

NARCIS (Netherlands)

Tafur Monroy, I.; Tangdiongga, E.

2002-01-01

The use of advanced transmission and switching techniques such as reconfigurable WDM optical crossconnects is enabling high capacity and flexible optical networking at ultra bit-rates reaching multi-terabits per second. These techniques also offer creative ways to improve the network connectivity

A method of simulating intensity modulation-direct detection WDM systems

Institute of Scientific and Technical Information of China (English)

HUANG Jing; YAO Jian-quan; LI En-bang

2005-01-01

In the simulation of Intensity Modulation-Direct Detection WDM Systems,when the dispersion and nonlinear effects play equally important roles,the intensity fluctuation caused by cross-phase modulation may be overestimated as a result of the improper step size.Therefore,the step size in numerical simulation should be selected to suppress false XPM intensity modulation (keep it much less than signal power).According to this criterion,the step size is variable along the fiber.For a WDM system,the step size depends on the channel separation.Different type of transmission fiber has different step size.In the split-step Fourier method,this criterion can reduce simulation time,and when the step size is bigger than 100 meters,the simulation accuracy can also be improved.

A novel survivable architecture for hybrid WDM/TDM passive optical networks

Science.gov (United States)

Qiu, Yang; Chan, Chun-Kit

2014-02-01

A novel tree-ring survivable architecture, which consists of an organization of a wavelength-division-multiplexing (WDM) tree from optical line terminal (OLT) to remote nodes (RNs) and a time division multiplexing (TDM) ring in each RN, is proposed for hybrid WDM/TDM passive optical networks. By utilizing the cyclic property of arrayed waveguide gratings (AWGs) and the single-ring topology among a group of optical network units (ONUs) in the remote node, not only the feeder and distribution fibers, but also any fiber failures in the RN rings are protected simultaneously. Five-Gbit/s transmissions under both normal working and protection modes were experimentally demonstrated and a traffic restoration time was successfully measured.

Experimental demonstrations of all-optical networking functions for WDM optical networks

Science.gov (United States)

Gurkan, Deniz

The deployment of optical networks will enable high capacity links between users but will introduce the problems associated with transporting and managing more channels. Many network functions should be implemented in optical domain; main reasons are: to avoid electronic processing bottlenecks, to achieve data-format and data-rate independence, to provide reliable and cost efficient control and management information, to simultaneously process multiple wavelength channel operation for wavelength division multiplexed (WDM) optical networks. The following novel experimental demonstrations of network functions in the optical domain are presented: Variable-bit-rate recognition of the header information in a data packet. The technique is reconfigurable for different header sequences and uses optical correlators as look-up tables. The header is processed and a signal is sent to the switch for a series of incoming data packets at 155 Mb/s, 622 Mb/s, and 2.5 Gb/s in a reconfigurable network. Simultaneous optical time-slot-interchange and wavelength conversion of the bits in a 2.5-Gb/s data stream to achieve a reconfigurable time/wavelength switch. The technique uses difference-frequency-generation (DFG) for wavelength conversion and fiber Bragg gratings (FBG) as wavelength-dependent optical time buffers. The WDM header recognition module simultaneously recognizing two header bits on each of two 2.5-Gbit/s WDM packet streams. The module is tunable to enable reconfigurable look-up tables. Simultaneous and independent label swapping and wavelength conversion of two WDM channels for a multi-protocol label switching (MPLS) network. Demonstration of label swapping of distinct 8-bit-long labels for two WDM data channels is presented. Two-dimensional code conversion module for an optical code-division multiple-access (O-CDMA) local area network (LAN) system. Simultaneous wavelength conversion and time shifting is achieved to enable flexible code conversion and increase code re

Generation of 1.024-Tb/s Nyquist-WDM phase-conjugated twin vector waves by a polarization-insensitive optical parametric amplifier for fiber-nonlinearity-tolerant transmission

DEFF Research Database (Denmark)

Liu, Xiang; Hu, Hao; Chandrasekhar, S.

2014-01-01

We experimentally demonstrate the generation of 1.024-Tb/s Nyquist-WDM phase-conjugated vector twin waves (PCTWs), consisting of eight 128-Gb/s polarization-division-multiplexed QPSK signals and their idlers, by a broadband polarization-insensitive fiber optic parametric amplifier. This novel all...

Adaptive Rates of High-Spectral-Efficiency WDM/SDM Channels Using PDM-1024-QAM Probabilistic Shaping

DEFF Research Database (Denmark)

Hu, Hao; Yankov, Metodi Plamenov; Da Ros, Francesco

2017-01-01

We demonstrate adaptive rates and spectral efficiencies in WDM/SDM transmission using probabilistically shaped PDM-1024-QAM signals, achieving up to 7-Tbit/s data rates per spatial-superchannel and up to 297.8-bit/s/Hz aggregate spectral efficiency using a 30-core fiber on 12.5 and 25GHz WDM grids...

Temporal Probabilistic Constellation Shaping for WDM Optical Communication Systems

DEFF Research Database (Denmark)

Yankov, Metodi Plamenov; Forchhammer, Søren

2016-01-01

Finite state machine sources transmitting QPSK are studied as input to WDM optical fiber systems with ideal distributed Raman amplification. The probabilities of successive constellation symbols are shaped for nonlinear transmission and gains of around 500km (5-10%) are demonstrated...

Temporal Probabilistic Constellation Shaping for WDM Optical Communication Systems

OpenAIRE

Yankov, Metodi Plamenov; Forchhammer, Søren

2016-01-01

Finite state machine sources transmitting QPSK are studied as input to WDM optical fiber systems with ideal distributed Raman amplification. The probabilities of successive constellation symbols are shaped for nonlinear transmission and gains of around 500km (5-10%) are demonstrated

A CLS-based survivable and energy-saving WDM-PON architecture

Science.gov (United States)

Zhu, Min; Zhong, Wen-De; Zhang, Zhenrong; Luan, Feng

2013-11-01

We propose and demonstrate an improved survivable and energy-saving WDM-PON with colorless ONUs. It incorporates both energy-saving and self-healing operations. A simple effective energy-saving scheme is proposed by including an energy-saving control unit in the OLT and a control unit at each ONU. The energy-saving scheme realizes both dozing and sleep (offline) modes, which greatly improves the energy-saving efficiency for WDM-PONs. An intelligent protection switching scheme is designed in the OLT, which can distinguish if an ONU is in dozing/sleep (offline) state or a fiber is faulty. Moreover, by monitoring the optical power of each channel on both working and protection paths, the OLT can know the connection status of every fiber path, thus facilitating an effective protection switching and a faster failure recovery. The improved WDM-PON architecture not only significantly reduces energy consumption, but also performs self-healing operation in practical operation scenarios. The scheme feasibility is experimentally verified with 10 Gbit/s downstream and 1.25 Gbit/s upstream transmissions. We also examine the energy-saving efficiency of our proposed energy-saving scheme by simulation, which reveals that energy saving mainly arises from the dozing mode, not from the sleep mode when the ONU is in the online state.

WDM hybrid microoptical transceiver with Bragg volume grating

Science.gov (United States)

Jeřábek, Vitezslav; Armas, Julio; Mareš, David; Prajzler, Václav

2012-02-01

The paper presents the design, simulation and construction results of the wavelength division multiplex bidirectional transceiver module (WDM transceiver) for the passive optical network (PON) of a fiber to the home (FTTH) topology network. WDM transceiver uses a microoptical hybrid integration technology with volume holographic Bragg grating triplex filter -VHGT and a collimation lenses imagine system for wavelength multiplexing/ demultiplexing. This transmission type VHGT filter has high diffraction angle, very low insertion loses and optical crosstalk, which guide to very good technical parameters of transceiver module. WDM transceiver has been constructed using system of a four micromodules in the new circle topology. The optical micromodule with VHGT filter and collimation and decollimation lenses, two optoelectronics microwave receiver micromodules for receiving download information (internet and digital TV signals) and optoelectronic transmitter micromodule for transmitting upload information. In the paper is presented the optical analysis of the optical imagine system by ray-transfer matrix. We compute and measure VHGT characteristics such as diffraction angle, diffraction efficiency and diffraction crosstalk of the optical system for 1310, 1490 and 1550 nm wavelength radiation. For the design of optoelectronic receiver micromodule was used the low signal electrical equivalent circuit for the dynamic performance signal analysis. In the paper is presented the planar form WDM transceiver with polymer optical waveguides and two stage interference demultiplexing optical filter as well.

High capacity fiber optic sensor networks using hybrid multiplexing techniques and their applications

Science.gov (United States)

Sun, Qizhen; Li, Xiaolei; Zhang, Manliang; Liu, Qi; Liu, Hai; Liu, Deming

2013-12-01

Fiber optic sensor network is the development trend of fiber senor technologies and industries. In this paper, I will discuss recent research progress on high capacity fiber sensor networks with hybrid multiplexing techniques and their applications in the fields of security monitoring, environment monitoring, Smart eHome, etc. Firstly, I will present the architecture of hybrid multiplexing sensor passive optical network (HSPON), and the key technologies for integrated access and intelligent management of massive fiber sensor units. Two typical hybrid WDM/TDM fiber sensor networks for perimeter intrusion monitor and cultural relics security are introduced. Secondly, we propose the concept of "Microstructure－Optical X Domin Refecltor (M-OXDR)" for fiber sensor network expansion. By fabricating smart micro-structures with the ability of multidimensional encoded and low insertion loss along the fiber, the fiber sensor network of simple structure and huge capacity more than one thousand could be achieved. Assisted by the WDM/TDM and WDM/FDM decoding methods respectively, we built the verification systems for long-haul and real-time temperature sensing. Finally, I will show the high capacity and flexible fiber sensor network with IPv6 protocol based hybrid fiber/wireless access. By developing the fiber optic sensor with embedded IPv6 protocol conversion module and IPv6 router, huge amounts of fiber optic sensor nodes can be uniquely addressed. Meanwhile, various sensing information could be integrated and accessed to the Next Generation Internet.

Mathematical Verification for Transmission Performance of Centralized Lightwave WDM-RoF-PON with Quintuple Services Integrated in Each Wavelength Channel

Directory of Open Access Journals (Sweden)

Shuai Chen

2015-01-01

Full Text Available Wavelength-division-multiplexing passive-optical-network (WDM-PON has been recognized as a promising solution of the “last mile” access as well as multibroadband data services access for end users, and WDM-RoF-PON, which employs radio-over-fiber (RoF technique in WDM-PON, is even a more attractive approach for future broadband fiber and wireless access for its strong availability of centralized multiservices transmission operation and its transparency for bandwidth and signal modulation formats. As for multiservices development in WDM-RoF-PON, various system designs have been reported and verified via simulation or experiment till now, and the scheme with multiservices transmitted in each single wavelength channel is believed as the one that has the highest bandwidth efficiency; however, the corresponding mathematical verification is still hard to be found in state-of-the-art literature. In this paper, system design and data transmission performance of a quintuple services integrated WDM-RoF-PON which jointly employs carrier multiplexing and orthogonal modulation techniques, have been theoretically analyzed and verified in detail; moreover, the system design has been duplicated and verified experimentally and the theory system of such WDM-RoF-PON scheme has thus been formed.

Feasibility analysis of WDM links for radar applications

Directory of Open Access Journals (Sweden)

D. Meena

2015-03-01

Full Text Available Active phased array antennas enhances the performance of modern radars by using multiple low power transmit/receive modules in place of a high power transmitter in conventional radars. Fully distributed phased array radars demand the distribution of various signals in radio frequency (RF and digital domain for real time operation. This is normally achieved through complex and bulky coaxial distribution networks. In this work, we intend to tap the inherent advantages of fiber links with wavelength division multiplexed (WDM technology and a feasibility study to adapt these links for radar applications is carried out. This is done by analysing various parameters like amplitude, delay, frequency and phase variation response of various radar waveforms over WDM links. This also includes performance evaluation of non-linear frequency modulation (NLFM signals, known for better signal to noise ratio (SNR to specific side lobe levels. NLFM waveforms are further analysed using pulse compression (PC technique. Link evaluation is also carried out using a standard simulation environment and is then experimentally verified with other waveforms like RF continuous wave (CW, pulsed RF and digital signals. Synchronization signals are generated from this variable duty cycle digital signals during real time radar operation. During evaluation of digital signals, variable transient effects for different duty cycles are observed from an amplifier configuration. A suppression method is proposed to eliminate this transient effects. Further, the link delay response is investigated using different lengths of fiber spools. It can be inferred from the experimental results that WDM links are capable of handling various signals significant to radar applications.

MIMO-OFDM WDM PON with DM-VCSEL for femtocells application

DEFF Research Database (Denmark)

Binti Othman, Maisara; Deng, Lei; Pang, Xiaodan

2011-01-01

We report on experimental demonstration of 2x2 MIMO-OFDM 5.6-GHz radio over fiber signaling over 20 km WDM-PON with directly modulated (DM) VCSELs for femtocells application. MIMO-OFDM algorithms effectively compensate for impairments in the wireless link. Error-free signal demodulation of 64...

The Advent of WDM and the All-Optical Network: A Reality Check.

Science.gov (United States)

Lutkowitz, Mark

1998-01-01

Discussion of the telecommunications industry focuses on WDM (wavelength division multiplexing) as a solution for dealing with capacity constraints. Highlights include fiber optic technology; cross-connecting and switching wavelengths; SONET (Synchronous Optical Network) and wavelength networking; and optical TDM (Time Division Multiplexing). (LRW)

Demonstration of digital fronthaul over self-seeded WDM-PON in commercial LTE environment.

Science.gov (United States)

Ma, Yiran; Xu, Zhiguang; Zhang, Chengliang; Lin, Huafeng; Wang, Qing; Zhou, Min; Wang, Heng; Yu, Jingwen; Wang, Xiaomu

2015-05-04

CPRI between BBU and RRU equipment is carried by self-seeded WDM-PON prototype system within commercial LTE end-to-end environment. Delay and jitter meets CPRI requirements while services demonstrated show the same performance as bare fiber.

Long Reach RFID-over-Fiber Distribution and Collection Network

DEFF Research Database (Denmark)

Madsen, Peter; Suhr, Lau Frejstrup; Vegas Olmos, Juan José

This paper presents an RFID-over-Fiber wireless track and trace system using active RFID tags. This paper demonstrates a system, operating over distances up to 30km of optical fiber and 50m of wireless readability.......This paper presents an RFID-over-Fiber wireless track and trace system using active RFID tags. This paper demonstrates a system, operating over distances up to 30km of optical fiber and 50m of wireless readability....

A SURVEY ON WAVELENGTH DIVISION MULTIPLEXING (WDM NETWORKS

Directory of Open Access Journals (Sweden)

G. Ramesh

2010-03-01

Full Text Available Communication networks have emerged as a source of empowerment in today’s society. At the global level, the Internet is becoming the backbone of the modern economy. The new generations in developed countries cannot even conceive of a world without broadband access to the Internet. The inability of the current Internet infrastructure to cope with the wide variety and ever growing number of users, emerging networked applications, usage patterns and business models is increasingly being recognized worldwide. The dynamic growth of Internet traffic and its bursty nature requires high transmission rate. With the advances and the progress in Wavelength Division Multiplexing (WDM technology, the amount of raw bandwidth available in fiber links has increased to high magnitude. This paper presents a survey on WDM networks from its development to the current status. Also an analysis on buffer size in optical networks for real time traffic was performed.

300 Gb/s IM/DD based SDM-WDM-PON with laserless ONUs

DEFF Research Database (Denmark)

Bao, Fangdi; Morioka, Toshio; Oxenløwe, Leif Katsuo

2018-01-01

A low-cost, high-speed SDM-WDM-PON architecture is proposed by using a multi-core fiber (MCF) and intensity modulation/directly detection (IM/DD). One of the MCF cores is used for sending laser sources from optical line terminal (OLT) to optical network unit (ONU), thus facilitating laserless...

BER and total throughput of asynchronous DS-OCDMA/WDM systems with multiple user interference

OpenAIRE

Ghiringhelli, F.; Zervas, M.N.

2003-01-01

The BER and throughput of Direct-Sequence OCDMA/WDM systems based on quadripolar codes and superstructured fiber Bragg gratings are statistically derived under asynchronous operation, intensity detection, and Multiple User Interference. Performance improvements with Forward Error Correction are included.

High-Capacity Multi-Core Fibers for Space-Division Multiplexing

DEFF Research Database (Denmark)

Ye, Feihong

The transmission capacity of the present optical fiber communication systems based on time division multiplexing (TDM) and wavelength-division multiplexing (WDM) using single-mode fibers (SMFs) is reaching its limit of around 100 Tbit/s per fiber due to the fiber nonlinearities, fiber fuse...... phenomenon and the optical amplifier bandwidth. To meet the ever increasing global data traffic growth and to overcome the looming capacity crunch, a new multiplexing technology using new optical fibers is urgently needed. Space-division multiplexing (SDM) is a promising scheme to overcome the capacity limit...... of the present SMF-based systems. Among the proposed SDM schemes, the one based on uncoupled multi-core fibers (MCFs) having multiple cores in a mutual cladding has proven effective in substantially increasing the transmission capacity per fiber with least system complexity as demonstrated in several state...

Empirical multichannel power consumption model for erbium-doped fiber amplifiers

DEFF Research Database (Denmark)

Saldaña Cercos, Silvia; de Paiva, Getulio E. R.; Argentato, Marcio Colazza

2015-01-01

In this paper we report on the first experimental power consumption analysis and model of single and multi-stage booster erbium-doped fiber amplifiers (EDFAs) with automatic gain control (AGC), accounting for channel number dependency. Results show that the amount of channels being amplified simu......-users, it is relevant to study channel number dependent power consumption for devising EDFA power efficient control and design.......In this paper we report on the first experimental power consumption analysis and model of single and multi-stage booster erbium-doped fiber amplifiers (EDFAs) with automatic gain control (AGC), accounting for channel number dependency. Results show that the amount of channels being amplified...... simultaneously contributes significantly, up to 48%, to the total power consumption due to the circuitry used for controlling the EDFA. As the number of simultaneous amplified WDM channels in high capacity long and medium reach transmission links reflects closely traffic patterns generated by end...

High Speed and High Spatial Density Parameter Measurement Using Fiber Optic Sensing Technology

Science.gov (United States)

Parker, Allen R. Jr. (Inventor); Chan, Hon Man (Inventor); Richards, William Lance (Inventor); Piazza, Anthony (Inventor); Hamory, Philip J (Inventor)

2017-01-01

The present invention is an improved fiber optic sensing system (FOSS) having the ability to provide both high spatial resolution and high frequency strain measurements. The inventive hybrid FOSS fiber combines sensors from high acquisition speed and low spatial resolution Wavelength-Division Multiplexing (WDM) systems and from low acquisition speed and high spatial resolution Optical Frequency Domain Reflection (OFDR) systems. Two unique light sources utilizing different wavelengths are coupled with the hybrid FOSS fiber to generate reflected data from both the WDM sensors and OFDR sensors operating on a single fiber optic cable without incurring interference from one another. The two data sets are then de-multiplexed for analysis, optionally with conventionally-available WDM and OFDR system analyzers.

Ultrahigh-Spectral-Efficiency WDM/SDM Transmission Using PDM-1024-QAM Probabilistic Shaping With Adaptive Rate

DEFF Research Database (Denmark)

Hu, Hao; Yankov, Metodi Plamenov; Da Ros, Francesco

2018-01-01

We demonstrate wavelength-division-multiplexed (WDM) and space-division-multiplexed (SDM) transmission of probabilistically shaped polarization-division-multiplexed (PDM) 1024-state quadrature amplitude modulation (QAM) channels over a 9.7-km single-mode 30-core fiber, achieving aggregated spectr...

GigaWaM—Next-Generation WDM-PON Enabling Gigabit Per-User Data Bandwidth

DEFF Research Database (Denmark)

Prince, Kamau; Gibbon, Timothy Braidwood; Rodes Lopez, Roberto

2012-01-01

The “Gigabit access passive optical network using wavelength division multiplexing” project aims to implement 64-Gb/s data transmission over 20-km single-mode fiber. Per-user symmetric data rates of 1-Gb/s will be achieved using wavelength division multiplexing passive optical network (WDM-PON) a...

A hybrid WDM/OCDMA ring with a dynamic add/drop function based on Fourier code for local area networks.

Science.gov (United States)

Choi, Yong-Kyu; Hosoya, Kenta; Lee, Chung Ghiu; Hanawa, Masanori; Park, Chang-Soo

2011-03-28

We propose and experimentally demonstrate a hybrid WDM/OCDMA ring with a dynamic add/drop function based on Fourier code for local area networks. Dynamic function is implemented by mechanically tuning the Fourier encoder/decoder for optical code division multiple access (OCDMA) encoding/decoding. Wavelength division multiplexing (WDM) is utilized for node assignment and 4-chip Fourier code recovers the matched signal from the codes. For an optical source well adapted to WDM channels and its short optical pulse generation, reflective semiconductor optical amplifiers (RSOAs) are used with a fiber Bragg grating (FBG) and gain-switched. To demonstrate we experimentally investigated a two-node hybrid WDM/OCDMA ring with a 4-chip Fourier encoder/decoder fabricated by cascading four FBGs with the bit error rate (BER) of <10(-9) for the node span of 10.64 km at 1.25 Gb/s.

Strain measurement using multiplexed fiber optic sensors

International Nuclear Information System (INIS)

Kwon, Il Bum; Kim, Chi Yeop; Yoon, Dong Jin; Lee, Seung Seok

2003-01-01

FBG(Fiber Bragg grating) sensor, which is one of the fiber optic sensors for the application of smart structures, can not only measure one specific point but also multiple points by multiplexing techniques. We have proposed a novel multiplexing technique of FBG sensor by the intensity modulation of light source. This technique is applicable to WDM(Wavelength Division Multiplexing) technique and number of sensors in this system can be increased by using this technique with WDM technique.

An OTDM-To-WDM Converter Using Optical Fourier Transformation

OpenAIRE

Khin Su Myat Min; Zaw Myo Lwin; Hla Myo Tun

2015-01-01

We demonstrate serial-to-parallel conversion of 40 Gbps optical time division multiplexed OTDM signal to 4x10 Gbps wavelength division-multiplexed WDM individual channels by using Optical Fourier Transformation OFT method. OFT is also called time lens technique and it is implemented by the combination of dispersive fiber and phase modulation. In this research electro-optic phase modulator EOM is used as time lens. As our investigations simulation results and bit error rate BER measurements ar...

Quad 14Gbps L-Band VCSEL-based System for WDM Migration of 4-lanes 56 Gbps Optical Data Links

DEFF Research Database (Denmark)

Estaran Tolosa, Jose Manuel; Rodes Lopez, Roberto; Pham, Tien Thang

2012-01-01

We report on migrating multiple lane link into a single WDM L-band VCSEL-based system. Experimental validation successfully achieves 10 km of SMF reach with 4x14Gbps and less than 0.5dB inter-channel crosstalk penalty.......We report on migrating multiple lane link into a single WDM L-band VCSEL-based system. Experimental validation successfully achieves 10 km of SMF reach with 4x14Gbps and less than 0.5dB inter-channel crosstalk penalty....

Ultrafast Hierarchical OTDM/WDM Network

Directory of Open Access Journals (Sweden)

Hideyuki Sotobayashi

2003-12-01

Full Text Available Ultrafast hierarchical OTDM/WDM network is proposed for the future core-network. We review its enabling technologies: C- and L-wavelength-band generation, OTDM-WDM mutual multiplexing format conversions, and ultrafast OTDM wavelengthband conversions.

WDM Network and Multicasting Protocol Strategies

Directory of Open Access Journals (Sweden)

Pinar Kirci

2014-01-01

Full Text Available Optical technology gains extensive attention and ever increasing improvement because of the huge amount of network traffic caused by the growing number of internet users and their rising demands. However, with wavelength division multiplexing (WDM, it is easier to take the advantage of optical networks and optical burst switching (OBS and to construct WDM networks with low delay rates and better data transparency these technologies are the best choices. Furthermore, multicasting in WDM is an urgent solution for bandwidth-intensive applications. In the paper, a new multicasting protocol with OBS is proposed. The protocol depends on a leaf initiated structure. The network is composed of source, ingress switches, intermediate switches, edge switches, and client nodes. The performance of the protocol is examined with Just Enough Time (JET and Just In Time (JIT reservation protocols. Also, the paper involves most of the recent advances about WDM multicasting in optical networks. WDM multicasting in optical networks is given as three common subtitles: Broadcast and-select networks, wavelength-routed networks, and OBS networks. Also, in the paper, multicast routing protocols are briefly summarized and optical burst switched WDM networks are investigated with the proposed multicast schemes.

All-optical equalization of power transients on four 40 Gbit/s WDM channels using a fiber-based device

DEFF Research Database (Denmark)

Kjær, Rasmus; Oxenløwe, Leif Katsuo; Palsdottir, Bera

2008-01-01

Simultaneous transient suppression of four transient-impaired 40 Gbit/s RZ-ASK WDM channels is demonstrated. Sensitivity improvements are in excess of 5 dB and transmission penalties are significantly reduced.......Simultaneous transient suppression of four transient-impaired 40 Gbit/s RZ-ASK WDM channels is demonstrated. Sensitivity improvements are in excess of 5 dB and transmission penalties are significantly reduced....

An OTDM-To-WDM Converter Using Optical Fourier Transformation

Directory of Open Access Journals (Sweden)

Khin Su Myat Min

2015-08-01

Full Text Available We demonstrate serial-to-parallel conversion of 40 Gbps optical time division multiplexed OTDM signal to 4x10 Gbps wavelength division-multiplexed WDM individual channels by using Optical Fourier Transformation OFT method. OFT is also called time lens technique and it is implemented by the combination of dispersive fiber and phase modulation. In this research electro-optic phase modulator EOM is used as time lens. As our investigations simulation results and bit error rate BER measurements are expressed.

Remote-seeded WDM-PON upgrade using linear semiconductor opticalamplifiers

Science.gov (United States)

Martínez, J. J.; Merayo, N.; Villafranca, A.; Garcés, I.

2013-05-01

In this work we have assessed the capacity of a linear (gain-clamped) semiconductor optical amplifier to enhance the budget of WDM PON network links for their evolution from FTTC to FTTH access. A wavelength-seeded network architecture has been considered, evaluating the performance improvement obtained by the use of an amplifier for the cases of link reach extension and optical splitting to reach end users. The evaluation measurements have shown that the extra budget is enough to compensate for the losses of a passive splitter up to atleast 1:16 division rate or to highly increment reach of the network.

A Grooming Nodes Optimal Allocation Method for Multicast in WDM Networks

Directory of Open Access Journals (Sweden)

Chengying Wei

2016-01-01

Full Text Available The grooming node has the capability of grooming multicast traffic with the small granularity into established light at high cost of complexity and node architecture. In the paper, a grooming nodes optimal allocation (GNOA method is proposed to optimize the allocation of the grooming nodes constraint by the blocking probability for multicast traffic in sparse WDM networks. In the proposed GNOA method, the location of each grooming node is determined by the SCLD strategy. The improved smallest cost largest degree (SCLD strategy is designed to select the nongrooming nodes in the proposed GNOA method. The simulation results show that the proposed GNOA method can reduce the required number of grooming nodes and decrease the cost of constructing a network to guarantee a certain request blocking probability when the wavelengths per fiber and transmitter/receiver ports per node are sufficient for the optical multicast in WDM networks.

Impairment analysis of WDM-PON based on low-cost tunable lasers

DEFF Research Database (Denmark)

Wagner, Christoph; Eiselt, Michael H.; Lawin, Mirko

2016-01-01

channel must be kept below 15%. Similar values result for the upstream pilot tones. In order to limit crosstalk, such systems require reduced launch power during wavelength tuning and can cover up to 40 km differential reach. These results confirm that WDM-PON based on low-cost lasers is a technically...

Adaptive Neuro-Fuzzy Based Gain Controller for Erbium-Doped Fiber Amplifiers

Directory of Open Access Journals (Sweden)

YUCEL, M.

2017-02-01

Full Text Available Erbium-doped fiber amplifiers (EDFA must have a flat gain profile which is a very important parameter such as wavelength division multiplexing (WDM and dense WDM (DWDM applications for long-haul optical communication systems and networks. For this reason, it is crucial to hold a stable signal power per optical channel. For the purpose of overcoming performance decline of optical networks and long-haul optical systems, the gain of the EDFA must be controlled for it to be fixed at a high speed. In this study, due to the signal power attenuation in long-haul fiber optic communication systems and non-equal signal amplification in each channel, an automatic gain controller (AGC is designed based on the adaptive neuro-fuzzy inference system (ANFIS for EDFAs. The intelligent gain controller is implemented and the performance of this new electronic control method is demonstrated. The proposed ANFIS-based AGC-EDFA uses the experimental dataset to produce the ANFIS-based sets and the rule base. Laser diode currents are predicted within the accuracy rating over 98 percent with the proposed ANFIS-based system. Upon comparing ANFIS-based AGC-EDFA and experimental results, they were found to be very close and compatible.

PAM4 based symmetrical 112-Gbps long-reach TWDM-PON

Science.gov (United States)

Wu, Liyu; Gao, Fan; Zhang, Minming; Fu, Songnian; Deng, Lei; Choi, Michael; Chang, Donald; Lei, Gordon K. P.; Liu, Deming

2018-02-01

We experimentally demonstrate cost effective symmetrical 112-Gbps long-reach passive optical network (LR-PON) over 70-km standard signal mode fiber (SSMF), based on pulse amplitude modulation (PAM)-4. Four 10G-class directly modulated lasers (DMLs) at C-band are used for achieving 4 × 28-Gbps downstream transmission, while two 18G-class DMLs at O-band are used to realize 2 × 56-Gbps upstream transmission, without any optical amplification in optical distributed network (ODN). Both dispersion compensation fiber (DCF) for downstream signal and praseodymium-doped fiber amplifier (PDFA) for upstream signal are equipped at optical line terminal (OLT). Meanwhile, sparse Volterra filter (SVF) equalizer is proposed to mitigate the transmission impairments with substantial reduction of computation complexity. Finally, we can successfully provide a loss budget of 33 dB per downstream wavelength channel, indicating of 64 optical network units (ONUs) with more than 1.25 Gbps per ONU.

Parametric Amplification, Wavelength Conversion, and Phase Conjugation of a 2.048-Tbit/s WDM PDM 16-QAM Signal

DEFF Research Database (Denmark)

Hu, Hao; Jopson, R. M.; Gnauck, A. H.

2015-01-01

We demonstrate polarization-independent parametric amplification of a 2.048-Tbit/s 8-WDM PDM 16-QAM signal and simultaneous wavelength conversion and phase conjugation in a highly nonlinear fiber. Two high-power continuous-wave pumps with orthogonal polarizations and counter-phase modulation are ...

One-to-six WDM multicasting of DPSK signals based on dual-pump four-wave mixing in a silicon waveguide

DEFF Research Database (Denmark)

Pu, Minhao; Hu, Hao; Ji, Hua

2011-01-01

We present WDM multicasting based on dual-pump four-wave mixing in a 3-mm long dispersion engineered silicon waveguide. One-to-six phase-preserving WDM multicasting of 10-Gb/s differential phase-shiftkeying (DPSK) data is experimentally demonstrated with bit-error rate measurements. All the six...

SPM and XPM crosstalk in WDM systems with DRA: Channel spacing and attenuation effects

Science.gov (United States)

Morsy, Emadeldeen; Fayed, Heba A.; Abd El Aziz, Ahmed; Aly, Moustafa H.

2018-06-01

This paper presents a theoretical analysis of a closed formula for nonlinear crosstalk due to self-phase modulation (SPM) and cross phase modulation (XPM) in wavelength division multiplexing (WDM) systems. The influence of channel spacing and attenuation on the system behavior is modeled and investigated. The system under consideration is a standard single-mode fiber (SSMF) with a single-span distributed Raman amplifier (DRA) and is operating at 100 Gbps.

Distributed Weak Fiber Bragg Grating Vibration Sensing System Based on 3 × 3 Fiber Coupler

Science.gov (United States)

Li, Wei; Zhang, Jian

2018-06-01

A novel distributed weak fiber Bragg gratings (FBGs) vibration sensing system has been designed to overcome the disadvantages of the conventional methods for optical fiber sensing networking, which are: low signal intensity in the usually adopted time-division multiplexing (TDM) technology, insufficient quantity of multiplexed FBGs in the wavelength-division multiplexing (WDM) technology, and that the mixed WDM/TDM technology measures only the physical parameters of the FBG locations but cannot perform distributed measurement over the whole optical fiber. This novel system determines vibration events in the optical fiber line according to the intensity variation of the interference signals between the adjacent weak FBG reflected signals and locates the vibration points accurately using the TDM technology. It has been proven by tests that this system performs vibration signal detection and demodulation in a way more convenient than the conventional methods for the optical fiber sensing system. It also measures over the whole optical fiber, therefore, distributed measurement is fulfilled, and the system locating accuracy is up to 20 m, capable of detecting any signals of whose drive signals lower limit voltage is 0.2 V while the frequency range is 3 Hz‒1 000 Hz. The system has the great practical significance and application value for perimeter surveillance systems.

All-optical ultra-high-speed OFDM to Nyquist-WDM conversion

DEFF Research Database (Denmark)

Guan, Pengyu; Røge, Kasper Meldgaard; Mulvad, Hans Christian Hansen

2015-01-01

We propose an all-optical ultra-high-speed OFDM to Nyquist-WDM conversion scheme based on complete OFT. An 8-subcarrier 640 Gbit/s DPSK OFDM super-channel is converted to eight 80-Gbit/s Nyquist-WDM channels with BER <10−9 performance for all channels.......We propose an all-optical ultra-high-speed OFDM to Nyquist-WDM conversion scheme based on complete OFT. An 8-subcarrier 640 Gbit/s DPSK OFDM super-channel is converted to eight 80-Gbit/s Nyquist-WDM channels with BER

Working Paper 2: WDM, Poverty & Equity | IDRC - International ...

International Development Research Centre (IDRC) Digital Library (Canada)

2010-12-08

Dec 8, 2010 ... This paper shows that WDM can contribute to poverty reduction, defined ... Series contributes to setting the stage for the next phase of WDM research. ... that 20% of the country's population has some form of physical disability.

Experimental 2.5 Gbit/s QPSK WDM coherent phase modulated radio-over-fibre link with digital demodulation by a K-means algorithm

DEFF Research Database (Denmark)

Guerrero Gonzalez, Neil; Caballero Jambrina, Antonio; Amaya Fernández, Ferney Orlando

2009-01-01

Highest reported bit rate of 2.5 Gbit/s for optically phase modulated radio-over-fibre link employing coherent detection is demonstrated. Demodulation of 3·2.5 Gbit/s QPSK modulated WDM channels, is achieved after 79km of transmission through deployed fiber....

POLICY BRIEF 1 - WDM Criteria | IDRC - International Development ...

International Development Research Centre (IDRC) Digital Library (Canada)

2012-01-18

Jan 18, 2012 ... Water demand management ― WDM ― can be hard to define. More an issue of policy than of technology, it is about managing and moderating our ... critical to the success of WDM at the policy and at the operational levels.

2x2 MIMO-OFDM Gigabit fiber-wireless access system based on polarization division multiplexed WDM-PON

DEFF Research Database (Denmark)

Deng, Lei; Pang, Xiaodan; Zhao, Ying

2012-01-01

We propose a spectral efficient radio over wavelength division multiplexed passive optical network (WDM-PON) system by combining optical polarization division multiplexing (PDM) and wireless multiple input multiple output (MIMO) spatial multiplexing techniques. In our experiment, a training-based...

Working Paper 2: WDM, Poverty & Equity | IDRC - International ...

International Development Research Centre (IDRC) Digital Library (Canada)

2012-01-23

Jan 23, 2012 ... Despite the growing practical and policy-level engagement with WDM, there has been little analytical or empirical effort devoted to its potential social implications. Establishing a better foundation for understanding the linkages between WDM and poverty is, therefore, very important. This paper shows that ...

Traffic Scheduling in WDM Passive Optical Network with Delay Guarantee

Institute of Scientific and Technical Information of China (English)

无

2005-01-01

WDM passive optical network becomes more favorable as the required bandwidth increases, but currently few media access control algorithms adapted to WDM access network. This paper presented a new scheduling algorithm for bandwidth sharing in WDM passive optical networks, which provides per-flow delay guarantee and supports variable-length packets scheduling. Through theoretical analysis and simulation, the end-to-end delay bound and throughput fairness of the algorithm was demonstrated.

Optical fiber reach extended FMCW radar for remote respiratory tracking

DEFF Research Database (Denmark)

Suhr, Lau Frejstrup; Tafur Monroy, Idelfonso; Vegas Olmos, Juan José

2017-01-01

Wireless monitoring of human vital signs such as breathing rate is a nonintrusive alternative to contemporary solutions relying on physical contact. To ease the installment, fiber optical transmission is used to extend the reach from the transmitter and receiver circuitry to the antenna subsystem....... In this paper, a frequency modulated carrier wave radar, operating at 25.7–26.6 GHz and utilizing optical fiber extension, was experimentally demonstrated to accurately recover the breathing rate of a human placed 1 m away from the radar antennas....

Key lessons — Twelve factors critical to the success of WDM at the ...

International Development Research Centre (IDRC) Digital Library (Canada)

2010-12-22

Dec 22, 2010 ... Water demand management (WDM) programs have been widely ... The criteria below are intended to help policymakers determine how best to ... implement and monitor WDM activities and to further the concept of WDM as ...

Export policies for multi-domain WDM networks

DEFF Research Database (Denmark)

Manolova, Anna Vasileva; Ruepp, Sarah Renée

2010-01-01

We analyze the performance of six export policies for a multi-domain routing protocol in WDM networks. We show that providing many AS-disjoint paths for survivability and load-balancing does not necessarily guarantee the lowest connection blocking......We analyze the performance of six export policies for a multi-domain routing protocol in WDM networks. We show that providing many AS-disjoint paths for survivability and load-balancing does not necessarily guarantee the lowest connection blocking...

Ultra-high capacity WDM-SDM optical access network with self-homodyne detection downstream and 32QAM-FBMC upstream.

Science.gov (United States)

Feng, Zhenhua; Xu, Liang; Wu, Qiong; Tang, Ming; Fu, Songnian; Tong, Weijun; Shum, Perry Ping; Liu, Deming

2017-03-20

Towards 100G beyond large-capacity optical access networks, wavelength division multiplexing (WDM) techniques incorporating with space division multiplexing (SDM) and affordable spectrally efficient advanced modulation formats are indispensable. In this paper, we proposed and experimentally demonstrated a cost-efficient multicore fiber (MCF) based hybrid WDM-SDM optical access network with self-homodyne coherent detection (SHCD) based downstream (DS) and direct detection optical filter bank multi carrier (DDO-FBMC) based upstream (US). In the DS experiments, the inner core of the 7-core fiber is used as a dedicated channel to deliver the local oscillator (LO) lights while the other 6 outer cores are used to transmit 4 channels of wavelength multiplexed 200-Gb/s PDM-16QAM-OFDM signals. For US transmission, 4 wavelengths with channel spacing of 100 GHz are intensity modulated with 30 Gb/s 32-QAM-FBMC and directly detected by a ~7 GHz bandwidth receiver after transmission along one of the outer core. The results show that a 4 × 6 × 200-Gb/s DS transmission can be realized over 37 km 7-core fiber without carrier frequency offset (CFO) and phase noise (PN) compensation even using 10 MHz linewidth DFB lasers. The SHCD based on MCF provides a compromise and cost efficient scheme between conventional intradyne coherent detection and intensity modulation and direct detection (IM/DD) schemes. Both US and DS have acceptable BER performance and high spectral efficiency.

Sensing Characteristics of Side-Hole Fiber-Based Long-Period Grating

Directory of Open Access Journals (Sweden)

Yi Xin

2013-01-01

Full Text Available Long-period gratings (LPGs have been fabricated in a side-hole fiber (SHF by using a pulsed CO2 laser. Sensing characteristics of this SHF-LPG to temperature surrounding refractive index and bend have been investigated. Experimental results show that resonant wavelength of the SHF-LPG has a blue shift with temperature with sensitivity of −0.11 nm/°C, a blue shift with increasing sensitivity with surrounding refractive index ranging from 1.335 to 1.44 (the maximum sensitivity is achieved when the surrounding refractive index reaches the effective index of the fiber cladding, and a red shift with bend-direction-dependent sensitivity up to 9.36 nm/m−1.

The emerging WDM EPON

CERN Document Server

Radivojević, Mirjana

2017-01-01

This book proposes dynamic wavelength and bandwidth allocation (DWBA), a hybrid of time-division multiplexing (TDM) and wavelength-division multiplexing (WDM), which offers a solution for service providers faced with multiservice networks. It discusses different models, architectures and implementations and evaluates their performance.

Solutions for 400 Gbit/s inter data center WDM transmission

DEFF Research Database (Denmark)

Dochhan, Annika; Eiselt, Nicklas; Griesser, Helmut

2016-01-01

We review some currently discussed solutions for 400 Gbit/s inter-data center WDM transmission for up to 100 km. We focus on direct detected solutions, namely PAM4 and DMT, and present two WDM systems based on these formats....

Fiber to the Home Using a PON Infrastructure

Science.gov (United States)

Lee, Chang-Hee; Sorin, Wayne V.; Kim, Byoung Yoon

2006-12-01

Traffic patterns in access networks have evolved from voice- and text-oriented services to video- and image-based services. This change will require new access networks that support high-speed (> 100 Mb/s), symmetric, and guaranteed bandwidths for future video services with high-definition TV quality. To satisfy the required bandwidth over a 20-km transmission distance, single-mode optical fiber is currently the only practical choice. To minimize the cost of implementing an FTTP solution, a passive optical network (PON) that uses a point-to-multipoint architecture is generally considered to be the best approach. There are several multiple-access techniques to share a single PON architecture, and the authors addressed several of these approaches such as time-division multiple access, wavelength-division multiple access, subcarrier multiple access, and code-division multiple access. Among these multiple techniques, they focus on time-division multiplexing (TDM)-PON and wavelength-division multiplexing (WDM)-PON, which will be the most promising candidates for practical future systems. A TDM-PON shares a single-transmission channel with multiple subscribers in time domain. Then, there exists tight coupling between subscribers. A WDM-PON provides point-to-point optical connectivity using a dedicated pair of wavelengths per user. While a TDM-PON appears to be a satisfactory solution for current bandwidth demands, the combination of future data-rate projections and traffic patterns coupled with recent advances in WDM technology may result in WDM-PON becoming the preferred solution for a future proof fiber-based access network.

A cost-effective structure of a centralized-light-source WDM-PON utilizing inverse-duobinary-RZ downstream and DPSK upstream

International Nuclear Information System (INIS)

Chen Long-Quan; Qiao Yao-Jun; Ji Yue-Feng

2013-01-01

In this paper, we propose a new structure of a centralized-light-source wavelength division multiplexed passive optical network (WDM-PON) utilizing inverse-duobinary-return-to-zero (inverse-duobinary-RZ) downstream and DPSK upstream. It reuses downstream light for the upstream modulation, which retrenches lasers assembled at each optical network unit (ONU), and ultimately cuts down the cost of ONUs a great deal. Meanwhile, a 50-km-reach WDM-PON experiment with 10-Gb/s inverse-duobinary-RZ downstream and 6-Gb/s DPSK upstream is demonstrated here. It is revealed to be a novel cost-effective alternative for the next generation access network. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Gaussian Process Regression for WDM System Performance Prediction

DEFF Research Database (Denmark)

Wass, Jesper; Thrane, Jakob; Piels, Molly

2017-01-01

Gaussian process regression is numerically and experimentally investigated to predict the bit error rate of a 24 x 28 CiBd QPSK WDM system. The proposed method produces accurate predictions from multi-dimensional and sparse measurement data.......Gaussian process regression is numerically and experimentally investigated to predict the bit error rate of a 24 x 28 CiBd QPSK WDM system. The proposed method produces accurate predictions from multi-dimensional and sparse measurement data....

Fiber-distributed feedback lasers for high-speed wavelength-division multiplexed networks

DEFF Research Database (Denmark)

Sejka, Milan; Hübner, Jörg; Varming, Poul

1996-01-01

Summary form only given. In conclusion, we have demonstrated that fiber DFB lasers constitute an excellent alternative to commercially available semiconductor DFB lasers. We have also shown that two fiber DFB lasers can be spliced together without any BER power penalty. Therefore, we suggest...... the possibility of using a single pump source for pumping a WDM laser array consisting of a number of fiber lasers spliced in series....

Dynamics of long ring Raman fiber laser

Science.gov (United States)

Sukhanov, Sergey V.; Melnikov, Leonid A.; Mazhirina, Yulia A.

2016-04-01

The numerical model for dynamics of long fiber ring Raman laser is proposed. The model is based on the transport equations and Courant-Isaacson-Rees numerical method. Different regimes of a long ring fiber Raman laser are investigated.

A multicast tree aggregation algorithm in wavelength-routed WDM networks

Science.gov (United States)

Cheng, Hsu-Chen; Kuo, Chin-Chun; Lin, Frank Y.

2005-02-01

Wavelength division multiplexing (WDM) has been considered a promising transmission technology in optical communication networks. With the continuous advance in optical technology, WDM network will play an important role in wide area backbone networks. Optical wavelength switching, compared with optical packet switching, is a more mature and more cost-effective choice for optical switching technologies. Besides, the technology of time division multiplexing in optical communication networks has been working smoothly for a long time. In the proposed research, the problem of multicast groups aggregation and multicast routing and wavelength assignment in wavelength-routed WDM network is studied. The optical cross connect switches in the problem are assumed to have limited optical multicast/splitting and TDM functionalities. Given the physical network topology and capacity, the objective is to maximize the total revenue by means of utmost merging multicast groups into larger macro-groups. The groups in the same macro-group will share a multicast tree to conduct data transmission. The problem is formulated as an optimization problem, where the objective function is to maximize the total revenue subject to capacity constraints of components in the optical network, wavelength continuity constraints, and tree topology constraints. The decision variables in the formulations include the merging results between groups, multicast tree routing assignment and wavelength assignment. The basic approach to the algorithm development for this model is Lagrangean relaxation in conjunction with a number of optimization techniques. In computational experiments, the proposed algorithms are evaluated on different network topologies and perform efficiently and effectively according to the experiment results.

Upstream vertical cavity surface-emitting lasers for fault monitoring and localization in WDM passive optical networks

Science.gov (United States)

Wong, Elaine; Zhao, Xiaoxue; Chang-Hasnain, Connie J.

2008-04-01

As wavelength division multiplexed passive optical networks (WDM-PONs) are expected to be first deployed to transport high capacity services to business customers, real-time knowledge of fiber/device faults and the location of such faults will be a necessity to guarantee reliability. Nonetheless, the added benefit of implementing fault monitoring capability should only incur minimal cost associated with upgrades to the network. In this work, we propose and experimentally demonstrate a fault monitoring and localization scheme based on a highly-sensitive and potentially low-cost monitor in conjunction with vertical cavity surface-emitting lasers (VCSELs). The VCSELs are used as upstream transmitters in the WDM-PON. The proposed scheme benefits from the high reflectivity of the top distributed Bragg reflector (DBR) mirror of optical injection-locked (OIL) VCSELs to reflect monitoring channels back to the central office for monitoring. Characterization of the fault monitor demonstrates high sensitivity, low bandwidth requirements, and potentially low output power. The added advantage of the proposed fault monitoring scheme incurs only a 0.5 dB penalty on the upstream transmissions on the existing infrastructure.

Water brief-WDM & wastewater reuse

International Development Research Centre (IDRC) Digital Library (Canada)

aalfouns

Wastewater Reuse for Water Demand Management in the Middle East and ... Among the substantial WDM tools in MENA is the use of wastewater to reduce the pressure on scarce freshwater .... recycled water to irrigate crops with associated ...

Estudo de topologias para redes WDM-PON

OpenAIRE

Guilherme Enéas Vaz Silva

2010-01-01

A demanda de largura de banda exigida pelos usuários de redes de acesso vem aumentando rapidamente e a rede óptica passiva baseada em multiplexação por divisão de comprimento de onda (WDM-PON) tem se destacado como a tecnologia capaz de suprir essa demanda. Dessa forma, este trabalho conduz, inicialmente, uma comparação entre uma rede WDM-PON ideal e uma rede TDM-PON, discutindo também aspectos de segurança desta última, bem como estratégias de migração entre estes dois esquemas. Devido ao cu...

SBIR-Long fluoride fiber

Science.gov (United States)

Jaeger, Raymond E.; Vacha, Lubos J.

1987-08-01

This report summarizes results obtained under a program aimed at developing new techniques for fabricating long lengths of heavy metal fluoride glass (HMFG) optical fiber. A new method for overcladding conventional HMFG preforms with a low melting oxide glass was developed, and improvements in the rotational casting method were made to increase preform length. The resulting composite glass canes consist of a fluoride glass overcoat layer to enhance strength and chemical durability. To show feasibility, prototype optical fiber preforms up to 1.6 cm in diameter with lengths of 22 cm were fabricated. These were drawn into optical fibers with lengths up to 900 meters.

Fiber breakage phenomena in long fiber reinforced plastic preparation

International Nuclear Information System (INIS)

Huang, Chao-Tsai; Tseng, Huan-Chang; Chang, Rong-Yeu; Vlcek, Jiri

2015-01-01

Due to the high demand of smart green, the lightweight technologies have become the driving force for the development of automotives and other industries in recent years. Among those technologies, using short and long fiber-reinforced plastics (FRP) to replace some metal components can reduce the weight of an automotive significantly. However, the microstructures of fibers inside plastic matrix are too complicated to manage and control during the injection molding through the screw, the runner, the gate, and then into the cavity. This study focuses on the fiber breakage phenomena during the screw plastification. Results show that fiber breakage is strongly dependent on screw design and operation. When the screw geometry changes, the fiber breakage could be larger even with lower compression ratio. (paper)

Health monitoring of unmanned aerial vehicle based on optical fiber sensor array

Science.gov (United States)

Luo, Yuxiang; Shen, Jingshi; Shao, Fei; Guo, Chunhui; Yang, Ning; Zhang, Jiande

2017-10-01

The unmanned aerial vehicle (UAV) in flight needs to face the complicated environment, especially to withstand harsh weather conditions, such as the temperature and pressure. Compared with conventional sensors, fiber Bragg grating (FBG) sensor has the advantages of small size, light weight, high reliability, high precision, anti-electromagnetic interference, long lift-span, moistureproof and good resistance to causticity. It's easy to be embedded in composite structural components of UAVs. In the paper, over 1000 FBG sensors distribute regularly on a wide range of UAVs body, combining wavelength division multiplexing (WDM), time division multiplexing (TDM) and multichannel parallel architecture. WDM has the advantage of high spatial resolution. TDM has the advantage of large capacity and wide range. It is worthful to constitute a sensor network by different technologies. For the signal demodulation of FBG sensor array, WDM works by means of wavelength scanning light sources and F-P etalon. TDM adopts the technology of optical time-domain reflectometry. In order to demodulate efficiently, the most proper sensor multiplex number with some reflectivity is given by the curves fitting. Due to the regular array arrangement of FBG sensors on the UAVs, we can acquire the health state of UAVs in the form of 3D visualization. It is helpful to master the information of health status rapidly and give a real-time health evaluation.

Homogenization of long fiber reinforced composites including fiber bending effects

DEFF Research Database (Denmark)

Poulios, Konstantinos; Niordson, Christian Frithiof

2016-01-01

This paper presents a homogenization method, which accounts for intrinsic size effects related to the fiber diameter in long fiber reinforced composite materials with two independent constitutive models for the matrix and fiber materials. A new choice of internal kinematic variables allows...... of the reinforcing fibers is captured by higher order strain terms, resulting in an accurate representation of the micro-mechanical behavior of the composite. Numerical examples show that the accuracy of the proposed model is very close to a non-homogenized finite-element model with an explicit discretization...

Single Source 5-dimensional (Space-, Wavelength-, Time-, Polarization-, Quadrature-) 43 Tbit/s Data Transmission of 6 SDM × 6 WDM × 1.2 Tbit/s Nyquist-OTDM-PDM-QPSK

DEFF Research Database (Denmark)

Hu, Hao; Ye, Feihong; Medhin, Ashenafi Kiros

2014-01-01

We demonstrate 43-Tbit/s transmission over 67.4-km seven-core fiber using a single source. Each of the 6 outer cores carries 6 Nyquist-WDM channels using 320-Gbaud Nyquist- OTDM-PDM-QPSK 330-GHz spaced, and the center core carries 10-GHz clock pulses....

Long fiber polymer composite property calculation in injection molding simulation

Science.gov (United States)

Jin, Xiaoshi; Wang, Jin; Han, Sejin

2013-05-01

Long fiber filled polymer composite materials have attracted a great attention and usage in recent years. However, the injection and compression molded long fiber composite materials possess complex microstructures that include spatial variations in fiber orientation and length. This paper presents the recent implemented anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model for predicting fiber orientation distribution[1] and a newly developed fiber breakage model[2] for predicting fiber length distribution in injection and compression molding simulation, and Eshelby-Mori-Tanaka model[3,4] with fiber-matrix de-bonding model[5] have been implemented to calculate the long fiber composite property distribution with predicted fiber orientation and fiber length distributions. A validation study on fiber orientation, fiber breakage and mechanical property distributions are given with injection molding process simulation.

US long distance fiber optic networks: Technology, evolution and advanced concepts. Volume 2: Fiber optic technology and long distance networks

Science.gov (United States)

1986-10-01

The study projects until 2000 the evolution of long distance fiber optic networks in the U.S. Volume 1 is the Executive Summary. Volume 2 focuses on fiber optic components and systems that are directly related to the operation of long-haul networks. Optimistic, pessimistic and most likely scenarios of technology development are presented. The activities of national and regional companies implementing fiber long haul networks are also highlighted, along with an analysis of the market and regulatory forces affecting network evolution. Volume 3 presents advanced fiber optic network concept definitions. Inter-LATA traffic is quantified and forms the basis for the construction of 11-, 15-, 17-, and 23-node networks. Using the technology projections from Volume 2, a financial model identifies cost drivers and determines circuit mile costs between any two LATAs. A comparison of fiber optics with alternative transmission concludes the report.

Enhanced noise tolerance for 10 Gb/s Bi-directional cross-wavelength reuse colorless WDM-PON by using spectrally shaped OFDM signals

Science.gov (United States)

Choudhury, Pallab K.

2018-05-01

Spectrally shaped orthogonal frequency division multiplexing (OFDM) signal for symmetric 10 Gb/s cross-wavelength reuse reflective semiconductor optical amplifier (RSOA) based colorless wavelength division multiplexed passive optical network (WDM-PON) is proposed and further analyzed to support broadband services of next generation high speed optical access networks. The generated OFDM signal has subcarriers in separate frequency ranges for downstream and upstream, such that the re-modulation noise can be effectively minimized in upstream data receiver. Moreover, the cross wavelength reuse approach improves the tolerance against Rayleigh backscattering noise due to the propagation of different wavelengths in the same feeder fiber. The proposed WDM-PON is successfully demonstrated for 25 km fiber with 16-QAM (quadrature amplitude modulation) OFDM signal having bandwidth of 2.5 GHz for 10 Gb/s operation and subcarrier frequencies in 3-5.5 GHz and DC-2.5 GHz for downstream (DS) and upstream (US) transmission respectively. The result shows that the proposed scheme maintains a good bit error rate (BER) performance below the forward error correction (FEC) limit of 3.8 × 10-3 at acceptable receiver sensitivity and provides a high resilience against re-modulation and Rayleigh backscattering noises as well as chromatic dispersion.

A novel WDM monitoring method

NARCIS (Netherlands)

Bergh, van de M.P.H.; Tol, van der J.J.G.M.; Dorren, H.J.S.

1999-01-01

A novel method to monitor the performance of WDM channels in an optical network is presented by analyzing the photo-diode current of a detected optical signal. From the photo-diode current, an amplitude histogram is generated, hereafter to be called the probability density function (PDF). By

All-optical WDM Regeneration of DPSK Signals using Optical Fourier Transformation and Phase Sensitive Amplification

DEFF Research Database (Denmark)

Guan, Pengyu; Røge, Kasper Meldgaard; Kjøller, Niels-Kristian

2015-01-01

We propose a novel all-optical WDM regeneration scheme for DPSK signals based on optical Fourier transformation and phase sensitive amplification. Phase regeneration of a WDM signal consisting of 4x10-Gbit/s phase noise degraded DPSK channels is demonstrated for the first time.......We propose a novel all-optical WDM regeneration scheme for DPSK signals based on optical Fourier transformation and phase sensitive amplification. Phase regeneration of a WDM signal consisting of 4x10-Gbit/s phase noise degraded DPSK channels is demonstrated for the first time....

Remotely controllable WDM-PON technology for wireless fronthaul/backhaul application

DEFF Research Database (Denmark)

Eiselt, Michael H.; Wagner, Christoph; Lawin, Mirko

2016-01-01

Low-cost WDM-PON solutions for fronthaul and backhaul applications will include remotely controlled tail-end transceivers. We report on control aspects of these transceivers and how standardization is evolving to enable these applications.......Low-cost WDM-PON solutions for fronthaul and backhaul applications will include remotely controlled tail-end transceivers. We report on control aspects of these transceivers and how standardization is evolving to enable these applications....

Protocol and networking design issues for local access WDM networks

OpenAIRE

Salvador, M.R.; Heemstra de Groot, S.M.; Niemegeers, I.G.M.M.

1999-01-01

This report gives an overview of some of the protocol and networking design issues that have been addressed in Flamingo, a major ongoing project which investigates the use of WDM optical technology in local access networks. Quality of service delivery and wavelength assignment are focused on in this report. A brief introduction to optical networks and WDM as well as a brief description of Flamingo are also included in this report.

Accounting for Fiber Bending Effects in Homogenization of Long Fiber Reinforced Composites

DEFF Research Database (Denmark)

Poulios, Konstantinos; Niordson, Christian Frithiof

2015-01-01

The present work deals with homogenized finite-element models of long fiber reinforced composite materials in the context of studying compressive failure modes such as the formation of kink bands and fiber micro-buckling. Compared to finite-element models with an explicit discretization of the ma......The present work deals with homogenized finite-element models of long fiber reinforced composite materials in the context of studying compressive failure modes such as the formation of kink bands and fiber micro-buckling. Compared to finite-element models with an explicit discretization...... of the material micro-structure including individual fibers, homogenized models are computationally more efficient and hence more suitable for modeling of larger and complex structure. Nevertheless, the formulation of homogenized models is more complicated, especially if the bending stiffness of the reinforcing...... fibers is to be taken into account. In that case, so-called higher order strain terms need to be considered. In this paper, important relevant works from the literature are discussed and numerical results from a new homogenization model are presented. The new model accounts for two independent...

Experimental Comparison of Gains in Achievable Information Rates from Probabilistic Shaping and Digital Backpropagation for DP-256QAM/1024QAM WDM Systems

DEFF Research Database (Denmark)

Porto da Silva, Edson; Yankov, Metodi Plamenov; Da Ros, Francesco

2016-01-01

Gains in achievable information rates from probabilistic shaping and digital backpropagation are compared for WDM transmission of 5 × 10 GBd DP-256QAM/1024QAM up to 1700 km of reach. The combination of both techniques its shown to provide gains of up to ∼0.5 bits/QAM symbol...

All-optical OXC transition strategy from WDM optical network to elastic optical network.

Science.gov (United States)

Chen, Xin; Li, Juhao; Guo, Bingli; Zhu, Paikun; Tang, Ruizhi; Chen, Zhangyuan; He, Yongqi

2016-02-22

Elastic optical network (EON) has been proposed recently as a spectrum-efficient optical layer to adapt to rapidly-increasing traffic demands instead of current deployed wavelength-division-multiplexing (WDM) optical network. In contrast with conventional WDM optical cross-connect (OXCs) based on wavelength selective switches (WSSs), the EON OXCs are based on spectrum selective switches (SSSs) which are much more expensive than WSSs, especially for large-scale switching architectures. So the transition cost from WDM OXCs to EON OXCs is a major obstacle to realizing EON. In this paper, we propose and experimentally demonstrate a transition OXC (TOXC) structure based on 2-stage cascading switching architectures, which make full use of available WSSs in current deployed WDM OXCs to reduce number and port count of required SSSs. Moreover, we propose a contention-aware spectrum allocation (CASA) scheme for EON built with the proposed TOXCs. We show by simulation that the TOXCs reduce the network capital expenditure transiting from WDM optical network to EON about 50%, with a minor traffic blocking performance degradation and about 10% accommodated traffic number detriment compared with all-SSS EON OXC architectures.

Telerobotic operation of structurally flexible, long-reach manipulators

International Nuclear Information System (INIS)

Kwon, D.S.; Hwang, D.H.; Babcock, S.M.

1994-01-01

As a part of the Department of Energy's Environmental Restoration and Waste Management Program, long-reach manipulators are being considered for the retrieval of waste from large storage tanks. Long-reach manipulators may have characteristics significantly different from those of typical industrial robots because of the flexibility of long links needed to cover the large workspace. To avoid structural vibrations during operation, control algorithms employing various types of shaping filters were investigated. A new approach that uses embedded simulation was developed and compared with others. In the new approach, generation of joint trajectories considering link flexibility was also investigated

An Optical Multicast Routing with Minimal Network Coding Operations in WDM Networks

Directory of Open Access Journals (Sweden)

Huanlin Liu

2014-01-01

Full Text Available Network coding can improve the optical multicast routing performance in terms of network throughput, bandwidth utilization, and traffic load balance. But network coding needs high encoding operations costs in all-optical WDM networks due to shortage of optical RAM. In the paper, the network coding operation is defined to evaluate the number of network coding operation cost in the paper. An optical multicast routing algorithm based on minimal number of network coding operations is proposed to improve the multicast capacity. Two heuristic criteria are designed to establish the multicast routing with low network coding cost and high multicast capacity. One is to select one path from the former K shortest paths with the least probability of dropping the multicast maximal capacity. The other is to select the path with lowest potential coding operations with the highest link shared degree among the multiple wavelength disjoint paths cluster from source to each destination. Comparing with the other multicast routing based on network coding, simulation results show that the proposed multicast routing algorithm can effectively reduce the times of network coding operations, can improve the probability of reaching multicast maximal capacity, and can keep the less multicast routing link cost for optical WDM networks.

Multichannel silicon WDM ring filters fabricated with DUV lithography

Science.gov (United States)

Lee, Jong-Moo; Park, Sahnggi; Kim, Gyungock

2008-09-01

We have fabricated 9-channel silicon wavelength-division-multiplexing (WDM) ring filters using 193 nm deep-ultraviolet (DUV) lithography and investigated the spectral properties of the ring filters by comparing the transmission spectra with and without an upper cladding. The average channel-spacing of the 9-channel WDM ring filter with a polymeric upper cladding is measured about 1.86 nm with the standard deviation of the channel-spacing about 0.34 nm. The channel crosstalk is about -30 dB, and the minimal drop loss is about 2 dB.

All-Optical Ultra-High-Speed OFDM to Nyquist-WDM Conversion Based on Complete Optical Fourier Transformation

DEFF Research Database (Denmark)

Guan, Pengyu; Røge, Kasper Meldgaard; Mulvad, Hans Christian Hansen

2016-01-01

We propose a novel all-optical ultra-high-speed orthogonal frequency-division multiplexing (OFDM) to Nyquist wavelength-division multiplexing (Nyquist-WDM) conversion scheme, achieved by exchanging the temporal and spectral profiles using a complete optical Fourier transformation (OFT). This scheme...... enables high-speed OFDM to Nyquist-WDM conversion without complex optical/electrical/optical conversion. The all-optical OFDM transmitter is based on the generation of OFDM symbols with a low duty cycle by rectangular temporal gating, which in combination with optical time-division multiplexing yields...... a higher symbol-rate OFDM signal. In the receiver, the converted Nyquist-WDM super-channel is WDM demultiplexed into individual Nyquist-WDM channels using a rectangular optical bandpass filter, followed by optical sampling at the intersymbol-interference free point. In the experimental demonstration...

Active plasmonics in WDM traffic switching applications

DEFF Research Database (Denmark)

Papaioannou, S.; Kalavrouziotis, D.; Vyrsokinos, K.

2012-01-01

-enabling characteristics of active plasmonic circuits with an ultra-low power 3 response time product represents a crucial milestone in the development of active plasmonics towards real telecom and datacom applications, where low-energy and fast TO operation with small-size circuitry is targeted........ The first active Dielectric-Loaded Surface Plasmon Polariton (DLSPP) thermo-optic (TO) switches with successful performance in single-channel 10 Gb/s data traffic environments have led the inroad towards bringing low-power active plasmonics in practical traffic applications. In this article, we introduce...... active plasmonics into Wavelength Division Multiplexed (WDM) switching applications, using the smallest TO DLSPP-based Mach-Zehnder interferometric switch reported so far and showing its successful performance in 4310 Gb/s low-power and fast switching operation. The demonstration of the WDM...

On the fly all-optical packet switching based on hybrid WDM/OCDMA labeling scheme

Science.gov (United States)

Brahmi, Houssem; Giannoulis, Giannis; Menif, Mourad; Katopodis, Vasilis; Kalavrouziotis, Dimitrios; Kouloumentas, Christos; Groumas, Panos; Kanakis, Giannis; Stamatiadis, Christos; Avramopoulos, Hercules; Erasme, Didier

2014-02-01

We introduce a novel design of an all-optical packet routing node that allows for the selection and forwarding of optical packets based on the routing information contained in hybrid wavelength division multiplexing/optical code division multiple access (WDM/OCDMA) labels. A stripping paradigm of optical code-label is adopted. The router is built around an optical-code gate that consists in an optical flip-flop controlled by two fiber Bragg grating correlators and is combined with a Mach-Zehnder interferometer (MZI)-based forwarding gate. We experimentally verify the proof-of-principle operation of the proposed self-routing node under NRZ and OCDMA packet traffic conditions. The successful switching of elastic NRZ payload at 40 Gb/s controlled by DS-OCDMA coded labels and the forwarding operation of encoded data using EQC codes are presented. Proper auto-correlation functions are obtained with higher than 8.1 dB contrast ratio, suitable to efficiently trigger the latching device with a contrast ratio of 11.6 dB and switching times below 3.8 ns. Error-free operation is achieved with 1.5 dB penalty for 40 Gb/s NRZ data and with 2.1 dB penalty for DS-OCDMA packets. The scheme can further be applied to large-scale optical packet switching networks by exploiting efficient optical coders allocated at different WDM channels.

An efficient mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks

Science.gov (United States)

Yu, Xiaojun; Xiao, Gaoxi; Cheng, Tee Hiang

2014-08-01

This paper proposes an efficient overlay multicast provisioning (OMP) mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks. To facilitate request provisioning, OMP jointly utilizes a data learning (DL) scheme on the IP/MPLS layer for logical link cost estimation, and a lightpath fragmentation (LPF) based method on the WDM layer for improving resource sharing in grooming process. Extensive simulations are carried out to evaluate the performance of OMP mechanism under different traffic loads, with either limited or unlimited port resources. Simulation results demonstrate that OMP significantly outperforms the existing methods. To evaluate the respective influences of the DL scheme and the LPF method on OMP performance, provisioning mechanisms only utilizing either the IP/MPLS layer DL scheme or the WDM layer LPF method are also devised. Comparison results show that both DL and LPF methods help improve OMP blocking performance, and contribution from the DL scheme is more significant when the fixed routing and first-fit wavelength assignment (RWA) strategy is adopted on the WDM layer. Effects of a few other factors, including definition of connection cost to be reported by the WDM layer to the IP/MPLS layer and WDM-layer routing method, on OMP performance are also evaluated.

Monolithically integrated 8-channel WDM reflective modulator

NARCIS (Netherlands)

Stopinski, S.T.; Malinowski, M.; Piramidowicz, R.; Smit, M.K.; Leijtens, X.J.M.

2013-01-01

In this work the design and characterization of a monolithically integrated photonic circuit acting as a reflective modulator for eight WDM channels is presented. The chip was designed and fabricated in a generic integration technology

Key Design Requirements for Long-Reach Manipulators

Energy Technology Data Exchange (ETDEWEB)

Kwon, D.S.

2001-01-01

Long-reach manipulators differ from industrial robots and teleoperators typically used in the nuclear industry in that the aspect ratio (length to diameter) of links is much greater and link flexibility, as well as joint or drive train flexibility, is likely to be significant. Long-reach manipulators will be required for a variety of applications in the Environmental Restoration and Waste Management Program. While each application will present specific functional, kinematic, and performance requirements, an approach for determining the kinematic applicability and performance characteristics is presented, with a focus on waste storage tank remediation. Requirements are identified, kinematic configurations are considered, and a parametric study of link design parameters and their effects on performance characteristics is presented.

Key design requirements for long-reach manipulators

International Nuclear Information System (INIS)

Kwon, D.S.; March-Leuba, S.; Babcock, S.M.; Hamel, W.R.

1993-09-01

Long-reach manipulators differ from industrial robots and teleoperators typically used in the nuclear industry in that the aspect ratio (length to diameter) of links is much greater and link flexibility, as well as joint or drive train flexibility, is likely to be significant. Long-reach manipulators will be required for a variety of applications in the Environmental Restoration and Waste Management Program. While each application will present specific functional kinematic, and performance requirements an approach for determining the kinematic applicability and performance characteristics is presented, with a focus on waste storage tank remediation. Requirements are identified, kinematic configurations are considered, and a parametric study of link design parameters and their effects on performance characteristics is presented

Key Design Requirements for Long-Reach Manipulators

International Nuclear Information System (INIS)

Kwon, D.S.

2001-01-01

Long-reach manipulators differ from industrial robots and teleoperators typically used in the nuclear industry in that the aspect ratio (length to diameter) of links is much greater and link flexibility, as well as joint or drive train flexibility, is likely to be significant. Long-reach manipulators will be required for a variety of applications in the Environmental Restoration and Waste Management Program. While each application will present specific functional, kinematic, and performance requirements, an approach for determining the kinematic applicability and performance characteristics is presented, with a focus on waste storage tank remediation. Requirements are identified, kinematic configurations are considered, and a parametric study of link design parameters and their effects on performance characteristics is presented

Bend-insensitive single-mode photonic crystal fiber with ultralarge effective area for dual applications

Science.gov (United States)

Islam, Md. Asiful; Alam, M. Shah

2013-05-01

A novel photonic crystal fiber (PCF) having circular arrangement of cladding air holes has been designed and numerically optimized to obtain a bend insensitive single mode fiber with large mode area for both wavelength division multiplexing (WDM) communication and fiber-to-the-home (FTTH) application. The bending loss of the proposed bent PCF lies in the range of 10-3 to 10-4 dB/turn or lower over 1300 to 1700 nm, and 2 × 10-4 dB/turn at the wavelength of 1550 nm for a 30-mm bend radius with a higher order mode (HOM) cut-off frequency below 1200 nm for WDM application. When the whole structure of the PCF is scaled down, a bending loss of 6.78×10-4 dB/turn at 1550 nm for a 4-mm bend radius is obtained, and the loss remains in the order of 10-4 dB/turn over the same range of wavelength with an HOM cut-off frequency below 700 nm, and makes the fiber useful for FTTH applications. Furthermore, this structure is also optimized to show a splice loss near zero for fusion-splicing to a conventional single-mode fiber (SMF).

Polarization Insensitive One-to-Six WDM Multicasting in a Silicon Nanowire

DEFF Research Database (Denmark)

Pu, Minhao; Hu, Hao; Peucheret, Christophe

2012-01-01

We present polarization insensitive one-to-six WDM multicasting based on nondegenerate four-wave mixing in a silicon nanowire with angled-pump scheme. Bit-error rate measurements are performed and error-free operation is achieved.......We present polarization insensitive one-to-six WDM multicasting based on nondegenerate four-wave mixing in a silicon nanowire with angled-pump scheme. Bit-error rate measurements are performed and error-free operation is achieved....

Long wavelength scintillators for fiber-optic applications

International Nuclear Information System (INIS)

Lyons, P.B.; Franks, L.; Lutz, S.; Flournoy, J.; Fullman, E.

1980-01-01

The use of fiber optics in plasma diagnostics has spurred the development of long wavelength scintillators with fast temporal characteristics. In this paper we describe several new liquid scintillator systems with fluorescent emissions maxima up to 730 nm. Subnanosecond scintillator FWHM response times have been obtained by the operation of liquid scintillators at elevated temperatures. Data on fiber system sensitivity versus fiber length and scintillator emission wavelength will be presented

Digital non-linear equalization for flexible capacity ultradense WDM channels for metro core networking

DEFF Research Database (Denmark)

Arlunno, Valeria; Zhang, Xu; Larsen, Knud J.

2011-01-01

carriers, we demonstrate that a digital non-linear equalization allow to mitigate inter-channel interference and improve overall system performance in terms of OSNR. Evaluation of the algorithm and comparison with an ultradense WDM system with coherent carriers generated from a single laser are also......An experimental demonstration of Ultradense WDM with advanced digital signal processing is presented. The scheme proposed allows the use of independent tunable DFB lasers spaced at 12.5 GHz for ultradense WDM PM-QPSK flexible capacity channels for metro core networking. To allocate extremely closed...

WDM Research Series: Working Paper No. 2

International Development Research Centre (IDRC) Digital Library (Canada)

IDRC CRDI

The other three papers of the Series focus on the issues of institutional structures ... Any approach that relates WDM to poverty and equity requires a set of working ..... If local irrigation system operation and maintenance investments and.

Massive WDM and TDM Soliton Transmission Systems : a ROSC Symposium

CERN Document Server

2002-01-01

This book summarizes the proceedings of the invited talks presented at the “International Symposium on Massive TDM and WDM Optical Soliton Tra- mission Systems” held in Kyoto during November 9–12, 1999. The symposium is the third of the series organized by Research Group for Optical Soliton C- munications (ROSC) chaired by Akira Hasegawa. The research group, ROSC, was established in Japan in April 1995 with a support of the Japanese Ministry of Post and Telecommunications to promote collaboration and information - change among communication service companies, communication industries and academic circles in the theory and application of optical solitons. The symposium attracted enthusiastic response from worldwide researchers in the field of soliton based communications and intensive discussions were made. In the symposium held in 1997, new concept of soliton transmission based on dispersion management of optical fibers were presented. This new soliton is now called the dispersion managed soliton. The p...

Self-homodyne optical OFDM for broadband WDM-PONs with crosstalk-free remodulation and enhanced tolerance to Rayleigh noise

Science.gov (United States)

Lyu, WeiChao; Wang, Andong; Xie, Dequan; Zhu, Long; Guan, Xun; Wang, Jian; Xu, Jing

2018-05-01

We propose a novel architecture for wavelength-division-multiplexed passive optical network (WDM-PON) that can simultaneously circumvent both remodulation crosstalk and Rayleigh noise, based on self-homodyne detection and optical orthogonal frequency-division multiplexing (OFDM) remodulation. The proposed self-homodyne detection at optical network unit (ONU) requires neither frequency offset compensation nor phase noise compensation, and thus can significantly reduce system complexity and power consumption. Bidirectional transmission of 12.5 Gb/s down- and up-stream signals, via single 25 km single-mode fiber without dispersion compensation, is demonstrated in a proof-of-concept experiment.

WDM Question and Answers | IDRC - International Development ...

International Development Research Centre (IDRC) Digital Library (Canada)

2011-01-04

Jan 4, 2011 ... Why is there growing concern about water issues in the MENA region? ... tend to leak, taps tend to drip and little is done to prevent water pollution. ... water demand management (WDM) and water supply management (WSM)?.

Ultra-wideband WDM VCSEL arrays by lateral heterogeneous integration

Science.gov (United States)

Geske, Jon

Advancements in heterogeneous integration are a driving factor in the development of evermore sophisticated and functional electronic and photonic devices. Such advancements will merge the optical and electronic capabilities of different material systems onto a common integrated device platform. This thesis presents a new lateral heterogeneous integration technology called nonplanar wafer bonding. The technique is capable of integrating multiple dissimilar semiconductor device structures on the surface of a substrate in a single wafer bond step, leaving different integrated device structures adjacent to each other on the wafer surface. Material characterization and numerical simulations confirm that the material quality is not compromised during the process. Nonplanar wafer bonding is used to fabricate ultra-wideband wavelength division multiplexed (WDM) vertical-cavity surface-emitting laser (VCSEL) arrays. The optically-pumped VCSEL arrays span 140 nm from 1470 to 1610 nm, a record wavelength span for devices operating in this wavelength range. The array uses eight wavelength channels to span the 140 nm with all channels separated by precisely 20 nm. All channels in the array operate single mode to at least 65°C with output power uniformity of +/- 1 dB. The ultra-wideband WDM VCSEL arrays are a significant first step toward the development of a single-chip source for optical networks based on coarse WDM (CWDM), a low-cost alternative to traditional dense WDM. The CWDM VCSEL arrays make use of fully-oxidized distributed Bragg reflectors (DBRs) to provide the wideband reflectivity required for optical feedback and lasing across 140 rim. In addition, a novel optically-pumped active region design is presented. It is demonstrated, with an analytical model and experimental results, that the new active-region design significantly improves the carrier uniformity in the quantum wells and results in a 50% lasing threshold reduction and a 20°C improvement in the peak

Composite Coiled Tubing for Extended Reach in Horizontal Oil Wells

DEFF Research Database (Denmark)

Costache, Andrei; Berggreen, Christian

2017-01-01

Conventional steel coiled tubing cannot reach along the entire length of very long horizontal oil wells. A lighter and more buoyant coiled tube is made possible using composite materials. The high stiffness to weight ratio of fiber reinforced polymers, coupled with a lower coefficient of friction......, has the potential of greatly extending the reach in horizontal oil wells. This study shows how to design composite coiled tubing and gives a comprehensive discussion about the most influential parameters. Several solutions, using glass-fiber and carbon are considered. Finite element models are used...

Exploring crosstalk noise generated in the N-port router used in the WDM-based ONoC

Science.gov (United States)

Zhang, Zhendong; Xie, Yiyuan; Song, Tingting; He, Chao; Li, Jiachao; Liu, Yong

2017-07-01

Compared with optical network-on-chip (ONoC) with single wavelength, ONoC adopting wavelength division multiplexing (WDM) technology possesses a very prominent advantage-higher bandwidth. Therefore, WDM-based ONoC has been considered one of the most promising ways to relieve the rapidly increasing traffic load in communication systems. A WDM-based router, as the core equipment of WDM-based ONoC, is influenced by crosstalk noise, especially the nonlinear crosstalk noise generated by the four-wave mixing effect. Thus, to explore the performance of the N-port nonblocking optical router using WDM, we propose a universal analytic model to analyze the transmission loss, crosstalk noise, optical signal-to-noise ratio (OSNR), and bit error ratio (BER). The research results show that crosstalk noise varies along with signals at different wavelengths in the same channel. For signals with the same wavelength, the noises generated in the different transmission paths are obviously different from each other. For research of transmission loss, OSNR, and BER, similar results can be obtained. Based on the eye diagrams, we can learn that crosstalk noise will cause signal distortion to a certain extent. With this model, capability of this kind of multiport optical router using WDM can be understood conveniently.

Optical switching properties of VO2 films driven by using WDM-aligned lasers

International Nuclear Information System (INIS)

Tsai, K.Y.; Wu, F.-H.; Shieh, H.-P.D.; Chin, T.-S.

2006-01-01

Vanadium dioxide (VO 2 ) film had been demonstrated a high speed IR shutter driven by total optical modulation. However, it usually required a higher power heating laser of high power and precise optical systems to cover the probe beam on the sample with a heating beam of larger area. A new optical system, simply composed of wavelength division multiplexing (WDM), fiber lens or convex lens system, and a glass sheet with VO 2 thin film on it, was easily assembled to utilize VO 2 film as an IR shutter, implying the possibility to highly miniaturize the VO 2 -based optical shutter. A permanent low-transmittance (PLT) region forms on the film within the probe beam, resulting in a decrease in average power of the probe beam. Another ring-type switching area (switching ring) forms around the PLT region, resulting in the transmittance switching of the probe beam synchronously with the heating signal. VO 2 films can be switched with the highest rate of a continuous square heating signal of 3 mW at 120 kHz. A heating pulse of 0.7 ns and 13 mW can be used to stimulate an IR pulse with fiber lens

Gender & WDM in the Middle East & North Africa

International Development Research Centre (IDRC) Digital Library (Canada)

nkhaled

WDM Research Report Series: Working Paper No. ... water-users themselves, coupled with an adequate enabling policy environment with the commitment ..... affect water quality, as well as, decrease food security and safety and are exposed ...

Damage Modeling Of Injection-Molded Short- And Long-Fiber Thermoplastics

International Nuclear Information System (INIS)

Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.; Phelps, Jay; Tucker, Charles L. III

2009-01-01

This article applies the recent anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model for predicting fiber orientation and a new damage model for injection-molded long-fiber thermoplastics (LFTs) to analyze progressive damage leading to total failure of injection-molded long-glass-fiber/polypropylene (PP) specimens. The ARD-RSC model was implemented in a research version of the Autodesk Moldflow Plastics Insight (MPI) processing code, and it has been used to simulate injection-molding of a long-glass-fiber/PP plaque. The damage model combines micromechanical modeling with a continuum damage mechanics description to predict the nonlinear behavior due to plasticity coupled with damage in LFTs. This model has been implemented in the ABAQUS finite element code via user-subroutines and has been used in the damage analyses of tensile specimens removed from the injection-molded long-glass-fiber/PP plaques. Experimental characterization and mechanical testing were performed to provide input data to support and validate both process modeling and damage analyses. The predictions are in agreement with the experimental results.

Modulational instability of short pulses in long optical fibers

DEFF Research Database (Denmark)

Shukla, P. K.; Juul Rasmussen, Jens

1986-01-01

The effect of time-derivative nonlinearity is incorporated into the study of the modulational instability of heat pulses propagating through long optical fibers. Conditions for soliton formation are discussed......The effect of time-derivative nonlinearity is incorporated into the study of the modulational instability of heat pulses propagating through long optical fibers. Conditions for soliton formation are discussed...

Thin film technologies for optoelectronic components in fiber optic communication

Science.gov (United States)

Perinati, Agostino

1998-02-01

will grow at an annual average rate of 22 percent from 1.3 million fiber-km in 1995 to 3.5 million fiber-km in 2000. The worldwide components market-cable, transceivers and connectors - 6.1 billion in 1994, is forecasted to grow and show a 19 percent combined annual growth rate through the year 2000 when is predicted to reach 17.38 billion. Fiber-in-the-loop and widespread use of switched digital services will dominate this scenario being the fiber the best medium for transmitting multimedia services. As long as communication will partially replace transportation, multimedia services will push forward technology for systems and related components not only for higher performances but for lower cost too in order to get the consumers wanting to buy the new services. In the long distance transmission area (trunk network) higher integration of electronic and optoelectronic functions are required for transmitter and receiver in order to allow for higher system speed, moving from 2.5 Gb/s to 5, 10, 40 Gb/s; narrow band wavelength division multiplexing (WDM) filters are required for higher transmission capacity through multiwavelength technique and for optical amplifier. In the access area (distribution network) passive components as splitters, couplers, filters are needed together with optical amplifiers and transceivers for point-to-multipoint optical signal distribution: main issue in this area is the total cost to be paid by the customer for basic and new services. Multimedia services evolution, through fiber to the home and to the desktop approach, will be mainly affected by the availability of technologies suitable for component consistent integration, high yield manufacturing processes and final low cost. In this paper some of the optoelectronic components and related thin film technologies expected to mainly affect the fiber optic transmission evolution, either for long distance telecommunication systems or for subscriber network, are presented.

Ultra-Long-Distance Hybrid BOTDA/Ф-OTDR

Directory of Open Access Journals (Sweden)

Yun Fu

2018-03-01

Full Text Available In the distributed optical fiber sensing (DOFS domain, simultaneous measurement of vibration and temperature/strain based on Rayleigh scattering and Brillouin scattering in fiber could have wide applications. However, there are certain challenges for the case of ultra-long sensing range, including the interplay of different scattering mechanisms, the interaction of two types of sensing signals, and the competition of pump power. In this paper, a hybrid DOFS system, which can simultaneously measure temperature/strain and vibration over 150 km, is elaborately designed via integrating the Brillouin optical time-domain analyzer (BOTDA and phase-sensitive optical time-domain reflectometry (Ф-OTDR. Distributed Raman and Brillouin amplifications, frequency division multiplexing (FDM, wavelength division multiplexing (WDM, and time division multiplexing (TDM are delicately fused to accommodate ultra-long-distance BOTDA and Ф-OTDR. Consequently, the sensing range of the hybrid system is 150.62 km, and the spatial resolution of BOTDA and Ф-OTDR are 9 m and 30 m, respectively. The measurement uncertainty of the BOTDA is ± 0.82 MHz. To the best of our knowledge, this is the first time that such hybrid DOFS is realized with a hundred-kilometer length scale.

Twelve factors critical to the success of WDM at the policy and at the ...

International Development Research Centre (IDRC) Digital Library (Canada)

IDRC CRDI

and monetary units. A WDM agency has to be able to show results (such as water savings measured in cubic meters for example) in order to compete for attention with older and better established supply-side agencies. Such data may be hard to find, or estimate, but it can be very persuasive in furthering the WDM agenda.

Long distance transmission through distributed erbium-doped fibers

DEFF Research Database (Denmark)

Rottwitt, Karsten; Povlsen, Jørn Hedegaard; Bjarklev, Anders Overgaard

1993-01-01

High bit rate, all-optical long-distance transmission could be created through the combined use of loss-compensating gain in erbium-doped fibers and solitons. A detailed analysis of the distributed erbium-doped fiber, including the spectral-gain dependency, is combined with an optimum design...... of the transmission fiber and general bit-error-rate calculations. Changes in wavenumber, group velocity, and fiber dispersion due to erbium doping in a single-mode fiber are evaluated, and a reduction in bit-error rates due to the erbium spectral-gain profile is shown. Transmission through distributed erbium......-doped fiber with 100-km separation between each pump-power station is shown, with a total bit-rate distance product of 55 Gb/s · Mm...

W-band radio-over-fiber propagation of two optically encoded wavelength channels

Science.gov (United States)

Eghbal, Morad Khosravi; Shadaram, Mehdi

2018-01-01

We propose a W-band wavelength-division multiplexing (WDM)-over-optical code-division multiple access radio-over-fiber system. This system offers capacity expansion by increasing the working frequency to millimeter wave region and by introducing optical encoding and multiwavelength multiplexing. The system's functionality is investigated by software modeling, and the results are presented. The generated signals are data modulated at 10 Gb/s and optically encoded for two wavelength channels and transmitted with a 20-km length of fiber. The received signals are optically decoded and detected. Also, encoding has improved the bit error rate (BER) versus the received optical power margin for the WDM setting by about 4 dB. In addition, the eye-diagram shows that the difference between received optical power levels at the BER of 10-12 to 10-3 is about 1.3% between two encoded channels. This method of capacity improvement is significantly important for the next generation of mobile communication, where millimeter wave signals will be widely used to deliver data to small cells.

Numerical Modelling of a Bidirectional Long Ring Raman Fiber Laser Dynamics

Science.gov (United States)

Sukhanov, S. V.; Melnikov, L. A.; Mazhirina, Yu A.

2017-11-01

The numerical model for the simulation of the dynamics of a bidirectional long ring Raman fiber laser is proposed. The model is based on the transport equations and Courant-Isaacson-Rees method. Different regimes of a bidirectional long ring Raman fiber laser and long time-domain realizations are investigated.

System performance of a 4-channel PHASAR WDM receiver operating at 1.2 Gbit/s

NARCIS (Netherlands)

Steenbergen, C.A.M.; van Deventer, M.O.; Vreede, de L.C.N.; Dam, van C.; Smit, M.K.; Verbeek, B.H.

1996-01-01

Phased arrays are important key components in wavelength-division multiplexing (WDM) systems. We have realized a 4-channel WDM receiver combining a phased array with photodetectors on InP with a Si bipolar transimpedance amplifier. The channels are spaced at 2.0 nm with a 1.0-nm flat passband. On

Distributed dual-parameter optical fiber sensor based on cascaded microfiber Fabry-Pérot interferometers

Science.gov (United States)

Xiang, Yang; Luo, Yiyang; Zhang, Wei; Liu, Deming; Sun, Qizhen

2017-04-01

We propose and demonstrate a distributed fiber sensor based on cascaded microfiber Fabry-Perot interferometers (MFPI) for simultaneous refractive index (SRI) and temperature measurement. By employing MFPI which is fabricated by taper-drawing the center of a uniform fiber Bragg grating (FBG) on standard fiber into a section of microfiber, dual parameters including SRI and temperature can be detected through demodulating the reflection spectrum of the MFPI. Further, wavelength-division-multiplexing (WDM) is applied to realize distributed dual-parameter fiber sensor by using cascaded MFPIs with different Bragg wavelengths. A prototype sensor system with 5 cascaded MFPIs is constructed to experimentally demonstrate the sensing performance.

Combined Optical and Electrical Spectrum Shaping for High-Baud-Rate Nyquist-WDM Transceivers

DEFF Research Database (Denmark)

Porto da Silva, Edson; Borkowski, Robert; Preussler, Stefan

2016-01-01

bandwidth is related to the optical comb parameters 25 and the pulse shaping of the modulating waveforms in the electrical domain. Such de- 26 pendence may result in broadening of the modulated spectra, which can degrade the 27 performance of Nyquist-WDM systems due to interchannel crosstalk penalties....... To investigate the benefits of the proposed approach, we demonstrate 32 the first WDM Nyquist-OTDM signal generation based on the periodic train of sinc pulses 33 and electrical spectrum shaping. Straight line transmission of five 112.5-Gbd Nyquist- 34 OTDM dual-polarization quadrature phase-shift keying (QPSK......We discuss the benefits and limitations of optical time-division multiplexing 22 (OTDM) techniques based on the optical generation of a periodic train of sinc pulses for 23 wavelength-division multiplexing (WDM) transmission at high baud rates. It is shown 24 how the modulated OTDM spectrum...

WDM production with intense relativistic electrons

Science.gov (United States)

Coleman, Josh; Andrews, Heather; Klasky, Mark; Colgan, James; Burris-Mog, Trevor; Creveling, Dan; Miller, Craig; Welch, Dale; Berninger, Mike

2016-10-01

The production of warm dense matter (WDM) through collisional heating with intense relativistic electrons is underway. A 100-ns-long monochromatic bunch of electrons with energies of 19.1-19.8 MeV and currents of 0.2-1.7 kA is used to heat 100- μm-thick foils with Z measuring the equation of state with particle beams and benchmark numerical models. Measurements indicate the formation of a warm dense plasma near the end of the pulse, which is on the order of the beam size. These plasmas expand 5 mm in the first microsecond and slow down to 1018 cm-3. At these densities our plasma is collisionally dominated making it possible to spectrally model the density and temperature in LTE. Preliminary density gradient measurements will also be presented indicating the spatial extent of the solid density cutoff. This work was supported by the National Nuclear Se- curity Administration of the U.S. Department of Energy under Contract No. DE-AC52-06NA25396.

Bioinspired design and macroscopic assembly of poly(vinyl alcohol)-coated graphene into kilometers-long fibers

Science.gov (United States)

Kou, Liang; Gao, Chao

2013-05-01

Nacre is characterized by its excellent mechanical performance due to the well-recognized ``brick and mortar'' structure. Many efforts have been applied to make nacre-mimicking materials, but it is still a big challenge to realize their continuous production. Here, we prepared sandwich-like building blocks of poly(vinyl alcohol) (PVA)-coated graphene, and achieved high-nanofiller-content kilometers-long fibers by continuous wet-spinning assembly technology. The fibers have a strict ``brick and mortar'' layered structure, with graphene sheet as rigid brick and PVA as soft mortar. The mortar thickness can be precisely tuned from 2.01 to 3.31 nm by the weight feed ratio of PVA to graphene, as demonstrated by both atomic force microscopy and X-ray diffraction measurements. The mechanical strength of the nacre-mimicking fibers increases with increasing the content of PVA, and it rises gradually from 81 MPa for the fiber with 53.1 wt% PVA to 161 MPa for the fiber with 65.8 wt% PVA. The mechanical performance of our fibers was independent of the molecular weight (MW) of PVA in the wide range of 2-100 kDa, indicating that low MW polymers can also be used to make strong nanocomposites. The tensile stress of fibers immersed in PVA 5 wt% solution reached ca. 200 MPa, surpassing the values of nacre and most of other nacre-mimicking materials. The nacre-mimicking fibers are highly electrically conductive (~350 S m-1) after immersing in hydroiodic acid, enabling them to connect a circuit to illuminate an LED lamp.Nacre is characterized by its excellent mechanical performance due to the well-recognized ``brick and mortar'' structure. Many efforts have been applied to make nacre-mimicking materials, but it is still a big challenge to realize their continuous production. Here, we prepared sandwich-like building blocks of poly(vinyl alcohol) (PVA)-coated graphene, and achieved high-nanofiller-content kilometers-long fibers by continuous wet-spinning assembly technology. The fibers

Flexible Transport Network Expansion via Open WDM Interfaces

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Skjoldstrup, Bjarke

2013-01-01

This paper presents a successful test-bed implementation of a multi-vendor transport network interconnection via open WDM interfaces. The concept of applying Alien Wavelengths (AWs) for network expansion was successfully illustrated via deployment of multi-domain/multi-vendor end-to-end OTN servi...

Fiber-optic communication systems

CERN Document Server

Agrawal, Govind P

2010-01-01

This book provides a comprehensive account of fiber-optic communication systems. The 3rd edition of this book is used worldwide as a textbook in many universities. This 4th edition incorporates recent advances that have occurred, in particular two new chapters. One deals with the advanced modulation formats (such as DPSK, QPSK, and QAM) that are increasingly being used for improving spectral efficiency of WDM lightwave systems. The second chapter focuses on new techniques such as all-optical regeneration that are under development and likely to be used in future communication systems. All othe

Real time algorithm temperature compensation in tunable laser / VCSEL based WDM-PON system

DEFF Research Database (Denmark)

Iglesias Olmedo, Miguel; Rodes Lopez, Roberto; Pham, Tien Thang

2012-01-01

We report on a real time experimental validation of a centralized algorithm for temperature compensation of tunable laser/VCSEL at ONU and OLT, respectively. Locking to a chosen WDM channel is shown for temperature changes over 40°C.......We report on a real time experimental validation of a centralized algorithm for temperature compensation of tunable laser/VCSEL at ONU and OLT, respectively. Locking to a chosen WDM channel is shown for temperature changes over 40°C....

OTDM-WDM Conversion Based on Time-Domain Optical Fourier Transformation with Spectral Compression

DEFF Research Database (Denmark)

Mulvad, Hans Christian Hansen; Palushani, Evarist; Galili, Michael

2011-01-01

We propose a scheme enabling direct serial-to-parallel conversion of OTDM data tributaries onto a WDM grid, based on optical Fourier transformation with spectral compression. Demonstrations on 320 Gbit/s and 640 Gbit/s OTDM data are shown.......We propose a scheme enabling direct serial-to-parallel conversion of OTDM data tributaries onto a WDM grid, based on optical Fourier transformation with spectral compression. Demonstrations on 320 Gbit/s and 640 Gbit/s OTDM data are shown....

Optical fronthauling for 5G mobile: A perspective of passive metro WDM technology

DEFF Research Database (Denmark)

Zou, Shihuan Jim; Wagner, Christoph; Eiselt, Michael

2017-01-01

We discuss the necessity of passive WDM technology in the 5G fronthaul application. The proof-of-concept field trial showed that the proposed system integrated seamlessly with the current wireless equipment and had no impact on services.......We discuss the necessity of passive WDM technology in the 5G fronthaul application. The proof-of-concept field trial showed that the proposed system integrated seamlessly with the current wireless equipment and had no impact on services....

Study on temperature sensitivity of topological insulators based on long-period fiber grating

Science.gov (United States)

Luo, Jianhua; Zhao, Chenghai; Li, Jianbo; He, Mengdong

2017-06-01

Based on a long-period fiber grating, we conducted experimental research on the temperature sensitivity of topological insulators. The long-period fiber grating and topological insulators solution were encapsulated in a capillary tube using UV glue, and the temperature response was measured. Within a range of 35 to 75 centigrade, one resonance dip of a long-period fiber grating exhibits a redshift of 1.536 nm. The temperature sensitivity is about 7.7 times of an ordinary long-period fiber grating's sensitivity (0.005 nm/°C). A numerical simulation is also performed on the basis of the experiments.

Efficiency studies for a tracking detector based on square 1.5 m long scintillating fibers read out by SiPM

International Nuclear Information System (INIS)

Sanchez Majos, S.; Achenbach, P.; Pochodzalla, J.

2009-01-01

A tracking detector based on 1.5 m long scintillating fibers is being developed for the electron arm of the KAOS spectrometer at the Mainz Microtron MAMI. Measurements on light attenuation, particle detection efficiencies and accidental coincidence rates with a prototype set-up using 2x2mm 2 fibers read out by silicon photomultipliers (SiPM) are presented. The highest efficiency at the lowest accidental coincidence rate was reached for high trigger thresholds at the largest SiPM bias voltages. The influence of signal attenuation and dispersion on detection efficiencies is discussed. The results are in good agreement with a Monte Carlo model that was used to predict detector characteristics for different fiber geometries.

Building new WDM regulations for the Namibian tourism sector on factors influencing current water-management practices at the enterprise level

Science.gov (United States)

Schachtschneider, Klaudia

Namibia's aridity is forcing its water sector to resort to new water resource management approaches, including water demand management (WDM). Such a change in management approach is facilitated through the country's opportunity at independence to rewrite and adapt its old policies, including those for water and tourism. Legal support for WDM through the Water Act and other sector-specific Acts is crucial to plan the practical implementation of WDM throughout the different water use sectors of Namibia. In order to be able to put the policy into practice, it is imperative to understand which factors motivate people to adopt WDM initiatives. Within the Namibian tourism industry three main factors have been identified which influence the water-management approaches at tourist facilities. This paper discusses how the water and tourism decision makers can consider these factors when developing new regulations to introduce WDM in the tourism sector.

Dynamic Bandwidth Allocation with Effective Utilization of Polling Interval over WDM/TDM PON

Science.gov (United States)

Ni, Cuiping; Gan, Chaoqin; Gao, Ziyue

2014-12-01

WDM/TDM (wavelength-division multiplexing/time-division multiplexing) PON (passive optical network) appears to be an attractive solution for the next generation optical access networks. Dynamic bandwidth allocation (DBA) plays a crucial role in efficiently and fairly allocating the bandwidth among all users in WDM/TDM PON. In this paper, two dynamic bandwidth allocation schemes (DBA1 and DBA2) are proposed to eliminate the idle time of polling cycles (i.e. polling interval), improve bandwidth utilization and make full use of bandwidth resources. The two DBA schemes adjust the time slot of sending request information and make fair scheduling among users to achieve the effective utilization of polling interval in WDM/TDM PON. The simulation and theoretical analyses verify that the proposed schemes outperform the conventional DBA scheme. We also make comparisons between the two schemes in terms of bandwidth utilization and average packet delay to further demonstrate the effectiveness of the scheme of DBA2.

Energy-efficient WDM-OFDM-PON employing shared OFDM modulation modules in optical line terminal.

Science.gov (United States)

Hu, Xiaofeng; Zhang, Liang; Cao, Pan; Wang, Kongtao; Su, Yikai

2012-03-26

We propose and experimentally demonstrate a scheme to improve the energy efficiency of wavelength division multiplexing - orthogonal frequency division multiplexing - passive optical networks (WDM-OFDM-PONs). By using an N × M opto-mechanic switch in optical line terminal (OLT), an OFDM modulation module is shared by several channels to deliver data to multiple users with low traffic demands during non-peak hours of the day, thus greatly reducing the number of operating devices and minimizing the energy consumption of the OLT. An experiment utilizing one OFDM modulation module to serve three optical network units (ONUs) in a WDM-OFDM-PON is performed to verify the feasibility of our proposal. Theoretical analysis and numerical calculation show that the proposed scheme can achieve a saving of 23.6% in the energy consumption of the OFDM modulation modules compared to conventional WDM-OFDM-PON.

Long-distance thermal temporal ghost imaging over optical fibers

Science.gov (United States)

Yao, Xin; Zhang, Wei; Li, Hao; You, Lixing; Wang, Zhen; Huang, Yidong

2018-02-01

A thermal ghost imaging scheme between two distant parties is proposed and experimentally demonstrated over long-distance optical fibers. In the scheme, the weak thermal light is split into two paths. Photons in one path are spatially diffused according to their frequencies by a spatial dispersion component, then illuminate the object and record its spatial transmission information. Photons in the other path are temporally diffused by a temporal dispersion component. By the coincidence measurement between photons of two paths, the object can be imaged in a way of ghost imaging, based on the frequency correlation between photons in the two paths. In the experiment, the weak thermal light source is prepared by the spontaneous four-wave mixing in a silicon waveguide. The temporal dispersion is introduced by single mode fibers of 50 km, which also could be looked as a fiber link. Experimental results show that this scheme can be realized over long-distance optical fibers.

Real-time distributed scheduling algorithm for supporting QoS over WDM networks

Science.gov (United States)

Kam, Anthony C.; Siu, Kai-Yeung

1998-10-01

Most existing or proposed WDM networks employ circuit switching, typically with one session having exclusive use of one entire wavelength. Consequently they are not suitable for data applications involving bursty traffic patterns. The MIT AON Consortium has developed an all-optical LAN/MAN testbed which provides time-slotted WDM service and employs fast-tunable transceivers in each optical terminal. In this paper, we explore extensions of this service to achieve fine-grained statistical multiplexing with different virtual circuits time-sharing the wavelengths in a fair manner. In particular, we develop a real-time distributed protocol for best-effort traffic over this time-slotted WDM service with near-optical fairness and throughput characteristics. As an additional design feature, our protocol supports the allocation of guaranteed bandwidths to selected connections. This feature acts as a first step towards supporting integrated services and quality-of-service guarantees over WDM networks. To achieve high throughput, our approach is based on scheduling transmissions, as opposed to collision- based schemes. Our distributed protocol involves one MAN scheduler and several LAN schedulers (one per LAN) in a master-slave arrangement. Because of propagation delays and limits on control channel capacities, all schedulers are designed to work with partial, delayed traffic information. Our distributed protocol is of the `greedy' type to ensure fast execution in real-time in response to dynamic traffic changes. It employs a hybrid form of rate and credit control for resource allocation. We have performed extensive simulations, which show that our protocol allocates resources (transmitters, receivers, wavelengths) fairly with high throughput, and supports bandwidth guarantees.

Wavelength-agnostic WDM-PON System

DEFF Research Database (Denmark)

Wagner, Christoph; Eiselt, Michael; Zou, S.

2016-01-01

on the standardization status of this lowcost system in the new ITU-T G.metro draft recommendation, in the context of autonomous tuning. We also discuss some low-effort implementations of the pilot-tone labels and investigate the impact of these labels on the transmission channels.......Next-generation WDM-PON solutions for metro and access systems will take advantage of remotely controlled wavelength-tunable ONUs to keep system costs as low as possible. For such a purpose, each ONU signal can be labeled by a pilot tone modulated onto the optical data stream. We report...

Novel OSNR Monitoring Technique in Dense WDM Systems using Inherently Generated CW Monitoring Channels

DEFF Research Database (Denmark)

Petersen, Martin Nordal

2007-01-01

We present a simple, yet effective OSNR monitoring technique based on an inherent effect in the optical modulator. Highly accurate OSNR monitoring is demonstrated in a 40 Gb/s dense WDM system with 50 GHz channel spacing.......We present a simple, yet effective OSNR monitoring technique based on an inherent effect in the optical modulator. Highly accurate OSNR monitoring is demonstrated in a 40 Gb/s dense WDM system with 50 GHz channel spacing....

Bioinspired design and macroscopic assembly of poly(vinyl alcohol)-coated graphene into kilometers-long fibers.

Science.gov (United States)

Kou, Liang; Gao, Chao

2013-05-21

Nacre is characterized by its excellent mechanical performance due to the well-recognized "brick and mortar" structure. Many efforts have been applied to make nacre-mimicking materials, but it is still a big challenge to realize their continuous production. Here, we prepared sandwich-like building blocks of poly(vinyl alcohol) (PVA)-coated graphene, and achieved high-nanofiller-content kilometers-long fibers by continuous wet-spinning assembly technology. The fibers have a strict "brick and mortar" layered structure, with graphene sheet as rigid brick and PVA as soft mortar. The mortar thickness can be precisely tuned from 2.01 to 3.31 nm by the weight feed ratio of PVA to graphene, as demonstrated by both atomic force microscopy and X-ray diffraction measurements. The mechanical strength of the nacre-mimicking fibers increases with increasing the content of PVA, and it rises gradually from 81 MPa for the fiber with 53.1 wt% PVA to 161 MPa for the fiber with 65.8 wt% PVA. The mechanical performance of our fibers was independent of the molecular weight (MW) of PVA in the wide range of 2-100 kDa, indicating that low MW polymers can also be used to make strong nanocomposites. The tensile stress of fibers immersed in PVA 5 wt% solution reached ca. 200 MPa, surpassing the values of nacre and most of other nacre-mimicking materials. The nacre-mimicking fibers are highly electrically conductive (∼350 S m(-1)) after immersing in hydroiodic acid, enabling them to connect a circuit to illuminate an LED lamp.

SDN-enabled dynamic WDM networks to address routing information inaccuracy

CSIR Research Space (South Africa)

Ravhuanzwo, Lusani

2016-11-01

Full Text Available Large dynamic wavelength-division multiplexed (WDM) networks based on the distributed control mechanism are susceptible to routing information inaccuracies. Factors such as non-negligible propagation delays, infrequent network state updates...

Five Wavelength DFB Fibre Laser Source for WDM Systems

DEFF Research Database (Denmark)

Hübner, Jörg; Varming, Poul; Kristensen, Martin

1997-01-01

Singlemode UV-induced distributed feedback (DFB) fibre lasers with a linewidth of lasers is verified by a 10 Gbit/s transmission experiment. Five DFB fibre lasers are cascaded and pumped by a single...... semiconductor laser, thereby forming a multiwavelength source for WDM systems...

All-fiber, long-active-length Fabry-Perot strain sensor.

Science.gov (United States)

Pevec, Simon; Donlagic, Denis

2011-08-01

This paper presents a high-sensitivity, all-silica, all-fiber Fabry-Perot strain-sensor. The proposed sensor provides a long active length, arbitrary length of Fabry-Perot cavity, and low intrinsic temperature sensitivity. The sensor was micro-machined from purposely-developed sensor-forming fiber that is etched and directly spliced to the lead-in fiber. This manufacturing process has good potential for cost-effective, high-volume production. Its measurement range of over 3000 µε, and strain-resolution better than 1 µε were demonstrated by the application of a commercial, multimode fiber-based signal processor.

WDM Systems and Networks Modeling, Simulation, Design and Engineering

CERN Document Server

Ellinas, Georgios; Roudas, Ioannis

2012-01-01

WDM Systems and Networks: Modeling, Simulation, Design and Engineering provides readers with the basic skills, concepts, and design techniques used to begin design and engineering of optical communication systems and networks at various layers. The latest semi-analytical system simulation techniques are applied to optical WDM systems and networks, and a review of the various current areas of optical communications is presented. Simulation is mixed with experimental verification and engineering to present the industry as well as state-of-the-art research. This contributed volume is divided into three parts, accommodating different readers interested in various types of networks and applications. The first part of the book presents modeling approaches and simulation tools mainly for the physical layer including transmission effects, devices, subsystems, and systems), whereas the second part features more engineering/design issues for various types of optical systems including ULH, access, and in-building system...

WDM-PON-compatible system for simultaneous distribution of gigabit baseband and wireless ultrawideband services with flexible bandwidth allocation

DEFF Research Database (Denmark)

Pham, Tien Thang; Yu, Xianbin; Gibbon, Timothy Braidwood

2011-01-01

In this paper, a novel and simple scheme to realize flexible access for gigabit wireline and impulse radio ultrawideband (IR-UWB) wireless services is proposed. The UWB signals are generated by multi-carrier upconverting and reshaping the baseband signals.The proposed system was experimentally...... demonstrated with the performances of 2.0-Gbps data in both baseband and UWB formats after 46-km single mode fiber transmission and further 0.5-m wireless for UWB data. The flexibility of the system is confirmed by investigating the system performance at different data rates including 1.0 Gbps and 1.6 Gbps....... Optical wavelength independency and data-rate variability of UWB signal generation makes the system attractive for potential wireline and wireless applications in existing WDM-PON systems....

Fiber-Optic Communication Links Suitable for On-Board Use in Modern Aircraft

Science.gov (United States)

Nguyen, Hung; Ngo, Duc; Alam, Mohammad F.; Atiquzzaman, Mohammed; Sluse, James; Slaveski, Filip

2004-01-01

The role of the Advanced Air Transportation Technologies program undertaken at the NASA Glenn Research Centers has been focused mainly on the improvement of air transportation safety, with particular emphasis on air transportation communication systems in on-board aircraft. The conventional solutions for digital optical communications systems specifically designed for local/metro area networks are, unfortunately, not capable of transporting the microwave and millimeter RF signals used in avionics systems. Optical networks capable of transporting RF signals are substantially different from the standard digital optical communications systems. The objective of this paper is to identify a number of different communication link architectures for RF/fiber optic transmission using a single backbone fiber for carrying VHF and UHF RF signals in the aircraft. To support these architectures, two approaches derived from both hybrid RF-optical and all-optical processing methodologies are discussed with single and multiple antennas for explicitly transporting VHF and UHF signals, while the relative merits and demerits of each architecture are also addressed. Furthermore, the experimental results of wavelength division multiplexing (WDM) link architecture from our test-bed platform, configured for aircraft environment to support simultaneous transmission of multiple RF signals over a single optical fiber, exhibit no appreciable signal degradation at wavelengths of both 1330 and 1550 nm, respectively. Our measurements of signal to noise ratio carried out for the transmission of FM and AM analog modulated signals at these wavelengths indicate that WDM is a fiber optic technology which is potentially suitable for avionics applications.

Thermal tuning On narrow linewidth fiber laser

Science.gov (United States)

Han, Peiqi; Liu, Tianshan; Gao, Xincun; Ren, Shiwei

2010-10-01

At present, people have been dedicated to high-speed and large-capacity optical fiber communication system. Studies have been shown that optical wavelength division multiplexing (WDM) technology is an effective means of communication to increase the channel capacity. Tunable lasers have very important applications in high-speed, largecapacity optical communications, and distributed sensing, it can provide narrow linewidth and tunable laser for highspeed optical communication. As the erbium-doped fiber amplifier has a large gain bandwidth, the erbium-doped fiber laser can be achieved lasing wavelength tunable by adding a tunable filter components, so tunable filter device is the key components in tunable fiber laser.At present, fiber laser wavelength is tuned by PZT, if thermal wavelength tuning is combined with PZT, a broader range of wavelength tuning is appearance . Erbium-doped fiber laser is used in the experiments,the main research is the physical characteristics of fiber grating temperature-dependent relationship and the fiber grating laser wavelength effects. It is found that the fiber laser wavelength changes continuously with temperature, tracking several temperature points observed the self-heterodyne spectrum and found that the changes in spectra of the 3dB bandwidth of less than 1kHz, and therefore the fiber laser with election-mode fiber Bragg grating shows excellent spectral properties and wavelength stability.

Dispersion Compensation Requirements for Optical CDMA Using WDM Lasers

International Nuclear Information System (INIS)

Mendez, A J; Hendandez, V J; Feng, H X C; Heritage, J P; Lennon, W J

2001-01-01

Optical code division multiple access (O-CDMA) uses very narrow transmission pulses and is thus susceptible to fiber optic link impairments. When the O-CDMA is implemented as wavelength/time (W/T) matrices which use wavelength division multiplexing (WDM) sources such as multi-frequency laser transmitters, the susceptibility may be higher due to: (a) the large bandwidth utilized and (b) the requirement that the various wavelength components of the codes be synchronized at the point of modulation and encoding as well as after (optical) correlation. A computer simulation based on the nonlinear Schroedinger equation, developed to study optical networking on the National Transparent Optical Network (NTON), was modified to characterize the impairments on the propagation and decoding of W/T matrix codes over a link of the NTON. Three critical link impairments were identified by the simulation: group velocity dispersion (GVD); the flatness of the optical amplifier gain; and the slope of the GVD. Subsequently, experiments were carried out on the NTON link to verify and refine the simulations as well as to suggest improvements in the W/T matrix signal processing design. The NTON link measurements quantified the O-CDMA dispersion compensation requirements. Dispersion compensation management is essential to assure the performance of W/T matrix codes

Investigation of a Pulsed 1550 nm Fiber Laser System (Briefing Charts)

Science.gov (United States)

2016-02-14

Pump dump and splice Pump dump and splice MFA 976 nm 15 W TFB TFB Pump dump and splice Waveform shaping Delay Power meter...filter 976 nm 7.6 W TFB WDM Pump dump and splice Pump dump and splice MFA 976 nm 15 W TFB TFB Pump dump and splice Waveform shaping...Multimode fiber to OSA or photodiode EOM EOM ASE filter ASE filter 976 nm 7.6 W TFB

Reconfigurable WDM-PON empowered by a low-cost 8-channel directly modulated laser module

Science.gov (United States)

Zhang, Yi-ming; Liu, Yu; Zhang, Zhi-ke; Zhao, Ze-ping; Tian, Ye; Zhu, Ning-hua

2017-11-01

A 10 Gbit/s 16-km-long reconfigurable wavelength-division-multiplexing passive optical network (WDM-PON) is presented empowered by a low-cost multi-channel directly modulated laser (DML) module. Compared with the case using discrete devices in conventional scheme, the proposed DML module provides a cost-effective solution with reduced complexity. The clear eye diagram and the bit error rate ( BER) of less than 2×10-7 with a sensitivity of -7 dBm are obtained. Due to the special packaging design, the crosstalk between channels under condition of simultaneous operation can be negligible.

Magnetomechanically induced long period fiber gratings

International Nuclear Information System (INIS)

Causado-Buelvas, Jesus D.; Gomez-Cardona, Nelson D.; Torres, Pedro

2008-01-01

In this work, we report a simple, flexible method to create long period fiber gratings mechanically by controlling the repulsion/attraction force between two magnets that pressing a plate with a periodic array of small glass cylinders to a short length of optical fiber. Via the photoelastic effect, the pressure points induce the required periodic refractive index modulation to create the LPFG. We found that the induced device exhibits spectral characteristics similar to those of other types of LPFG. As the optical properties of LPFGs are directly related to the nature of the applied perturbations, we show, to our knowledge for the frrst time, how is the evolution of birefringence effects in mechanically induced LPFGs

λ-Selection Strategy in C+L Band 1-Pbit/s (448 WDM/19-Core/128 Gbit/s/channel) Flex-Grid Space Division Multiplexed Transmission

DEFF Research Database (Denmark)

Asif, Rameez; Ye, Feihong; Morioka, Toshio

2015-01-01

In this paper, an inter-core crosstalk based wavelength selection scheme has been proposed for flex-grid superchannels in space division multiplexed transmission. The two λ-selection strategies are categorized as: (a) aligned wavelength super-channels (Aλ-SCs), where all super-channels are placed...... at same λ in all the cores and (b) interleaved wavelength super-channels (Iλ-SCs), where all super-channels are placed at different λ in all the neighboring cores. It is depicted that system performance is improved for DP-16QAM channels in 1-Pbit/s (448 WDM/19 Core/128 Gbit/s/channel) 60 km fiber link...

Kerr nonlinearity mitigation in 5 × 28-GBd PDM16-QAM signal transmission over a dispersion-uncompensated link with backward-pumpeddistributed Raman amplification

DEFF Research Database (Denmark)

Sackey, I.; Da Ros, Francesco; Jazayerifar, M.

2014-01-01

We present experimental and numerical investigations of Kerr nonlinearity compensation in a 400-km standard single-mode fiber link with distributed Raman amplification with backward pumping. A dual-pump polarization-independent fiber-based optical parametric amplifier is used for mid-link spectra...... to numerical simulations with good agreement. It is also shown with simulations that a maximum transmission reach of 2400 km enabled by the optical phase conjugator is possible for the WDM signal...

Experimental Demonstration of an Electro-Absorption Modulated Laser for High-Speed Transmissions at 1.55-μm Window Using Digital Signal Processing

Directory of Open Access Journals (Sweden)

Fotini Karinou

2017-02-01

Full Text Available We experimentally investigate the transmission performance of 56 Gb/s four-level pulse amplitude modulation (PAM-4 over 30-km standard single mode fiber (SMF using a C-band EML for low-cost metro and short-reach wavelength division multiplexing (WDM applications. Bit error rate (BER performance below the HD-FEC threshold is achieved for up to 30-km maximum reported distance without employing dispersion compensation fiber (DCF in the link.

Experimental study of coexistence of multi-band OFDM-UWB and OFDM-baseband signals in long-reach PONs using directly modulated lasers.

Science.gov (United States)

Morgado, José A P; Fonseca, Daniel; Cartaxo, Adolfo V T

2011-11-07

Transmission of coexisting Orthogonal Frequency Division Multiplexing (OFDM)-baseband (BB) and multi-band OFDM-ultra-wideband (UWB) signals along long-reach passive optical networks using directly modulated lasers (DML) is experimentally demonstrated.When optimized modulation indexes are used, bit error ratios not exceeding 5 × 10⁻⁴ can be achieved by all (OFDM-BB and three OFDM-UWB sub-bands) signals for a reach of 100 km of standard single-mode fiber (SSMF) and optical signal-to-noise ratios not lower than 25dB@0.1 nm. It is experimentally shown that, for the SSMF reach of 100km, the optimized performance of coexisting OFDM-BB and OFDM-UWB signals is mainly imposed by the combination of two effects: the SSMF dispersion-induced nonlinear distortion of the OFDM-UWB signals caused by the OFDM-BB and OFDM-UWB signals, and the further degradation of the OFDM-UWB signals with higher frequency, due to the reduced DML bandwidth.

Two-dimensional priority-based dynamic resource allocation algorithm for QoS in WDM/TDM PON networks

Science.gov (United States)

Sun, Yixin; Liu, Bo; Zhang, Lijia; Xin, Xiangjun; Zhang, Qi; Rao, Lan

2018-01-01

Wavelength division multiplexing/time division multiplexing (WDM/TDM) passive optical networks (PON) is being viewed as a promising solution for delivering multiple services and applications. The hybrid WDM / TDM PON uses the wavelength and bandwidth allocation strategy to control the distribution of the wavelength channels in the uplink direction, so that it can ensure the high bandwidth requirements of multiple Optical Network Units (ONUs) while improving the wavelength resource utilization. Through the investigation of the presented dynamic bandwidth allocation algorithms, these algorithms can't satisfy the requirements of different levels of service very well while adapting to the structural characteristics of mixed WDM / TDM PON system. This paper introduces a novel wavelength and bandwidth allocation algorithm to efficiently utilize the bandwidth and support QoS (Quality of Service) guarantees in WDM/TDM PON. Two priority based polling subcycles are introduced in order to increase system efficiency and improve system performance. The fixed priority polling subcycle and dynamic priority polling subcycle follow different principles to implement wavelength and bandwidth allocation according to the priority of different levels of service. A simulation was conducted to study the performance of the priority based polling in dynamic resource allocation algorithm in WDM/TDM PON. The results show that the performance of delay-sensitive services is greatly improved without degrading QoS guarantees for other services. Compared with the traditional dynamic bandwidth allocation algorithms, this algorithm can meet bandwidth needs of different priority traffic class, achieve low loss rate performance, and ensure real-time of high priority traffic class in terms of overall traffic on the network.

X-ray beam transfer between hollow fibers for long-distance transport

International Nuclear Information System (INIS)

Tanaka, Yoshihito; Matsushita, Ryuki; Shiraishi, Ryutaro; Hasegawa, Takayuki; Ishikawa, Kiyoshi; Sawada, Kei; Kohmura, Yoshiki; Takahashi, Isao

2016-01-01

Fiber optics for controlling the x-ray beam trajectory has been examined at the synchrotron facility of SPring-8. Up to now, we have achieved beam deflection by several tens of milli-radian and axis shift of around 75 mm with a 1.5 m-long flexible hollow glass capillary. The achievable beam deflecting angle, axis shift, and timing delay are, in principle, proportional to the length, the square of length and the cube of length, respectively. Thus, for further applications, requiring larger beam shift and pulse delay, longer fibers are indispensable. In order to achieve long-distance transport using the fiber, we thus examined the connection transferring x-rays between fibers in an experimental hutch. The acceptance angle at the input end and the throughput efficiency of the second fiber is consistent with the consideration of the output beam divergence of the first fiber. The enhancement of the transfer efficiency is also discussed for the cases of a closer joint and the use of a refractive lens as a coupler.

X-ray beam transfer between hollow fibers for long-distance transport

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Yoshihito, E-mail: tanaka@sci.u-hyogo.ac.jp; Matsushita, Ryuki; Shiraishi, Ryutaro; Hasegawa, Takayuki; Ishikawa, Kiyoshi [Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Sayo-gun, Hyogo 678-1297 (Japan); Sawada, Kei; Kohmura, Yoshiki [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Takahashi, Isao [Department of Physics, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 Japan (Japan)

2016-07-27

Fiber optics for controlling the x-ray beam trajectory has been examined at the synchrotron facility of SPring-8. Up to now, we have achieved beam deflection by several tens of milli-radian and axis shift of around 75 mm with a 1.5 m-long flexible hollow glass capillary. The achievable beam deflecting angle, axis shift, and timing delay are, in principle, proportional to the length, the square of length and the cube of length, respectively. Thus, for further applications, requiring larger beam shift and pulse delay, longer fibers are indispensable. In order to achieve long-distance transport using the fiber, we thus examined the connection transferring x-rays between fibers in an experimental hutch. The acceptance angle at the input end and the throughput efficiency of the second fiber is consistent with the consideration of the output beam divergence of the first fiber. The enhancement of the transfer efficiency is also discussed for the cases of a closer joint and the use of a refractive lens as a coupler.

The Audacity of Fiber-Wireless (FiWi) Networks

Science.gov (United States)

Maier, Martin; Ghazisaidi, Navid; Reisslein, Martin

A plethora of enabling optical and wireless technologies have been emerging that can be used to build future-proof bimodal fiber-wireless (FiWi) broadband access networks. After overviewing key enabling radio-over-fiber (RoF) and radio-and-fiber (R&F) technologies and briefly surveying the state of the art of FiWi networks, we introduce an Ethernet-based access-metro FiWi network, called SuperMAN, that integrates next-generation WiFi and WiMAX networks with WDM-enhanced EPON and RPR networks. Throughout the paper we pay close attention to the technical challenges and opportunities of FiWi networks, but also elaborate on their societal benefits and potential to shift the current research focus from optical-wireless networking to the exploitation of personal and in-home computing facilities to create new unforeseen services and applications as we are about to enter the Petabyte age.

White Rabbit Precision Time Protocol on Long-Distance Fiber Links

NARCIS (Netherlands)

Dierikx, E.F.; Dierikx, A.E.; Fordell, T.; Myyry, J.; Koponen, P.; Merimaa, M.; Pinkert, T.J.; Koelemeij, J.C.J.; Peek, H.Z.; Smets, R.

2016-01-01

The application of White Rabbit precision time protocol (WR-PTP) in long-distance optical fiber links has been investigated. WR-PTP is an implementation of PTP in synchronous Ethernet optical fiber networks, originally intended for synchronization of equipment within a range of 10 km. This paper

Loss mechanisms in hollow-core fibers

DEFF Research Database (Denmark)

Lyngsøe, Jens Kristian; Mangan, B.J.; Jakobsen, C.

2009-01-01

With the recent advances in digital signal processing (DSP), coherent detection is currently living its second life in the world of fiber-optics. First generation transponders using coherent detection are coming to the market, and a significant amount of research is being invested in this area....... With the rise of digital signal processing as an integral part of optical communication systems, most of the complexity is shifted from the optical/analogue to the electrical/digital domain. This will fundamentally change the way we should design our systems. At the same time, new generations of WDM systems...

Short-wavelength multiline erbium-doped fiber ring laser by a broadband long-period fiber grating inscribed in a taper transition

International Nuclear Information System (INIS)

Anzueto-Sánchez, G; Martínez-Rios, A

2014-01-01

A stable multiwavelength all-fiber erbium-doped fiber ring laser (EDFRL) based on a broadband long-period fiber grating (LPFG) inscribed in a fiber taper transition is presented. The LPFG’s characteristics were engineered to provide a higher loss at the natural lasing wavelength of the laser cavity. The LPFG inscribed on a taper transition provided a depth greater than 25 dB, and posterior chemical etching provided a broad notch band to inhibit laser generation on the long-wavelength side of the EDF gain. Up to four simultaneous laser wavelengths are generated in the range of 1530–1535 nm. (paper)

Upgrade of optical WDM transport systems introducing linerates at 40 Gbit/s per channel

Science.gov (United States)

Schneiders, Malte; Vorbeck, Sascha; Aust, Nora

2006-10-01

Driven by high growth rates of internet traffic the question of upgrading existing optical metro-, regio- and long haul transport networks introducing 40 Gbit/s/λ is one of the most important questions today and in the near future. Current WDM Systems in photonic networks are commonly operated at linerates of 2.5 and 10 Gbit/s/λ. Induced by market analyses and the historical development of transport systems some work has already been carried out to evaluate update scenarios from 10 to 40 Gbit/s channel data rates. Due to the inherent quadruplication of the bandwidth per channel, limitations due to linear and non-linear transmission impairments become stronger resulting in a highly increased complexity of link engineering, potentially increasing the capital and operational expenditures. A lot of work is therefore in progress, which targets at the relaxation of constraints for 40 Gbit/s transmission to find the most efficient upgrade strategies. One approach towards an increased robustness against signal distortions is the introduction of more advanced modulation formats. Different modulation schemes show strongly different optical WDM transmission characteristics. The choice of the appropriate format does not only depend on the technical requirements, but also on economical considerations as an increased transmitter- and receiver-complexity will drive the transponder price. This article presents investigations on different modulation formats for the upgrade of existing metro-/ regio and long haul transport networks. Tolerances and robustness against the main degrading effects dispersion, noise and nonlinearities are considered together with mitigation strategies like the adaptation of dispersion maps. Results from numerical simulations are provided for some of the most promising modulation formats like NRZ, RZ, CS-RZ, Optical Duobinary and DPSK.

Long-term strain response of polymer optical fiber FBG sensors

DEFF Research Database (Denmark)

Bundalo, Ivan-Lazar; Nielsen, Kristian; Woyessa, Getinet

2017-01-01

We report on the viscoelastic response of PMMA microstructured polymer optical fibers (mPOFs) when exposed to long periods of strain and relaxation, with the strain period ranging from 0.5 min to 50 min. The behavior of the fibers was monitored by inscribing a fiber Bragg grating (FBG) in them...... and tracking the reflection peak. We demonstrate that the fiber, when relaxing from strains of up to 0.9%, has a two-phase recovery: initially linear (elastic driven) and subsequently nonlinear (viscoelastic driven) contraction. The linear (elastic) relaxation wavelength range depends both on the strain level...

On stiffening cables of a long reach manipulator

International Nuclear Information System (INIS)

Wang, S.L.; Santiago, P.

1996-01-01

A long reach manipulator will be used for waste remediation in large underground storage tanks. The manipulator's slenderness makes it flexible and difficult to control. A low-cost and effective method to enhance the manipulator's stiffness is proposed in this research by using suspension cables. These cables can also be used to accurately measure the position of the manipulator's wrist

WDM Question and Answers | CRDI - Centre de recherches pour le ...

International Development Research Centre (IDRC) Digital Library (Canada)

Why is there growing concern about water issues in the MENA region? ... Sometimes it is easier to define what is WDM is not about than to define what it is about. ... You can take part in this on-going regional effort by writing articles and ...

Full distortion induced by dispersion evaluation and optical bandwidth constraining of fiber Bragg grating demultiplexers over analogue SCM systems.

Science.gov (United States)

Martinez, Alfonso; Pastor, Daniel; Capmany, Jose

2002-12-30

We provide a full analysis of the distortion effects produced by the first and second order in-band dispersion of fiber Bragg grating based optical demultiplexers over analogue SCM (Sub Carrier Multiplexed) signals. Optical bandwidth utilization ranges for Dense WDM network are calculated considering different SCM system cases of frequency extension and modulation conditions.

Characterization technique for long optical fiber cavities based on beating spectrum of multi-longitudinal mode fiber laser and beating spectrum in the RF domain

Science.gov (United States)

Adib, George A.; Sabry, Yasser M.; Khalil, Diaa

2016-03-01

The characterization of long fiber cavities is essential for many systems to predict the system practical performance. The conventional techniques for optical cavity characterization are not suitable for long fiber cavities due to the cavities' small free spectral ranges and due to the length variations caused by the environmental effects. In this work, we present a novel technique to characterize long fiber cavities using multi-longitudinal mode fiber laser source and RF spectrum analyzer. The fiber laser source is formed in a ring configuration, where the fiber laser cavity length is chosen to be 15 km to ensure that the free spectral range is much smaller than the free spectral range of the characterized passive fiber cavities. The method has been applied experimentally to characterize ring cavities with lengths of 6.2 m and 2.4 km. The results are compared to theoretical predictions with very good agreement.

Analizar el rendimiento de los receptores en una red TDM/WDM pon (red óptica pasiva)

OpenAIRE

Romero Chafla, Luis Fernando

2016-01-01

The rapid increase of Internet users deserve transmission rates higher data rates and greater capacity in terms of number of users. However, this should be achieved at a reasonable cost. TDM (Time Division Multiplexing) and WDM (Wavelength Division Multiplexing) technologies are most used. TDM allows us to offer extend services to many users (sacrificing bandwidth), low speed, at a reasonable cost. WDM meanwhile has the capacity to serve a greater number of users and provide higher transmissi...

Optical resonance analysis of reflected long period fiber gratings with metal film overlay

Science.gov (United States)

Zhang, Guiju; Cao, Bing; Wang, Chinua; Zhao, Minfu

2008-11-01

We present the experimental results of a novel single-ended reflecting surface plasma resonance (SPR) based long period fiber grating (LPFG) sensor. A long period fiber grating sensing device is properly designed and fabricated with a pulsed CO2 laser writing system. Different nm-thick thin metal films are deposited on the fiber cladding and the fiber end facet for the excitation of surface plasma waves (SPWs) and the reflection of the transmission spectrum of the LPFG with doubled interaction between metal-dielectric interfaces of the fiber to enhance the SPW of the all-fiber SPR-LPFG sensing system. Different thin metal films with different thicknesses are investigated. The effect of the excited SPW transmission along the fiber cladding-metal interface with silver and aluminum films is observed. It is found that different thicknesses of the metal overlay show different resonant behaviors in terms of resonance peak situation, bandwidth and energy loss. Within a certain range, thinner metal film shows narrower bandwidth and deeper peak loss.

Relationship between fiber degradation and residence time distribution in the processing of long fiber reinforced thermoplastics

Directory of Open Access Journals (Sweden)

2008-08-01

Full Text Available Long fiber reinforced thermoplastics (LFT were processed by in-line compounding equipment with a modified single screw extruder. A pulse stimulus response technique using PET spheres as the tracer was adopted to obtain residence time distribution (RTD of extrusion compounding. RTD curves were fitted by the model based on the supposition that extrusion compounding was the combination of plug flow and mixed flow. Characteristic parameters of RTD model including P the fraction of plug flow reactor (PFR and d the fraction of dead volume of continuous stirred tank reactor (CSTR were used to associate with fiber degradation presented by fiber length and dispersion. The effects of screw speed, mixing length and channel depth on RTD curves, and characteristic parameters of RTD models as well as their effects on the fiber degradation were investigated. The influence of shear force with different screw speeds and variable channel depth on fiber degradation was studied and the main impetus of fiber degradation was also presented. The optimal process for obtaining the balance of fiber length and dispersion was presented.

Protocol and networking design issues for local access WDM networks

NARCIS (Netherlands)

Salvador, M.R.; Heemstra de Groot, S.M.; Niemegeers, I.G.M.M.

This report gives an overview of some of the protocol and networking design issues that have been addressed in Flamingo, a major ongoing project which investigates the use of WDM optical technology in local access networks. Quality of service delivery and wavelength assignment are focused on in this

Time lens based optical fourier transformation for advanced processing of spectrally-efficient OFDM and N-WDM signals

DEFF Research Database (Denmark)

Guan, Pengyu; Røge, Kasper Meldgaard; Morioka, Toshio

2016-01-01

We review recent progress in the use of time lens based optical Fourier transformation for advanced optical signal processing, with focus on all-optical generation, detection and format conversion of spectrally-efficient OFDM and N-WDM signals.......We review recent progress in the use of time lens based optical Fourier transformation for advanced optical signal processing, with focus on all-optical generation, detection and format conversion of spectrally-efficient OFDM and N-WDM signals....

Simulation and measurement of optical access network with different types of optical-fiber amplifiers

Science.gov (United States)

Latal, Jan; Vogl, Jan; Koudelka, Petr; Vitasek, Jan; Siska, Petr; Liner, Andrej; Papes, Martin; Vasinek, Vladimir

2012-01-01

The optical access networks are nowadays swiftly developing in the telecommunications field. These networks can provide higher data transfer rates, and have great potential to the future in terms of transmission possibilities. Many local internet providers responded to these facts and began gradually installing optical access networks into their originally built networks, mostly based on wireless communication. This allowed enlargement of possibilities for end-users in terms of high data rates and also new services such as Triple play, IPTV (Internet Protocol television) etc. However, with this expansion and building-up is also related the potential of reach in case of these networks. Big cities, such as Prague, Brno, Ostrava or Olomouc cannot be simply covered, because of their sizes and also because of their internal regulations given by various organizations in each city. Standard logical and also physical reach of EPON (IEEE 802.3ah - Ethernet Passive Optical Network) optical access network is about 20 km. However, for networks based on Wavelength Division Multiplex the reach can be up to 80 km, if the optical-fiber amplifier is inserted into the network. This article deals with simulation of different types of amplifiers for WDM-PON (Wavelength Division Multiplexing-Passive Optical Network) network in software application Optiwave OptiSystem and than are the values from the application and from real measurement compared.

Parallel Void Thread in Long-Reach Ethernet Passive Optical Networks

KAUST Repository

Elrasad, Amr; Shihada, Basem

2015-01-01

This work investigates void filling (idle periods) in long-reach Ethernet passive optical networks. We focus on reducing grant delays and hence reducing the average packet delay. We introduce a novel approach called parallel void thread (PVT), which

Novel tunable optical filter employing a fiber loop mirror for synthesis applications in WDM

OpenAIRE

Vázquez García, María Carmen; Vargas Palma, Salvador Elías; Sánchez-Pena, José Manuel

2001-01-01

A novel optical filter employing a fiber loop mirror within an amplified ring resonator is presented. The fiber loop mirror allows tuning by changing the coupling factor of a coupler. The device can be used as a building block to synthesize optical filters, as previously reported, saving components. Publicado

Optical RAM row access using WDM-enabled all-passive row/column decoders

Science.gov (United States)

Papaioannou, Sotirios; Alexoudi, Theoni; Kanellos, George T.; Miliou, Amalia; Pleros, Nikos

2014-03-01

Towards achieving a functional RAM organization that reaps the advantages offered by optical technology, a complete set of optical peripheral modules, namely the Row (RD) and Column Decoder (CD) units, is required. In this perspective, we demonstrate an all-passive 2×4 optical RAM RD with row access operation and subsequent all-passive column decoding to control the access of WDM-formatted words in optical RAM rows. The 2×4 RD exploits a WDM-formatted 2-bit-long memory WordLine address along with its complementary value, all of them encoded on four different wavelengths and broadcasted to all RAM rows. The RD relies on an all-passive wavelength-selective filtering matrix (λ-matrix) that ensures a logical `0' output only at the selected RAM row. Subsequently, the RD output of each row drives the respective SOA-MZI-based Row Access Gate (AG) to grant/block the entry of the incoming data words to the whole memory row. In case of a selected row, the data word exits the row AG and enters the respective CD that relies on an allpassive wavelength-selective Arrayed Waveguide Grating (AWG) for decoding the word bits into their individual columns. Both RD and CD procedures are carried out without requiring any active devices, assuming that the memory address and data word bits as well as their inverted values will be available in their optical form by the CPU interface. Proof-of-concept experimental verification exploiting cascaded pairs of AWGs as the λ-matrix is demonstrated at 10Gb/s, providing error-free operation with a peak power penalty lower than 0.2dB for all optical word channels.

Persistent muscle fiber regeneration in long term denervation. Past, present, future

Directory of Open Access Journals (Sweden)

Ugo Carraro

2015-03-01

Full Text Available Despite the ravages of long term denervation there is structural and ultrastructural evidence for survival of muscle fibers in mammals, with some fibers surviving at least ten months in rodents and 3-6 years in humans. Further, in rodents there is evidence that muscle fibers may regenerate even after repeated damage in the absence of the nerve, and that this potential is maintained for several months after denervation. While in animal models permanently denervated muscle sooner or later loses the ability to contract, the muscles may maintain their size and ability to function if electrically stimulated soon after denervation. Whether in mammals, humans included, this is a result of persistent de novo formation of muscle fibers is an open issue we would like to explore in this review. During the past decade, we have studied muscle biopsies from the quadriceps muscle of Spinal Cord Injury (SCI patients suffering with Conus and Cauda Equina syndrome, a condition that fully and irreversibly disconnects skeletal muscle fibers from their damaged innervating motor neurons. We have demonstrated that human denervated muscle fibers survive years of denervation and can be rescued from severe atrophy by home-based Functional Electrical Stimulation (h-bFES. Using immunohistochemistry with both non-stimulated and the h-bFES stimulated human muscle biopsies, we have observed the persistent presence of muscle fibers which are positive to labeling by an antibody which specifically recognizes the embryonic myosin heavy chain (MHCemb. Relative to the total number of fibers present, only a small percentage of these MHCemb positive fibers are detected, suggesting that they are regenerating muscle fibers and not pre-existing myofibers re-expressing embryonic isoforms. Although embryonic isoforms of acetylcholine receptors are known to be re-expressed and to spread from the end-plate to the sarcolemma of muscle fibers in early phases of muscle denervation, we suggest

A new architecture and MAC protocol for fully flexible hybrid WDM/TDM PON

NARCIS (Netherlands)

Das, G.; Lannoo, B.; Jung, H.D.; Koonen, A.M.J.; Colle, D.; Pickavet, M.; Demeester, P.

2009-01-01

In this paper we propose a novel architecture and MAC protocol for a scalable, cost effective WDM / TDM PON providing fully flexible dynamic bandwidth allocation for upstream and downstream data transmission.

Multi-granularity Bandwidth Allocation for Large-Scale WDM/TDM PON

Science.gov (United States)

Gao, Ziyue; Gan, Chaoqin; Ni, Cuiping; Shi, Qiongling

2017-12-01

WDM (wavelength-division multiplexing)/TDM (time-division multiplexing) PON (passive optical network) is being viewed as a promising solution for delivering multiple services and applications, such as high-definition video, video conference and data traffic. Considering the real-time transmission, QoS (quality of services) requirements and differentiated services model, a multi-granularity dynamic bandwidth allocation (DBA) in both domains of wavelengths and time for large-scale hybrid WDM/TDM PON is proposed in this paper. The proposed scheme achieves load balance by using the bandwidth prediction. Based on the bandwidth prediction, the wavelength assignment can be realized fairly and effectively to satisfy the different demands of various classes. Specially, the allocation of residual bandwidth further augments the DBA and makes full use of bandwidth resources in the network. To further improve the network performance, two schemes named extending the cycle of one free wavelength (ECoFW) and large bandwidth shrinkage (LBS) are proposed, which can prevent transmission from interruption when the user employs more than one wavelength. The simulation results show the effectiveness of the proposed scheme.

Multicast routing for wavelength-routed WDM networks with dynamic membership

Science.gov (United States)

Huang, Nen-Fu; Liu, Te-Lung; Wang, Yao-Tzung; Li, Bo

2000-09-01

Future broadband networks must support integrated services and offer flexible bandwidth usage. In our previous work, we explore the optical link control layer on the top of optical layer that enables the possibility of bandwidth on-demand service directly over wavelength division multiplexed (WDM) networks. Today, more and more applications and services such as video-conferencing software and Virtual LAN service require multicast support over the underlying networks. Currently, it is difficult to provide wavelength multicast over the optical switches without optical/electronic conversions although the conversion takes extra cost. In this paper, based on the proposed wavelength router architecture (equipped with ATM switches to offer O/E and E/O conversions when necessary), a dynamic multicast routing algorithm is proposed to furnish multicast services over WDM networks. The goal is to joint a new group member into the multicast tree so that the cost, including the link cost and the optical/electronic conversion cost, is kept as less as possible. The effectiveness of the proposed wavelength router architecture as well as the dynamic multicast algorithm is evaluated by simulation.

Sensing Features of Long Period Gratings in Hollow Core Fibers

Directory of Open Access Journals (Sweden)

Agostino Iadicicco

2015-04-01

Full Text Available We report on the investigation of the sensing features of the Long-Period fiber Gratings (LPGs fabricated in hollow core photonic crystal fibers (HC-PCFs by the pressure assisted Electric Arc Discharge (EAD technique. In particular, the characterization of the LPG in terms of shift in resonant wavelengths and changes in attenuation band depth to the environmental parameters: strain, temperature, curvature, refractive index and pressure is presented. The achieved results show that LPGs in HC-PCFs represent a novel high performance sensing platform for measurements of different physical parameters including strain, temperature and, especially, for measurements of environmental pressure. The pressure sensitivity enhancement is about four times greater if we compare LPGs in HC and standard fibers. Moreover, differently from LPGs in standard fibers, these LPGs realized in innovative fibers, i.e., the HC-PCFs, are not sensitive to surrounding refractive index.

Multicast backup reprovisioning problem for Hamiltonian cycle-based protection on WDM networks

Science.gov (United States)

Din, Der-Rong; Huang, Jen-Shen

2014-03-01

As networks grow in size and complexity, the chance and the impact of failures increase dramatically. The pre-allocated backup resources cannot provide 100% protection guarantee when continuous failures occur in a network. In this paper, the multicast backup re-provisioning problem (MBRP) for Hamiltonian cycle (HC)-based protection on WDM networks for the link-failure case is studied. We focus on how to recover the protecting capabilities of Hamiltonian cycle against the subsequent link-failures on WDM networks for multicast transmissions, after recovering the multicast trees affected by the previous link-failure. Since this problem is a hard problem, an algorithm, which consists of several heuristics and a genetic algorithm (GA), is proposed to solve it. The simulation results of the proposed method are also given. Experimental results indicate that the proposed algorithm can solve this problem efficiently.

Bandwidth Allocation Method by Service for WDM EPON

Institute of Scientific and Technical Information of China (English)

Yongseok; Chang; Changgyu; Choi; Jonghoon; Eom; Sungho; Kim

2003-01-01

A WDM(Wavelength Division Multiplexing) EPON(Ethernet Passive Optical Network) is an economical and efficient access network that has attracted significant research attention in recent years. A MAC(Media Access Control) Protocol of PON is based on TDMA(Time Division Multiple Access) basically, we can classify this protocol into a fixed length slot assignment method suitable for leased line supporting Qos(Quality of Service) and a variable length slot assignment method suitable for LAN/MAN with the best ...

An agent-based QoS provisioning mechanism for WDM optical networks

Science.gov (United States)

Ouyang, Yong; Zeng, Qingji; Yue, Ling

2004-04-01

This paper addresses QoS provisioning mechanisms in the WDM optical networks. With the appearance of metropolitan optical network, a hierarchical metro and wide area optical network will be envisioned in the near future. This hierarchical optical transport network is often divided into optical domains by geography, administration and technology, which usually employ different QoS routing algorithms and policies. To provide end-to-end optical QoS is becoming a new challenge for the optical network design. In this paper, we first give an overview of issues on the QoS provisioning in data, control and management planes of the WDM optical network. And then three provisioning approaches are analyzed and compared. Finally, we propose an agent-based hybrid centralized/distributed QoS provisioning mechanism based on the concept of domain agent. This agent-based hybrid mechanism employs centralized approach in the domain and distributed approach between domains. It offers scalability and intra-domain optimal QoS routing. It also keeps independence and interoperability between domains.

All-fiber optical mode switching based on cascaded mode selective couplers for short-reach MDM networks

Science.gov (United States)

Ren, Fang; Li, Juhao; Wu, Zhongying; Yu, Jinyi; Mo, Qi; Wang, Jianping; He, Yongqi; Chen, Zhangyuan; Li, Zhengbin

2017-04-01

We propose and experimentally demonstrate an all-fiber optical mode switching structure supporting independent switching, exchanging, adding, and dropping functionalities in which each mode can be switched individually. The mode switching structure consists of cascaded mode selective couplers (MSCs) capable of exciting and selecting specific higher order modes in few-mode fibers with high efficiency and one multiport optical switch routing the independent spatial modes to their destinations. The data carried on three different spatial modes can be switched, exchanged, added, and dropped through this all-fiber structure. For this experimental demonstration, optical on-off-keying (OOK) signals at 10-Gb/s carried on three spatial modes are successfully processed with open and clear eye diagrams. The mode switch exhibits power penalties of less than 3.1 dB after through operation, less than 2.7 dB after exchange operation, less than 2.8 dB after switching operation, and less than 1.6 dB after mode adding and dropping operations at the bit-error rate (BER) of 10-3, while all three channels carried on three spatial modes are simultaneously routed. The proposed structure, compatible with current optical switching networks based on single-mode fibers, can potentially be used to expand the switching scalability in advanced and flexible short-reach mode-division multiplexing-based networks.

Optical Switching for Dynamic Distribution of Wireless-over-Fiber Signals

DEFF Research Database (Denmark)

Rodes Lopez, Guillermo Arturo; Vegas Olmos, Juan José; Karinou, Fotini

2012-01-01

In this paper, we report on an experimental validation of dynamic distribution of wireless-over-fiber by employing optical switching using semiconductor optical amplifiers; the rest of the network was designed according to the channel distribution over the optical spectra required by the optical...... switch. An experimental validation was also conducted. The experiment consists of a four wavelength division multiplexed (WDM) channel system operating on a WiMax frequency band, and employing an orthogonal frequency-division multiplexing (OFDM) modulation at 625 Mbit/s per channel, transmission...... of the data over 20 km of optical fiber, and active switching in a one-by-sixteen active optical switch. The results show a negligible power penalty on each channel, for both the best and the worst case in terms of inter-channel crosstalk....

Construction of implantable optical fibers for long-term optogenetic manipulation of neural circuits.

Science.gov (United States)

Sparta, Dennis R; Stamatakis, Alice M; Phillips, Jana L; Hovelsø, Nanna; van Zessen, Ruud; Stuber, Garret D

2011-12-08

In vivo optogenetic strategies have redefined our ability to assay how neural circuits govern behavior. Although acutely implanted optical fibers have previously been used in such studies, long-term control over neuronal activity has been largely unachievable. Here we describe a method to construct implantable optical fibers to readily manipulate neural circuit elements with minimal tissue damage or change in light output over time (weeks to months). Implanted optical fibers readily interface with in vivo electrophysiological arrays or electrochemical detection electrodes. The procedure described here, from implant construction to the start of behavioral experimentation, can be completed in approximately 2-6 weeks. Successful use of implantable optical fibers will allow for long-term control of mammalian neural circuits in vivo, which is integral to the study of the neurobiology of behavior.

Fiber optic liquid-level sensor using a long fiber Bragg grating

Science.gov (United States)

Ricchiuti, Amelia L.; Barrera, David; Nonaka, Koji; Sales, Salvador

2013-05-01

A technique for liquid-level sensors based on a long fiber Bragg grating (FBG) is presented and experimentally demonstrated. The measurement system is based on the measurement of the central frequency distribution of the FBG based on time-frequency domain analysis. A short optical pulse is injected into a 10-cm long FBG mounted in a container. The back-reflected pulse is scanned by means of an oscilloscope. When part of the grating is immersed in a liquid having temperature higher than the surrounding ambient, the structure of the uniform grating is distorted and its time-frequency response changes. A spatial resolution of 2 mm, given by the input pulse duration, and a 10-cm long measurement range are achieved. Liquid-temperature sensing has also been implemented by scanning the spectral response of the FBG by means of a CW laser and an OSA.

Experimental demonstration of 608Gbit/s short reach transmission employing half-cycle 16QAM Nyquist-SCM signal and direct detection with 25Gbps EML.

Science.gov (United States)

Zhong, Kangping; Zhou, Xian; Wang, Yiguang; Wang, Liang; Yuan, Jinhui; Yu, Changyuan; Lau, Alan Pak Tao; Lu, Chao

2016-10-31

In this paper, we experimentally demonstrated an IM/DD short reach transmission system with a total capacity of 608Gbit/s (net capacity of 565.4Gbit/s exclude 7% FEC overhead) employing half-cycle 16QAM Nyquist-SCM signal and 25Gbps EML at O band. Direct detection-faster than Nyquist (DD-FTN) technique was employed to compensate channel impairments. Number of taps of DD-LMS and tap coefficient of post filter in DD-FTN were experimentally studied for different baud rates. Single-lane 152Gbit/s transmission over 10km of SSMF was experimentally demonstrated. Employing a 4-lanes LAN-WDM architecture, a total capacity of 608Gbit/s transmission over 2km was successfully achieved with a receiver sensitivity lower than -4dBm. To the best of authors' knowledge, this is the highest reported baud rate of half-cycle 16QAM Nyquist-SCM signal and the highest bit rate employing IM/DD and 25Gbps EML in a four lanes LAN-WDM architecture for short reach systems in the O band.

Application of Notched Long-Period Fiber Grating Based Sensor for CO2 Gas Sensing

Science.gov (United States)

Wu, Chao-Wei; Chiang, Chia-Chin

2016-01-01

An inductively coupled plasma etching process to fabricate notched long-period fiber gratings for CO2 gas sensing is proposed in this article. In the gas sensing test, the 15% mixed CO2 gas was used for characterization of CO2 adsorption by the amine-modified nanoporous silica foams of the notched long-period fiber grating sensor. The results shows the spectra were changed with the CO2 gas flow within 13 min. During the absorption process, the transmission of the resonant dip was decreased by 2.884 dB. Therefore, the proposed notched long-period fiber grating gas sensor shows good performance and is suitable as a gas sensor for monitoring the CO2 adsorption process.

10 Gb/s bidirectional single fibre long reach PON link with distributed Raman amplification

DEFF Research Database (Denmark)

Tafur Monroy, Idelfonso; Kjær, Rasmus; Jeppesen, Palle

2006-01-01

We report operation of a single fibre bidirectional 80 km long reach PON link with symmetric up- and-downstream data rate of 10 Gb/s supported by distributed Raman fibre amplification only.......We report operation of a single fibre bidirectional 80 km long reach PON link with symmetric up- and-downstream data rate of 10 Gb/s supported by distributed Raman fibre amplification only....

VCSEL Transmission at 10 Gb/s for 20 km Single Mode Fiber WDM-PON without Dispersion Compensation or Injection Locking

DEFF Research Database (Denmark)

Gibbon, Timothy Braidwood; Prince, Kamau; Pham, Tien Thang

2011-01-01

how off-center wavelength filtering of the VCSEL spectrum at an array waveguide grating can be used to mitigate the effect of chirp and the dispersion penalty. Transmission at 10Gb/s VCSEL over 23.6 km of single mode fiber is experimentally demonstrated, with a dispersion penalty of only 2.9 d......B. Simulated results are also presented which show that off-center wavelength filtering can extend the 10 Gb/s network reach from 11.7 km to 25.8 km for a 4 dB dispersion penalty. This allows for cheap and simple dispersion mitigation in next generation VCSEL based optical access networks....

POLICY BRIEF 1 - WDM Criteria | CRDI - Centre de recherches pour ...

International Development Research Centre (IDRC) Digital Library (Canada)

18 janv. 2012 ... Water demand management ― WDM ― can be hard to define. More an issue of policy than of technology, it is about managing and moderating our demands for good quality fresh water. It is less a matter of piping and pumps and more a tool for changing the ways we use water and the rates at which we ...

Energy-Saving Mechanism in WDM/TDM-PON Based on Upstream Network Traffic

Directory of Open Access Journals (Sweden)

Paola Garfias

2014-08-01

Full Text Available One of the main challenges of Passive Optical Networks (PONs is the resource (bandwidth and wavelength management. Since it has been shown that access networks consume a significant part of the overall energy of the telecom networks, the resource management schemes should also consider energy minimization strategies. To sustain the increased bandwidth demand of emerging applications in the access section of the network, it is expected that next generation optical access networks will adopt the wavelength division/time division multiplexing (WDM/TDM technique to increase PONs capacity. Compared with traditional PONs, the architecture of a WDM/TDM-PON requires more transceivers/receivers, hence they are expected to consume more energy. In this paper, we focus on the energy minimization in WDM/TDM-PONs and we propose an energy-efficient Dynamic Bandwidth and Wavelength Allocation mechanism whose objective is to turn off, whenever possible, the unnecessary upstream traffic receivers at the Optical Line Terminal (OLT. We evaluate our mechanism in different scenarios and show that the proper use of upstream channels leads to relevant energy savings. Our proposed energy-saving mechanism is able to save energy at the OLT while maintaining the introduced penalties in terms of packet delay and cycle time within an acceptable range. We might highlight the benefits of our proposal as a mechanism that maximizes the channel utilization. Detailed implementation of the proposed algorithm is presented, and simulation results are reported to quantify energy savings and effects on network performance on different network scenarios.

A new design of photonic crystal fiber with ultra-flattened dispersion to simultaneously minimize the dispersion and confinement loss

Science.gov (United States)

Olyaee, Saeed; Taghipour, Fahimeh

2011-02-01

Photonic crystal fibers (PCFs) are highly suitable transmission media for wavelength-division-multiplexing (WDM) systems, in which low and ultra-flattened dispersion of PCFs is extremely desirable. It is also required to concurrently achieve both a low confinement loss as well as a large effective area in a wide range of wavelengths. Relatively low dispersion with negligible variation has become feasible in the wavelength range of 1.1 to 1.8μm through the proposed design in this paper. According to a new structure of PCF presented in this study, the dispersion slope is 6.8×10-4ps/km.nm2 and the confinement loss reaches below 10-6 dB/km in this range, while at the same time an effective area of more than 50μm2 has been attained. For the analysis of this PCF, finite-difference time-domain (FDTD) method with the perfectly matched layers (PML) boundary conditions has been used.

Key lessons: Twelve factors critical to the success of WDM at the ...

International Development Research Centre (IDRC) Digital Library (Canada)

English · Français ... Key lessons: Twelve factors critical to the success of WDM at the policy and at the operational levels ... from slums in central New Delhi to the city's desolate periphery face daily indignities and danger as they collect water o.

Input shaping methods for telerobotic operation of flexible, long-reach manipulators

International Nuclear Information System (INIS)

Kwon, Dong-Soo; Hwang, Dong-Hwan; Babcock, S.M.

1994-01-01

Among the Environmental Restoration and Waste Management Program of the U.S. Department of Energy, the remediation of radioactive waste from the underground storage tank challenges the state-of-the-art equipment and methods. Long-reach manipulators are being considered to be one of the most advantageous approaches for the retrieval of waste from large storage tanks. Because of long-reach manipulator's high payload capacity and high length-to-cross-section ratios, such manipulator system exhibits significant structural flexibility. To avoid structural vibrations during operation, control algorithms employing various types of shaping filters were investigated. A robust notch filtering method and an impulse shaping method were evaluated. In addition to that, a new approach that uses imbedded simulation was developed and compared with others. In the new approach, joint trajectories have been generated considering the flexible link dynamics

Field Trial of 40 Gb/s Optical Transport Network using Open WDM Interfaces

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Ruepp, Sarah Renée; Petersen, Martin Nordal

2013-01-01

An experimental field-trail deployment of a 40Gb/s open WDM interface in an operational network is presented, in cross-carrier interconnection scenario. Practical challenges of integration and performance measures for both native and alien channels are outlined....

On achievable rates for long-haul fiber-optic communications

NARCIS (Netherlands)

Fehenberger, T.; Alvarado, A.; Bayvel, P.; Hanik, N.

2015-01-01

Lower bounds on mutual information (MI) of long-haul optical fiber systems for hard-decision and soft-decision decoding are studied. Ready-to-use expressions to calculate the MI are presented. Extensive numerical simulations are used to quantify how changes in the optical transmitter, receiver, and

Integration of Optically Generated Impulse Radio UWB Signals into Baseband WDM-PON

DEFF Research Database (Denmark)

Pham, Tien Thang; Yu, Xianbin; Dittmann, Lars

2011-01-01

We propose a compact integration system to simultaneously provide wireline and wireless (baseband and ultra-wide band (UWB)) services to end-users in a WDM-PON. A 1-Gbps UWB signal is optically generated and shares the same wavelength with the baseband signal. Error-free performance was achieved...

Electromechanical behavior of fiber-reinforced dielectric elastomer membrane

Directory of Open Access Journals (Sweden)

Chi Li

2015-04-01

Full Text Available Based on its large deformation, light weight, and high energy density, dielectric elastomer (DE has been used as driven muscle in many areas. We design the fiber-reinforced DE membrane by adding fibers in the membrane. The deformation and driven force direction of the membrane can be tuned by changing the fiber arrangements. The actuation in the perpendicular direction of the DE membrane with long fibers first increases and then decreases by the increasing of the fiber spacing in the perpendicular direction. The horizontal actuation of the membrane decreases by decreasing the spacing of short fibers. In the membrane-inflating structure, the radially arranged fibers will break the axisymmetric behavior of the structure. The top area of the inflated balloon without fiber will buckle up when the voltage reaches a certain level. Finite element simulations based on nonlinear field theory are conducted to investigate the effects of fiber arrangement and verify the experimental results. This work can guide the design of fiber-reinforced DE.

Multiwavelength Raman-fiber-laser-based long-distance remote sensor for simultaneous measurement of strain and temperature.

Science.gov (United States)

Han, Young-Geun; Tran, T V A; Kim, Sang-Hyuck; Lee, Sang Bae

2005-06-01

We propose a simple and flexible multiwavelength Raman-fiber-laser-based long-distance remote-sensing scheme for simultaneous measurement of strain and temperature by use of fiber Bragg gratings. By combining two uniform fiber Bragg gratings with a tunable chirped fiber grating, we readily achieve simultaneous two-channel sensing probes with a high extinction ratio of more than approximately 50 dB over a 50-km distance. When strain and temperature are applied, lasing wavelength separation and shift occur, respectively, since the two uniform fiber Bragg gratings have identical material composition and different cladding diameters. This allows simultaneous measurement of strain and temperature for long-distance sensing applications of more than 50 km.

Multi-channel WDM RZ-to-NRZ format conversion at 50 Gbit/s based on single silicon microring resonator

DEFF Research Database (Denmark)

Ding, Yunhong; Peucheret, Christophe; Pu, Minhao

2010-01-01

We comprehensively analyze multiple WDM channels RZ-to- NRZ format conversion using a single microring resonator. The scheme relies on simultaneous suppression of the first order harmonic components in the spectra of all the RZ channels. An optimized silicon microring resonator with free spectral...... range of 100 GHz and Q value of 7900 is designed and fabricated for this purpose. Multi-channel RZ-to-NRZ format conversion is demonstrated experimentally at 50 Gbit/s for WDM channels with 200 GHz channel spacing using the fabricated device. Bit error rate (BER)measurements show very good conversion...

A New Wavelength Optimization and Energy-Saving Scheme Based on Network Coding in Software-Defined WDM-PON Networks

Science.gov (United States)

Ren, Danping; Wu, Shanshan; Zhang, Lijing

2016-09-01

In view of the characteristics of the global control and flexible monitor of software-defined networks (SDN), we proposes a new optical access network architecture dedicated to Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) systems based on SDN. The network coding (NC) technology is also applied into this architecture to enhance the utilization of wavelength resource and reduce the costs of light source. Simulation results show that this scheme can optimize the throughput of the WDM-PON network, greatly reduce the system time delay and energy consumption.

Dissolution of short and long rockwool and glasswool fibers by macrophages in flowthrough cell culture.

Science.gov (United States)

Luoto, K; Holopainen, M; Kangas, J; Kalliokoski, P; Savolainen, K

1998-07-01

Dissolution of MMVF (man-made vitreous fibers) by macrophages has previously been studied utilizing cell cultures in wells. A new, more dynamic method has been developed to explore the effects of macrophages on MMVF dissolution. In this method, the culture medium flows through a membrane on which the macrophages and fibers are placed. The dissolution of short and long rockwool and glasswool fibers was investigated in the present study by macrophages by assessing the dissolution of Si (silicon), Fe (iron), and Al (aluminium) from the fibers. Dissolution of these elements usually increased as a function of time. Generally, the dissolution of elements from the fibers in the flowthrough culture exceeded that observed with the culture in wells system. The dissolution of glasswool fibers was greater in medium than in cell culture, whereas the opposite was true for rockwool fibers. Dissolution of Si was greater from glasswool than from rockwool fibers, while the opposite was true for Fe and Al. Macrophages that had phagocytized fibers in flowthrough culture contained Si, and there were also precipitations with Si in the samples. The fibers in the flowthrough culture also exhibited surface changes such as breakings, pittings, etching, and peeling. The short rockwool fibers tended to fracture more than short glasswool fibers, while long glasswool fibers were more extensively broken than short glasswool fibers. The results with this new, dynamic, flowthrough culture method with macrophages demonstrate that this method provides valuable information on the abilities of macrophages to dissolve MMVF leading to subsequent morphological changes of fibers.

Parametric design studies of long-reach manipulators

International Nuclear Information System (INIS)

Kwon, D.S.; March-Leuba, S.; Babcock, S.M.; Burks, B.L.; Hamel, W.R.

1993-01-01

A number of different approaches have been studied for remediation of waste storage tanks at various sites. One of the most promising approaches is the use of a high-capacity, long-reach manipulation (LRM) system with a variety of end effectors for dislodging the waste. LRMs may have characteristics significantly different from those of industrial robots due to the long links needed to cover the large workspace. Because link lengths are much greater than their diameters, link flexibility, as well as joint or drive train flexibility, is likely to be significant. LRMs will be required for a variety of applications in the Environmental Restoration and Waste Management Program. While each application will present specific functional, kinematic, and performance requirements, a design approach for determining the kinematic applicability and performance characteristics considering link flexibility is presented with a focus on waste storage tank remediation. This paper addresses key design issues for LRM-based waste retrieval systems. It discusses the effects of parameters such as payload capacity, storage tanks size, and access port diameter on manipulator structural design. The estimated weight, fundamental natural frequency, and static deflection of the manipulator have been calculated for various parameter conditions

Wavelength division multiplexing a practical engineering guide

CERN Document Server

Grobe, Klaus

2013-01-01

In this book, Optical Wavelength Division Multiplexing (WDM) is approached from a strictly practical and application-oriented point of view. Based on the characteristics and constraints of modern fiber-optic components, transport systems and fibers, the text provides relevant rules of thumb and practical hints for technology selection, WDM system and link dimensioning, and also for network-related aspects such as wavelength assignment and resilience mechanisms. Actual 10/40 Gb/s WDM systems are considered, and a preview of the upcoming 100 Gb/s systems and technologies for even higher bit rate

White Rabbit Precision Time Protocol on Long-Distance Fiber Links.

Science.gov (United States)

Dierikx, Erik F; Wallin, Anders E; Fordell, Thomas; Myyry, Jani; Koponen, Petri; Merimaa, Mikko; Pinkert, Tjeerd J; Koelemeij, Jeroen C J; Peek, Henk Z; Smets, Rob

2016-07-01

The application of White Rabbit precision time protocol (WR-PTP) in long-distance optical fiber links has been investigated. WR-PTP is an implementation of PTP in synchronous Ethernet optical fiber networks, originally intended for synchronization of equipment within a range of 10 km. This paper discusses the results and limitations of two implementations of WR-PTP in the existing communication fiber networks. A 950-km WR-PTP link was realized using unidirectional paths in a fiber pair between Espoo and Kajaani, Finland. The time transfer on this link was compared (after initial calibration) against a clock comparison by GPS precise point positioning (PPP). The agreement between the two methods remained within [Formula: see text] over three months of measurements. Another WR-PTP implementation was realized between Delft and Amsterdam, the Netherlands, by cascading two links of 137 km each. In this case, the WR links were realized as bidirectional paths in single fibers. The measured time offset between the starting and end points of the link was within 5 ns with an uncertainty of 8 ns, mainly due to the estimated delay asymmetry caused by chromatic dispersion.

A reconfigurable all-optical VPN based on XGM effect of SOA in WDM PON

Science.gov (United States)

Hu, Xiaofeng; Zhang, Liang; Cao, Pan; Wang, Tao; Su, Yikai

2010-12-01

We propose and experimentally demonstrate a reconfigurable all-optical VPN scheme enabling intercommunications among different ONUs in a WDM PON. Reconfiguration is realized by dynamically setting wavelength conversion of optical VPN signal using a SOA in the OLT.

From Process Modeling to Elastic Property Prediction for Long-Fiber Injection-Molded Thermoplastics

International Nuclear Information System (INIS)

Nguyen, Ba Nghiep; Kunc, Vlastimil; Frame, Barbara J.; Phelps, Jay; Tucker III, Charles L.; Bapanapalli, Satish K.; Holbery, James D.; Smith, Mark T.

2007-01-01

This paper presents an experimental-modeling approach to predict the elastic properties of long-fiber injection-molded thermoplastics (LFTs). The approach accounts for fiber length and orientation distributions in LFTs. LFT samples were injection-molded for the study, and fiber length and orientation distributions were measured at different locations for use in the computation of the composite properties. The current fiber orientation model was assessed to determine its capability to predict fiber orientation in LFTs. Predicted fiber orientations for the studied LFT samples were also used in the calculation of the elastic properties of these samples, and the predicted overall moduli were then compared with the experimental results. The elastic property prediction was based on the Eshelby-Mori-Tanaka method combined with the orientation averaging technique. The predictions reasonably agree with the experimental LFT data

Fiber laser with combined feedback of core and cladding modes assisted by an intracavity long-period grating.

Science.gov (United States)

Sáez-Rodriguez, D; Cruz, J L; Díez, A; Andrés, M V

2011-05-15

We present a fiber laser made in a single piece of conventional doped-core fiber that operates by combined feedback of the fundamental core mode LP((0,1)) and the high-order cladding mode LP((0,10)). The laser is an all-fiber structure that uses two fiber Bragg gratings and a long-period grating to select the modes circulating in the cavity; the laser emits at the coupling wavelength between the core mode LP((0,1)) and the counterpropagating cladding mode LP((0,10)) in the Bragg gratings. This work demonstrates the feasibility of high-order mode fiber lasers assisted by long-period gratings. © 2011 Optical Society of America

Short-pulse propagation in fiber optical parametric amplifiers

DEFF Research Database (Denmark)

Cristofori, Valentina

Fiber optical parametric amplifiers (FOPAs) are attractive because they can provide large gain over a broad range of central wavelengths, depending only on the availability of a suitable pump laser. In addition, FOPAs are suitable for the realization of all-optical signal processing functionalities...... transfer can be reduced in saturated F OPAs. In order to characterize propagation impairments such as dispersion and Kerr effect, affecting signals reaching multi-terabit per second per channel, short pulses on the order of 500 fs need to be considered. Therefore, a short pulses fiber laser source...... is implemented to obtain an all-fiber system. The advantages of all fiber-systems are related to their reliability, long-term stability and compactness. Fiber optical parametric chirped pulse amplification is promising for the amplification of such signals thanks to the inherent compatibility of FOPAs with fiber...

Optical fiber cabling technologies for flexible access network

Science.gov (United States)

Tanji, Hisashi

2008-07-01

Fiber-to-the-home (FTTH) outside plant infrastructure should be so designed and constructed as to flexibly deal with increasing subscribers and system evolution to be expected in the future, taking minimization of total cost (CAPEX and OPEX) into consideration. With this in mind, fiber access architectures are reviewed and key technologies on optical fiber and cable for supporting flexible access network are presented. Low loss over wide wavelength (low water peak) and bend-insensitive single mode fiber is a future proof solution. Enhanced separable ribbon facilitates mid-span access to individual fibers in a cable installed, improving fiber utilizing efficiency and flexibility of distribution design. It also contributes to an excellent low PMD characteristic which could be required for video RF overlay system or high capacity long reach metro-access convergence network in the future. Bend-insensitive fiber based cabling technique including field installable connector greatly improves fiber/cable handling in installation and maintenance work.

US long distance fiber optic networks: Technology, evolution and advanced concepts. Volume 3: Advanced networks and economics

Science.gov (United States)

1986-10-01

This study projects until 2000 the evolution of long distance fiber optic networks in the U.S. Volume 1 is the executive Summary. Volume 2 focuses on fiber optic components and systems that are directly related to the operation of long-haul networks. Optimistic, pessimistic and most likely scenarios of technology development are presented. The activities of national and regional companies implementing fiber long haul networks are also highlighted, along with an analysis of the market and regulatory forces affecting network evolution. Volume 3 presents advanced fiber optic network concept definitions. Inter-LATA traffic is quantified and forms the basis for the construction of 11-, 15-, 17-, and 23-node networks. Using the technology projections from Volume 2, a financial model identifies cost drivers and determines circuit mile costs between any two LATAs. A comparison of fiber optics with alternative transmission concludes the report.

Cost and Availability Analysis of 2- and 3-Connected WDM Networks Physical Interconnection

DEFF Research Database (Denmark)

Gutierrez Lopez, Jose Manuel; Riaz, M. Tahir; Pedersen, Jens Myrup

2012-01-01

for the best trade-off among the relevant parameters for the network. In this paper we analyze this trade-off by studying 2-and 3-connected graphs to be used as WDM (Wavelength Division Multiplexing) networks physical infrastructure. The experiments show how the way links are distributed to interconnect...

Bending Characteristics Change of Long-Period fiber Grating due to Co-doping of Boron for Optical fiber Sensors

International Nuclear Information System (INIS)

Moon, Dae Seung; Chung, Young Joo

2005-01-01

In long-period fiber grating (LPFG) to be made up optical fiber sensors, resonance coupling occurs between the forward-propagating core mode and cladding modes at the wavelength that satisfy the Phase matching condition. The resonance wavelength and the coupling strength depends strongly on the external environment like temperature, strain, and ambient index. These characteristics can be utilized for various applications as optical fiber sensors. Fabrication of optical fiber gratings is typically based on the photosensitivity effect, i.e. the permanent change of the refractive index upon irradiation of the UV beam, and therefore, fabrication of the optical fiber with high phososensitivity is an important part of the research on optical fiber gratings. In this work, we measured the effort of to-doping of boron on the index difference between the core and cladding of the optical fiber and the sensitivity of the LPFC to the temperature and bending changes. We observed that the index difference between the core and the cladding decreased by (1.69x10 -4 /SCCM) and the temperature sensitivity of the resonance wavelength shirt decreased by (0.01145nm/ .deg. C/SCCM). The dependence or the bending-induced changes or the transmission characteristics of LPFG on the tore-cladding index difference was investigated experimentally. The measurement results indicate that the bending sensitivity increases as the index difference decreases

16 channel WDM regeneration in a single phase-sensitive amplifier through optical Fourier transformation

DEFF Research Database (Denmark)

Guan, Pengyu; Da Ros, Francesco; Lillieholm, Mads

2016-01-01

We demonstrate simultaneous phase regeneration of 16-WDM DPSK channels using optical Fourier transformation and a single phase-sensitive amplifier. The BERs of 16-WDM×10-Gbit/s phase noise degraded DPSK signals are improved by 0.4-1.3 orders of magnitude...

3D tomodosimetry using long scintillating fibers: A feasibility study

International Nuclear Information System (INIS)

Goulet, Mathieu; Archambault, Louis; Beaulieu, Luc; Gingras, Luc

2013-01-01

Purpose: 3D dosimetry is recognized as an ideal for patient-specific quality assurance (QA) of highly conformal radiotherapy treatments. However, existing 3D dosimeters are not straightforward to implement in the clinic, as their read-out procedure is often tedious and their accuracy, precision, and/or sample size exhibit limitations. The purpose of this work is to develop a 3D dosimeter based on the concept of tomodosimetry inside concentric cylindrical planes using long scintillating fibers for the QA of modern radiotherapy techniques such as intensity-modulated radiation therapy (IMRT) or intensity-modulated arc therapy (IMAT).Methods: Using a model-based simulation, scintillating fibers were modeled on three concentric cylindrical planes of radii 2.5, 5.0, and 7.5 cm, inside a 10 cm radius water-equivalent cylinder phantom. The phantom was set to rotate around its central axis, made parallel to the linac gantry axis of rotation. Light acquisitions were simulated using the calculated dose from the treatment planning software and reconstructed in each cylindrical plane at a resolution of 1 mm 2 using a total-variation minimization iterative reconstruction algorithm. The 3D dose was then interpolated from the reconstructed cylindrical plane doses at a resolution of 1 mm 3 . Different scintillating fiber patterns were compared by varying the angle of each fiber in its cylindrical plane and introducing a light-tight cut in each fiber. The precision of the reconstructed cylindrical dose distribution was evaluated using a Poisson modeling of the acquired light signals and the accuracy of the interpolated 3D dose was evaluated using an IMRT clinical plan for a prostate case.Results: Straight scintillating fiber patterns with light-tight cuts were the most accurate in cylindrical dose reconstruction, showing less than 0.5 mm distance-to-agreement in dose gradients and a mean local dose difference of less than 0.2% in the high dose region for a 10 × 10 cm 2 field. The

Combined long reach and dexterous manipulation for waste storage tank applications

International Nuclear Information System (INIS)

Burks, B.L.; Armstrong, G.A.; Butler, P.L.; Boissiere, P.

1991-01-01

One of the highest priority environmental restoration tasks within the Department of Energy (DOE) is the remediation of single-shell waste storage tanks (WSTs), especially those suspected of, or documented as, leakers. Most currently proposed approaches for remediation of large underground WSTs require application of remotely operated long-reach (greater than 10 m), high-lift capacity (greater than 200 kg) manipulator systems. Because of the complexity of in-tank hardware, waste forms, remediation tasks, and variety of end-effector tools, these manipulator systems must also be capable of performing a diverse set of dexterous manipulations. This presentation will describe the integration of a Spar RMS 2500 manipulator system, a Schilling Titan-7F manipulator, and control systems developed at ORNL and SNL to provide a combined long reach and dexterous manipulation system. The purpose of integrating these two manipulator systems was to study and demonstrate their combined performance, evaluate design requirements for a deployed system, and provide a testbed for control and end-effector technologies that might be applicable to remediation of WSTs. 5 refs

Performance evaluation of coherent WDM PS-QPSK (HEXA) accounting for non-linear fiber propagation effects.

Science.gov (United States)

Poggiolini, P; Bosco, G; Carena, A; Curri, V; Forghieri, F

2010-05-24

Coherent-detection (CoD) permits to fully exploit the four-dimensional (4D) signal space consisting of the in-phase and quadrature components of the two fiber polarizations. A well-known and successful format exploiting such 4D space is Polarization-multiplexed QPSK (PM-QPSK). Recently, new signal constellations specifically designed and optimized in 4D space have been proposed, among which polarization-switched QPSK (PS-QPSK), consisting of a 8-point constellation at the vertices of a 4D polychoron called hexadecachoron. We call it HEXA because of its geometrical features and to avoid acronym mix-up with PM-QPSK, as well as with other similar acronyms. In this paper we investigate the performance of HEXA in direct comparison with PM-QPSK, addressing non-linear propagation over realistic links made up of 20 spans of either standard single mode fiber (SSMF) or non-zero dispersion-shifted fiber (NZDSF). We show that HEXA not only confirms its theoretical sensitivity advantage over PM-QPSK in back-to-back, but also shows a greater resilience to non-linear effects, allowing for substantially increased span loss margins. As a consequence, HEXA appears as an interesting option for dual-format transceivers capable to switch on-the-fly between PM-QPSK and HEXA when channel propagation degrades. It also appears as a possible direct competitor of PM-QPSK, especially over NZDSF fiber and uncompensated links.

Performance Analysis of a Threshold-Based Parallel Multiple Beam Selection Scheme for WDM FSO Systems

KAUST Repository

Nam, Sung Sik; Alouini, Mohamed-Slim; Ko, Young-Chai

2018-01-01

In this paper, we statistically analyze the performance of a threshold-based parallel multiple beam selection scheme for a free-space optical (FSO) based system with wavelength division multiplexing (WDM) in cases where a pointing error has occurred

Sensitivity of a long-period optical fiber grating bend sensor

DEFF Research Database (Denmark)

Rathje, Jacob; Svalgaard, Mikael; Hübner, Jörg

1998-01-01

We have investigated the sensitivity of long-period fiber gratings used in curvature measuring fibre optic sensors and found a bend coefficient of 0.77 dB cm/mrad. In the current setup this corresponds to the ability of detecting curvatures with a radius up to approximately 200 m...

Design and implementation of flexible TWDM-PON with PtP WDM overlay based on WSS for next-generation optical access networks

Science.gov (United States)

Wu, Bin; Yin, Hongxi; Qin, Jie; Liu, Chang; Liu, Anliang; Shao, Qi; Xu, Xiaoguang

2016-09-01

Aiming at the increasing demand of the diversification services and flexible bandwidth allocation of the future access networks, a flexible passive optical network (PON) scheme combining time and wavelength division multiplexing (TWDM) with point-to-point wavelength division multiplexing (PtP WDM) overlay is proposed for the next-generation optical access networks in this paper. A novel software-defined optical distribution network (ODN) structure is designed based on wavelength selective switches (WSS), which can implement wavelength and bandwidth dynamical allocations and suits for the bursty traffic. The experimental results reveal that the TWDM-PON can provide 40 Gb/s downstream and 10 Gb/s upstream data transmission, while the PtP WDM-PON can support 10 GHz point-to-point dedicated bandwidth as the overlay complement system. The wavelengths of the TWDM-PON and PtP WDM-PON are allocated dynamically based on WSS, which verifies the feasibility of the proposed structure.

Turbo Equalization Techniques Toward Robust PDM 16-QAM Optical Fiber Transmission

DEFF Research Database (Denmark)

Arlunno, Valeria; Caballero Jambrina, Antonio; Borkowski, Robert

2014-01-01

In this paper, we show numerically and experimentally that turbo equalization (TE) is an efficient technique to mitigate performance degradations stemming from optical fiber propagation effects in both optical fiber dispersion managed and unmanaged coherent detection links. The effectiveness....... As TE can be included in the current coherent detection transceiver technologies and complement other equalization techniques, it has prospects for application in next-generation high-capacity and long-reach optical transmission links....

Recording of long-period gratings in special single-mode fibers by a CO2 laser

International Nuclear Information System (INIS)

Cisarovsky, Petr; Dunovsky, Jiri; Kolarik, Ladislav; Todorov, Filip; Kasik, Ivan; Matejec, Vlastimil

2006-01-01

The paper deals with the fabrication of long-period gratings (LPG) in special optical fibers with an inverted parabolic-index profile of the cladding by periodically exposing the fibers to radiation of a high-power CO 2 laser. Details on the fiber fabrication and preparation of LPGs with a period of about 1 mm in the fibers are presented. The fabricated LPGs were evaluated on the basis of their transmission spectra determined by measuring the output spectral density of the fiber with the LPGs. It is shown that the position of the band and its strength depend on the laser beam velocity, beam power and the interaction time of radiation with the fiber

High-power ultralong-wavelength Tm-doped silica fiber laser cladding-pumped with a random distributed feedback fiber laser.

Science.gov (United States)

Jin, Xiaoxi; Du, Xueyuan; Wang, Xiong; Zhou, Pu; Zhang, Hanwei; Wang, Xiaolin; Liu, Zejin

2016-07-15

We demonstrated a high-power ultralong-wavelength Tm-doped silica fiber laser operating at 2153 nm with the output power exceeding 18 W and the slope efficiency of 25.5%. A random distributed feedback fiber laser with the center wavelength of 1173 nm was employed as pump source of Tm-doped fiber laser for the first time. No amplified spontaneous emissions or parasitic oscillations were observed when the maximum output power reached, which indicates that employing 1173 nm random distributed feedback fiber laser as pump laser is a feasible and promising scheme to achieve high-power emission of long-wavelength Tm-doped fiber laser. The output power of this Tm-doped fiber laser could be further improved by optimizing the length of active fiber, reflectivity of FBGs, increasing optical efficiency of pump laser and using better temperature management. We also compared the operation of 2153 nm Tm-doped fiber lasers pumped with 793 nm laser diodes, and the maximum output powers were limited to ~2 W by strong amplified spontaneous emission and parasitic oscillation in the range of 1900-2000 nm.

Preparing to reach: selecting an adaptive long-latency feedback controller

OpenAIRE

Ahmadi-Pajouh, Mohammad Ali; Towhidkhah, Farzad; Shadmehr, Reza

2012-01-01

In a voluntary movement, the nervous system specifies not only the motor commands, but also the gains associated with reaction to sensory feedback. For example, suppose that during reaching a perturbation tends to push the hand to the left. With practice, the brain not only learns to produce commands that predictively compensate for the perturbation, but also increases the long-latency reflex gain associated with leftward displacements of the arm. That is, the brain learns a feedback controll...

Long-Period Gratings in Highly Germanium-Doped, Single-Mode Optical Fibers for Sensing Applications

Science.gov (United States)

Schlangen, Sebastian; Bremer, Kort; Zheng, Yulong; Böhm, Sebastian; Steinke, Michael; Wellmann, Felix; Neumann, Jörg; Overmeyer, Ludger

2018-01-01

Long-period fiber gratings (LPGs) are well known for their sensitivity to external influences, which make them interesting for a large number of sensing applications. For these applications, fibers with a high numerical aperture (i.e., fibers with highly germanium (Ge)-doped fused silica fiber cores) are more attractive since they are intrinsically photosensitive, as well as less sensitive to bend- and microbend-induced light attenuations. In this work, we introduce a novel method to inscribe LPGs into highly Ge-doped, single-mode fibers. By tapering the optical fiber, and thus, tailoring the effective indices of the core and cladding modes, for the first time, an LPG was inscribed into such fibers using the amplitude mask technique and a KrF excimer laser. Based on this novel method, sensitive LPG-based fiber optic sensors only a few millimeters in length can be incorporated in bend-insensitive fibers for use in various monitoring applications. Moreover, by applying the described inscription method, the LPG spectrum can be influenced and tailored according to the specific demands of a particular application. PMID:29702600

Long-Period Gratings in Highly Germanium-Doped, Single-Mode Optical Fibers for Sensing Applications

Directory of Open Access Journals (Sweden)

Sebastian Schlangen

2018-04-01

Full Text Available Long-period fiber gratings (LPGs are well known for their sensitivity to external influences, which make them interesting for a large number of sensing applications. For these applications, fibers with a high numerical aperture (i.e., fibers with highly germanium (Ge-doped fused silica fiber cores are more attractive since they are intrinsically photosensitive, as well as less sensitive to bend- and microbend-induced light attenuations. In this work, we introduce a novel method to inscribe LPGs into highly Ge-doped, single-mode fibers. By tapering the optical fiber, and thus, tailoring the effective indices of the core and cladding modes, for the first time, an LPG was inscribed into such fibers using the amplitude mask technique and a KrF excimer laser. Based on this novel method, sensitive LPG-based fiber optic sensors only a few millimeters in length can be incorporated in bend-insensitive fibers for use in various monitoring applications. Moreover, by applying the described inscription method, the LPG spectrum can be influenced and tailored according to the specific demands of a particular application.

Gain transient control for wavelength division multiplexed access networks using semiconductor optical amplifiers

DEFF Research Database (Denmark)

Gibbon, Timothy Braidwood; Osadchiy, Alexey Vladimirovich; Kjær, Rasmus

2009-01-01

Gain transients can severely hamper the upstream network performance in wavelength division multiplexed (WDM) access networks featuring erbium doped fiber amplifiers (EDFAs) or Raman amplification. We experimentally demonstrate for the first time using 10 Gb/s fiber transmission bit error rate...... measurements how a near-saturated semiconductor optical amplifier (SOA) can be used to control these gain transients. An SOA is shown to reduce the penalty of transients originating in an EDFA from 2.3 dB to 0.2 dB for 10 Gb/s transmission over standard single mode fiber using a 231-1 PRBS pattern. The results...... suggest that a single SOA integrated within a WDM receiver at the metro node could offer a convenient all-optical solution for upstream transient controlin WDM access networks....

Fiber optical parametric amplifiers in optical communication systems

Science.gov (United States)

Marhic (†), Michel E; Andrekson, Peter A; Petropoulos, Periklis; Radic, Stojan; Peucheret, Christophe; Jazayerifar, Mahmoud

2015-01-01

The prospects for using fiber optical parametric amplifiers (OPAs) in optical communication systems are reviewed. Phase-insensitive amplifiers (PIAs) and phase-sensitive amplifiers (PSAs) are considered. Low-penalty amplification at/or near 1 Tb/s has been achieved, for both wavelength- and time-division multiplexed formats. High-quality mid-span spectral inversion has been demonstrated at 0.64 Tb/s, avoiding electronic dispersion compensation. All-optical amplitude regeneration of amplitude-modulated signals has been performed, while PSAs have been used to demonstrate phase regeneration of phase-modulated signals. A PSA with 1.1-dB noise figure has been demonstrated, and preliminary wavelength-division multiplexing experiments have been performed with PSAs. 512 Gb/s have been transmitted over 6,000 km by periodic phase conjugation. Simulations indicate that PIAs could reach data rate x reach products in excess of 14,000 Tb/s × km in realistic wavelength-division multiplexed long-haul networks. Technical challenges remaining to be addressed in order for fiber OPAs to become useful for long-haul communication networks are discussed. PMID:25866588

Fiber Pulling Apparatus

Science.gov (United States)

Workman, Gary L.; Smith, Guy A.; OBrien, Sue; Adcock, Leonard

1998-01-01

The fiber optics industry has grown into a multi-billion marketplace that will continue to grow into the 21st century. Optical fiber communications is currently dominated by silica glass technology. Successful efforts to improve upon the low loss transmission characteristics of silica fibers have propelled the technology into the forefront of the communications industry. However, reaching the theoretical transmission capability of silica fiber through improved processing has still left a few application areas in which other fiber systems can provide an influential role due to specific characteristics of high theoretical transmission in the 2 - 3 micron wavelength region. One of the other major materials used for optical fibers is the systems based upon Heavy Metal Fluoride Glass (HMFG). Commercial interest is driven primarily by the potential for low loss repeaterless infrared fibers. An example of the major communications marketplace which would benefit from the long distance repeaterless capability of infrared fibers is the submarine cables which link the continents. When considering commercial interests, optical fiber systems provide a healthy industrial position which continues to expand. Major investments in the systems used for optical fiber communications have continued to increase each year and are predicted to continue well into the next century. Estimates of 8.5% compounded annually are predicted through 1999 for the North American market and 1 1 % worldwide. The growth for the optical fiber cable itself is expected to continue between 44 and 50 per cent of the optical fiber communications budget through 1999. The total budget in 1999 world-wide is expected to be in the neighborhood of $9 billion. Another survey predicts that long haul telecommunications represents 15% of a world-wide fiber optics market in 1998. The actual amount allotted to cable was not specified. However, another market research had predicted that the cable costs alone represents more

A packaged, low-cost, robust optical fiber strain sensor based on small cladding fiber sandwiched within periodic polymer grating.

Science.gov (United States)

Chiang, Chia-Chin; Li, Chein-Hsing

2014-06-02

In the present study, a novel packaged long-period fiber grating (PLPFG) strain sensor is first presented. The MEMS process was utilized to fabricate the packaged optical fiber strain sensor. The sensor structure consisted of etched optical fiber sandwiched between two layers of thick photoresist SU-8 3050 and then packaged with poly (dimethylsiloxane) (PDMS) polymer material to construct the PLPFG strain sensor. The PDMS packaging material was used to prevent the glue effect, wherein glue flows into the LPFG structure and reduces coupling strength, in the surface bonding process. Because the fiber grating was packaged with PDMS material, it was effectively protected and made robust. The resonance attenuation dip of PLPFG grows when it is loading. This study explored the size effect of the grating period and fiber diameter of PLPFG via tensile testing. The experimental results found that the best strain sensitivity of the PLPFG strain sensor was -0.0342 dB/με, and that an R2 value of 0.963 was reached.

Long-range distributed optical fiber hot-wire anemometer based on chirped-pulse ΦOTDR.

Science.gov (United States)

Garcia-Ruiz, Andres; Dominguez-Lopez, Alejandro; Pastor-Graells, Juan; Martins, Hugo F; Martin-Lopez, Sonia; Gonzalez-Herraez, Miguel

2018-01-08

We demonstrate a technique allowing to develop a fully distributed optical fiber hot-wire anemometer capable of reaching a wind speed uncertainty of ≈ ±0.15m/s (±0.54km/h) at only 60 mW/m of dissipated power in the sensing fiber, and within only four minutes of measurement time. This corresponds to similar uncertainty values than previous papers on distributed optical fiber anemometry but requires two orders of magnitude smaller dissipated power and covers at least one order of magnitude longer distance. This breakthrough is possible thanks to the extreme temperature sensitivity and single-shot performance of chirped-pulse phase-sensitive optical time domain reflectometry (ΦOTDR), together with the availability of metal-coated fibers. To achieve these results, a modulated current is fed through the metal coating of the fiber, causing a modulated temperature variation of the fiber core due to Joule effect. The amplitude of this temperature modulation is strongly dependent on the wind speed at which the fiber is subject. Continuous monitoring of the temperature modulation along the fiber allows to determine the wind speed with singular low power injection requirements. Moreover, this procedure makes the system immune to temperature drifts of the fiber, potentially allowing for a simple field deployment. Being a much less power-hungry scheme, this method also allows for monitoring over much longer distances, in the orders of 10s of km. We expect that this system can have application in dynamic line rating and lateral wind monitoring in railway catenary wires.

Transfer function of radio over fiber multimode fiber optic links considering third-order dispersion.

Science.gov (United States)

Capmany, J; Gasulla, Ivana

2007-08-20

Although a considerable number of multimode fiber (MMF) links operate in a wavelength region around 850 nm where chromatic dispersion of a given modal group mu is described adequately by the second derivative beta(mu) (2) of the propagation constant beta(mu)(omega), there is also an increasing interest in MMF links transmitting in the second spectral window (@1300nm) where this second derivative vanishes being thus necessary to consider the third derivative beta(mu) (3) in the evaluation of the transfer function of the multimode fiber link. We present in this paper, for the first time to our knowledge, an analytical model for the transfer function of a multimode fiber (MMF) optic link taken into account the impact of third-order dispersion. The model extends the operation of a previously reported one for second-order dispersion. Our results show that the performance of broadband radio over fiber transmission through middle-reach distances can be improved by working at the minimum-dispersion wavelength as long as low-linewidth lasers are employed.

A differential detection scheme of spectral shifts in long-period fiber gratings

Science.gov (United States)

Zhelyazkova, Katerina; Eftimov, Tinko; Smietana, Mateusz; Bock, Wojtek

2010-10-01

In this work we present an analysis of the response of a compact, simple and inexpensive optoelectronic sensor system intended to detect spectral shifts of a long-period fiber grating (LPG). The system makes use of a diffraction grating and a couple of receiving optical fibers that pick up signals at two different wavelengths. This differential detection system provides the same useful information from an LPG-based sensor as with a conventional laboratory system using optical spectrum analyzers for monitoring the minimum offset of LPG. The design of the fiber detection pair as a function of the parameters of the dispersion grating, the pick-up fiber and the LPG parameters, is presented in detail. Simulation of the detection system responses is presented using real from spectral shifts in nano-coated LPGs caused by the evaporation of various liquids such as water, ethanol and acetone, which are examples of corrosive, flammable and hazardous substances. Fiber optic sensors with similar detection can find applications in structural health monitoring for moisture detection, monitoring the spillage of toxic and flammable substances in industry etc.

Optical pulse multiplication and temporal coding using true time delay achieved by long-period fiber gratings in dispersion compensating fiber.

Science.gov (United States)

Eom, Tae Joong; Kim, Sun-Jong; Kim, Tae-Young; Park, Chang-Soo; Lee, Byeong

2004-12-27

We present an optical pulse multiplication and a temporal coding method for OCDMA systems. The true time delay among the pulses was obtained by utilizing the difference in the propagation speeds of the core and the co-propagating cladding modes coupled by long-period fiber gratings. By cascadin gratings we could get an equally spaced 40 GHz pulse train from a 10 GHz train. Various coding and decoding of a pulse train were possible by controlling the separations among the gratings. The dispersion compensating fiber having an inner cladding structure enabled to have the gratings that were not sensitive to the polymer jacket of the fiber and allowed shortening the device length.

Gossypium barbadense genome sequence provides insight into the evolution of extra-long staple fiber and specialized metabolites.

Science.gov (United States)

Liu, Xia; Zhao, Bo; Zheng, Hua-Jun; Hu, Yan; Lu, Gang; Yang, Chang-Qing; Chen, Jie-Dan; Chen, Jun-Jian; Chen, Dian-Yang; Zhang, Liang; Zhou, Yan; Wang, Ling-Jian; Guo, Wang-Zhen; Bai, Yu-Lin; Ruan, Ju-Xin; Shangguan, Xiao-Xia; Mao, Ying-Bo; Shan, Chun-Min; Jiang, Jian-Ping; Zhu, Yong-Qiang; Jin, Lei; Kang, Hui; Chen, Shu-Ting; He, Xu-Lin; Wang, Rui; Wang, Yue-Zhu; Chen, Jie; Wang, Li-Jun; Yu, Shu-Ting; Wang, Bi-Yun; Wei, Jia; Song, Si-Chao; Lu, Xin-Yan; Gao, Zheng-Chao; Gu, Wen-Yi; Deng, Xiao; Ma, Dan; Wang, Sen; Liang, Wen-Hua; Fang, Lei; Cai, Cai-Ping; Zhu, Xie-Fei; Zhou, Bao-Liang; Jeffrey Chen, Z; Xu, Shu-Hua; Zhang, Yu-Gao; Wang, Sheng-Yue; Zhang, Tian-Zhen; Zhao, Guo-Ping; Chen, Xiao-Ya

2015-09-30

Of the two cultivated species of allopolyploid cotton, Gossypium barbadense produces extra-long fibers for the production of superior textiles. We sequenced its genome (AD)2 and performed a comparative analysis. We identified three bursts of retrotransposons from 20 million years ago (Mya) and a genome-wide uneven pseudogenization peak at 11-20 Mya, which likely contributed to genomic divergences. Among the 2,483 genes preferentially expressed in fiber, a cell elongation regulator, PRE1, is strikingly At biased and fiber specific, echoing the A-genome origin of spinnable fiber. The expansion of the PRE members implies a genetic factor that underlies fiber elongation. Mature cotton fiber consists of nearly pure cellulose. G. barbadense and G. hirsutum contain 29 and 30 cellulose synthase (CesA) genes, respectively; whereas most of these genes (>25) are expressed in fiber, genes for secondary cell wall biosynthesis exhibited a delayed and higher degree of up-regulation in G. barbadense compared with G. hirsutum, conferring an extended elongation stage and highly active secondary wall deposition during extra-long fiber development. The rapid diversification of sesquiterpene synthase genes in the gossypol pathway exemplifies the chemical diversity of lineage-specific secondary metabolites. The G. barbadense genome advances our understanding of allopolyploidy, which will help improve cotton fiber quality.

Fiber-wireless convergence in next-generation communication networks systems, architectures, and management

CERN Document Server

Chang, Gee-Kung; Ellinas, Georgios

2017-01-01

This book investigates new enabling technologies for Fi-Wi convergence. The editors discuss Fi-Wi technologies at the three major network levels involved in the path towards convergence: system level, network architecture level, and network management level. The main topics will be: a. At system level: Radio over Fiber (digitalized vs. analogic, standardization, E-band and beyond) and 5G wireless technologies; b. Network architecture level: NGPON, WDM-PON, BBU Hotelling, Cloud Radio Access Networks (C-RANs), HetNets. c. Network management level: SDN for convergence, Next-generation Point-of-Presence, Wi-Fi LTE Handover, Cooperative MultiPoint. • Addresses the Fi-Wi convergence issues at three different levels, namely at the system level, network architecture level, and network management level • Provides approaches in communication systems, network architecture, and management that are expected to steer the evolution towards fiber-wireless convergence • Contributions from leading experts in the field of...

Silicon photonics WDM transmitter with single section semiconductor mode-locked laser

Science.gov (United States)

Müller, Juliana; Hauck, Johannes; Shen, Bin; Romero-García, Sebastian; Islamova, Elmira; Azadeh, Saeed Sharif; Joshi, Siddharth; Chimot, Nicolas; Moscoso-Mártir, Alvaro; Merget, Florian; Lelarge, François; Witzens, Jeremy

2015-04-01

We demonstrate a wavelength domain-multiplexed (WDM) optical link relying on a single section semiconductor mode-locked laser (SS-MLL) with quantum dash (Q-Dash) gain material to generate 25 optical carriers spaced by 60.8 GHz, as well as silicon photonics (SiP) resonant ring modulators (RRMs) to modulate individual optical channels. The link requires optical reamplification provided by an erbium-doped fiber amplifier (EDFA) in the system experiments reported here. Open eye diagrams with signal quality factors (Q-factors) above 7 are measured with a commercial receiver (Rx). For higher compactness and cost effectiveness, reamplification of the modulated channels with a semiconductor optical amplifier (SOA) operated in the linear regime is highly desirable. System and device characterization indicate compatibility with the latter. While we expect channel counts to be primarily limited by the saturation output power level of the SOA, we estimate a single SOA to support more than eight channels. Prior to describing the system experiments, component design and detailed characterization results are reported including design and characterization of RRMs, ring-based resonant optical add-drop multiplexers (RR-OADMs) and thermal tuners, S-parameters resulting from the interoperation of RRMs and RR-OADMs, and characterization of Q-Dash SS-MLLs reamplified with a commercial SOA. Particular emphasis is placed on peaking effects in the transfer functions of RRMs and RR-OADMs resulting from transient effects in the optical domain, as well as on the characterization of SS-MLLs in regard to relative intensity noise (RIN), stability of the modes of operation, and excess noise after reamplification.

System for testing optical fibers

Science.gov (United States)

Golob, John E. [Olathe, KS; Looney, Larry D. [Los Alamos, NM; Lyons, Peter B. [Los Alamos, NM; Nelson, Melvin A. [Santa Barbara, CA; Davies, Terence J. [Santa Barbara, CA

1980-07-15

A system for measuring a combination of optical transmission properties of fiber optic waveguides. A polarized light pulse probe is injected into one end of the optical fiber. Reflections from discontinuities within the fiber are unpolarized whereas reflections of the probe pulse incident to its injection remain polarized. The polarized reflections are prevented from reaching a light detector whereas reflections from the discontinuities reaches the detector.

Survivability and Impairment-aware Routing in Optical Networks : An Algorithmic Study

NARCIS (Netherlands)

Beshir, A.A.

2011-01-01

Optical networks employing Wavelength Division Multiplexing (WDM) technology allow the multiplexing of several independent wavelength channels into a fiber. Since each wavelength channel operates independently at several Gb/s, WDM optical networks offer a tremendous transport capacity (which is in

Experimental Study of Nonlinear Phase Noise and its Impact on WDM Systems with DP-256QAM

DEFF Research Database (Denmark)

Yankov, Metodi Plamenov; Da Ros, Francesco; Porto da Silva, Edson

2016-01-01

A probabilistic method for mitigating the phase noise component of the non-linear interference in WDM systems with Raman amplification is experimentally demonstrated. The achieved gains increase with distance and are comparable to the gains of single-channel digital back-propagation....

Testing FSO WDM communication system in simulation software optiwave OptiSystem in different atmospheric environments

Science.gov (United States)

Vanderka, Ales; Hajek, Lukas; Bednarek, Lukas; Latal, Jan; Vitasek, Jan; Hejduk, Stanislav; Vasinek, Vladimir

2016-09-01

In this article the author's team deals with using Wavelength Division Multiplexing (WDM) for Free Space Optical (FSO) Communications. In FSO communication occurs due to the influence of atmospheric effect (attenuation, and fluctuation of the received power signal, influence turbulence) and the WDM channel suffers from interchannel crosstalk. There is considered only the one direction. The behavior FSO link was tested for one or eight channels. Here we will be dealing with modulation schemes OOK (On-Off keying), QAM (Quadrature Amplitude Modulation) and Subcarrier Intensity Modulation (SIM) based on a BPSK (Binary Phase Shift Keying). Simulation software OptiSystem 14 was used for tasting. For simulation some parameters were set according to real FSO link such as the datarate 1.25 Gbps, link range 1.4 km. Simulated FSO link used wavelength of 1550 nm with 0.8 nm spacing. There is obtained the influence of crosstalk and modulation format for the BER, depending on the amount of turbulence in the propagation medium.

Long term strain behavior of PMMA based polymer optical fibers

DEFF Research Database (Denmark)

Bundalo, Ivan-Lazar; Nielsen, Kristian; Woyessa, Getinet

2015-01-01

We are reporting on the viscoelasticity of PMMA based Fiber Bragg Grating (FBG) strain sensors when exposed to repeated sequences of long term strain and relaxation with various duty-cycles. In terms of the FBG wavelength and how it follows the strain cycle, we have shown that in the small strain...... regime (up to 1%) an elastic-dominated fast relaxing range, which is followed by a mainly viscous relaxation, depends both on the strain level and on the strain duration. For a small ratio of the strain-relax durations, this fast relaxation range stays almost the same. However, with increasing strain...... duration, for the same relaxation time, this range will be shortened, which might influence the sensing capabilities of the fiber sensor....

Long period gratings in multimode optical fibers: application in chemical sensing

Science.gov (United States)

Thomas Lee, S.; Dinesh Kumar, R.; Suresh Kumar, P.; Radhakrishnan, P.; Vallabhan, C. P. G.; Nampoori, V. P. N.

2003-09-01

We propose and demonstrate a new technique for evanescent wave chemical sensing by writing long period gratings in a bare multimode plastic clad silica fiber. The sensing length of the present sensor is only 10 mm, but is as sensitive as a conventional unclad evanescent wave sensor having about 100 mm sensing length. The minimum measurable concentration of the sensor reported here is 10 nmol/l and the operating range is more than 4 orders of magnitude. Moreover, the detection is carried out in two independent detection configurations viz., bright field detection scheme that detects the core-mode power and dark field detection scheme that detects the cladding mode power. The use of such a double detection scheme definitely enhances the reliability and accuracy of the results. Furthermore, the cladding of the present fiber need not be removed as done in conventional evanescent wave fiber sensors.

Long period gratings written in large-mode area photonic crystal fiber

DEFF Research Database (Denmark)

Nodop, D.; Linke, S.; Jansen, F.

2008-01-01

We report for the first time, to the best of our knowledge, on the fabrication and characterization of CO2-laser written long-period gratings in a large-mode area photonic crystal fiber with a core diameter of 25 mu m. The gratings have low insertion losses ( 10 d...

Comprehensive long distance and real-time pipeline monitoring system based on fiber optic sensing

Energy Technology Data Exchange (ETDEWEB)

Nikles, Marc; Ravet, Fabien; Briffod, Fabien [Omnisens S.A., Morges (Switzerland)

2009-07-01

An increasing number of pipelines are constructed in remote regions affected by harsh environmental conditions. These pipeline routes often cross mountain areas which are characterized by unstable grounds and where soil texture changes between winter and summer increase the probability of hazards. Due to the long distances to be monitored and the linear nature of pipelines, distributed fiber optic sensing techniques offer significant advantages and the capability to detect and localize pipeline disturbance with great precision. Furthermore pipeline owner/operators lay fiber optic cable parallel to transmission pipelines for telecommunication purposes and at minimum additional cost monitoring capabilities can be added to the communication system. The Brillouin-based Omnisens DITEST monitoring system has been used in several long distance pipeline projects. The technique is capable of measuring strain and temperature over 100's kilometers with meter spatial resolution. Dedicated fiber optic cables have been developed for continuous strain and temperature monitoring and their deployment along the pipeline has enabled permanent and continuous pipeline ground movement, intrusion and leak detection. This paper presents a description of the fiber optic Brillouin-based DITEST sensing technique, its measurement performance and limits, while addressing future perspectives for pipeline monitoring. (author)

Compact frequency-modulation Q-switched single-frequency fiber laser at 1083 nm

International Nuclear Information System (INIS)

Zhang, Yuanfei; Feng, Zhouming; Xu, Shanhui; Mo, Shupei; Yang, Changsheng; Li, Can; Gan, Jiulin; Chen, Dongdan; Yang, Zhongmin

2015-01-01

A compact frequency-modulation Q-switched single-frequency fiber laser is demonstrated at 1083 nm. The short linear resonant cavity consists of a 12 mm long homemade Yb 3+ -doped phosphate fiber and a pair of fiber Bragg gratings (FBGs) in which the Q-switching and the frequency excursion is achieved by a tensile-induced period modulation. Over 375 MHz frequency-tuning range is achieved with a modulation frequency varying from tens to hundreds of kilohertz. The highest peak power of the output pulse reaching 6.93 W at the repetition rate of 10 kHz is obtained. (paper)

200 Gbit/s 16QAM WDM transmission over a fully integrated cladding pumped 7-Core MCF System

DEFF Research Database (Denmark)

Castro, C.; Jain, S.; Jung, Y.

2017-01-01

A complete, realistic integrated system is investigated, consisting of directly spliced 7-core MCF, cladding-pumped 7-core amplifiers, isolators, and couplers. The system is demonstrated in a 16QAM C-band WDM scenario over 720 km....

Spatial, contextual and working memory are not affected by the absence of mossy fiber long-term potentiation and depression

NARCIS (Netherlands)

Hensbroek, R.A.; Kamal, A.; Baars, A.M.; Verhage, M.; Spruijt, B.M.

2003-01-01

The mossy fibers of the hippocampus display NMDA-receptor independent long-term plasticity. A number of studies addressed the role of mossy fiber long-term plasticity in memory, but have provided contrasting results. Here, we have exploited a genetic model, the rab3A null-mutant, which is

An enhanced DWBA algorithm in hybrid WDM/TDM EPON networks with heterogeneous propagation delays

Science.gov (United States)

Li, Chengjun; Guo, Wei; Jin, Yaohui; Sun, Weiqiang; Hu, Weisheng

2011-12-01

An enhanced dynamic wavelength and bandwidth allocation (DWBA) algorithm in hybrid WDM/TDM PON is proposed and experimentally demonstrated. In addition to the fairness of bandwidth allocation, this algorithm also considers the varying propagation delays between ONUs and OLT. The simulation based on MATLAB indicates that the improved algorithm has a better performance compared with some other algorithms.

Optimal Golomb Ruler Sequences Generation for Optical WDM Systems: A Novel Parallel Hybrid Multi-objective Bat Algorithm

Science.gov (United States)

Bansal, Shonak; Singh, Arun Kumar; Gupta, Neena

2017-02-01

In real-life, multi-objective engineering design problems are very tough and time consuming optimization problems due to their high degree of nonlinearities, complexities and inhomogeneity. Nature-inspired based multi-objective optimization algorithms are now becoming popular for solving multi-objective engineering design problems. This paper proposes original multi-objective Bat algorithm (MOBA) and its extended form, namely, novel parallel hybrid multi-objective Bat algorithm (PHMOBA) to generate shortest length Golomb ruler called optimal Golomb ruler (OGR) sequences at a reasonable computation time. The OGRs found their application in optical wavelength division multiplexing (WDM) systems as channel-allocation algorithm to reduce the four-wave mixing (FWM) crosstalk. The performances of both the proposed algorithms to generate OGRs as optical WDM channel-allocation is compared with other existing classical computing and nature-inspired algorithms, including extended quadratic congruence (EQC), search algorithm (SA), genetic algorithms (GAs), biogeography based optimization (BBO) and big bang-big crunch (BB-BC) optimization algorithms. Simulations conclude that the proposed parallel hybrid multi-objective Bat algorithm works efficiently as compared to original multi-objective Bat algorithm and other existing algorithms to generate OGRs for optical WDM systems. The algorithm PHMOBA to generate OGRs, has higher convergence and success rate than original MOBA. The efficiency improvement of proposed PHMOBA to generate OGRs up to 20-marks, in terms of ruler length and total optical channel bandwidth (TBW) is 100 %, whereas for original MOBA is 85 %. Finally the implications for further research are also discussed.

Fast Inscription of Long Period Gratings in Microstructured Polymer Optical Fibers

DEFF Research Database (Denmark)

Min, Rui; Marques, Carlos; Nielsen, Kristian

2018-01-01

We demonstrate 20 dB long period grating (LPG) fast inscription in microstructured polymer optical fibers (mPOFs) using a point-by-point technique obtaining an LPG total length of 25 mm. Two 248 nm UV laser pulses of 15 ns duration have been employed for every inscription point, which means a time...

Input shaping filter methods for the control of structurally flexible, long-reach manipulators

International Nuclear Information System (INIS)

Kwon, Dong-Soo; Hwang, Dong-Hwan; Babcock, S.M.; Burks, B.L.

1993-01-01

Within the Environmental Restoration and Waste Management Program of the US Department of Energy, the remediation of single-shell radioactive waste storage tanks is one of the areas that challenge state-of-the-art equipment and methods. Concepts that utilize long-reach manipulators are being seriously considered for this task. Due to high payload capacity and high length-to-cross-section ratio requirements, these long-reach manipulator systems are expected to exhibit significant structural flexibility. To avoid structural vibrations during operation, various types of shaping filter methods have been investigated. A robust notch filtering method and an impulse shaping method were used as simulation benchmarks. In addition to that, two very different approaches have been developed and compared. One new approach, referred to as a ''feedforward simulation filter,'' uses imbedded simulation with complete knowledge of the system dynamics. The other approach, ''fuzzy shaping method,'' employs a fuzzy logic method to modify the joint trajectory from the desired end-position trajectory without precise knowledge of the system dynamics

A slotted access control protocol for metropolitan WDM ring networks

Science.gov (United States)

Baziana, P. A.; Pountourakis, I. E.

2009-03-01

In this study we focus on the serious scalability problems that many access protocols for WDM ring networks introduce due to the use of a dedicated wavelength per access node for either transmission or reception. We propose an efficient slotted MAC protocol suitable for WDM ring metropolitan area networks. The proposed network architecture employs a separate wavelength for control information exchange prior to the data packet transmission. Each access node is equipped with a pair of tunable transceivers for data communication and a pair of fixed tuned transceivers for control information exchange. Also, each access node includes a set of fixed delay lines for synchronization reasons; to keep the data packets, while the control information is processed. An efficient access algorithm is applied to avoid both the data wavelengths and the receiver collisions. In our protocol, each access node is capable of transmitting and receiving over any of the data wavelengths, facing the scalability issues. Two different slot reuse schemes are assumed: the source and the destination stripping schemes. For both schemes, performance measures evaluation is provided via an analytic model. The analytical results are validated by a discrete event simulation model that uses Poisson traffic sources. Simulation results show that the proposed protocol manages efficient bandwidth utilization, especially under high load. Also, comparative simulation results prove that our protocol achieves significant performance improvement as compared with other WDMA protocols which restrict transmission over a dedicated data wavelength. Finally, performance measures evaluation is explored for diverse numbers of buffer size, access nodes and data wavelengths.

Distributed Long-Gauge Optical Fiber Sensors Based Self-Sensing FRP Bar for Concrete Structure

OpenAIRE

Tang, Yongsheng; Wu, Zhishen

2016-01-01

Brillouin scattering-based distributed optical fiber (OF) sensing technique presents advantages for concrete structure monitoring. However, the existence of spatial resolution greatly decreases strain measurement accuracy especially around cracks. Meanwhile, the brittle feature of OF also hinders its further application. In this paper, the distributed OF sensor was firstly proposed as long-gauge sensor to improve strain measurement accuracy. Then, a new type of self-sensing fiber reinforced p...

High Power (50W) WDM Space Lasercom 1.5um Fiber Laser Transmitter, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Fibertek proposes to develop and demonstrate a spaceflight prototype of a wideband, high power (up to 50W), polarization maintaining (PM), 1.5-um fiber laser...

Integrated 1 GHz 4-channel InP phasar based WDM-receiver with Si bipolar frontend array

NARCIS (Netherlands)

Steenbergen, C.A.M.; Vreede, de L.C.N.; Dam, van C.; Scholtes, T.L.M.; Smit, M.K.; Tauritz, J.L.; Pedersen, J.W.; Moerman, I.; Verbeek, B.H.; Baets, R.G.F.

1995-01-01

An integrated 4-channel WDM-receiver frontend with 1 GHz channel bandwidth is described. The receiver consists of an integrated wavelength demultiplexer with photodiodes in InP technology connected through bond wires with a 4 channel Si bipolar transimpedance amplifier mounted on an epoxy board. The

Design of device driver program for PCI data acquisition adapters based on WDM of windows 2000

International Nuclear Information System (INIS)

Yuan Weihua; Qiao Weimin; Jing Lan; Zhu Haijun

2003-01-01

The paper describes the design of device driver program for PCI data acquisition adapters based on WDM of Windows 2000. Give an actual example of PCI6208. Now, several data acquisition adapters based in this method are using in national big science engineer HIRFL-CSR. (authors)

Control issues related to bilateral teleoperation of long-reach, flexible manipulators

International Nuclear Information System (INIS)

Love, L.J.

1997-01-01

A challenging problem presently being addressed by the Department of Energy (DOE) is the extraction of large volumes of hazardous waste from underground waste storage facilities. The nature of the material requires the use of robotic and teleoperated systems. Furthermore, the constraints of the storage tanks require the use of long reach manipulators. These robots are characterized by their large workspace and reduced mass. Unfortunately, this reduction in mass increases structural compliance, making these robots susceptible to vibration. Until recently, no attempt has been made to provide the operator any type of force reflection due to the compliance of the slave robot. This paper addresses the control of bilateral teleoperation systems that use long-reach, flexible manipulators. Analysis and experiments show that the compliance of the slave robot directly affects the stability of the teleoperation system. This study suggests that this may be controlled by increasing the damping on the master robot. However, this increase in target damping increases the energy an operator must exert during the execution of a task. A new teleoperation strategy adapts the target impedance of the master robot to variations in the identified impedance of the remote environment coupled to the slave robot. Experiments show increased performance due to a decrease in the energy the operator must provide during task execution

Arc-Induced Long Period Gratings from Standard to Polarization-Maintaining and Photonic Crystal Fibers

Directory of Open Access Journals (Sweden)

Flavio Esposito

2018-03-01

Full Text Available In this work, we report about our recent results concerning the fabrication of Long Period Grating (LPG sensors in several optical fibers, through the Electric Arc Discharge (EAD technique. In particular, the following silica fibers with both different dopants and geometrical structures are considered: standard Ge-doped, photosensitive B/Ge codoped, P-doped, pure-silica core with F-doped cladding, Panda type Polarization-maintaining, and Hollow core Photonic crystal fiber. An adaptive platform was developed and the appropriate “recipe” was identified for each fiber, in terms of both arc discharge parameters and setup arrangement, for manufacturing LPGs with strong and narrow attenuation bands, low insertion losses, and short length. As the fabricated devices have appealing features from the application point of view, the sensitivity characteristics towards changes in different external perturbations (i.e., surrounding refractive index, temperature, and strain are investigated and compared, highlighting the effects of different fiber composition and structure.

Attenuation of hippocampal mossy fiber long-term potentiation by low micromolar concentrations of zinc.

Science.gov (United States)

Takeda, Atsushi; Kanno, Shingo; Sakurada, Naomi; Ando, Masaki; Oku, Naoto

2008-10-01

The role of zinc in long-term potentiation (LTP) at hippocampal mossy fiber synapses is controversial because of the contrary results obtained when using zinc chelators. On the basis of the postulation that exogenous zinc enhances the action of zinc released from mossy fibers, mossy fiber LTP after tetanic stimulation (100 Hz, 1 sec) was checked in the presence of exogenous zinc at low micromolar concentrations. Mossy fiber LTP was significantly attenuated in the presence of 5-30 microM ZnCl(2), and the amplitude of field excitatory postsynaptic potentials 60 min after tetanic stimulation was decreased to almost the basal level. Mossy fiber LTP was also attenuated in the presence of 5 microM ZnCl(2) 5 min after tetanic stimulation. The present study is the first to demonstrate that low micromolar concentrations of zinc attenuate mossy fiber LTP. When mossy fiber LTP was induced in the presence of CaEDTA and ZnAF-2 DA, a membrane-impermeable and a membrane-permeable zinc chelator, respectively, extracellular and intracellular chelation of zinc enhanced a transient posttetanic potentiation (PTP) without altering LTP. It is likely that zinc released by tetanic stimulation is immediately taken up into the mossy fibers and attenuates mossy fiber PTP. These results suggest that attenuation of PTP rather than LTP at mossy fiber synapses is a more physiological role for endogenous zinc. Targeting molecules of zinc in mossy fiber LTP seem to be different between during and after LTP induction because of the differential synaptic activity between them. (c) 2008 Wiley-Liss, Inc.

Monolithic all-PM femtosecond Yb-doped fiber laser using photonic bandgap fibers

DEFF Research Database (Denmark)

Liu, Xiaomin; Lægsgaard, Jesper; Turchinovich, Dmitry

2009-01-01

We present a monolithic Yb fiber laser, dispersion managed by an all-solid photonic bandgap fiber, and pulse compressed in a hollow-core photonic crystal fiber. The laser delivers 9 nJ, 275-fs long pulses at 1035 nm.......We present a monolithic Yb fiber laser, dispersion managed by an all-solid photonic bandgap fiber, and pulse compressed in a hollow-core photonic crystal fiber. The laser delivers 9 nJ, 275-fs long pulses at 1035 nm....

Fiber webs

Science.gov (United States)

Roger M. Rowell; James S. Han; Von L. Byrd

2005-01-01

Wood fibers can be used to produce a wide variety of low-density three-dimensional webs, mats, and fiber-molded products. Short wood fibers blended with long fibers can be formed into flexible fiber mats, which can be made by physical entanglement, nonwoven needling, or thermoplastic fiber melt matrix technologies. The most common types of flexible mats are carded, air...

Self-Seeded RSOA-Fiber Cavity Lasers vs. ASE Spectrum-Sliced or Externally Seeded Transmitters—A Comparative Study

Directory of Open Access Journals (Sweden)

Simon A. Gebrewold

2015-12-01

Full Text Available Reflective semiconductor optical amplifier fiber cavity lasers (RSOA-FCLs are appealing, colorless, self-seeded, self-tuning and cost-efficient upstream transmitters. They are of interest for wavelength division multiplexed passive optical networks (WDM-PONs based links. In this paper, we compare RSOA-FCLs with alternative colorless sources, namely the amplified spontaneous emission (ASE spectrum-sliced and the externally seeded RSOAs. We compare the differences in output power, signal-to-noise ratio (SNR, relative intensity noise (RIN, frequency response and transmission characteristics of these three sources. It is shown that an RSOA-FCL offers a higher output power over an ASE spectrum-sliced source with SNR, RIN and frequency response characteristics halfway between an ASE spectrum-sliced and a more expensive externally seeded RSOA. The results show that the RSOA-FCL is a cost-efficient WDM-PON upstream source, borrowing simplicity and cost-efficiency from ASE spectrum slicing with characteristics that are, in many instances, good enough to perform short-haul transmission. To substantiate our statement and to quantitatively compare the potential of the three schemes, we perform data transmission experiments at 5 and 10 Gbit/s.

Dispersion-optimized optical fiber for high-speed long-haul dense wavelength division multiplexing transmission

Science.gov (United States)

Wu, Jindong; Chen, Liuhua; Li, Qingguo; Wu, Wenwen; Sun, Keyuan; Wu, Xingkun

2011-07-01

Four non-zero-dispersion-shifted fibers with almost the same large effective area (Aeff) and optimized dispersion properties are realized by novel index profile designing and modified vapor axial deposition and modified chemical vapor deposition processes. An Aeff of greater than 71 μm2 is obtained for the designed fibers. Three of the developed fibers with positive dispersion are improved by reducing the 1550nm dispersion slope from 0.072ps/nm2/km to 0.063ps/nm2/km or 0.05ps/nm2/km, increasing the 1550nm dispersion from 4.972ps/nm/km to 5.679ps/nm/km or 7.776ps/nm/km, and shifting the zero-dispersion wavelength from 1500nm to 1450nm. One of these fibers is in good agreement with G655D and G.656 fibers simultaneously, and another one with G655E and G.656 fibers; both fibers are beneficial to high-bit long-haul dense wavelength division multiplexing systems over S-, C-, and L-bands. The fourth developed fiber with negative dispersion is also improved by reducing the 1550nm dispersion slope from 0.12ps/nm2/km to 0.085ps/nm2/km, increasing the 1550nm dispersion from -4ps/nm/km to -6.016ps/nm/km, providing facilities for a submarine transmission system. Experimental measurements indicate that the developed fibers all have excellent optical transmission and good macrobending and splice performances.

Implantable fiber-optic interface for parallel multisite long-term optical dynamic brain interrogation in freely moving mice

Science.gov (United States)

Doronina-Amitonova, L. V.; Fedotov, I. V.; Ivashkina, O. I.; Zots, M. A.; Fedotov, A. B.; Anokhin, K. V.; Zheltikov, A. M.

2013-01-01

Seeing the big picture of functional responses within large neural networks in a freely functioning brain is crucial for understanding the cellular mechanisms behind the higher nervous activity, including the most complex brain functions, such as cognition and memory. As a breakthrough toward meeting this challenge, implantable fiber-optic interfaces integrating advanced optogenetic technologies and cutting-edge fiber-optic solutions have been demonstrated, enabling a long-term optogenetic manipulation of neural circuits in freely moving mice. Here, we show that a specifically designed implantable fiber-optic interface provides a powerful tool for parallel long-term optical interrogation of distinctly separate, functionally different sites in the brain of freely moving mice. This interface allows the same groups of neurons lying deeply in the brain of a freely behaving mouse to be reproducibly accessed and optically interrogated over many weeks, providing a long-term dynamic detection of genome activity in response to a broad variety of pharmacological and physiological stimuli. PMID:24253232

Fiber and Prebiotics: Mechanisms and Health Benefits

Science.gov (United States)

Slavin, Joanne

2013-01-01

The health benefits of dietary fiber have long been appreciated. Higher intakes of dietary fiber are linked to less cardiovascular disease and fiber plays a role in gut health, with many effective laxatives actually isolated fiber sources. Higher intakes of fiber are linked to lower body weights. Only polysaccharides were included in dietary fiber originally, but more recent definitions have included oligosaccharides as dietary fiber, not based on their chemical measurement as dietary fiber by the accepted total dietary fiber (TDF) method, but on their physiological effects. Inulin, fructo-oligosaccharides, and other oligosaccharides are included as fiber in food labels in the US. Additionally, oligosaccharides are the best known “prebiotics”, “a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-bring and health.” To date, all known and suspected prebiotics are carbohydrate compounds, primarily oligosaccharides, known to resist digestion in the human small intestine and reach the colon where they are fermented by the gut microflora. Studies have provided evidence that inulin and oligofructose (OF), lactulose, and resistant starch (RS) meet all aspects of the definition, including the stimulation of Bifidobacterium, a beneficial bacterial genus. Other isolated carbohydrates and carbohydrate-containing foods, including galactooligosaccharides (GOS), transgalactooligosaccharides (TOS), polydextrose, wheat dextrin, acacia gum, psyllium, banana, whole grain wheat, and whole grain corn also have prebiotic effects. PMID:23609775

Fiber and Prebiotics: Mechanisms and Health Benefits

Directory of Open Access Journals (Sweden)

Joanne Slavin

2013-04-01

Full Text Available The health benefits of dietary fiber have long been appreciated. Higher intakes of dietary fiber are linked to less cardiovascular disease and fiber plays a role in gut health, with many effective laxatives actually isolated fiber sources. Higher intakes of fiber are linked to lower body weights. Only polysaccharides were included in dietary fiber originally, but more recent definitions have included oligosaccharides as dietary fiber, not based on their chemical measurement as dietary fiber by the accepted total dietary fiber (TDF method, but on their physiological effects. Inulin, fructo-oligosaccharides, and other oligosaccharides are included as fiber in food labels in the US. Additionally, oligosaccharides are the best known “prebiotics”, “a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-bring and health.” To date, all known and suspected prebiotics are carbohydrate compounds, primarily oligosaccharides, known to resist digestion in the human small intestine and reach the colon where they are fermented by the gut microflora. Studies have provided evidence that inulin and oligofructose (OF, lactulose, and resistant starch (RS meet all aspects of the definition, including the stimulation of Bifidobacterium, a beneficial bacterial genus. Other isolated carbohydrates and carbohydrate-containing foods, including galactooligosaccharides (GOS, transgalactooligosaccharides (TOS, polydextrose, wheat dextrin, acacia gum, psyllium, banana, whole grain wheat, and whole grain corn also have prebiotic effects.

Application of cellulosic nanofibers to replace with imported long- fiber pulps in paper made from bagasse

Directory of Open Access Journals (Sweden)

Reza ghofran

2017-02-01

Full Text Available In this research, different additives of cellulose nanofibers, cationic starch and polyacrylamide to bagasse pulp and their impact on the handsheet strengths were investigated aiming to replace with imported long-fiber softwood pulp in Pars paper factory. For this purpose, first 3% bleached bagasse cellulose nanofibers, 3% unbleached nano-lignocellulosic fibers, 0.5, 0.7 and 1% cationic starch, and 0.03, 0.05 and 0.1% cationic polyacrylamide were added separately to bagasse pulp. In the next stage,3% bleached bagasse cellulose nanofibers and 3% unbleached nano-lignocellulosic fibers along with 0.5% cationic starch or 0.05% cationic polyacrylamide were used. The results showed, adding nano-cellulose fibers along with cationic polyacrylamide or starch have increased handsheet strengths significantly. Yet, the best treatment was the addition of 3% nano-lignocellulose along with 0.5% cationic starch which resulted in the higher tensile and burst strengths and lower tear and fold strengths than that of adding 12.5% long fibers to bagasse pulp. So that, comparing with paper made from pure bagasse pulp it showed the increase of 16.57% in tensile index, 8.47% in burst index, 9.77% in tear index, and 168.85% in folding strength.

Seed Yield of Long Fiber Flax (Linum usitatissimum L. Plants Depending on Rates of Sawing of Seed and Mineral Fertilization

Directory of Open Access Journals (Sweden)

М. Ф. Рибак

2010-10-01

Full Text Available Impact of rates of sawing of seed and fertilization on seed productivity of Kameniar and Irma Long Fiber Flax in the conditions of Ukrainian Woodlands are highlighted. A trustworthy proportion is established of factors influence, in particular, of the sawing and fertilization rates, on Long Fiber Flax yield formation.

Long-distance fiber optic sensing solutions for pipeline leakage, intrusion, and ground movement detection

Science.gov (United States)

Nikles, Marc

2009-05-01

An increasing number of pipelines are constructed in remote regions affected by harsh environmental conditions where pipeline routes often cross mountain areas which are characterized by unstable grounds and where soil texture changes between winter and summer increase the probability of hazards. Third party intentional interference or accidental intrusions are a major cause of pipeline failures leading to large leaks or even explosions. Due to the long distances to be monitored and the linear nature of pipelines, distributed fiber optic sensing techniques offer significant advantages and the capability to detect and localize pipeline disturbance with great precision. Furthermore pipeline owner/operators lay fiber optic cable parallel to transmission pipelines for telecommunication purposes and at minimum additional cost monitoring capabilities can be added to the communication system. The Brillouin-based Omnisens DITEST monitoring system has been used in several long distance pipeline projects. The technique is capable of measuring strain and temperature over 100's kilometers with meter spatial resolution. Dedicated fiber optic cables have been developed for continuous strain and temperature monitoring and their deployment along the pipeline has enabled permanent and continuous pipeline ground movement, intrusion and leak detection. This paper presents a description of the fiber optic Brillouin-based DITEST sensing technique, its measurement performance and limits, while addressing future perspectives for pipeline monitoring. The description is supported by case studies and illustrated by field data.

All-optical multi-wavelength conversion with negative power penalty by a commercial SOA-MZI for WDM wavelength multicast

NARCIS (Netherlands)

Yan, N.; Jung, H.D.; Tafur Monroy, I.; Waardt, de H.; Koonen, A.M.J.

2007-01-01

WDM wavelength multicast is demonstrated by all-optical multi-wavelength conversion at 10 Gb/s using a commercial SOA-MZI. We report for the first time simultaneous one-to-four conversion with negative power penalty of 1.84 dB.

Recent Developments in Fiber Optics Humidity Sensors.

Science.gov (United States)

Ascorbe, Joaquin; Corres, Jesus M; Arregui, Francisco J; Matias, Ignacio R

2017-04-19

A wide range of applications such as health, human comfort, agriculture, food processing and storage, and electronic manufacturing, among others, require fast and accurate measurement of humidity. Sensors based on optical fibers present several advantages over electronic sensors and great research efforts have been made in recent years in this field. The present paper reports the current trends of optical fiber humidity sensors. The evolution of optical structures developed towards humidity sensing, as well as the novel materials used for this purpose, will be analyzed. Well-known optical structures, such as long-period fiber gratings or fiber Bragg gratings, are still being studied towards an enhancement of their sensitivity. Sensors based on lossy mode resonances constitute a platform that combines high sensitivity with low complexity, both in terms of their fabrication process and the equipment required. Novel structures, such as resonators, are being studied in order to improve the resolution of humidity sensors. Moreover, recent research on polymer optical fibers suggests that the sensitivity of this kind of sensor has not yet reached its limit. Therefore, there is still room for improvement in terms of sensitivity and resolution.

Parametric amplification and wavelength conversion of a 2.048-Tbit/s WDM PDM 16-QAM signal

DEFF Research Database (Denmark)

Hu, Hao; Jopson, R. M.; Gnauck, A. H.

2014-01-01

We demonstrate polarisation-insensitive parametric amplification in highly nonlinear fibre of a 2.048-Tbit/s dense WDM PDM 16-QAM signal with ∼10 dB on-off gain and simultaneous wavelength conversion and phase conjugation, with mean Q2 penalties of only 0.6 dB and 0.4 dB....

Tailoring Chirped Moiré Fiber Bragg Gratings for Wavelength-Division-Multiplexing and Optical Code-Division Multiple-Access Applications

Science.gov (United States)

Chen, Lawrence R.; Smith, Peter W. E.

The design and fabrication of chirped Moiré fiber Bragg gratings (CMGs) are presented, which can be used in either (1) transmission as passband filters for providing wavelength selectivity in wavelength-division-multiplexed (WDM) systems or (2) reflection as encoding/decoding elements to decompose short broadband pulses in both wavelength and time in order to implement an optical code-division multiple-access (OCDMA) system. In transmission, the fabricated CMGs have single or multiple flattened passbands ( 12 dB isolation and near constant in-band group delay. It is shown that these filters do not produce any measurable dispersion-induced power penalties when used to provide wavelength selectivity in 2.5 Gbit/s systems. It is also demonstrated how CMGs can be used in reflection to encode/decode short pulses from a wavelength-tunable mode-locked Er-doped fiber laser.

Exploring the atomic structure and conformational flexibility of a 320 Å long engineered viral fiber using X-ray crystallography

Energy Technology Data Exchange (ETDEWEB)

Bhardwaj, Anshul [Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA 19107 (United States); Casjens, Sherwood R. [University of Utah School of Medicine, Salt Lake City, UT 84112 (United States); Cingolani, Gino, E-mail: gino.cingolani@jefferson.edu [Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA 19107 (United States)

2014-02-01

This study presents the crystal structure of a ∼320 Å long protein fiber generated by in-frame extension of its repeated helical coiled-coil core. Protein fibers are widespread in nature, but only a limited number of high-resolution structures have been determined experimentally. Unlike globular proteins, fibers are usually recalcitrant to form three-dimensional crystals, preventing single-crystal X-ray diffraction analysis. In the absence of three-dimensional crystals, X-ray fiber diffraction is a powerful tool to determine the internal symmetry of a fiber, but it rarely yields atomic resolution structural information on complex protein fibers. An 85-residue-long minimal coiled-coil repeat unit (MiCRU) was previously identified in the trimeric helical core of tail needle gp26, a fibrous protein emanating from the tail apparatus of the bacteriophage P22 virion. Here, evidence is provided that an MiCRU can be inserted in frame inside the gp26 helical core to generate a rationally extended fiber (gp26-2M) which, like gp26, retains a trimeric quaternary structure in solution. The 2.7 Å resolution crystal structure of this engineered fiber, which measures ∼320 Å in length and is only 20–35 Å wide, was determined. This structure, the longest for a trimeric protein fiber to be determined to such a high resolution, reveals the architecture of 22 consecutive trimerization heptads and provides a framework to decipher the structural determinants for protein fiber assembly, stability and flexibility.

Exploring the atomic structure and conformational flexibility of a 320 Å long engineered viral fiber using X-ray crystallography

International Nuclear Information System (INIS)

Bhardwaj, Anshul; Casjens, Sherwood R.; Cingolani, Gino

2014-01-01

This study presents the crystal structure of a ∼320 Å long protein fiber generated by in-frame extension of its repeated helical coiled-coil core. Protein fibers are widespread in nature, but only a limited number of high-resolution structures have been determined experimentally. Unlike globular proteins, fibers are usually recalcitrant to form three-dimensional crystals, preventing single-crystal X-ray diffraction analysis. In the absence of three-dimensional crystals, X-ray fiber diffraction is a powerful tool to determine the internal symmetry of a fiber, but it rarely yields atomic resolution structural information on complex protein fibers. An 85-residue-long minimal coiled-coil repeat unit (MiCRU) was previously identified in the trimeric helical core of tail needle gp26, a fibrous protein emanating from the tail apparatus of the bacteriophage P22 virion. Here, evidence is provided that an MiCRU can be inserted in frame inside the gp26 helical core to generate a rationally extended fiber (gp26-2M) which, like gp26, retains a trimeric quaternary structure in solution. The 2.7 Å resolution crystal structure of this engineered fiber, which measures ∼320 Å in length and is only 20–35 Å wide, was determined. This structure, the longest for a trimeric protein fiber to be determined to such a high resolution, reveals the architecture of 22 consecutive trimerization heptads and provides a framework to decipher the structural determinants for protein fiber assembly, stability and flexibility

Performance analysis of a threshold-based parallel multiple beam selection scheme for WDM-based systems for Gamma-Gamma distributions

KAUST Repository

Nam, Sung Sik; Yoon, Chang Seok; Alouini, Mohamed-Slim

2017-01-01

In this paper, we statistically analyze the performance of a threshold-based parallel multiple beam selection scheme (TPMBS) for Free-space optical (FSO) based system with wavelength division multiplexing (WDM) in cases where a pointing error has

Photonic network R and D activities in Japan

Science.gov (United States)

Kitayama, Ken-ichi; Miki, Tetsuya; Morioka, Toshio; Tsushima, Hideaki; Koga, Masafumi; Mori, Kazuyuki; Araki, Soichiro; Sato, Ken-ichi; Onaka, Hiroshi; Namiki, Shu; Aovama, Tomonori

2005-11-01

R and D activities on photonic networks in Japan are presented. First, milestones in current, ongoing R and D programs supported by Japanese government agencies are introduced, including long-distance and WDM fiber transmission, wavelength routing, optical burst switching, and control plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP over WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R and D programs for photonic networks over the next five years until 2010, by focusing on the report which has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R and D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis through the customer's initiative, to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

Photonic Network R&D Activities in Japan-Current Activities and Future Perspectives

Science.gov (United States)

Kitayama, Ken-Ichi; Miki, Tetsuya; Morioka, Toshio; Tsushima, Hideaki; Koga, Masafumi; Mori, Kazuyuki; Araki, Soichiro; Sato, Ken-Ichi; Onaka, Hiroshi; Namiki, Shu; Aoyama, Tomonori

2005-10-01

R&D activities on photonic networks in Japan are presented. First, milestones in current ongoing R&D programs supported by Japanese government agencies are introduced, including long-distance and wavelength division multiplexing (WDM) fiber transmission, wavelength routing, optical burst switching (OBS), and control-plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP-over-WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R&D programs for photonic networks over the next 5 years until 2010, by focusing on the report that has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R&D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis, through the customer's initiative to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

Extended chaotic domain in the long optical fibers based on SBS process

International Nuclear Information System (INIS)

Gao, Junbo; Ding, Yingchun; Chen, Zhaoyang; Lin, Chengyou

2014-01-01

Chaotic stimulated Brillouin scattering (SBS) in optical fibers with weak external optical feedback has been investigated experimentally and theoretically. However, only the bifurcation route to chaos through period-one and quasi-periodic emission was discovered in the former work because the chaotic domain is very short in the general nonlinear system. In order to control the chaos process and observe finer periodic-orbit structures, a novel experiment was designed to extend the chaotic domain by using long optical fibers in the SBS system. In this experiment, the period-one, period-doubling, period-four and period-eight cycle routes to the chaos laser process as well as the more details of chaos, have been observed.

Modeling the video distribution link in the Next Generation Optical Access Networks

International Nuclear Information System (INIS)

Amaya, F; Cardenas, A; Tafur, I

2011-01-01

In this work we present a model for the design and optimization of the video distribution link in the next generation optical access network. We analyze the video distribution performance in a SCM-WDM link, including the noise, the distortion and the fiber optic nonlinearities. Additionally, we consider in the model the effect of distributed Raman amplification, used to extent the capacity and the reach of the optical link. In the model, we use the nonlinear Schroedinger equation with the purpose to obtain capacity limitations and design constrains of the next generation optical access networks.

Enhanced refractive index sensor using a combination of a long period fiber grating and a small core singlemode fiber structure

International Nuclear Information System (INIS)

Wu, Qiang; Ma, Youqiao; Yang, Minwei; Semenova, Yuliya; Wang, Pengfei; Farrell, Gerald; Chan, Hai Ping; Yuan, Jinhui; Yan, Binbin; Yu, Chongxiu

2013-01-01

An enhanced refractive index (RI) sensor based on a combination of a long period fiber grating (LPG) and a small core singlemode fiber (SCSMF) structure is proposed and developed. Since the LPG and SCSMF transmission spectra experience a blue and a red shift respectively as the surrounding RI (SRI) increases, the sensitivity is improved by measuring the separation between the resonant wavelengths of the LPG and SCSMF structures. Experimental results show that the sensor has a sensitivity of 1028 nm/SRI unit in the SRI range from 1.422 to 1.429, which is higher than individual sensitivities of either structure alone used in the experiment. Experimental results agree well with simulation results. (paper)

Hybrid RSOA and fibre raman amplified long reach feeder link for WiMAX-on-fibre

DEFF Research Database (Denmark)

Amaya Fernández, Ferney Orlando; Martinez, Javier; Yu, Xianbin

2009-01-01

A distributed fibre Raman amplified long reach optical access feeder link using a reflective semiconductor optical amplifier in the remote base station is experimentally demonstrated for supporting WiMAXover- fibre transmission. The measured values for the error vector magnitude for quadrature...

Ways to Boost Fiber

Science.gov (United States)

... can help to lower cholesterol. Third, it helps prevent constipation and diverticulosis. And fourth, adequate fiber from food ... is similar to a new sponge; it needs water to plump up pass smoothly. If you ... or constipation. Before you reach for the fiber supplements, consider ...

A rigorous analysis of digital pre-emphasis and DAC resolution for interleaved DAC Nyquist-WDM signal generation in high-speed coherent optical transmission systems

Science.gov (United States)

Weng, Yi; Wang, Junyi; He, Xuan; Pan, Zhongqi

2018-02-01

The Nyquist spectral shaping techniques facilitate a promising solution to enhance spectral efficiency (SE) and further reduce the cost-per-bit in high-speed wavelength-division multiplexing (WDM) transmission systems. Hypothetically, any Nyquist WDM signals with arbitrary shapes can be generated by the use of the digital signal processing (DSP) based electrical filters (E-filter). Nonetheless, in actual 100G/ 200G coherent systems, the performance as well as DSP complexity are increasingly restricted by cost and power consumption. Henceforward it is indispensable to optimize DSP to accomplish the preferred performance at the least complexity. In this paper, we systematically investigated the minimum requirements and challenges of Nyquist WDM signal generation, particularly for higher-order modulation formats, including 16 quadrature amplitude modulation (QAM) or 64QAM. A variety of interrelated parameters, such as channel spacing and roll-off factor, have been evaluated to optimize the requirements of the digital-to-analog converter (DAC) resolution and transmitter E-filter bandwidth. The impact of spectral pre-emphasis has been predominantly enhanced via the proposed interleaved DAC architecture by at least 4%, and hence reducing the required optical signal to noise ratio (OSNR) at a bit error rate (BER) of 10-3 by over 0.45 dB at a channel spacing of 1.05 symbol rate and an optimized roll-off factor of 0.1. Furthermore, the requirements of sampling rate for different types of super-Gaussian E-filters are discussed for 64QAM Nyquist WDM transmission systems. Finally, the impact of the non-50% duty cycle error between sub-DACs upon the quality of the generated signals for the interleaved DAC structure has been analyzed.

Low-peak-to-average power ratio and low-complexity asymmetrically clipped optical orthogonal frequency-division multiplexing uplink transmission scheme for long-reach passive optical network.

Science.gov (United States)

Zhou, Ji; Qiao, Yaojun

2015-09-01

In this Letter, we propose a discrete Hartley transform (DHT)-spread asymmetrically clipped optical orthogonal frequency-division multiplexing (DHT-S-ACO-OFDM) uplink transmission scheme in which the multiplexing/demultiplexing process also uses the DHT algorithm. By designing a simple encoding structure, the computational complexity of the transmitter can be reduced from O(Nlog(2)(N)) to O(N). At the probability of 10(-3), the peak-to-average power ratio (PAPR) of 2-ary pulse amplitude modulation (2-PAM)-modulated DHT-S-ACO-OFDM is approximately 9.7 dB lower than that of 2-PAM-modulated conventional ACO-OFDM. To verify the feasibility of the proposed scheme, a 4-Gbit/s DHT-S-ACO-OFDM uplink transmission scheme with a 1∶64 way split has been experimentally implemented using 100-km standard single-mode fiber (SSMF) for a long-reach passive optical network (LR-PON).

Evaluation of the Impact of Coherent and Incoherent Crosstalk on the Performance of Wavelength-agnostic WDM-PON Systems

DEFF Research Database (Denmark)

Wagner, Christoph; Eiselt, Michael; Grobe, Klaus

2015-01-01

Wavelength-agnostic WDM-PON systems recently got a lot of interest as low-cost solution for metro area networking. Here, wavelength-agnostic means that the wavelength from the optical network unit to the optical line terminal is not known by the optical network unit a priori. Furthermore, calibra...

Cost-effective TCM-based WDM-PON for highly asymmetric traffic conditions.

Science.gov (United States)

Lee, Danbi; Kwon, Won-Bae; Chae, Chang-Joon; Park, Chang-Soo

2015-11-16

A time compression multiplexing (TCM)-based wavelength division multiplexing passive optical network (WDM-PON) using a reflective semiconductor optical amplifier (RSOA) is proposed, and its feasibility is experimentally demonstrated. In the proposed system, the RSOA pre-amplifies a 10 Gb/s downstream signal and modulates the RSOA output, wavelength-locked to the downstream signal, with a 1.25 Gb/s upstream signal simultaneously. The sensitivity of the downstream signal is improved by about 3 dB through the RSOA. The downstream and upstream signals have power penalties of about 0.1 dB and 1.1 dB, respectively, at bit error rates (BERs) of 10(-9) after 20 km transmission.

Plasmonic Optical Fiber-Grating Immunosensing: A Review.

Science.gov (United States)

Guo, Tuan; González-Vila, Álvaro; Loyez, Médéric; Caucheteur, Christophe

2017-11-26

Plasmonic immunosensors are usually made of a noble metal (in the form of a film or nanoparticles) on which bioreceptors are grafted to sense analytes based on the antibody/antigen or other affinity mechanism. Optical fiber configurations are a miniaturized counterpart to the bulky Kretschmann prism and allow easy light injection and remote operation. To excite a surface plasmon (SP), the core-guided light is locally outcoupled. Unclad optical fibers were the first configurations reported to this end. Among the different architectures able to bring light in contact with the surrounding medium, a great quantity of research is today being conducted on metal-coated fiber gratings photo-imprinted in the fiber core, as they provide modal features that enable SP generation at any wavelength, especially in the telecommunication window. They are perfectly suited for use with cost-effective high-resolution interrogators, allowing both a high sensitivity and a low limit of detection to be reached in immunosensing. This paper will review recent progress made in this field with different kinds of gratings: uniform, tilted and eccentric short-period gratings as well as long-period fiber gratings. Practical cases will be reported, showing that such sensors can be used in very small volumes of analytes and even possibly applied to in vivo diagnosis.

Plasmonic Optical Fiber-Grating Immunosensing: A Review

Directory of Open Access Journals (Sweden)

Tuan Guo

2017-11-01

Full Text Available Plasmonic immunosensors are usually made of a noble metal (in the form of a film or nanoparticles on which bioreceptors are grafted to sense analytes based on the antibody/antigen or other affinity mechanism. Optical fiber configurations are a miniaturized counterpart to the bulky Kretschmann prism and allow easy light injection and remote operation. To excite a surface plasmon (SP, the core-guided light is locally outcoupled. Unclad optical fibers were the first configurations reported to this end. Among the different architectures able to bring light in contact with the surrounding medium, a great quantity of research is today being conducted on metal-coated fiber gratings photo-imprinted in the fiber core, as they provide modal features that enable SP generation at any wavelength, especially in the telecommunication window. They are perfectly suited for use with cost-effective high-resolution interrogators, allowing both a high sensitivity and a low limit of detection to be reached in immunosensing. This paper will review recent progress made in this field with different kinds of gratings: uniform, tilted and eccentric short-period gratings as well as long-period fiber gratings. Practical cases will be reported, showing that such sensors can be used in very small volumes of analytes and even possibly applied to in vivo diagnosis.

First generation long-reach manipulator for retrieval of waste from Hanford single-shell tanks

International Nuclear Information System (INIS)

Gibbons, P.W.; McDaniel, L.B.

1994-10-01

The US Department of Energy, Richland Operations Office, has established the Tank Waste Remediation System to resolve environmental and safety issues related to underground waste-storage tanks at the Hanford Site. The Tank Waste Remediation System has identified the use of an advanced-technology, long-reach manipulator system as a low-water-addition retrieval alternative to past-practice sluicing

Direct-detection optical OFDM superchannel for long-reach PON using pilot regeneration.

Science.gov (United States)

Hu, Rong; Yang, Qi; Xiao, Xiao; Gui, Tao; Li, Zhaohui; Luo, Ming; Yu, Shaohua; You, Shanhong

2013-11-04

We demonstrate a novel long-reach PON downstream scheme based on the regenerated pilot assisted direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) superchannel transmission. We use the optical comb source to form DDO-OFDM superchannel, and reserve the center carrier as a seed pilot. The seed pilot is further tracked and reused to generate multiple optical carriers at the local exchange. Each regenerated pilot carrier is selected to beat with an adjacent OFDM sub-band at ONU, so that the electrical bandwidth limitation can be much released compared to the conventional DDO-OFDM superchannel detection. With the proposed proof-of-concept architecture, we experimentally demonstrated a 116.7 Gb/s superchannel OFDM-PON system with transmission reach of 100 km, and 1:64 splitting ratio. We analyze the impact of carrier-to-sideband power ratio (CSPR) on system performance. The experiment result shows that, 5 dB power margin is still remained at ONU using such technique.

Distributed Long-Gauge Optical Fiber Sensors Based Self-Sensing FRP Bar for Concrete Structure.

Science.gov (United States)

Tang, Yongsheng; Wu, Zhishen

2016-02-25

Brillouin scattering-based distributed optical fiber (OF) sensing technique presents advantages for concrete structure monitoring. However, the existence of spatial resolution greatly decreases strain measurement accuracy especially around cracks. Meanwhile, the brittle feature of OF also hinders its further application. In this paper, the distributed OF sensor was firstly proposed as long-gauge sensor to improve strain measurement accuracy. Then, a new type of self-sensing fiber reinforced polymer (FRP) bar was developed by embedding the packaged long-gauge OF sensors into FRP bar, followed by experimental studies on strain sensing, temperature sensing and basic mechanical properties. The results confirmed the superior strain sensing properties, namely satisfied accuracy, repeatability and linearity, as well as excellent mechanical performance. At the same time, the temperature sensing property was not influenced by the long-gauge package, making temperature compensation easy. Furthermore, the bonding performance between self-sensing FRP bar and concrete was investigated to study its influence on the sensing. Lastly, the sensing performance was further verified with static experiments of concrete beam reinforced with the proposed self-sensing FRP bar. Therefore, the self-sensing FRP bar has potential applications for long-term structural health monitoring (SHM) as embedded sensors as well as reinforcing materials for concrete structures.

A novel WDM passive optical network architecture supporting two independent multicast data streams

Science.gov (United States)

Qiu, Yang; Chan, Chun-Kit

2012-01-01

We propose a novel scheme to perform optical multicast overlay of two independent multicast data streams on a wavelength-division-multiplexed (WDM) passive optical network. By controlling a sinusoidal clock signal and shifting the wavelength at the optical line terminal (OLT), the delivery of the two multicast data, being carried by the generated optical tones, can be independently and flexibly controlled. Simultaneous transmission of 10-Gb/s unicast downstream and upstream data as well as two independent 10-Gb/s multicast data was successfully demonstrated.

Ultra-Wideband Radar for Breath Tracking with Optical Fiber for Remote Reach Extension

DEFF Research Database (Denmark)

Suhr, Lau Frejstrup; Tafur Monroy, Idelfonso; Vegas Olmos, Juan José

2016-01-01

We report on the experimental demonstration of an UWB radar with fiber extension for remote breath tracking through 10 cm of concrete. The radar is based on telecom class equipment.......We report on the experimental demonstration of an UWB radar with fiber extension for remote breath tracking through 10 cm of concrete. The radar is based on telecom class equipment....

Watt-level ~2 μm laser output in Tm3+-doped tungsten tellurite glass double-cladding fiber.

Science.gov (United States)

Li, Kefeng; Zhang, Guang; Hu, Lili

2010-12-15

We report, for the first time to the best of our knowledge, a watt level cw fiber laser at ~2 μm from a piece of 40-cm-long newly developed highly thulium-doped (3.76 × 10(20) ions/cm(3)) tungsten tellurite glass double cladding fiber pumped by a commercial 800 nm laser diode. The maximum output power of the fiber laser reaches 1.12 W. The slope efficiency and the optical-optical efficiency with respect to the absorbed pump are 20% and 16%, respectively. The lasing threshold is 1.46 W, and the lasing wavelength is centered at 1937 nm.

Tradeoffs in process strategy games with application in the WDM reconfiguration problem

DEFF Research Database (Denmark)

Cohen, Nathann; Coudert, David; Mazauric, Dorian

2011-01-01

We consider a variant of the graph searching games that models the routing reconfiguration problem in WDM networks. In the digraph processing game, a team of agents aims at processing, or clearing, the vertices of a digraph D. We are interested in two different measures: (1) the total number...... tradeoffs may happen even for a basic class of digraphs. On the other hand, we exhibit classes of graphs for which good tradeoffs can be achieved. We finally detail the relationship between this game and the routing reconfiguration problem. In particular, we prove that any instance of the processing game, i...

Study on basalt fiber parameters affecting fiber-reinforced mortar

Science.gov (United States)

Orlov, A. A.; Chernykh, T. N.; Sashina, A. V.; Bogusevich, D. V.

2015-01-01

This article considers the effect of different dosages and diameters of basalt fibers on tensile strength increase during bending of fiberboard-reinforced mortar samples. The optimal dosages of fiber, providing maximum strength in bending are revealed. The durability of basalt fiber in an environment of cement, by means of microscopic analysis of samples of fibers and fiberboard-reinforced mortar long-term tests is examined. The article also compares the behavior of basalt fiber in the cement stone environment to a glass one and reveals that the basalt fiber is not subject to destruction.

Optical self-injection mode-locking of semiconductor optical amplifier fiber ring with electro-absorption modulation—fundamentals and applications

International Nuclear Information System (INIS)

Chi, Yu-Chieh; Lin, Gong-Ru

2013-01-01

The optical self-injection mode-locking of a semiconductor optical amplifier incorporated fiber ring laser (SOAFL) with spectrally sliced multi-channel carriers is demonstrated for applications. The synthesizer-free SOAFL pulse-train is delivered by optical injection mode-locking with a 10 GHz self-pulsed electro-absorption modulator (EAM). Such a coupled optical and electronic resonator architecture facilitates a self-feedback oscillation with a higher Q-factor and lower phase/intensity noises when compared with conventional approaches. The theoretical model of such an injection-mode-locking SOAFL is derived to improve the self-pulsating performance of the optical return-to-zero (RZ) carrier, thus providing optimized pulsewidth, pulse extinction ratio, effective Q-factor, frequency variation and timing jitter of 11.4 ps, 9.1 dB, 4 × 10 5 , −1 bi-directional WDM transmission network with down-stream RZ binary phase-shift keying (RZ-BPSK) and up-stream re-modulated RZ on–off-keying (RZ-OOK) formats. Under BPSK/OOK bi-directional data transmission, the self-pulsed harmonic mode-locking SOAFL simultaneously provides four to six WDM channels for down-stream RZ-BPSK and up-stream RZ-OOK formats with receiving sensitivities of −17 and −15.2 dBm at a bit error rate of 10 −9 , respectively. (paper)

Optical fiber spectrophotometer

International Nuclear Information System (INIS)

Zhuang Weixin; Tian Guocheng; Ye Guoan; Zhou Zhihong; Cheng Weiwei; Huang Lifeng; Liu Suying; Tang Yanji; Hu Jingxin; Zhao Yonggang

1998-12-01

A method called 'Two Arm's Photo out and Electricity Send-back' is introduced. UV-365 UV/VIS/NIR spectrophotometer has been reequipped by this way with 5 meters long optical fiber. Another method called 'One Arm's Photo out and Photo Send-back' is also introduced. λ 19 UV/VIS/NIR spectrophotometer has been reequipped by this way with 10 meters long optical fiber. Optical fiber spectrophotometer can work as its main set. So it is particularly applicable to radio activity work

Feasibility of Fiber Bragg Grating and Long-Period Fiber Grating Sensors under Different Environmental Conditions

Directory of Open Access Journals (Sweden)

Jian-Neng Wang

2010-11-01

Full Text Available This paper presents the feasibility of utilizing fiber Bragg grating (FBG and long-period fiber grating (LPFG sensors for nondestructive evaluation (NDE of infrastructures using Portland cement concretes and asphalt mixtures for temperature, strain, and liquid-level monitoring. The use of hybrid FBG and LPFG sensors is aimed at utilizing the advantages of two kinds of fiber grating to implement NDE for monitoring strains or displacements, temperatures, and water-levels of infrastructures such as bridges, pavements, or reservoirs for under different environmental conditions. Temperature fluctuation and stability tests were examined using FBG and LPFG sensors bonded on the surface of asphalt and concrete specimens. Random walk coefficient (RWC and bias stability (BS were used for the first time to indicate the stability performance of fiber grating sensors. The random walk coefficients of temperature variations between FBG (or LPFG sensor and a thermocouple were found in the range of −0.7499 °C/ to −1.3548 °C/. In addition, the bias stability for temperature variations, during the fluctuation and stability tests with FBG (or LPFG sensors were within the range of 0.01 °C/h with a 15–18 h time cluster to 0.09 °C/h with a 3–4 h time cluster. This shows that the performance of FBG or LPFG sensors is comparable with that of conventional high-resolution thermocouple sensors under rugged conditions. The strain measurement for infrastructure materials was conducted using a packaged FBG sensor bonded on the surface of an asphalt specimen under indirect tensile loading conditions. A finite element modeling (FEM was applied to compare experimental results of indirect tensile FBG strain measurements. For a comparative analysis between experiment and simulation, the FEM numerical results agreed with those from FBG strain measurements. The results of the liquid-level sensing tests show the LPFG-based sensor could discriminate five stationary liquid

Evidence of a middle longitudinal fasciculus in the human brain from fiber dissection

Science.gov (United States)

Maldonado, Igor Lima; de Champfleur, Nicolas Menjot; Velut, Stéphane; Destrieux, Christophe; Zemmoura, Ilyess; Duffau, Hugues

2013-01-01

A rostrocaudal pathway connecting the temporal and parietal lobes was described in monkeys using autoradiography and was named the middle longitudinal fasciculus (MdLF). Recently, the use of diffusion tensor tractography has allowed it to be depicted in human volunteers. In the present study, a technique of fiber dissection was used in 18 cadaveric human brains to investigate the presence of this fasciculus and to detail its anatomical relationships. On the basis of our findings, fiber dissection provides evidence for a long horizontal bundle medial to the arcuate fasciculus and extending to the superior temporal gyrus. Its fibers occupy the lateral-most layer of the upper portion of the stratum sagittale and partially cover the inferior fronto-occipital fasciculus, which is situated deeper and slightly inferiorly. Whereas MdLF fibers continue on a relatively superficial level to reach the superior temporal gyrus, the inferior fronto-occipital fasciculus penetrates the deep temporal white matter and crosses the insular lobe. Although diffusion tensor imaging suggests that the MdLF terminates in the angular gyrus, this was not confirmed by the present study. These long association fibers continue onward posteriorly into upper portions of the occipital lobe. Further studies are needed to understand the role of the MdLF in brain function. PMID:23621438

Evaluation of correlated digital back propagation and extended Kalman filtering for non-linear mitigation in PM-16-QAM WDM systems

Science.gov (United States)

Pakala, Lalitha; Schmauss, Bernhard

2017-01-01

We investigate the individual and combined performance of correlated digital back propagation (CDBP) and extended Kalman filtering (EKF) in mitigating inter and intra-channel non-linearities in wavelength division multiplexed (WDM) systems. The afore-mentioned algorithms are verified through numerical simulations on 28 Gbaud polarization multiplexed (PM) 16-quadrature amplitude modulation (16-QAM) 9-channel WDM system with 50 GHz spacing. A single channel CDBP with one-step-per-span based on asymmetric split step Fourier method (A-SSFM) with optimized non-linear coefficient has been employed. We also study an amplitude dependent optimization (AO) of the non-linear coefficient for CDBP which shows an improvement of ≍ 0.8 dB compared to the conventional optimized CDBP, in the non-linear regime. Moreover, our proposed carrier phase and amplitude noise estimation (CPANE) algorithm based on EKF outperforms AO-CDBP in both linear and non-linear regimes with an enhanced performance besides significantly reduced complexity. We further investigate the combined performance of AO-CDBP and EKF which results in an enhanced non-linear tolerance at the expense of increased computational cost trading off to the number of required CDBP steps per span. Furthermore, we also analyze the impact of cross phase modulation (XPM) on the combined performance of AO-CDBP and EKF by varying the number of WDM channels. Numerical results show that the obtained gain from employing AO-CDBP prior to EKF reduces with increasing effects of XPM. Additionally, we also discuss the computational complexity of the aforementioned algorithms.

A high spatial resolution distributed optical fiber grating sensing system based on OFDR

Science.gov (United States)

Dong, Ke; Xiong, Yuchuan; Wen, Hongqiao; Tong, Xinlin; Zhang, Cui; Deng, Chengwei

2017-10-01

A distributed optical fiber grating sensing system with large capacity and high spatial resolution is presented. Since highdensity identical weak grating array was utilized as sensing fiber, the multiplexing number was greatly increased, meanwhile, optical frequency domain reflectometry (OFDR) technology was used to implement high resolution distributed sensing system. In order to eliminate the nonlinear effect of tunable light source, a windowed FFT algorithm based on cubic spline interpolation was applied. The feasibility of the algorithm was experimentally testified, ultimately, the spatial resolution of system can reach mm-level. The influence of the crosstalk signal in the grating array on the OFDR system was analyzed. A method that a long enough delay fiber was added before the first FBG to remove crosstalk signal was proposed. The experiment was verified using an optical fiber with 113 uniform Bragg gratings at an interval of 10cm whose reflectivity are less than 1%. It demonstrates that crosstalk signal and measurement signal can be completely separated in the distance domain after adding a long enough delay fiber. Finally, the temperature experiment of distributed grating sensing system was carried out. The results display that each raster's center wavelength in the fiber link is independent of each other and the center wavelength drift has a good linear relationship with the temperature. The sensitivity of linear fitting is equal to 11.1pm/°C.

Long-reach manipulators for decommissioning

International Nuclear Information System (INIS)

Webster, D.A.; Challinor, S.F.

1993-01-01

A survey of redundant facilities at Sellafield has identified that in many cases the conventional means of deploying remote handling equipment are not appropriate and that novel means must be employed. However, decommissioning is not a value adding activity and so expensive one off designs must be avoided. The paper will describe BNFL's approach to the synthesis from proprietary parts of a manipulator which can lift 3 te at a horizontal reach of over 5 metres and yet can still perform the dextrous manipulation necessary to remove small items. It will also cover the development of the manipulator control systems and the adaption of commercial handtools to be manipulator friendly. (author)

Two Fiber Optical Fiber Thermometry

Science.gov (United States)

Jones, Mathew R.; Farmer, Jeffery T.; Breeding, Shawn P.

2000-01-01

An optical fiber thermometer consists of an optical fiber whose sensing tip is given a metallic coating. The sensing tip of the fiber is essentially an isothermal cavity, so the emission from this cavity will be approximately equal to the emission from a blackbody. Temperature readings are obtained by measuring the spectral radiative heat flux at the end of the fiber at two wavelengths. The ratio of these measurements and Planck's Law are used to infer the temperature at the sensing tip. Optical fiber thermometers have high accuracy, excellent long-term stability and are immune to electromagnetic interference. In addition, they can be operated for extended periods without requiring re-calibration. For these reasons. it is desirable to use optical fiber thermometers in environments such as the International Space Station. However, it has recently been shown that temperature readings are corrupted by emission from the fiber when extended portions of the probe are exposed to elevated temperatures. This paper will describe several ways in which the reading from a second fiber can be used to correct the corrupted temperature measurements. The accuracy and sensitivity to measurement uncertainty will be presented for each method.

1 Tb/s x km multimode fiber link combining WDM transmission and low-linewidth lasers.

Science.gov (United States)

Gasulla, I; Capmany, J

2008-05-26

We have successfully demonstrated an error-free transmission of 10 x 20 Gb/s 200 GHz-spaced ITU channels through a 5 km link of 62.5-microm core-diameter graded-index multimode silica fiber. The overall figure corresponds to an aggregate bit rate per length product of 1 Tb/s x km, the highest value ever reported to our knowledge. Successful transmission is achieved by a combination of low-linewidth DFB lasers and the central launch technique.

Modeling the video distribution link in the Next Generation Optical Access Networks

DEFF Research Database (Denmark)

Amaya, F.; Cárdenas, A.; Tafur Monroy, Idelfonso

2011-01-01

In this work we present a model for the design and optimization of the video distribution link in the next generation optical access network. We analyze the video distribution performance in a SCM-WDM link, including the noise, the distortion and the fiber optic nonlinearities. Additionally, we...... consider in the model the effect of distributed Raman amplification, used to extent the capacity and the reach of the optical link. In the model, we use the nonlinear Schrödinger equation with the purpose to obtain capacity limitations and design constrains of the next generation optical access networks....

Fiber-Optic Chemical Sensors and Fiber-Optic Bio-Sensors

Science.gov (United States)

Pospíšilová, Marie; Kuncová, Gabriela; Trögl, Josef

2015-01-01

This review summarizes principles and current stage of development of fiber-optic chemical sensors (FOCS) and biosensors (FOBS). Fiber optic sensor (FOS) systems use the ability of optical fibers (OF) to guide the light in the spectral range from ultraviolet (UV) (180 nm) up to middle infrared (IR) (10 µm) and modulation of guided light by the parameters of the surrounding environment of the OF core. The introduction of OF in the sensor systems has brought advantages such as measurement in flammable and explosive environments, immunity to electrical noises, miniaturization, geometrical flexibility, measurement of small sample volumes, remote sensing in inaccessible sites or harsh environments and multi-sensing. The review comprises briefly the theory of OF elaborated for sensors, techniques of fabrications and analytical results reached with fiber-optic chemical and biological sensors. PMID:26437407

Fiber-Optic Chemical Sensors and Fiber-Optic Bio-Sensors.

Science.gov (United States)

Pospíšilová, Marie; Kuncová, Gabriela; Trögl, Josef

2015-09-30

This review summarizes principles and current stage of development of fiber-optic chemical sensors (FOCS) and biosensors (FOBS). Fiber optic sensor (FOS) systems use the ability of optical fibers (OF) to guide the light in the spectral range from ultraviolet (UV) (180 nm) up to middle infrared (IR) (10 μm) and modulation of guided light by the parameters of the surrounding environment of the OF core. The introduction of OF in the sensor systems has brought advantages such as measurement in flammable and explosive environments, immunity to electrical noises, miniaturization, geometrical flexibility, measurement of small sample volumes, remote sensing in inaccessible sites or harsh environments and multi-sensing. The review comprises briefly the theory of OF elaborated for sensors, techniques of fabrications and analytical results reached with fiber-optic chemical and biological sensors.

Analysis of self-homodyne detection for 6-mode fiber with low-modal crosstalk

Science.gov (United States)

Guo, Meng; Hu, Guijun

2017-12-01

In this paper, we present an appropriate analysis on self-homodyne coherent system with 56 × 5 × 3 Gb / s WDM-PDM-MDM quadrature phase-shift keying (QPSK) signals using 6-mode weakly coupled few mode fiber. The mode division technology can effectively improve the spectral efficiency (SE) of self-homodyne detection. Of all the LP modes, LP01 mode is used to transmit the pilot tone (PT), while the others for signal channels. The influence of inter-mode crosstalk is analyzed. The proposed frequency domain MMA shows a better BER performance for intra-mode crosstalk elimination. The path-length misalignment's influence caused by mode differential group delay (MDGD) is also investigated. The system tolerance for different laser's line-width is compared as well as the influence of PT filter's bandwidth.

Vector rectangular-shape laser based on reduced graphene oxide interacting with a long fiber taper.

Science.gov (United States)

Gao, Lei; Zhu, Tao; Huang, Wei; Zeng, Jing

2014-10-01

A vector dual-wavelength rectangular-shape laser (RSL) based on a long fiber taper deposited with reduced graphene oxide is proposed, where nonlinearity is enhanced due to a large evanescent-field-interacting length and strong field confinement of an 8 mm fiber taper with a waist diameter of 4 μm. Graphene flakes are deposited uniformly on the taper waist with light pressure effect, so this structure guarantees both excellent saturable absorption and high nonlinearity. The RSL with a repetition rate of 7.9 MHz shows fast polarization switching in two orthogonal polarization directions, and temporal and spectral characteristics are investigated.

Long fiber Bragg grating sensor interrogation using discrete-time microwave photonic filtering techniques.

Science.gov (United States)

Ricchiuti, Amelia Lavinia; Barrera, David; Sales, Salvador; Thevenaz, Luc; Capmany, José

2013-11-18

A novel technique for interrogating photonic sensors based on long fiber Bragg gratings (FBGs) is presented and experimentally demonstrated, dedicated to detect the presence and the precise location of several spot events. The principle of operation is based on a technique used to analyze microwave photonics (MWP) filters. The long FBGs are used as quasi-distributed sensors. Several hot-spots can be detected along the FBG with a spatial accuracy under 0.5 mm using a modulator and a photo-detector (PD) with a modest bandwidth of less than 1 GHz. The proposed interrogation system is intrinsically robust against environmental changes.

Refractive index and temperature sensors based on no-core fiber cascaded with long period fiber grating

Science.gov (United States)

Zhang, Jianming; Pu, Shengli; Rao, Jie; Yao, Tianjun

2018-05-01

A kind of compact fibre-optic sensor based on no-core fibre (NCF) cascaded with a strong coupling long-period fibre grating (LPFG) is proposed and experimentally demonstrated. The sensing mechanism is based on the Mach-Zehnder-like interference between the core fundamental mode and cladding mode of the fibre structure. The NCF and LPFG are used as the mode exciter and combiner, respectively. Due to the particular properties of the strong coupling LPFG, the measurements of refractive index (RI) and temperature with high sensitivity are realized by monitoring the transmission spectrum with intensity and wavelength interrogation techniques, respectively. The achieved RI sensitivity reaches -580.269 dB/RIU in the range of 1.436-1.454 and the temperature sensitivity reaches 27.2 pm/°C.

Collagen Fiber Orientation in Primate Long Bones.

Science.gov (United States)

Warshaw, Johanna; Bromage, Timothy G; Terranova, Carl J; Enlow, Donald H

2017-07-01

Studies of variation in orientation of collagen fibers within bone have lead to the proposition that these are preferentially aligned to accommodate different kinds of load, with tension best resisted by fibers aligned longitudinally relative to the load, and compression best resisted by transversely aligned fibers. However, previous studies have often neglected to consider the effect of developmental processes, including constraints on collagen fiber orientation (CFO), particularly in primary bone. Here we use circularly polarized light microscopy to examine patterns of CFO in cross-sections from the midshaft femur, humerus, tibia, radius, and ulna in a range of living primate taxa with varied body sizes, phylogenetic relationships and positional behaviors. We find that a preponderance of longitudinally oriented collagen is characteristic of both periosteal primary and intracortically remodeled bone. Where variation does occur among groups, it is not simply understood via interpretations of mechanical loads, although prioritized adaptations to tension and/or shear are considered. While there is some suggestion that CFO may correlate with body size, this relationship is neither consistent nor easily explicable through consideration of size-related changes in mechanical adaptation. The results of our study indicate that there is no clear relationship between CFO and phylogenetic status. One of the principle factors accounting for the range of variation that does exist is primary tissue type, where slower depositing bone is more likely to comprise a larger proportion of oblique to transverse collagen fibers. Anat Rec, 300:1189-1207, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Traffic grooming in WDM optical network with grooming resources at Max Connectivity nodes

Science.gov (United States)

Paul, Partha; Rawat, Balbeer Singh; Ghorai, S. K.

2012-12-01

In this paper, we propose Max Connectivity grooming in WDM mesh networks under static lightpath connection requests. The grooming and wavelength conversion resources are placed at the nodes having maximum connections. We propose a heuristic genetic algorithm (GA) model to solve grooming, routing and wavelength assignment. The GA algorithm has been used to optimize the cost of grooming and wavelength conversion resources. The blocking probability has been investigated under different lightpath connections. The performance of Max Connectivity grooming has been compared with other grooming policies. Our results indicate the improvement of resource utilization with minimum blocking probability.

InP-based monolithically integrated 1310/1550nm diplexer/triplexer

Science.gov (United States)

Silfvenius, C.; Swillo, M.; Claesson, J.; Forsberg, E.; Akram, N.; Chacinski, M.; Thylén, L.

2008-11-01

Multiple streams of high definition television (HDTV) and improved home-working infrastructure are currently driving forces for potential fiber to the home (FTTH) customers [1]. There is an interest to reduce the cost and physical size of the FTTH equipment. The current fabrication methods have reached a cost minimum. We have addressed the costchallenge by developing 1310/(1490)/1550nm bidirectional diplexers, by monolithic seamless integration of lasers, photodiodes and wavelength division multiplexing (WDM) couplers into one single InP-based device. A 250nm wide optical gain profile covers the spectrum from 1310 to 1550nm and is the principal building block. The device fabrication is basically based on the established configuration of using split-contacts on continuos waveguides. Optical and electrical cross-talks are further addressed by using a Y-configuration to physically separate the components from each other and avoid inline configurations such as when the incoming signal travels through the laser component or vice versa. By the eliminated butt-joint interfaces which can reflect light between components or be a current leakage path and by leaving optically absorbing (unpumped active) material to surround the components to absorb spontaneous emission and nonintentional reflections the devices are optically and electrically isolated from each other. Ridge waveguides (RWG) form the waveguides and which also maintain the absorbing material between them. The WDM functionality is designed for a large optical bandwidth complying with the wide spectral range in FTTH applications and also reducing the polarization dependence of the WDM-coupler. Lasing is achieved by forming facet-free, λ/4-shifted, DFB (distributed feedback laser) lasers emitting directly into the waveguide. The photodiodes are waveguide photo-diodes (WGPD). Our seamless technology is also able to array the single channel diplexers to 4 to 12 channel diplexer arrays with 250μm fiber port

1887 nm lasing in Tm3+-doped TeO2-BaF2-Y2O3 glass microstructured fibers

Science.gov (United States)

Wang, Shunbin; Yao, Chuanfei; Jia, Zhixu; Qin, Guanshi; Qin, Weiping

2017-04-01

In this paper, we demonstrate ∼2 μm lasing in Tm3+-doped fluorotellurite microstructured fibers. The Tm3+-doped fibers are based on TeO2-BaF2-Y2O3 glasses and fabricated by using a rod-in-tube method. Under the pump of a 1570 nm Er3+-doped fiber laser, lasing at 1887 nm is obtained in a ∼42.5 cm long Tm3+-doped fiber with a threshold pump power of 94 mW. As the pump power increases to 780 mW, the obtained maximum unsaturated power reaches up to ∼408 mW with a slop efficiency of ∼58.1%. This result indicates that the Tm3+-doped fluorotellurite fibers are promising gain media for ∼2 μm fiber lasers.

Device Characterization of High Performance Quantum Dot Comb Laser

KAUST Repository

Rafi, Kazi

2012-01-01

and video) in FTTH and FTTP-based WDM-PON networks, metropolitan area network (MAN), and short-reach rack-to-rack optical computer communications, a versatile and cost effective WDM transmitter design is required, where several DFB lasers can be replaced

Characterization, Long-Term Behavior Evaluation and Thermomechanical Properties of Untreated and Treated Flax Fiber-Reinforced Composites

Science.gov (United States)

Amiri, Ali

In recent years there has been a resurgence of interest in the usage of natural fiber reinforced composites in more advanced structural applications. Consequently, the need for improving their mechanical properties as well as service life and long-term behavior modeling and predictions has arisen. In a step towards further development of these materials, in this study, two newly developed biobased resins, derived from soybean oil, methacrylated epoxidized sucrose soyate and double methacrylated epoxidized sucrose soyate are combined with untreated and alkaline treated flax fiber to produce novel biocomposites. Vinyl ester reinforced with flax fiber is used as control in addition to comparing properties of biobased composites against commercial pultruded composites. Effects of alkaline treatment of flax fiber as well as addition of 1% acrylic resin to vinyl ester and the two mentioned biobased resins on mechanical properties are studied. Properties are evaluated in short-term and also, after being exposed to accelerated weathering (i.e. UV and moisture). Moreover, long-term creep of these novel biobased composites and effect of fiber and matrix treatment on viscoelastic behavior is investigated using Time-temperature superposition (TTS) principle. Based on the results of this study, the TTS provides an accelerated method for evaluation of mechanical properties of biobased composites, and satisfactory master curves are achieved by use of this principle. Also, fiber and matrix treatments were effective in increasing mechanical properties of biobased composites in short-term, and treatments delayed the creep response and slowed the process of creep in composites under study in the steady state region. Overall, results of this study reveal the successful production of biocomposites having properties that meet or exceed those of conventional pultruded members while maintaining high biocontent. Composites using treated flax fiber and newly developed resins showed less

Dynamic multicast routing scheme in WDM optical network

Science.gov (United States)

Zhu, Yonghua; Dong, Zhiling; Yao, Hong; Yang, Jianyong; Liu, Yibin

2007-11-01

During the information era, the Internet and the service of World Wide Web develop rapidly. Therefore, the wider and wider bandwidth is required with the lower and lower cost. The demand of operation turns out to be diversified. Data, images, videos and other special transmission demands share the challenge and opportunity with the service providers. Simultaneously, the electrical equipment has approached their limit. So the optical communication based on the wavelength division multiplexing (WDM) and the optical cross-connects (OXCs) shows great potentials and brilliant future to build an optical network based on the unique technical advantage and multi-wavelength characteristic. In this paper, we propose a multi-layered graph model with inter-path between layers to solve the problem of multicast routing wavelength assignment (RWA) contemporarily by employing an efficient graph theoretic formulation. And at the same time, an efficient dynamic multicast algorithm named Distributed Message Copying Multicast (DMCM) mechanism is also proposed. The multicast tree with minimum hops can be constructed dynamically according to this proposed scheme.

Role of Fiber Length on Phagocytosis & Inflammatory Response

Science.gov (United States)

Turkevich, Leonid; Stark, Carahline; Champion, Julie

2014-03-01

Asbestos fibers have long been associated with lung cancer death. The inability of immune cells (e.g. macrophages) to effectively remove asbestos leads to chronic inflammation and disease. This study examines the role of fiber length on toxicity at the cellular level using model glass fibers. A major challenge is obtaining single diameter fibers but differing in length. Samples of 1 micron diameter fibers with different length distributions were prepared: short fibers (less than 15 microns) by aggressive crushing, and long fibers (longer than 15 microns) by successive sedimentation. Time-lapse video microscopy monitored the interaction of MH-S murine alveolar macrophages with the fibers: short fibers were easily internalized by the macrophages, but long fibers resisted internalization over many hours. Production of TNF- α (tumor necrosis factor alpha), a general inflammatory secreted cytokine, and Cox-2 (cyclo-oxygenase-2), an enzyme that produces radicals, each exhibited a dose-dependence that was greater for long than for short fibers. These results corroborate the importance of fiber length in both physical and biochemical cell response and support epidemiological observations of higher toxicity for longer fibers.

Fiber-Optic Chemical Sensors and Fiber-Optic Bio-Sensors

Directory of Open Access Journals (Sweden)

Marie Pospíšilová

2015-09-01

Full Text Available This review summarizes principles and current stage of development of fiber-optic chemical sensors (FOCS and biosensors (FOBS. Fiber optic sensor (FOS systems use the ability of optical fibers (OF to guide the light in the spectral range from ultraviolet (UV (180 nm up to middle infrared (IR (10 μm and modulation of guided light by the parameters of the surrounding environment of the OF core. The introduction of OF in the sensor systems has brought advantages such as measurement in flammable and explosive environments, immunity to electrical noises, miniaturization, geometrical flexibility, measurement of small sample volumes, remote sensing in inaccessible sites or harsh environments and multi-sensing. The review comprises briefly the theory of OF elaborated for sensors, techniques of fabrications and analytical results reached with fiber-optic chemical and biological sensors.

A long-baseline interferometer employing single-mode fiber optics

Science.gov (United States)

Shaklan, Stuart

The idea of the Fiber-Linked Optical Array Telescope proposed by Connes (1987) is to mount several small optical telescopes around the perimeter of a radio dish or other large steerable structure, couple the light into single-mode (SM) fibers, and use the fibers to coherently combine the beams at the output. This paper examines the important properties of SM fibers and then discusses the whole system in general terms, starting with the telescopes and following the light through to the detectors, along with the results of laboratory experiments evaluating the performance of SM fibers. The imaging capabilities of the array were simulated, and it was found that, using 10 telescopes on a 440-m dish, the array obtains images with resolution of the order of 2 milliarc seconds in the visible range.

Detection of 2-mm-long strained section in silica fiber using slope-assisted Brillouin optical correlation-domain reflectometry

Science.gov (United States)

Lee, Heeyoung; Mizuno, Yosuke; Nakamura, Kentaro

2018-02-01

Slope-assisted Brillouin optical correlation-domain reflectometry is a single-end-access distributed Brillouin sensing technique with high spatial resolution and high-speed operation. We have recently discovered its unique feature, that is, strained or heated sections even shorter than nominal resolution can be detected, but its detailed characterization has not been carried out. Here, after experimentally characterizing this “beyond-nominal-resolution” effect, we show its usefulness by demonstrating the detection of a 2-mm-long strained section along a silica fiber. We also demonstrate the detection of a 5-mm-long heated section along a polymer optical fiber. The lengths of these detected sections are smaller than those of the other demonstrations reported so far.

Compressive Behavior of Fiber-Reinforced Concrete with End-Hooked Steel Fibers

Directory of Open Access Journals (Sweden)

Seong-Cheol Lee

2015-03-01

Full Text Available In this paper, the compressive behavior of fiber-reinforced concrete with end-hooked steel fibers has been investigated through a uniaxial compression test in which the variables were concrete compressive strength, fiber volumetric ratio, and fiber aspect ratio (length to diameter. In order to minimize the effect of specimen size on fiber distribution, 48 cylinder specimens 150 mm in diameter and 300 mm in height were prepared and then subjected to uniaxial compression. From the test results, it was shown that steel fiber-reinforced concrete (SFRC specimens exhibited ductile behavior after reaching their compressive strength. It was also shown that the strain at the compressive strength generally increased along with an increase in the fiber volumetric ratio and fiber aspect ratio, while the elastic modulus decreased. With consideration for the effect of steel fibers, a model for the stress–strain relationship of SFRC under compression is proposed here. Simple formulae to predict the strain at the compressive strength and the elastic modulus of SFRC were developed as well. The proposed model and formulae will be useful for realistic predictions of the structural behavior of SFRC members or structures.

Compressive Behavior of Fiber-Reinforced Concrete with End-Hooked Steel Fibers.

Science.gov (United States)

Lee, Seong-Cheol; Oh, Joung-Hwan; Cho, Jae-Yeol

2015-03-27

In this paper, the compressive behavior of fiber-reinforced concrete with end-hooked steel fibers has been investigated through a uniaxial compression test in which the variables were concrete compressive strength, fiber volumetric ratio, and fiber aspect ratio (length to diameter). In order to minimize the effect of specimen size on fiber distribution, 48 cylinder specimens 150 mm in diameter and 300 mm in height were prepared and then subjected to uniaxial compression. From the test results, it was shown that steel fiber-reinforced concrete (SFRC) specimens exhibited ductile behavior after reaching their compressive strength. It was also shown that the strain at the compressive strength generally increased along with an increase in the fiber volumetric ratio and fiber aspect ratio, while the elastic modulus decreased. With consideration for the effect of steel fibers, a model for the stress-strain relationship of SFRC under compression is proposed here. Simple formulae to predict the strain at the compressive strength and the elastic modulus of SFRC were developed as well. The proposed model and formulae will be useful for realistic predictions of the structural behavior of SFRC members or structures.

Quad 14 Gbps L-band VCSEL-based system for WDM migration of 4-lanes 56 Gbps optical data links

DEFF Research Database (Denmark)

Estaran Tolosa, Jose Manuel; Rodes Lopez, Roberto; Pham, Tien Thang

2012-01-01

We report on migrating multiple-lane link into an L-band VCSEL-based WDM system. Experimental validation achieves successful transmission over 10 km of SMF at 4x14Gbps. Inter-channel crosstalk penalty is observed to be less than 0.5 dB and a transmission penalty around 1 dB. The power budget margin...

Core-cladding mode coupling and recoupling in photonic crystal fiber for enhanced overlap of evanescent field using long-period gratings

Czech Academy of Sciences Publication Activity Database

He, Z.; Zhu, Y.; Kaňka, Jiří; Du, H.

2010-01-01

Roč. 18, č. 2 (2010), s. 507-512 ISSN 1094-4087 R&D Projects: GA ČR GA102/08/1719 Institutional research plan: CEZ:AV0Z20670512 Keywords : Photonic crystal fiber * Long-period grating * Fiber-optic evanescent sensor Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.749, year: 2010

Complete Fiber/Copper Cable Solution for Long-Term Temperature and Pressure Measurement in Supercritical Reservoirs and EGS Wells

Energy Technology Data Exchange (ETDEWEB)

Pastouret, Alan [Draka Cableteq USA, Inc., North Dighton, MA (United States); Gooijer, Frans [Draka Cableteq USA, Inc., North Dighton, MA (United States); Overton, Bob [Draka Cableteq USA, Inc., North Dighton, MA (United States); Jonker, Jan [Draka Cableteq USA, Inc., North Dighton, MA (United States); Curley, Jim [Draka Cableteq USA, Inc., North Dighton, MA (United States); Constantine, Walter [Draka Cableteq USA, Inc., North Dighton, MA (United States); Waterman, Kendall Miller [Draka Cableteq USA, Inc., North Dighton, MA (United States)

2015-11-13

High Temperature insulated wire and optical fiber cable is a key enabling technology for the Geothermal Technologies Program (GTP). Without insulated electrical wires and optical fiber, downhole temperature and pressure sensors, flow meters and gauges cannot communicate with the surface. Unfortunately, there are currently no insulated electrical wire or fiber cable constructions capable of surviving for extended periods of deployment in a geothermal well (240-325°C) or supercritical (374°C) reservoir. This has severely hindered engineered reservoir creation, management and utilization, as hot zones and cool water intrusions cannot be understood over time. The lack of a insulated electrical wire and fiber cable solution is a fundamental limitation to the viability of this energy source. The High Temperature Downhole Tools target specification is development of tools and sensors for logging and monitoring wellbore conditions at depths of up to 10,000 meters and temperatures up to 374oC. It well recognized in the industry that no current electronic or fiber cable can be successfully deployed in a well and function successfully for more a few days at temperatures over 240oC. The goal of this project was to raise this performance level significantly. Prysmian Group’s objective in this project was to develop a complete, multi-purpose cable solution for long-term deployment in geothermal wells/reservoirs that can be used with the widest variety of sensors. In particular, the overall project objective was to produce a manufacturable cable design that can perform without serious degradation: • At temperatures up to 374°C; • At pressures up to 220 bar; • In a hydrogen-rich environment; and • For the life of the well (> 5 years). This cable incorporates: • Specialty optical fibers, with specific glass chemistry and high temperature and pressure protective coatings for data communication and distributed temperature and pressure sensing, and • High

Resonant filtered fiber amplifiers

DEFF Research Database (Denmark)

Alkeskjold, Thomas Tanggaard; Laurila, Marko; Olausson, Christina Bjarnal Thulin

2013-01-01

In this paper we present our recent result on utilizing resonant/bandgap fiber designs to achieve high performance ytterbium doped fiber amplifers for achieving diffraction limited beam quality in large mode area fibers, robust bending performance and gain shaping for long wavelength operation...

An Optical Fiber Viscometer Based on Long-Period Fiber Grating Technology and Capillary Tube Mechanism

Directory of Open Access Journals (Sweden)

Jian-Neng Wang

2010-12-01

Full Text Available This work addresses the development and assessment of a fiber optical viscometer using a simple and low-cost long-period fiber grating (LPFG level sensor and a capillary tube mechanism. Previous studies of optical viscosity sensors were conducted by using different optical sensing methods. The proposed optical viscometer consists of an LPFG sensor, a temperature-controlled chamber, and a cone-shaped reservoir where gravitational force could cause fluid to flow through the capillary tube. We focused on the use of LPFGs as level sensors and the wavelength shifts were not used to quantify the viscosity values of asphalt binders. When the LPFG sensor was immersed in the constant volume (100 mL AC-20 asphalt binder, a wavelength shift was observed and acquired using LabVIEW software and GPIB controller. The time spent between empty and 100 mL was calculated to determine the discharge time. We simultaneously measured the LPFG-induced discharge time and the transmission spectra both in hot air and AC-20 asphalt binder at five different temperatures, 60, 80, 100, 135, and 170 Celsius. An electromechanical rotational viscometer was also used to measure the viscosities, 0.15–213.80 Pa·s, of the same asphalt binder at the above five temperatures. A non-linear regression analysis was performed to convert LPFG-induced discharge time into viscosities. Comparative analysis shows that the LPFG-induced discharge time agreed well with the viscosities obtained from the rotational viscometer.

Single channel and WDM transmission of 28 Gbaud zero-guard-interval CO-OFDM.

Science.gov (United States)

Zhuge, Qunbi; Morsy-Osman, Mohamed; Mousa-Pasandi, Mohammad E; Xu, Xian; Chagnon, Mathieu; El-Sahn, Ziad A; Chen, Chen; Plant, David V

2012-12-10

We report on the experimental demonstration of single channel 28 Gbaud QPSK and 16-QAM zero-guard-interval (ZGI) CO-OFDM transmission with only 1.34% overhead for OFDM processing. The achieved transmission distance is 5120 km for QPSK assuming a 7% forward error correction (FEC) overhead, and 1280 km for 16-QAM assuming a 20% FEC overhead. We also demonstrate the improved tolerance of ZGI CO-OFDM to residual inter-symbol interference compared to reduced-guard-interval (RGI) CO-OFDM. In addition, we report an 8-channel wavelength-division multiplexing (WDM) transmission of 28 Gbaud QPSK ZGI CO-OFDM signals over 4160 km.

Fiber-optic laser-induced breakdown spectroscopy of zirconium metal in air: Special features of the plasma produced by a long-pulse laser

Science.gov (United States)

Matsumoto, Ayumu; Ohba, Hironori; Toshimitsu, Masaaki; Akaoka, Katsuaki; Ruas, Alexandre; Sakka, Tetsuo; Wakaida, Ikuo

2018-04-01

The decommissioning of the Tokyo Electric Power Company (TEPCO) Fukushima Daiichi Nuclear Power Plant is an essential issue in nuclear R&D. Fiber-optic laser-induced breakdown spectroscopy (Fiber-optic LIBS) could be used for in-situ elemental analysis of the inside of the damaged reactors. To improve the performances under difficult conditions, using a long-pulse laser can be an efficient alternative. In this work, the emission spectra of zirconium metal in air obtained for a normal-pulse laser (6 ns) and a long-pulse laser (100 ns) (wavelength: 1064 nm, pulse energy: 12.5 mJ, spot diameter: 0.35 mm) are compared to investigate the fundamental aspects of fiber-optic LIBS with the long-pulse laser. The spectral features are considerably different: when the long-pulse laser is used, the atomic and molecular emission is remarkably enhanced. The enhancement of the atomic emission at the near infrared (NIR) region would lead to the observation of emission lines with minimum overlapping. To understand the differences in the spectra induced respectively from the normal-pulse laser and the long-pulse laser, photodiode signals, time-resolved spectra, plasma parameters, emission from the ambient air, and emission regions are investigated, showing the particular characteristics of the plasma produced by the long-pulse laser.

Commercially Available Activated Carbon Fiber Felt Enables Efficient Solar Steam Generation.

Science.gov (United States)

Li, Haoran; He, Yurong; Hu, Yanwei; Wang, Xinzhi

2018-03-21

Sun-driven steam generation is now possible and has the potential to help meet future energy needs. Current technologies often use solar condensers to increase solar irradiance. More recently, a technology for solar steam generation that uses heated surface water and low optical concentration is reported. In this work, a commercially available activated carbon fiber felt is used to generate steam efficiently under one sun illumination. The evaporation rate and solar conversion efficiency reach 1.22 kg m -2 h -1 and 79.4%, respectively. The local temperature of the evaporator with a floating activated carbon fiber felt reaches 48 °C. Apart from the high absorptivity (about 94%) of the material, the evaporation performance is enhanced thanks to the well-developed pores for improved water supply and steam escape and the low thermal conductivity, which enables reduced bulk water temperature increase. This study helps to find a promising material for solar steam generation using a water evaporator that can be produced economically (∼6 $/m 2 ) with long-term stability.

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites. Topical Report

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Ba Nghiep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Jin [Autodesk, Inc., Ithaca, NY (United States); Costa, Franco [Autodesk, Inc., Ithaca, NY (United States); Lambert, Gregory [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Baird, Donald G. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Sharma, Bhisham A. [Purdue Univ., West Lafayette, IN (United States); Kijewski, Seth A. [Purdue Univ., West Lafayette, IN (United States); Sangid, Michael D. [Purdue Univ., West Lafayette, IN (United States); Gandhi, Umesh N. [Toyota Research Inst. North America, Ann Arbor, MI (United States); Wollan, Eric J. [PlastiComp, Inc., Winona, MN (United States); Roland, Dale [PlastiComp, Inc., Winona, MN (United States); Mori, Steven [Magna Exteriors and Interiors Corporation, Aurora, ON (Canada); Tucker, III, Charles L. [Univ. of Illinois, Urbana-Champaign, IL (United States)

2016-06-01

This project aimed to integrate, optimize, and validate the fiber orientation and length distribution models previously developed and implemented in the Autodesk® Simulation Moldflow® Insight (ASMI) software package for injection-molded long-carbon-fiber (LCF) thermoplastic composite structures. The project was organized into two phases. Phase 1 demonstrated the ability of the advanced ASMI package to predict fiber orientation and length distributions in LCF/polypropylene (PP) and LCF/polyamide-6, 6 (PA66) plaques within 15% of experimental results. Phase 2 validated the advanced ASMI package by predicting fiber orientation and length distributions within 15% of experimental results for a complex three-dimensional (3D) Toyota automotive part injection-molded from LCF/PP and LCF/PA66 materials. Work under Phase 2 also included estimate of weight savings and cost impacts for a vehicle system using ASMI and structural analyses of the complex part. The present report summarizes the completion of Phases 1 and 2 work activities and accomplishments achieved by the team comprising Pacific Northwest National Laboratory (PNNL); Purdue University (Purdue); Virginia Polytechnic Institute and State University (Virginia Tech); Autodesk, Inc. (Autodesk); PlastiComp, Inc. (PlastiComp); Toyota Research Institute North America (Toyota); Magna Exteriors and Interiors Corp. (Magna); and University of Illinois. Figure 1 illustrates the technical approach adopted in this project that progressed from compounding LCF/PP and LCF/PA66 materials, to process model improvement and implementation, to molding and modeling LCF/PP and LCF/PA66 plaques. The lessons learned from the plaque study and the successful validation of improved process models for fiber orientation and length distributions for these plaques enabled the project to go to Phase 2 to mold, model, and optimize the 3D complex part.

Compact and high-sensitivity 100-Gb/s (4 × 25 Gb/s) APD-ROSA with a LAN-WDM PLC demultiplexer.

Science.gov (United States)

Yoshimatsu, Toshihide; Nada, Masahiro; Oguma, Manabu; Yokoyama, Haruki; Ohno, Tetsuichiro; Doi, Yoshiyuki; Ogawa, Ikuo; Takahashi, Hiroshi; Yoshida, Eiji

2012-12-10

We demonstrate an integrated 100 GbE receiver optical sub-assembly (ROSA) that incorporates a monolithic four-channel avalanche photodiode (APD) array and a planer lightwave circuit (PLC) based LAN-WDM demultiplexer. A record minimum receiver sensitivity of -20 dBm and 50-km error-free SMF transmission without an optical amplifier have been achieved.

INFLUENCE OF POLARIZATION MODE DISPERSION ON THE EFFECT OF CROSS-PHASE MODULATION IN INTENSITY MODULATION-DIRECT DETECTION WDM TRANSMISSION SYSTEM

Directory of Open Access Journals (Sweden)

M S Islam

2010-03-01

Full Text Available Cross-phase modulation (XPM changes the state-of-polarization (SOP of the channels through nonlinear polarization rotation and induces nonlinear time dependent phase shift for polarization components that leads to amplitude modulation of the propagating waves in a wavelength division multiplexing (WDM system. Due to the presence of birefringence, the angle between the SOP changes randomly and as a result polarization mode dispersion (PMD causes XPM modulation amplitude fluctuation random in the perturbed channel. In this paper we analytically determine the probability density function of the random angle between the SOP of pump and probe, and evaluate the impact of polarization mode dispersion on XPM in terms of bit error rate, channel spacing etc for a two channel intensity modulation-direct detection WDM system at 10 Gb/s. It is found that the XPM induced crosstalk is polarization independent for channel spacing greater than 3 nm or PMD coefficient larger than 2 ps/√km. We also investigate the dependence of SOP variance on PMD coefficient and channel spacing.

Effect of cellulase treatment of long fiber fraction on strength ...

African Journals Online (AJOL)

fiber and unbeaten short-fiber fractions. The obtained test results have indicate that the application of enzyme on appropriate fiber fraction have positive effects on the strength properties of the corrugated medium. The short span compression ...

WDM Optical Access Network for Full-Duplex and Reconfigurable Capacity Assignment Based on PolMUX Technique

Directory of Open Access Journals (Sweden)

Jose Mora

2014-12-01

Full Text Available We present a novel bidirectional WDM-based optical access network featuring reconfigurable capacity assignment. The architecture relies on the PolMUX technique allowing a compact, flexible, and bandwidth-efficient router in addition to source-free ONUs and color-less ONUs for cost/complexity minimization. Moreover, the centralized architecture contemplates remote management and control of polarization. High-quality transmission of digital signals is demonstrated through different routing scenarios where all channels are dynamically assigned in both downlink and uplink directions.

Fiber Optic Long Period Grating Based Sensor for Coconut Oil Adulteration Detection

Directory of Open Access Journals (Sweden)

T. M. Libish

2010-03-01

Full Text Available We report the development and demonstration of a Long-Period Grating (LPG based optical fiber sensor for determining the adulteration of coconut oil by palm oil. The fundamental principle of detection is the sensitive dependence of the resonance peaks of LPG on the changes of the refractive index of the environmental medium around the cladding surface of the grating. Refractive index sensing with LPGs employs light coupling between core and cladding modes in the grating section. The transmittance spectra of a long period grating element immersed in different mixtures of coconut oil and palm oil were recorded. Results show that resonance wavelengths and transmission intensities varied as a function of the adulteration level of coconut oil. Detection limit of adulteration was found to be 2 % for coconut oil–palm oil binary mixture.

Variation, heritability and association of yield, fiber and morphological traits in a near long staple upland cotton population

International Nuclear Information System (INIS)

Shao, D.; Wang, T.; Zhang, H.; Zhu, J.; Tang, F.

2016-01-01

Development of near long staple (NLS) cotton germplasm represents a remarkable improvement in fiber properties of upland genotypes without compromising yield potential. This study aimed to evaluate a NLS population for variability in yield, fiber and morphological traits, investigate heritability and genetic advance of these traits, and analyze the interrelationships among them. The NLS lines exhibited large variation for lint yield per hectare and bolls per plant, while little variation for fiber properties. The highest genotypic (GCV) and phenotypic (PCV) coefficient of variation were recorded by lint yield per hectare (25.10%, 23.00%) followed by bolls per plant (18.88%, 16.38%). High heritability along with high response to selection was documented in plant height, bolls per plant and lint yield per hectare indicating that the additive gene function model in the inheritance of these traits and direct selection can be profitably applied on them. Favourable associations were found among fiber length, strength and fineness in this population. It is concluded that there is a great potential in the NSL population for further enhancing yield while maintaining high fiber quality. (author)

Fabrication of high quality, ultra-long fiber Bragg gratings: up to 2 million periods in phase.

Science.gov (United States)

Gagné, Mathieu; Loranger, Sébastien; Lapointe, Jerome; Kashyap, Raman

2014-01-13

The fabrication and characterization of high quality ultra-long (up to 1m) fiber Bragg gratings (FBGs) is reported. A moving phase mask and an electro-optic phase-modulation (EOPM) based interferometer are used with a high precision 1-meter long translation stage and compared. A novel interferometer position feedback scheme to simplify the fabrication process is proposed and analyzed. The ultra-long uniform FBGs show near perfect characteristics of a few picometers bandwidth, symmetrical, near theory-matching group-delay and transmission spectra. Grating characterization using optical backscattering reflectometry and chirped FBGs are also demonstrated. Limitations of the schemes are discussed.

Control of a long reach manipulator with suspension cables for waste storage tank remediation. Final report

International Nuclear Information System (INIS)

Wang, S.L.

1994-01-01

A long reach manipulator will be used for waste remediation in large underground storage tanks. The manipulator's slenderness makes it flexible and difficult to control. A low-cost and effective method to enhance the manipulator's stiffness is proposed in this research by using suspension cables. These cables can also be used to accurately measure the position of the manipulator's wrist

WDM packet switch architectures and analysis of the influence of tunable wavelength converters on the performance

DEFF Research Database (Denmark)

Danielsen, Søren Lykke; Mikkelsen, Benny; Jørgensen, Carsten

1997-01-01

A detailed analytical traffic model for a photonic wavelength division multiplexing (WDM) packet switch block is presented and the requirements to the buffer size is analyzed. Three different switch architectures are considered, each of them representing different complexities in terms of component.......e., the possibility of several outlets sharing the same physical buffer. For the three architectures presented here, a tradeoff in the buffer architectures is addressed: a buffer physically shared among an outlets requires many wavelengths internally in the switch block, whereas, architectures with buffers dedicated...

Low-cost coherent receiver for long-reach optical access network using single-ended detection.

Science.gov (United States)

Zhang, Xuebing; Li, Zhaohui; Li, Jianping; Yu, Changyuan; Lau, Alan Pak Tao; Lu, Chao

2014-09-15

A low-cost coherent receiver using two 2×3 optical hybrids and single-ended detection is proposed for long-reach optical access network. This structure can detect the two polarization components of polarization division multiplexing (PDM) signals. Polarization de-multiplexing and signal-to-signal beat interference (SSBI) cancellation are realized by using only three photodiodes. Simulation results for 40 Gb/s PDM-OFDM transmissions indicate that the low-cost coherent receiver has 3.2 dB optical signal-to-noise ratio difference compared with the theoretical value.

Optical stealth transmission based on super-continuum generation in highly nonlinear fiber over WDM network.

Science.gov (United States)

Zhu, Huatao; Wang, Rong; Pu, Tao; Fang, Tao; Xiang, Peng; Zheng, Jilin; Chen, Dalei

2015-06-01

In this Letter, the optical stealth transmission carried by super-continuum spectrum optical pulses generated in highly nonlinear fiber is proposed and experimentally demonstrated. In the proposed transmission scheme, super-continuum signals are reshaped in the spectral domain through a wavelength-selective switch and are temporally spread by a chromatic dispersion device to achieve the same noise-like characteristic as the noise in optical networks, so that in both the time domain and the spectral domain, the stealth signals are hidden in public channel. Our experimental results show that compared with existing schemes where stealth channels are carried by amplified spontaneous emission noise, super-continuum signal can increase the transmission performance and robustness.

Contribución al estudio y optimización de dispositivos basados en holografía dinámica para su uso en redes ópticas pasivas multiplexadas en longitud de onda Wdm-Pon

OpenAIRE

Martín Minguez, Alfredo

2007-01-01

La utilización de Redes Ópticas Pasivas Multiplexadas por División en el Tiempo (TDMPON), y más recientemente de las Redes Ópticas Pasivas Multiplexadas en Longitud de Onda (WDM-PON), con sus dos principales tecnologías, CWDM y DWDM, en distintas topologías de red para optimizar los recursos disponibles, implica el uso de diversos componentes ópticos como transmisores, receptores, de/multiplexores, filtros, etc. Es en este contexto donde el uso de dispositivos holográficos, WDM sintonizables,...

4.7 Gbit/s transmission over 50m long 1mm diameter multi-core plastic optical fiber

NARCIS (Netherlands)

Yang, H.; Tangdiongga, E.; Lee, S.C.J.; Okonkwo, C.M.; Boom, van den H.P.A.; Randel, S.; Koonen, A.M.J.

2010-01-01

We report, for the first time, 4.7 Gbit/s transmission over 50 m long 1 mm diameter multi-core step-index plastic optical fiber, employing discrete multitone techniques and low-cost optical transceiver. A spectral efficiency of 13 bit/s/Hz is demonstrated.

Disrupted Structural Brain Network in AD and aMCI: A Finding of Long Fiber Degeneration.

Science.gov (United States)

Fang, Rong; Yan, Xiao-Xiao; Wu, Zhi-Yuan; Sun, Yu; Yin, Qi-Hua; Wang, Ying; Tang, Hui-Dong; Sun, Jun-Feng; Miao, Fei; Chen, Sheng-Di

2015-01-01

Although recent evidence has emerged that Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) patients show both regional brain abnormalities and topological degeneration in brain networks, our understanding of the effects of white matter fiber aberrations on brain network topology in AD and aMCI is still rudimentary. In this study, we investigated the regional volumetric aberrations and the global topological abnormalities in AD and aMCI patients. The results showed a widely distributed atrophy in both gray and white matters in the AD and aMCI groups. In particular, AD patients had weaker connectivity with long fiber length than aMCI and normal control (NC) groups, as assessed by fractional anisotropy (FA). Furthermore, the brain networks of all three groups exhibited prominent economical small-world properties. Interestingly, the topological characteristics estimated from binary brain networks showed no significant group effect, indicating a tendency of preserving an optimal topological architecture in AD and aMCI during degeneration. However, significantly longer characteristic path length was observed in the FA weighted brain networks of AD and aMCI patients, suggesting dysfunctional global integration. Moreover, the abnormality of the characteristic path length was negatively correlated with the clinical ratings of cognitive impairment. Thus, the results therefore suggested that the topological alterations in weighted brain networks of AD are induced by the loss of connectivity with long fiber lengths. Our findings provide new insights into the alterations of the brain network in AD and may indicate the predictive value of the network metrics as biomarkers of disease development.

Spectral shaping of an all-fiber torsional acousto-optic tunable filter.

Science.gov (United States)

Ko, Jeakwon; Lee, Kwang Jo; Kim, Byoung Yoon

2014-12-20

Spectral shaping of an all-fiber torsional acousto-optic (AO) tunable filter is studied. The technique is based on the axial modulation of AO coupling strength along a highly birefringent optical fiber, which is achieved by tailoring the outer diameter of the fiber along its propagation axis. Two kinds of filter spectral shaping schemes-Gaussian apodization and matched filtering with triple resonance peaks-are proposed and numerically investigated under realistic experimental conditions: at the 50-cm-long AO interaction length of the fiber and at half of the original fiber diameter as the minimum thickness of the tailored fiber section. The results show that the highest peak of sidelobe spectra in filter transmission is suppressed from 11.64% to 0.54% via Gaussian modulation of the AO coupling coefficient (κ). Matched filtering with triple resonance peaks operating with a single radio frequency signal is also achieved by cosine modulation of κ, of which the modulation period determines the spectral distance between two satellite peaks located in both wings of the main resonance peak. The splitting of two satellite peaks in the filter spectra reaches 48.2 nm while the modulation period varies from 7.7 to 50 cm. The overall peak power of two satellite resonances is calculated to be 22% of the main resonance power. The results confirm the validity and practicality of our approach, and we predict robust and stable operation of the designed all-fiber torsional AO filters.

Experimental 2.5-Gb/s QPSK WDM phase-modulated radio-over-fiber link with digital demodulation by a K-means algorithm

DEFF Research Database (Denmark)

Guerrero Gonzalez, Neil; Zibar, Darko; Caballero Jambrina, Antonio

2010-01-01

Highest reported bit rate of 2.5 Gb/s for optically phase modulated radio-over-fiber (RoF) link, employing digital coherent detection, is demonstrated. Demodulation of 3$,times,$ 2.5 Gb/s quadrature phase-shift keying modulated wavelength-division-multiplexed RoF channels is achieved after 79 km ...... of transmission through deployed fiber. Error-free performance (bit-error rate corresponding to $10^{{-}4}$) is achieved using a digital coherent receiver in combination with a $K$-means algorithm for radio-frequency phase recovery....

Exploring the atomic structure and conformational flexibility of a 320 Å long engineered viral fiber using X-ray crystallography.

Science.gov (United States)

Bhardwaj, Anshul; Casjens, Sherwood R; Cingolani, Gino

2014-02-01

Protein fibers are widespread in nature, but only a limited number of high-resolution structures have been determined experimentally. Unlike globular proteins, fibers are usually recalcitrant to form three-dimensional crystals, preventing single-crystal X-ray diffraction analysis. In the absence of three-dimensional crystals, X-ray fiber diffraction is a powerful tool to determine the internal symmetry of a fiber, but it rarely yields atomic resolution structural information on complex protein fibers. An 85-residue-long minimal coiled-coil repeat unit (MiCRU) was previously identified in the trimeric helical core of tail needle gp26, a fibrous protein emanating from the tail apparatus of the bacteriophage P22 virion. Here, evidence is provided that an MiCRU can be inserted in frame inside the gp26 helical core to generate a rationally extended fiber (gp26-2M) which, like gp26, retains a trimeric quaternary structure in solution. The 2.7 Å resolution crystal structure of this engineered fiber, which measures ∼320 Å in length and is only 20-35 Å wide, was determined. This structure, the longest for a trimeric protein fiber to be determined to such a high resolution, reveals the architecture of 22 consecutive trimerization heptads and provides a framework to decipher the structural determinants for protein fiber assembly, stability and flexibility.

Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers

International Nuclear Information System (INIS)

Rodríguez-Uicab, O.; Avilés, F.; Gonzalez-Chi, P.I; Canché-Escamilla, G.; Duarte-Aranda, S.; Yazdani-Pedram, M.; Toro, P.; Gamboa, F.; Mazo, M.A.; Nistal, A.; Rubio, J.

2016-01-01

Highlights: • The surface of aramid fibers was functionalized by two acid treatments. • The treatment based on HNO_3/H_2SO_4 reduced the mechanical properties of the fibers. • CNTs were deposited on the aramid fibers, reaching electrical conductivity. • Homogeneous CNT distribution was achieved by using pristine fibers or chlorosulfonic acid. - Abstract: Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating (“sizing”), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

Boron isotope fractionation in column chromatography with glucamine type fibers

International Nuclear Information System (INIS)

Sonoda, Akinari; Makita, Yoji; Hirotsu, Takahiro

2008-01-01

Glucamine type polymers have specific affinity toward boric acid and borate ion. Among them, Chelest Fiber GRY-L showed larger fractionation for boron isotopes than other polymers in our previous study. For this study, we used Chelest Fibers with different fiber lengths (1.0 mm, 0.5 mm, and 0.3 mm) as column packing materials to perform chromatographic separation of boron isotopes. The shorter fiber has larger packing density when packed into the column using a dry method. The 0.3-mm-long fiber has a larger backpressure than fibers of other lengths. Boron adsorption capacities were measured using the breakthrough operation. At this time, the 0.5-mm-long fiber showed the highest capacity. When we measured the isotope ratio profile for fibers of different length using column chromatography, 0.5-mm-long fibers displayed the highest boron isotope fractionation. The 0.5-mm-long fiber is promising as a packing material of column chromatography for boron isotope separation. We also changed operation methods. The lower eluent concentration and the slower flow rate are suitable for boron isotope separation. (author)

A nonuniform-polarization high-energy ultra-broadband laser with a long erbium-doped fiber

International Nuclear Information System (INIS)

Mao, Dong

2013-01-01

We have experimentally investigated nonuniformly polarized broadband high-energy pulses delivered from a mode-locked laser with an ultra-long erbium-doped fiber (EDF). The pulses exhibit a broadband spectrum of ∼73 nm and can avoid optical wave breaking at high-pump regimes. The polarization states of the pulses evolve from uniform to nonuniform at each round trip in the oscillator, which is distinct from other pulses. Remarkably, the output pulses broaden in anomalous- or normal-dispersion regimes while they can be shortened with an EDF amplifier external to the cavity. Our results suggest that the long EDF results in a nonuniform-polarization state and plays a decisive role in the formation of high-energy pulses. (paper)

Sensitivity Enhancement in Low Cutoff Wavelength Long-Period Fiber Gratings by Cladding Diameter Reduction

Directory of Open Access Journals (Sweden)

Ignacio Del Villar

2017-09-01

Full Text Available The diameter of long-period fiber gratings (LPFGs fabricated in optical fibers with a low cutoff wavelength was be reduced by hydrofluoric acid etching, enhancing the sensitivity to refractive index by more than a factor of 3, to 2611 nm/refractive index unit in the range from 1.333 to 1.4278. The grating period selected for the LPFGs allowed access to the dispersion turning point at wavelengths close to the visible range of the optical spectrum, where optical equipment is less expensive. As an example of an application, a pH sensor based on the deposition of a polymeric coating was analyzed in two situations: with an LPFG without diameter reduction and with an LPFG with diameter reduction. Again, a sensitivity increase of a factor of near 3 was obtained, demonstrating the ability of this method to enhance the sensitivity of thin-film-coated LPFG chemical sensors.

Sensitivity Enhancement in Low Cutoff Wavelength Long-Period Fiber Gratings by Cladding Diameter Reduction.

Science.gov (United States)

Del Villar, Ignacio; Partridge, Matthew; Rodriguez, Wenceslao Eduardo; Fuentes, Omar; Socorro, Abian Bentor; Diaz, Silvia; Corres, Jesus Maria; James, Stephen Wayne; Tatam, Ralph Peter

2017-09-13

The diameter of long-period fiber gratings (LPFGs) fabricated in optical fibers with a low cutoff wavelength was be reduced by hydrofluoric acid etching, enhancing the sensitivity to refractive index by more than a factor of 3, to 2611 nm/refractive index unit in the range from 1.333 to 1.4278. The grating period selected for the LPFGs allowed access to the dispersion turning point at wavelengths close to the visible range of the optical spectrum, where optical equipment is less expensive. As an example of an application, a pH sensor based on the deposition of a polymeric coating was analyzed in two situations: with an LPFG without diameter reduction and with an LPFG with diameter reduction. Again, a sensitivity increase of a factor of near 3 was obtained, demonstrating the ability of this method to enhance the sensitivity of thin-film-coated LPFG chemical sensors.

Optical Fiber Thermometer Based on Fiber Bragg Gratings

Science.gov (United States)

Rosli, Ekbal Bin; Mohd. Noor, Uzer

2018-03-01

Fiber Bragg grating has generated much interest in use as sensors to measure strain, temperature, and other physical parameters. It also the most common component used to develop this sensor with the advantages of simple, intrinsic sensing elements, electrically passive operation, EMI immunity, high sensitivity, compact size and potentially low cost [6]. This paper reports the design of an optical fiber thermometer based on fiber Bragg gratings. The system was developed for detecting temperature and strain by monitoring the shift of Bragg wavelength. The shifting of Bragg wavelength is used to indicate the temperature and strain due to the change in the surrounding temperature and strain. When the temperature and strain reach the exact wavelength level of the system, the temperature and strain value will display on the Arduino liquid crystal display (LCD). The optical fiber will provide the broadband light source and after passing the FBG the Bragg wavelength into the optical spectrum analyzer (OSA). The system is based on FBG as a physical quantity sensor. The temperatures measured is taken from the water bath and that of the strain is provided by amount of slotted mass used. The outcome of this project is to characterize the Bragg wavelength shifting from the fiber Bragg grating output. As the conclusion, this project provides an efficient optical fiber thermometer in measuring temperature and strain in order to replace the use of conventional electrical instruments.

Long-term monitoring of temperature in the subsoil using Fiber Optic Distributed Sensing

Science.gov (United States)

Susanto, Kusnahadi; Malet, Jean-Philippe; Gance, Julien; Marc, Vincent

2017-04-01

Monitoring changes in soil water content in the vadose zone of soils is a great importance for various hydrological, agronomical, ecological and environmental studies. By using soil temperature measurements with Fiber-Optic Distributed Temperature Sensing (FO-DTS), we can indirectly document soil water changes at high spatial and temporal frequency. In this research, we installed an observatory of soil temperature on a representative black marl slope of the long-term Draix-Bléone hydrological observatory (South French Alps, Réseau de Basins-Versants / RBV). A 350 m long reinforced fiber optic cable was buried at 0.05, 0.10 and 0.15 m of depths and installed at the soil surface. The total length of the monitored profile is 60 m, and it three different soil units consisting of argillaceous weathered black marls, silty colluvium under grass and silty colluvium under forest. Soil temperature is measured every 6 minutes at a spatial resolution of 0.50 m using a double-ended configuration. Both passive and active (heating of the FO) is used to document soil water changes. We present the analysis of a period of 6 months of temperature measurements (January-July 2016). Changes in soil temperature at various temporal scales (rainfall event, season) and for the three units are discussed. These changes indicate different processes of water infiltration at different velocities in relation to the presence of roots and the soil permeability. We further test several inversion strategies to estimate soil water content from the thermal diffusivity of the soils using simple and more complex thermal models. Some limitations of using this indirect technique for long-term monitoring are also presented. The work is supported by the research project HYDROSLIDE and the large infrastructure project CRITEX funded by the French Research Agency (ANR).

Preface to the special issue on ;Optical Communications Exploiting the Space Domain;

Science.gov (United States)

Wang, Jian; Yu, Siyuan; Li, Guifang

2018-02-01

The demand for high capacity optical communications will continue to be driven by the exponential growth of global internet traffic. Optical communications are about the exploitation of different physical dimensions of light waves, including complex amplitude, frequency (or wavelength), time, polarization, etc. Conventional techniques such as wavelength-division multiplexing (WDM), time-division multiplexing (TDM) and polarization-division multiplexing (PDM) have almost reached their scalability limits. Space domain is the only known physical dimension left and space-division multiplexing (SDM) seems the only option to further scale the transmission capacity and spectral efficiency of optical communications. In recent years, few-mode fiber (FMF), multi-mode fiber (MMF), multi-core fiber (MCF) and few-mode multi-core fiber (FM-MCF) have been widely explored as promising candidates for fiber-based SDM. The challenges for SDM include efficient (de)multiplexer, amplifiers, and multiple-input multiple-output (MIMO) digital signal processing (DSP) techniques. Photonic integration will also be a key technology to SDM. Meanwhile, free-space and underwater optical communications have also exploited the space domain to increase the transmission capacity and spectral efficiency. The challenges include long-distance transmission limited by propagation loss, divergence, scattering and turbulence. Very recently, helically phased light beams carrying orbital angular momentum (OAM) have also seen potential applications both in free-space, underwater and fiber-based optical communications. Actually, different mode bases such as linearly polarized (LP) modes and OAM modes can be employed for SDM. Additionally, SDM could be used in chip-scale photonic interconnects and data center optical interconnects. Quantum processing exploiting the space domain is of great interest. The information capacity limit and physical layer security in SDM optical communications systems are important

Femtosecond Fiber Lasers

Science.gov (United States)

Bock, Katherine J.

-order dispersion contribution from the diffraction gratings inside the laser cavity was studied, as it was also considered to be an energy-limiting factor. No significant effect was found as a result of third-order dispersion; however, a region of operation was observed where two different pulse regimes were found at the same values of net cavity group velocity dispersion. Results verify the main idea and indicate that a long length of low-doped gain fiber is preferable to a shorter, more highly doped one. The low-doped fiber in an otherwise equivalent cavity allows the nonlinear phase shift to grow at a slower rate, which results in the pulse achieving a higher peak power before reaching the nonlinear phase shift threshold at which optical wave breaking occurs. For a range of net cavity group velocity dispersion values, the final result is that the low doped fiber generates pulses of approximately twice the value of energy of the highly-doped gain fiber. Two techniques of mode-locking cavities were investigated to achieve this result. The first cavity used NPE mode-locking which masked the results, and the second used a SESAM for mode-locking which gave clear results supporting the hypothesis.

Cladding modes of optical fibers: properties and applications

International Nuclear Information System (INIS)

Ivanov, Oleg V; Nikitov, Sergei A; Gulyaev, Yurii V

2006-01-01

One of the new methods of fiber optics uses cladding modes for controlling propagation of radiation in optical fibers. This paper reviews the results of studies on the propagation, excitation, and interaction of cladding modes in optical fibers. The resonance between core and cladding modes excited by means of fiber Bragg gratings, including tilted ones, is analyzed. Propagation of cladding modes in microstructured fibers is considered. The most frequently used method of exciting cladding modes is described, based on the application of long-period fiber gratings. Examples are presented of long-period gratings used as sensors and gain equalizers for fiber amplifiers, as well as devices for coupling light into and out of optical fibers. (instruments and methods of investigation)

Photonic crystal fiber technology for compact fiber-delivered high-power ultrafast fiber lasers

Science.gov (United States)

Triches, Marco; Michieletto, Mattia; Johansen, Mette M.; Jakobsen, Christian; Olesen, Anders S.; Papior, Sidsel R.; Kristensen, Torben; Bondue, Magalie; Weirich, Johannes; Alkeskjold, Thomas T.

2018-02-01

Photonic crystal fiber (PCF) technology has radically impacted the scientific and industrial ultrafast laser market. Reducing platform dimensions are important to decrease cost and footprint while maintaining high optical efficiency. We present our recent work on short 85 μm core ROD-type fiber amplifiers that maintain single-mode performance and excellent beam quality. Robust long-term performance at 100 W average power and 250 kW peak power in 20 ps pulses at 1030 nm wavelength is presented, exceeding 500 h with stable performance in terms of both polarization and power. In addition, we present our recent results on hollow-core ultrafast fiber delivery maintaining high beam quality and polarization purity.

New Polylactic Acid Composites Reinforced with Artichoke Fibers

OpenAIRE

Botta, Luigi; Fiore, Vincenzo; Scalici, Tommaso; Valenza, Antonino;  , Roberto

2015-01-01

In this work, artichoke fibers were used for the first time to prepare poly(lactic acid) (PLA)-based biocomposites. In particular, two PLA/artichoke composites with the same fiber loading (10% w/w) were prepared by the film-stacking method: the first one (UNID) reinforced with unidirectional long artichoke fibers, the second one (RANDOM) reinforced by randomly-oriented long artichoke fibers. Both composites were mechanically characterized in tensile mode by quasi-static and dynamic mechanica...

Single Mode Fiber Optic Transceiver Using Short Wavelength Active Devices In Long Wavelength Fiber

Science.gov (United States)

Gillham, Frederick J.; Campbell, Daniel R.; Corke, Michael; Stowe, David W.

1990-01-01

Presently, single mode optical fiber technology is being utilized in systems to supply telephone service to the subscriber. However, in an attempt to be competitive with copper based systems, there are many development programs underway to determine the most cost effective solution while still providing a service that will either satisfy or be upgradeable to satisfy the demands of the consumer for the next 10 to 20 years. One such approach is to combine low cost laser transmitters and silicon receivers, which have been developed for the "compact disc" industry, with fiber that operates in the single mode regime at 1300 nm. In this paper, an optical transceiver will be presented, consisting of a compact disc laser, a silicon detector and a single mode coupler at 1300 nm. A possible system layout is presented which operates at 780 nm bi-directionally for POTS and upgradeable to 1300 nm for video services. There are several important design criteria that have to be considered in the development of such a system which will be addressed. These include: 1. Optimization of coupled power from laser to fiber while maintaining stable launched conditions over a wide range of environmental conditions. 2. Consideration of the multimode operation of the 1300 nm single mode fiber while operating in the 780 nm wavelength region. 3. Development of a low cost pseudo-wavelength division multiplexer for 1300 nm single mode/780 nm multimode operation and a low cost dual mode 50/50, 780 nm splitter using 1300 nm fiber. Details will be given of the design criteria and solution in terms of optimized design. Results of the performance of several prototype devices will be given with indications of the merits of this approach and where further development effort should be applied.

Self-protecting nonlinear compression in a solid fiber for long-term stable ultrafast lasers at 2 μm wavelength

Science.gov (United States)

Stutzki, Fabian; Gaida, Christian; Gebhardt, Martin; Jauregui, Cesar; Limpert, Jens; Tünnermann, Andreas; Pupeza, Ioachim

2017-02-01

Ultrashort-pulse laser systems are an enabling technology for numerous applications. The stability of such systems is especially crucial for frequency metrology and high precision spectroscopy. Thulium-based fiber lasers are an ideal starting point as a reliable and yet powerful source for the nonlinear conversion towards the mid-IR region. Recently, we have demonstrated that nonlinear self-compression in a fused silica solid-core fiber allows for few-cycle pulse duration with up to 24 MW peak power using a high-repetition rate thulium-based fiber laser system operating at around 2 μm wavelength [1]. This experiment operates near the self-focusing limit of about 24 MW for circular polarization, which increases the requirements for the system stability due to the risk of a fiber damage. Here, we present a self-protecting nonlinear compression regime allowing for long-term operation and high output-pulse stability with very similar output performance.

THE VELOCITY FUNCTION IN THE LOCAL ENVIRONMENT FROM ΛCDM AND ΛWDM CONSTRAINED SIMULATIONS

International Nuclear Information System (INIS)

Zavala, J.; Jing, Y. P.; Faltenbacher, A.; Yepes, G.; Hoffman, Y.; Gottloeber, S.; Catinella, B.

2009-01-01

Using constrained simulations of the local universe for generic cold dark matter (CDM) and for 1 keV warm dark matter (WDM), we investigate the difference in the abundance of dark matter halos in the local environment. We find that the mass function (MF) within 20 h -1 Mpc of the Local Group is ∼2 times larger than the universal MF in the 10 9 -10 13 h -1 M sun mass range. Imposing the field of view of the ongoing H I blind survey Arecibo Legacy Fast ALFA (ALFALFA) in our simulations, we predict that the velocity function (VF) in the Virgo-direction region (VdR) exceeds the universal VF by a factor of 3. Furthermore, employing a scheme to translate the halo VF into a galaxy VF, we compare the simulation results with a sample of galaxies from the early catalog release of ALFALFA. We find that our simulations are able to reproduce the VF in the 80-300 km s -1 velocity range, having a value ∼10 times larger than the universal VF in the VdR. In the low-velocity regime, 35-80 km s -1 , the WDM simulation reproduces the observed flattening of the VF. In contrast, the simulation with CDM predicts a steep rise in the VF toward lower velocities; for V max = 35 km s -1 , it forecasts ∼10 times more sources than the ones observed. If confirmed by the complete ALFALFA survey, our results indicate a potential problem for the CDM paradigm or for the conventional assumptions about energetic feedback in dwarf galaxies.

Strength and conductivity of unidirectional copper composites reinforced by continuous SiC fibers

International Nuclear Information System (INIS)

Kimmig, S.; Allen, I.; You, J.H.

2013-01-01

A SiC long fiber-reinforced copper composite offers a beneficial combination of high strength and high thermal conductivity at elevated temperatures. Both properties make the composite a promising material for the heat sink of high-heat-flux components. In this work, we developed a novel Cu/SiC f composite using the Sigma fiber. Based on HIP technique, a metallurgical process was established for fabricating high quality specimens using a TiC interface coating. Extensive tensile tests were conducted on the unidirectionally reinforced composite at 20 °C and 300 °C for a wide range of fiber volume fraction (V f ). In this paper, a large amount of test data is presented. The transversal thermal conductivity varies from 260 to 130 W/mK at 500 °C as V f is increased from 13% to 37%. The tensile strength reached up to 1246 MPa at 20 °C for V f = 37.6%, where the fracture strain was limited to 0.8%. The data of both elastic modulus and ultimate strength exhibited a good agreement with the rule-of-mixture predictions indicating a high quality of the materials. The strength of the composite with the Sigma fibers turned out to be superior to those of the SCS6 fibers at 300 °C, although the SCS6 fiber actually has a higher strength than the Sigma fiber. The fractographic pictures of tension test and fiber push-out test manifested a sufficient interfacial bonding

Design of differential optical absorption spectroscopy long-path telescopes based on fiber optics.

Science.gov (United States)

Merten, André; Tschritter, Jens; Platt, Ulrich

2011-02-10

We present a new design principle of telescopes for use in the spectral investigation of the atmosphere and the detection of atmospheric trace gases with the long-path differential optical absorption spectroscopy (DOAS) technique. A combination of emitting and receiving fibers in a single bundle replaces the commonly used coaxial-Newton-type combination of receiving and transmitting telescope. This very simplified setup offers a higher light throughput and simpler adjustment and allows smaller instruments, which are easier to handle and more portable. The higher transmittance was verified by ray-tracing calculations, which result in a theoretical factor threefold improvement in signal intensity compared with the old setup. In practice, due to the easier alignment and higher stability, up to factor of 10 higher signal intensities were found. In addition, the use of a fiber optic light source provides a better spectral characterization of the light source, which results in a lower detection limit for trace gases studied with this instrument. This new design will greatly enhance the usability and the range of applications of active DOAS instruments.

Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers

Energy Technology Data Exchange (ETDEWEB)

Rodríguez-Uicab, O. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Avilés, F., E-mail: faviles@cicy.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Gonzalez-Chi, P.I; Canché-Escamilla, G.; Duarte-Aranda, S. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Yazdani-Pedram, M. [Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, S. Livingstone 1007, Independencia, Santiago (Chile); Toro, P. [Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Av. Beauchef 850, Santiago (Chile); Gamboa, F. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Mérida, Depto. de Física Aplicada, Km. 6 Antigua Carretera a Progreso, 97310 Mérida, Yucatán (Mexico); Mazo, M.A.; Nistal, A.; Rubio, J. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain)

2016-11-01

Highlights: • The surface of aramid fibers was functionalized by two acid treatments. • The treatment based on HNO{sub 3}/H{sub 2}SO{sub 4} reduced the mechanical properties of the fibers. • CNTs were deposited on the aramid fibers, reaching electrical conductivity. • Homogeneous CNT distribution was achieved by using pristine fibers or chlorosulfonic acid. - Abstract: Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating (“sizing”), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

Photonic crystal fibers for supercontinuum generation pumped by a gain-switched CW fiber laser

DEFF Research Database (Denmark)

Larsen, Casper; Noordegraaf, Danny; Hansen, Kim P.

2012-01-01

Supercontinuum generation in photonics crystal fibers (PCFs) pumped by CW lasers yields high spectral power density and average power. However, such systems require very high pump power and long nonlinear fibers. By on/off modulating the pump diodes of the fiber laser, the relaxation oscillations...... of the laser can be exploited to enhance the broadening process. The physics behind the supercontinuum generation is investigated by sweeping the fiber length, the zero dispersion wavelength, and the fiber nonlinearity. We show that by applying gain-switching a high average output power of up to 30 W can...

Vertical‐cavity surface‐emitting laser based digital coherent detection for multigigabit long reach passive optical links

DEFF Research Database (Denmark)

Rodes Lopez, Roberto; Jensen, Jesper Bevensee; Zibar, Darko

2011-01-01

We report on experimental demonstration of digital coherent detection based on a directly modulated vertical‐cavity surface‐emitting laser with bit rate up to 10 Gbps. This system allows a cooler‐less, free running, and unamplified transmission without optical dispersion compensation up to 105 km...... at 5 Gbps long reach passive optical links. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2462–2464, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26331...

Thulium fiber laser lithotripsy using a muzzle brake fiber tip

Science.gov (United States)

Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2017-02-01

The Thulium fiber laser (TFL) is being explored as an alternative to Holmium:YAG laser for lithotripsy. TFL beam profile allows coupling of higher power into smaller fibers than multimode Holmium laser beam, without proximal fiber tip degradation. A smaller fiber provides more space in ureteroscope working channel for increased saline irrigation and allows maximum ureteroscope flexion. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback, but increased retropulsion. In this study, a "fiber muzzle brake" was tested for reducing fiber burnback and stone retropulsion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-OD, 360-μm-ID tube with 275-μm thru hole located 250-μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed, ex vivo. Small stones with a mass of 40 +/- 4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25 +/- 4 s (n=10), without distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers. The muzzle brake fiber tip provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

Optimized radiation-hardened erbium doped fiber amplifiers for long space missions

Science.gov (United States)

Ladaci, A.; Girard, S.; Mescia, L.; Robin, T.; Laurent, A.; Cadier, B.; Boutillier, M.; Ouerdane, Y.; Boukenter, A.

2017-04-01

In this work, we developed and exploited simulation tools to optimize the performances of rare earth doped fiber amplifiers (REDFAs) for space missions. To describe these systems, a state-of-the-art model based on the rate equations and the particle swarm optimization technique is developed in which we also consider the main radiation effect on REDFA: the radiation induced attenuation (RIA). After the validation of this tool set by confrontation between theoretical and experimental results, we investigate how the deleterious radiation effects on the amplifier performance can be mitigated following adequate strategies to conceive the REDFA architecture. The tool set was validated by comparing the calculated Erbium-doped fiber amplifier (EDFA) gain degradation under X-rays at ˜300 krad(SiO2) with the corresponding experimental results. Two versions of the same fibers were used in this work, a standard optical fiber and a radiation hardened fiber, obtained by loading the previous fiber with hydrogen gas. Based on these fibers, standard and radiation hardened EDFAs were manufactured and tested in different operating configurations, and the obtained data were compared with simulation data done considering the same EDFA structure and fiber properties. This comparison reveals a good agreement between simulated gain and experimental data (vulnerability in terms of gain. The presented approach is a complementary and effective tool for hardening by device techniques and opens new perspectives for the applications of REDFAs and lasers in harsh environments.

Performance evaluation of distributed wavelength assignment in WDM optical networks

Science.gov (United States)

Hashiguchi, Tomohiro; Wang, Xi; Morikawa, Hiroyuki; Aoyama, Tomonori

2004-04-01

In WDM wavelength routed networks, prior to a data transfer, a call setup procedure is required to reserve a wavelength path between the source-destination node pairs. A distributed approach to a connection setup can achieve a very high speed, while improving the reliability and reducing the implementation cost of the networks. However, along with many advantages, several major challenges have been posed by the distributed scheme in how the management and allocation of wavelength could be efficiently carried out. In this thesis, we apply a distributed wavelength assignment algorithm named priority based wavelength assignment (PWA) that was originally proposed for the use in burst switched optical networks to the problem of reserving wavelengths of path reservation protocols in the distributed control optical networks. Instead of assigning wavelengths randomly, this approach lets each node select the "safest" wavelengths based on the information of wavelength utilization history, thus unnecessary future contention is prevented. The simulation results presented in this paper show that the proposed protocol can enhance the performance of the system without introducing any apparent drawbacks.

Modal noise impact in radio over fiber multimode fiber links.

Science.gov (United States)

Gasulla, I; Capmany, J

2008-01-07

A novel analysis is given on the statistics of modal noise for a graded-index multimode fiber (MMF) link excited by an analog intensity modulated laser diode. We present the speckle contrast as a function of the power spectrum of the modulated source and the transfer function of the MMF which behaves as an imperfect transversal microwave photonic filter. The theoretical results confirm that the modal noise is directly connected with the coherence properties of the optical source and show that the performance of high-frequency Radio Over Fiber (ROF) transmission through MMF links for short and middle reach distances is not substantially degraded by modal noise.

Widely tunable asymmetric long-period fiber grating with high sensitivity using optical polymer on laser-ablated cladding.

Science.gov (United States)

Chen, Nan-Kuang; Hsu, Der-Yi; Chi, Sien

2007-08-01

We demonstrate high-efficiency, wideband-tunable, laser-ablated long-period fiber gratings that use an optical polymer overlay. Portions of the fiber cladding are periodically removed by CO(2) laser pulses to induce periodic index changes for coupling the core mode into cladding modes. An optical polymer with a high thermo-optic coefficient with a dispersion distinct from that of silica is used on a deep-ablated cladding structure so that the effective indices of cladding modes become dispersive and the resonant wavelengths can be efficiently tuned. The tuning efficiency can be as high as 15.8 nm/ degrees C, and the tuning range can be wider than 105 nm (1545-1650 nm).

Long Term Resource Monitoring Program Annual Status Report, 1999: Macroinvertebrate Sampling in Six Reaches of the Upper Mississippi River System

National Research Council Canada - National Science Library

Sauer, Jennifer

2000-01-01

In 1992, macroinvertebrate sampling was initiated in Pools 4, 8, 13, 26, and the Open River reach of the Mississippi River, and La Orange Pool of the Illinois River as part of the Long Term Resource Monitoring Program...

Fiber optic muzzle brake tip for reducing fiber burnback and stone retropulsion during thulium fiber laser lithotripsy

Science.gov (United States)

Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2017-01-01

The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy. The near single-mode TFL beam allows coupling of higher power into smaller optical fibers than the multimode Holmium laser beam profile, without proximal fiber tip degradation. A smaller fiber is desirable because it provides more space in the ureteroscope working channel for increased saline irrigation rates and allows maximum ureteroscope deflection. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. A "fiber muzzle brake" was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-outer-diameter, 360-μm-inner-diameter tube with a 275-μm-diameter through hole located 250 μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. Small stones with a mass of 40±4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25±4 s (n=10) without visible distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers, respectively. The muzzle brake fiber tip simultaneously provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

Random fiber laser based on artificially controlled backscattering fibers.

Science.gov (United States)

Wang, Xiaoliang; Chen, Daru; Li, Haitao; She, Lijuan; Wu, Qiong

2018-01-10

The random fiber laser (RFL), which is a milestone in laser physics and nonlinear optics, has attracted considerable attention recently. Most previously reported RFLs are based on distributed feedback of Rayleigh scattering amplified through the stimulated Raman-Brillouin scattering effect in single-mode fibers, which require long-distance (tens of kilometers) single-mode fibers and high threshold, up to watt level, due to the extremely small Rayleigh scattering coefficient of the fiber. We proposed and demonstrated a half-open-cavity RFL based on a segment of an artificially controlled backscattering single-mode fiber with a length of 210 m, 310 m, or 390 m. A fiber Bragg grating with a central wavelength of 1530 nm and a segment of artificially controlled backscattering single-mode fiber fabricated by using a femtosecond laser form the half-open cavity. The proposed RFL achieves thresholds of 25 mW, 30 mW, and 30 mW, respectively. Random lasing at a wavelength of 1530 nm and extinction ratio of 50 dB is achieved when a segment of 5 m erbium-doped fiber is pumped by a 980 nm laser diode in the RFL. A novel RFL with many short cavities has been achieved with low threshold.

Chronic in vivo stability assessment of carbon fiber microelectrode arrays

Science.gov (United States)

Patel, Paras R.; Zhang, Huanan; Robbins, Matthew T.; Nofar, Justin B.; Marshall, Shaun P.; Kobylarek, Michael J.; Kozai, Takashi D. Y.; Kotov, Nicholas A.; Chestek, Cynthia A.

2016-12-01

Objective. Individual carbon fiber microelectrodes can record unit activity in both acute and semi-chronic (∼1 month) implants. Additionally, new methods have been developed to insert a 16 channel array of carbon fiber microelectrodes. Before assessing the in vivo long-term viability of these arrays, accelerated soak tests were carried out to determine the most stable site coating material. Next, a multi-animal, multi-month, chronic implantation study was carried out with carbon fiber microelectrode arrays and silicon electrodes. Approach. Carbon fibers were first functionalized with one of two different formulations of PEDOT and subjected to accelerated aging in a heated water bath. After determining the best PEDOT formula to use, carbon fiber arrays were chronically implanted in rat motor cortex. Some rodents were also implanted with a single silicon electrode, while others received both. At the end of the study a subset of animals were perfused and the brain tissue sliced. Tissue sections were stained for astrocytes, microglia, and neurons. The local reactive responses were assessed using qualitative and quantitative methods. Main results. Electrophysiology recordings showed the carbon fibers detecting unit activity for at least 3 months with average amplitudes of ∼200 μV. Histology analysis showed the carbon fiber arrays with a minimal to non-existent glial scarring response with no adverse effects on neuronal density. Silicon electrodes showed large glial scarring that impacted neuronal counts. Significance. This study has validated the use of carbon fiber microelectrode arrays as a chronic neural recording technology. These electrodes have demonstrated the ability to detect single units with high amplitude over 3 months, and show the potential to record for even longer periods. In addition, the minimal reactive response should hold stable indefinitely, as any response by the immune system may reach a steady state after 12 weeks.

Water-Resistant Material from Recovered Fibers and Acrylic Emulsion Terpolymer

Directory of Open Access Journals (Sweden)

Fushan Chen

2014-01-01

Full Text Available Styrene (SM, methyl methacrylate (MMA, and butyl acrylate (BA were used to synthesize a polyacrylic emulsion by core-shell emulsion polymerization. The solid content of the emulsion reached 40% using reasonable reactive emulsifier contents and feeding modes. Then, the emulsion and a fiber were dispersed, coated, and dried together. Finally, fiber-based water-resistant material was successfully fabricated. The experimental results showed that under the conditions of a monomer mass ratio of 1:1:1 and a mass ratio of polyacrylic emulsion to fiber of 2:1, the Cobb value of the material reached 5.0 g/m2. The tensile strength, elongation, and breaking length were 7.4225 kN/m, 1.0%, and 11.706 km, respectively. Using scanning electron microscopy (SEM to analyze the surface morphology and internal structure of products, the reasons for the high water resistance of fiber-based material was due to the bonding and filling effects of the polyacrylic emulsion on the fibers. For tightly bound fibers, the porous structures formed in fiber-based boards were reduced. On the other hand, the polyacrylic emulsion filled the gaps between fibers. This filling effect led to a continuous structure, and the water resistance of the material was further enhanced.

Demonstration of two-user, 10-Gbits/s optical code-division multiple-access system implemented by using cascaded long-period fiber gratings formed in dispersion-compensating fiber with inner-cladding structure

Science.gov (United States)

Kim, Sun-Jong; Eom, Tae-Jung; Kim, Tae-Young; Lee, Byeong Ha; Park, Chang-Soo

2005-09-01

A two-user, 10-Gbits/s optical code-division multiple-access system implemented by using cascaded long-period fiber gratings formed in a dispersion-compensating fiber (DCF) is demonstrated. Our results show that the sensitivity of cladding modes to the refractive index change on the cladding surface is greatly reduced by utilizing the inner-cladding mode of the DCF. Two pairs of encoder/decoder are constructed and the performance is evaluated by measuring bit error rate (BER). With an interferer, a BER of 1.5×10-12 is measured at a received optical power of -6 dBm.

Mechanical Properties of Oil Palm Empty Fruit Bunch Fiber

Science.gov (United States)

Gunawan, Fergyanto E.; Homma, Hiroomi; Brodjonegoro, Satryo S.; Hudin, Afzer Bin Baseri; Zainuddin, Aryanti Binti

In tropical countries such as Indonesia and Malaysia, the empty fruit bunches are wastes of the oil palm industry. The wastes are abundantly available and has reached a level that severely threats the environment. Therefore, it is a great need to find useful applications of those waste materials; but firstly, the mechanical properties of the EFB fiber should be quantified. In this work, a small tensile test machine is manufactured, and the tensile test is performed on the EFB fibers. The results show that the strength of the EFB fiber is strongly affected by the fiber diameter; however, the fiber strength is relatively low in comparison to other natural fibers.

Integration of FBG Strain Sensors in WDM Networks, Effects on Quality Factor

Directory of Open Access Journals (Sweden)

Ali Al-Lawati

2009-06-01

Full Text Available A study of the effect of integrating an FBG sensor in a four wavelength WDM communications system operating at 1550 nm is presented. The simulations considered focus on the mutual effects of both the sensing and the communications systems. The effect of power levels of the interrogating optical source on the performance of the two systems is also investigated under excitation levels of up to 10 dBm. The network layout used in the simulations is based on an actual optical link in Oman having a variety of spans. The results obtained at data rates of 2.5 and 10 Gbps with variable strains up to ±600 μs show a good tolerance in terms of quality of transmission for the two systems. However, the greater the strain values, the more noticeable are the degradations of transmission quality parameters of the communications system.

Mode conversion in hybrid optical fiber coupler

Science.gov (United States)

Stasiewicz, Karol A.; Marc, P.; Jaroszewicz, Leszek R.

2012-04-01

Designing of all in-line fiber optic systems with a supercontinuum light source gives some issues. The use of a standard single mode fiber (SMF) as an input do not secure single mode transmission in full wavelength range. In the paper, the experimental results of the tested hybrid fiber optic coupler were presented. It was manufactured by fusing a standard single mode fiber (SMF28) and a photonic crystal fiber (PCF). The fabrication process is based on the standard fused biconical taper technique. Two types of large mode area fibers (LMA8 and LAM10 NKT Photonics) with different air holes arrangements were used as the photonic crystal fiber. Spectral characteristics within the range of 800 nm - 1700 nm were presented. All process was optimized to obtain a mode conversion between SMF and PCF and to reach a single mode transmission in the PCF output of the coupler.

Watershed Data Management (WDM) database for West Branch DuPage River streamflow simulation, DuPage County, Illinois, January 1, 2007, through September 30, 2013

Science.gov (United States)

Bera, Maitreyee

2017-10-16

The U.S. Geological Survey (USGS), in cooperation with the DuPage County Stormwater Management Department, maintains a database of hourly meteorological and hydrologic data for use in a near real-time streamflow simulation system. This system is used in the management and operation of reservoirs and other flood-control structures in the West Branch DuPage River watershed in DuPage County, Illinois. The majority of the precipitation data are collected from a tipping-bucket rain-gage network located in and near DuPage County. The other meteorological data (air temperature, dewpoint temperature, wind speed, and solar radiation) are collected at Argonne National Laboratory in Argonne, Ill. Potential evapotranspiration is computed from the meteorological data using the computer program LXPET (Lamoreux Potential Evapotranspiration). The hydrologic data (water-surface elevation [stage] and discharge) are collected at U.S.Geological Survey streamflow-gaging stations in and around DuPage County. These data are stored in a Watershed Data Management (WDM) database.This report describes a version of the WDM database that is quality-assured and quality-controlled annually to ensure datasets are complete and accurate. This database is named WBDR13.WDM. It contains data from January 1, 2007, through September 30, 2013. Each precipitation dataset may have time periods of inaccurate data. This report describes the methods used to estimate the data for the periods of missing, erroneous, or snowfall-affected data and thereby improve the accuracy of these data. The other meteorological datasets are described in detail in Over and others (2010), and the hydrologic datasets in the database are fully described in the online USGS annual water data reports for Illinois (U.S. Geological Survey, 2016) and, therefore, are described in less detail than the precipitation datasets in this report.

Design of FHiRE: the Fiber High Resolution Echelle Spectrograph

Science.gov (United States)

Pierce, Michael J.; McLane, Jacob N.; Pilachowski, C. A.; Kobulnicky, Henry; Jang-Condell, Hannah

2018-01-01

The enormous success of the Kepler mission in the discovery of transiting exoplanets implies that the majority of stars have planetary systems. NASA's upcomming Transiting Exoplanet Survey Satellite (TESS) is designed to survey the brightest stars over the entire sky, systems that are accessible to spectroscopic follow-up with mid-sized telescopes. We have undertaken the development of a precision radial velocity spectrograph with the goal of providing ground-based suppoert for TESS. The instrument, known as FHiRE (Fiber High Resolution Echelle spectrograph), is being developed in collaboration with Indiana University and will deployed at the 2.3-meter telescope of the Wyoming InfraRed Observatory (WIRO). FHiRE features a traditional white pupil echelle design with R ~ 60,000 that is fed via two optical fibers from the telescope. Both the science fiber and a simultaneously sampled Thorium-Argon comparison fiber will make use of double mode scramblers. FHiRE itself will be housed within a vacuum enclosure in order to minimize any temperatue variations of the instrument and maximize its radial velocity precision. Together, these two features should enable FHiRE to reach a long-term velocity precision of < 1 m/s. We present the design of FHiRE and its expected performance. In a companion poster (Jang-Condell et al.) we will present the exoplanet science goals of the project.

WDM compatible and electrically tunable SPE-OCDMA system based on the temporal self-imaging effect.

Science.gov (United States)

Tainta, S; Amaya, W; Erro, M J; Garde, M J; Sales, S; Muriel, M A

2011-02-01

A coding/decoding setup for a spectral phase encoding optical code-division multiple access (SPE-OCDMA) system has been developed. The proposal is based on the temporal self-imaging effect and the use of an easily tunable electro-optic phase modulator to achieve line-by-line coding of the transmitted signal, thus assuring compatibility with WDM techniques. Modulation of the code is performed at the same rate as the data, avoiding the use of high-bandwidth electro-optic modulators. As proof of concept of the technique, experimental results are presented for a back-to-back coder/decoder setup transmitting a 10 GHz unmodulated optical pulse train within an 80 GHz optical window and using 8-chip Hadamard codes.

Calculation of fast neutron dose in plastic-coated optical fibers

International Nuclear Information System (INIS)

Siebert, B.R.L.; Henschel, H.

1998-01-01

The dose of fast neutrons in optical fibers with hydrogen-containing coating materials is considerably increased by energetic recoil protons. Their contribution to the dose in a SiO 2 fiber core is calculated by the Monte Carlo method for different fiber geometries and a fiber optic cable. With 14 MeV neutrons the dose in a single fiber is increased by about 21%, whereas in fiber bundles the dose increase can reach about 170%. Maximum dose enhancement in fiber bundles (about 610%) occurs at neutron energies around 5.5 MeV. The dose increase caused by 14 MeV neutrons in the fiber of a typical laboratory cable is about 124%

VPIsystems industry training program on computer-aided design of fiber optic communication systems

Science.gov (United States)

Richter, Andre; Chan, David K. C.

2002-05-01

In industry today, professional Photonic Design Automation (PDA) tools are a necessity to enable fast development cycles for the design of optical components, systems and networks. The training of industrial personnel is of great importance in facilitating the full usability of PDA tools tailored to meet these demands. As the market leader of design and planning tools for system integrators and manufacturers of optical transmission systems and components, VPIsystems offers a set of two-day training courses. Attendees are taught on the design of metro WDM networks, high speed DWDM and ultra long-haul WDM systems, analogue and digital cable access systems, EDFA and Raman amplifiers, as well as active devices and circuits. The course work compromises of: (1) lectures on physical and modeling background topics; (2) creation of typical simulation scenarios and; (3) the analysis of results. This course work is facilitated by guided, hands-on lab exercises using VPIsystems software for a variety of practical design situations. In classes of up to 15, each attendee is allocated a computer, thereby allowing for a thorough and speedy training for the individual in all of the covered topics as well as for any extra-curriculum topics to be covered. Since 1999, more than 750 people have graduated from over 60 training courses. In this paper, details of VPIsystems Industry training program will be presented.

Thermal Stress-Induced Depolarization Loss in Conventional and Panda-Shaped Photonic Crystal Fiber Lasers

Science.gov (United States)

Mousavi, Seyedeh Laleh; Sabaeian, Mohammad

2016-10-01

We report on the modeling of the depolarization loss in the conventional and panda-shaped photonic crystal fiber lasers (PCFLs) due to the self-heating of the fiber, which we call it thermal stress-induced depolarization loss (TSIDL). We first calculated the temperature distribution over the fiber cross sections and then calculated the thermal stresses/strains as a function of heat load per meter. Thermal stress-induced birefringence (TSIB), which is defined as | n x - n y |, in the core and cladding regions was calculated. Finally, TSIDL was calculated for the conventional and panda-shaped PCFLs as a function of fiber length and, respectively, saturated values of 22 and 25 % were obtained which were independent of heat load per meter. For panda-shaped PCFLs, prior to being saturated, an oscillating and damping behavior against the fiber length was seen where in some lengths reached 35 %. The results are close to an experimental value of 30 % reported for a pulsed PCFL (Limpert et al., Opt Express 12:1313-1319, 2004) where the authors reported a degree of polarization of 70 % (i.e., a depolarization of 30 %). The most important result of this work is a saturation behavior of TSIDL at long-enough lengths of the fiber laser which is independent of heat load per meter. To our knowledge, this the first report of TSIBL for PCFLs.

Projeto de EDFAs com controle automatico de ganho totalmente optico para aplicações em redes WDM

OpenAIRE

Julio Cesar Rodrigues Fernandes de Oliveira

2004-01-01

Resumo: A variação na potência da entrada em amplificadores ópticos a fibra dopada com Érbio (EDFAs) induz alterações em seu ganho. No caso de sistemas ou redes WDM onde o número de canais acoplados ao amplificador varia, o ganho torna-se dependente do número de canais que estão sendo transmitidos, especialmente se o amplificador opera saturado. Este trabalho apresenta o desenvolvimento e a avaliação experimental de uma técnica de controle de ganho totalmente óptica para EDFAs. Esta técnica d...

High-efficiency ytterbium-free erbium-doped all-glass double cladding silicate glass fiber for resonantly-pumped fiber lasers.

Science.gov (United States)

Qiang, Zexuan; Geng, Jihong; Luo, Tao; Zhang, Jun; Jiang, Shibin

2014-02-01

A highly efficient ytterbium-free erbium-doped silicate glass fiber has been developed for high-power fiber laser applications at an eye-safe wavelength near 1.55 μm. Our preliminary experiments show that high laser efficiency can be obtained from a relatively short length of the gain fiber when resonantly pumped at 1535 nm in both core- and cladding-pumping configurations. With a core-pumping configuration as high as 75%, optical-to-optical efficiency and 4 W output power were obtained at 1560 nm from a 1 m long gain fiber. When using a cladding-pumping configuration, approximately 13 W output power with 67.7% slope efficiency was demonstrated from a piece of 2 m long fiber. The lengths of silicate-based gain fiber are much shorter than their silica-based counterparts used in other experiments, which is significantly important for high-power narrow-band and/or pulsed laser applications.

Ultrastrong Bioinspired Graphene-Based Fibers via Synergistic Toughening.

Science.gov (United States)

Zhang, Yuanyuan; Li, Yuchen; Ming, Peng; Zhang, Qi; Liu, Tianxi; Jiang, Lei; Cheng, Qunfeng

2016-04-13

Ultrastrong bioinspired graphene-based fibers are designed and prepared via synergistic toughening of ionic and covalent bonding. The tensile strength reaches up to 842.6 MPa and is superior to all other reported graphene-based fibers. In addition, its electrical conductivity is as high as 292.4 S cm(-1). This bioinspired synergistic toughening strategy supplies new insight toward the construction of integrated high-performance graphene-based fibers in the near future. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radiative characterization of random fibrous media with long cylindrical fibers: Comparison of single- and multi-RTE approaches

Science.gov (United States)

Randrianalisoa, Jaona; Haussener, Sophia; Baillis, Dominique; Lipiński, Wojciech

2017-11-01

Radiative heat transfer is analyzed in participating media consisting of long cylindrical fibers with a diameter in the limit of geometrical optics. The absorption and scattering coefficients and the scattering phase function of the medium are determined based on the discrete-level medium geometry and optical properties of individual fibers. The fibers are assumed to be randomly oriented and positioned inside the medium. Two approaches are employed: a volume-averaged two-intensity approach referred to as multi-RTE approach and a homogenized single-intensity approach referred to as the single-RTE approach. Both approaches require effective properties, determined using direct Monte Carlo ray tracing techniques. The macroscopic radiative transfer equations (for single intensity or two volume-averaged intensities) with the corresponding effective properties are solved using Monte Carlo techniques and allow for the determination of the radiative flux distribution as well as overall transmittance and reflectance of the medium. The results are compared against predictions by the direct Monte Carlo simulation on the exact morphology. The effects of fiber volume fraction and optical properties on the effective radiative properties and the overall slab radiative characteristics are investigated. The single-RTE approach gives accurate predictions for high porosity fibrous media (porosity about 95%). The multi-RTE approach is recommended for isotropic fibrous media with porosity in the range of 79-95%.

Influence of the optical fiber type on the performances of fiber-optics current sensor dedicated to plasma current measurement in ITER.

Science.gov (United States)

Aerssens, Matthieu; Descamps, Frédéric; Gusarov, Andrei; Mégret, Patrice; Moreau, Philippe; Wuilpart, Marc

2015-07-01

In this paper, we compare, by means of simulations using the Jones formalism, the performances of several optical fiber types (low birefringence and spun fibers) for the measurement of plasma current in international thermonuclear experimental reactor (ITER). The main results presented in this paper concern the minimum value of the ratio between the beat length and the spun period, which allows meeting the ITER current measurement specifications. Assuming a high-birefringence spun fiber with a beat length of 3 mm, we demonstrate that the minimum ratio between the beat length and the spun period is 4.4 when considering a 28 m long sensing fiber surrounding the vacuum vessel. This minimum ratio rises to 10.14 when a 100 m long lead fiber connecting the interrogating system to the sensing fiber is taken into account.

Growth of single-crystal YAG fiber optics.

Science.gov (United States)

Nie, Craig D; Bera, Subhabrata; Harrington, James A

2016-07-11

Single-crystal YAG (Y3Al5O12) fibers have been grown by the laser heated pedestal growth technique with losses as low as 0.3 dB/m at 1.06 μm. These YAG fibers are as long as about 60 cm with diameters around 330 μm. The early fibers were grown from unoriented YAG seed fibers and these fibers exhibited facet steps or ridges on the surface of the fiber. However, recently we have grown fibers using an oriented seed to grow step-free fibers. Scattering losses made on the fibers indicate that the scattering losses are equal to about 30% of the total loss.

Higher Order Mode Fibers

DEFF Research Database (Denmark)

Israelsen, Stine Møller

This PhD thesis considers higher order modes (HOMs) in optical fibers. That includes their excitation and characteristics. Within the last decades, HOMs have been applied both for space multiplexing in optical communications, group velocity dispersion management and sensing among others......-radial polarization as opposed to the linear polarization of the LP0X modes. The effect is investigated numerically in a double cladding fiber with an outer aircladding using a full vectorial modesolver. Experimentally, the bowtie modes are excited using a long period grating and their free space characteristics...... and polarization state are investigated. For this fiber, the onset of the bowtie effect is shown numerically to be LP011. The characteristics usually associated with Bessel-likes modes such as long diffraction free length and selfhealing are shown to be conserved despite the lack of azimuthal symmetry...

Fiber optic neutron imaging system: calibration

International Nuclear Information System (INIS)

Malone, R.M.; Gow, C.E.; Thayer, D.R.

1981-01-01

Two neutron imaging experiments using fiber optics have been performed at the Nevada Test Site. In each experiment, an array of scintillator fluor tubes is exposed to neutrons. Light is coupled out through radiation resistant PCS fibers (8-m long) into high-bandwidth, graded index fibers. For image reconstruction to be accurate, common timing differences and transmission variations between fiber optic channels are needed. The calibration system featured a scanning pulsed dye laser, a specially designed fiber optic star coupler, a tektronix 7912AD transient digitizer, and a DEC PDP 11/34 computing system

32-core Dense SDM Unidirectional Transmission of PDM-16QAM Signals Over 1600 km Using Crosstalk-managed Single-mode Heterogeneous Multicore Transmission Line

DEFF Research Database (Denmark)

Mizuno, Takayuki; Shibahara, K.; Ono, Hirotaka

2016-01-01

We demonstrate 32-core dense space-division multiplexed (DSDM) unidirectional transmission of PDM-16QAM 20-WDM signals over 1644.8 km employing a low-crosstalk single-mode heterogeneous 32-core fiber in a partial recirculating-loop system....

All-fiber polarization switch

Science.gov (United States)

Knape, Harald; Margulis, Walter

2007-03-01

We report an all-fiber polarization switch made out of silica-based microstructured fiber suitable for Q-switching all-fiber lasers. Nanosecond high-voltage pulses are used to heat and expand an internal electrode to cause λ/2-polarization rotation in less than 10 ns for 1.5 μm light. The 10 cm long component has an experimentally measured optical insertion loss of 0.2 dB and a 0-10 kHz repetition frequency capacity and has been durability tested for more than 109 pulses.

Which Flexible Ureteroscopes (Digital vs. Fiber-Optic) Can Easily Reach the Difficult Lower Pole Calices and Have Better End-Tip Deflection: In Vitro Study on K-Box. A PETRA Evaluation.

Science.gov (United States)

Dragos, Laurian B; Somani, Bhaskar K; Sener, Emre T; Buttice, Salvatore; Proietti, Silvia; Ploumidis, Achilles; Iacoboaie, Catalin T; Doizi, Steeve; Traxer, Olivier

2017-07-01

Modern flexible ureteroscopes (fURSs) have good deflection, but despite this, approaching an acute angled calix can still be difficult. The goals of our in vitro study were to assess the ability of the available modern fURSs to effectively access the sharp angled calices and to compare the end-tip deflection of the various fiber-optic and digital fURSs. Using a bench-training model for FURS (K-Box, Porgès-Coloplast), we tried to access an acute angled calix with nine different fURSs (BOA vision, COBRA vision, R.Wolf; FLEX X 2 , FLEX Xc, K.Storz; LithoVue, Boston Scientific; URF-P5, URF-P6, URF-V, URF-V2, Olympus). Passing the fURSs through a ureteral access sheath (ReTrace, Porgès-Coloplast), the maximum end-tip deflection for every fURS was measured with the tip extended out from the sheath at 1, 2, 3, and 4 cm. Two ranking methods were designed for scoring the fURSs, one based on total ranking points and the other on total degrees of deflection. While all fiber-optic fURSs (except URF-P6) were able to access the sharp angled calix, none of the digital fURSs (except FLEX Xc) reached the difficult angled calix. Similarly, all fiber-optic fURSs had better end-tip deflection compared with the digital fURSs, except FLEX Xc, which was as deflectable as the fiber-optic fURSs. The fURSs showed an end-tip deflection (median difference of almost 21°) in favor of fiber-optic fURSs. Based on the scoring, the highest ranked fURS (best deflection) was FLEX X2 and the lowest ranked fURS (worst deflection) was URF-V2. Digital fURSs were less effective in accessing the sharp angled calix and they had lesser end-tip deflection compared with the fiber-optic counterparts. When approaching a difficult lower pole calix, it might be better to use a fiber-optic fURS.

Optic fiber pulse-diagnosis sensor of traditional Chinese medicine

Science.gov (United States)

Ni, J. S.; Jin, W.; Zhao, B. N.; Zhang, X. L.; Wang, C.; Li, S. J.; Zhang, F. X.; Peng, G. D.

2013-09-01

The wrist-pulse is a kind of signals, from which a lot of physiological and pathological status of patients are deduced according to traditional Chinese medicine theories. This paper designs a new optic fiber wrist-pulse sensor that based on a group of FBGs. Sensitivity of the optic fiber wrist-pulse measurement system reaches 0.05% FS and the range reaches 50kPa. Frequency response is from 0 Hz to 5 kHz. A group of typical pulse signal is given out in the paper to compare different status of patient. It will improve quantification of pulse diagnosis greatly.

Sharp burnout failure observed in high current-carrying double-walled carbon nanotube fibers

Science.gov (United States)

Song, Li; Toth, Geza; Wei, Jinquan; Liu, Zheng; Gao, Wei; Ci, Lijie; Vajtai, Robert; Endo, Morinobu; Ajayan, Pulickel M.

2012-01-01

We report on the current-carrying capability and the high-current-induced thermal burnout failure modes of 5-20 µm diameter double-walled carbon nanotube (DWNT) fibers made by an improved dry-spinning method. It is found that the electrical conductivity and maximum current-carrying capability for these DWNT fibers can reach up to 5.9 × 105 S m - 1 and over 1 × 105 A cm - 2 in air. In comparison, we observed that standard carbon fiber tended to be oxidized and burnt out into cheese-like morphology when the maximum current was reached, while DWNT fiber showed a much slower breakdown behavior due to the gradual burnout in individual nanotubes. The electron microscopy observations further confirmed that the failure process of DWNT fibers occurs at localized positions, and while the individual nanotubes burn they also get aligned due to local high temperature and electrostatic field. In addition a finite element model was constructed to gain better understanding of the failure behavior of DWNT fibers.

Temperature-referenced high-sensitivity point-probe optical fiber chem-sensors based on cladding etched fiber Bragg gratings

OpenAIRE

Zhou, Kaiming; Chen, Xianfeng F.; Zhang, Lin; Bennion, Ian

2004-01-01

Point-probe optical fiber chem-sensors have been implemented using cladding etched fiber Bragg gratings. The sensors possess refractive index sensing capability that can be utilized to measure chemical concentrations. The Bragg wavelength shift reaches 8 nm when the index of surrounding medium changes from 1.33 to 1.44, giving maximum sensitivity more than 10 times higher than that of previously reported devices. More importantly, the dual-grating configuration of the point-probe sensors offe...

Improved terbium-doped, lithium-loaded glass scintillator fibers

International Nuclear Information System (INIS)

Spector, G.B.; McCollum, T.; Spowart, A.R.

1993-01-01

An improved terbium-doped, 6 Li-loaded glass scintillator has been drawn into fibers. Tests indicate that the neutron detection response of the fibers is superior to the response with fibers drawn from the original terbium-doped glass. The new fibers offer less attenuation (1/e length of ∝40 cm) and improved gamma ray/neutron discrimination. The improved fibers will be incorporated in a scintillator fiber optic long counter for neutron detection. (orig.)

Study of corrosion using long period fiber gratings coated with iron exposed to salty water

Science.gov (United States)

Coelho, L.; Santos, J. L.; Jorge, P. A. S.; de Almeida, J. M. M.

2017-04-01

A study of long period fiber gratings (LPFG) over coated with iron (Fe) and subjected to oxidation in water with different sodium chloride (NaCl) concentrations is presented. The formation of iron oxides and hydroxides was monitored in real time by following the features of the LPFG attenuation band. Preliminary results show that Fe coated LPFGs can be used as sensors for early warning of corrosion in offshore and in coastal projects where metal structures made of iron alloys are in contact with sea or brackish water.

Simple immunoglobulin G sensor based on thin core single-mode fiber

Science.gov (United States)

Zheng, Yingfang; Lang, Tingting; Shen, Tingting; Shen, Changyu

2018-03-01

In this paper, a simple fiber biosensor (FOB) for immunoglobulin G (IgG) detection is designed and experimentally verified. The FOB is constructed by a 20 mm long thin core single-mode fiber (TCSMF) sandwiched between two single-mode optical fibers (SMFs). First, the refractive index (RI) sensitivity of the fiber structures is calculated by the beam propagation method. The refractive index sensing experiment is performed using different concentrations of glycerol solutions, and the experimental results are mostly consistent with the simulation predictions. The experimental RI sensitivity increases with the surrounding RI and reaches 82.7 nm/RIU. Then the surface of the FOB is functionalized by APTES for covalent bonding. The human IgG and goat anti-human IgG are chosen as a bioconjugated pair to examine the bio-sensing effectiveness of this FOB. The sensitivity of IgG detection is determined to be 10.4 nm/(mg/ml). And the serum IgG concentration in normal adults lies within the range of 6-16 mg/ml (Worsfold et al., 1985), so the sensor is applicable to human IgG monitoring. The specificity of the FOB is also verified by a contrast experiment conducted using rabbit immunoglobulin G. The proposed FOB is simple, low loss, cost-effective, and can be used for various biological and chemical applications.

Bi-based superconducting fibers with high critical parameters

International Nuclear Information System (INIS)

Huo Yujing; He Yusheng; Liu Menglin; Mao Sining; Cai Liying; Wang Ying; Zhang Jincang; He Aisheng; Wang Jinsong

1991-01-01

Superconducting fibers of Bi(Pb)-Sr-Ca-Cu-O high Tc superconducting materials have been prepared by means of the laser-heated pedestal growth (LHPG) method. The highest zero resistance temperature T c0 reaches is 114K, and the highest critical current density J c (77K, O T) is greater than 5000 A/cm 2 . As-grown superconducting fibers were successfully fabricated without post growth heat treatment. Amorphous materials were used for the first time to make high quality fibers. The influence of growth conditions, thermal treatment and the composition of the fibers were discussed. (author). 5 refs., 7 figs., 3 tabs

Guiding hard x rays with glass polycapillary fiber

International Nuclear Information System (INIS)

Xiao, Q.F.; Ponomarev, I.Y.; Kolomitsev, A.I.; Gibson, D.M.; Dilmanian, F.A.; Nachaliel, E.

1993-01-01

X rays can be guided through a polycapillary fiber by multiple total reflections from the smooth channel walls of the fiber. Using monochromatic Synchrotron Radiation at energies of 22 and 44 keV, we measured the efficiency of transmission of x rays through polycapillary fibers with channel diameters of about 13 μm. Efficiencies of 57.3% and 54.5% for 22 keV and 44 keV x rays, respectively, were obtained with a 120-mm-long straight polycapillary fiber aligned with the incident beam. These values are close to the open fraction of the fiber, which is about 60%. In addition, transmission efficiency was measured as a function of the tilt angle between the incident beam and the axis of the fiber. We also measured the transmission efficiency as a function of the deflection angle for a 114-mm-long curved polycapillary fiber. The measurements are compared with a ray-tracing simulation

Hole-assisted fiber based fiber fuse terminator supporting 22 W input

Science.gov (United States)

Tsujikawa, Kyozo; Kurokawa, Kenji; Hanzawa, Nobutomo; Nozoe, Saki; Matsui, Takashi; Nakajima, Kazuhide

2018-05-01

We investigated the air hole structure in hole-assisted fiber (HAF) with the aim of terminating fiber fuse propagation. We focused on two structural parameters c/MFD and S1/S2, which are related respectively to the position and area of the air holes, and mapped their appropriate values for terminating fiber fuse propagation. Here, MFD is the mode field diameter, c is the diameter of an inscribed circle linking the air holes, S1 is the total area of the air holes, and S2 is the area of a circumscribed circle linking the air holes. On the basis of these results, we successfully realized a compact fiber fuse terminator consisting of a 1.35 mm-long HAF, which can terminate fiber fuse propagation even with a 22 W input. In addition, we observed fiber fuse termination using a high-speed camera. We additionally confirmed that the HAF-based fiber fuse terminator is effective under various input power conditions. The penetration length of the optical discharge in the HAF was only less than 300 μm when the input power was from 2 to 22 W.

Agave Americana Leaf Fibers

Directory of Open Access Journals (Sweden)

Ashish Hulle

2015-02-01

Full Text Available The growing environmental problems, the problem of waste disposal and the depletion of non-renewable resources have stimulated the use of green materials compatible with the environment to reduce environmental impacts. Therefore, there is a need to design products by using natural resources. Natural fibers seem to be a good alternative since they are abundantly available and there are a number of possibilities to use all the components of a fiber-yielding crop; one such fiber-yielding plant is Agave Americana. The leaves of this plant yield fibers and all the parts of this plant can be utilized in many applications. The “zero-waste” utilization of the plant would enable its production and processing to be translated into a viable and sustainable industry. Agave Americana fibers are characterized by low density, high tenacity and high moisture absorbency in comparison with other leaf fibers. These fibers are long and biodegradable. Therefore, we can look this fiber as a sustainable resource for manufacturing and technical applications. Detailed discussion is carried out on extraction, characterization and applications of Agave Americana fiber in this paper.

Double resonance long period fiber grating for detection of E. coli in trace concentration by choosing a proper bacteriophage

Science.gov (United States)

Chiniforooshan, Y.; Celebanska, A.; Janik, M.; Mikulic, P.; Haddad, F.; Perreault, J.; Bock, W. J.

2017-04-01

There is a critical need of a fast, specific and reliable assay for biological species. To address this need, long period fiber gratings (LPFG) among other fiber optic sensors can be used because of their high sensitivity to changes in surrounding medium. In this work we fabricated and used two over-etched LPFGs. One of them was covered with T4 Phage and the other was covered with MS2 phage that both specifically bind with Escherichia coli (E. coli) bacteria. This bacterium is a major cause of the food contaminations and outbreaks. We showed achieving a highest sensitivity region of the LPFG and the way to fine tune to that region by over-etching the grating. Finally, using the highly sensitive LPFG platform we could detect E. coli at concentrations as low as 100 colony forming units (CFU), by covering the LPFG with an optimized bio-functionalization of the fiber surface with MS2 bacteriophage.

Extended-length fiber optic carbon dioxide monitoring

Science.gov (United States)

Delgado-Alonso, Jesus; Lieberman, Robert A.

2013-05-01

This paper discusses the design and performance of fiber optic distributed intrinsic sensors for dissolved carbon dioxide, based on the use optical fibers fabricated so that their entire lengths are chemically sensitive. These fibers use a polymer-clad, silica-core structure where the cladding undergoes a large, reversible, change in optical absorbance in the presence of CO2. The local "cladding loss" induced by this change is thus a direct indication of the carbon dioxide concentration in any section of the fiber. To create these fibers, have developed a carbon dioxide-permeable polymer material that adheres well to glass, is physically robust, has a refractive index lower than fused silica, and acts as excellent hosts for a unique colorimetric indicator system that respond to CO2. We have used this proprietary material to produce carbon-dioxide sensitive fibers up to 50 meters long, using commercial optical fiber fabrication techniques. The sensors have shown a measurement range of dissolved CO2 of 0 to 1,450 mg/l (0 to 100% CO2 saturation), limit of detection of 0.3 mg/l and precision of 1.0 mg/l in the 0 to 50 mg/l dissolved CO2 range, when a 5 meter-long sensor fiber segment is used. Maximum fiber length, minimum detectable concentration, and spatial resolution can be adjusted by adjusting indicator concentration and fiber design.

Advanced integrated WDM system for POF communication

Science.gov (United States)

Haupt, M.; Fischer, U. H. P.

2009-01-01

Polymer Optical Fibres (POFs) show clear advantages compared to copper and glass fibres. In essence, POFs are inexpensive, space-saving and not susceptible to electromagnetic interference. Thus, the usage of POFs have become a reasonable alternative in short distance data communication. Today, POFs are applied in a wide number of applications due to these specific advantages. These applications include automotive communication systems and in-house-networks. State-of-the-art is to transmit data with only one channel over POF, this limits the bandwidth. To solve this problem, an integrated MUX/DEMUX-element for WDM over POF is designed and developed to use multiple channels. This integration leads to low costs, therefore this component is suitable for mass market applications. The fundamental idea is to separate the chromatic parts of the light in its monochromatic components by means of a grating based on an aspheric mirror. Due to the high NA of the POF the setup has to be designed in a 3D-approach. Therefore this setup cannot be compared with the planar solutions available on market, they would result high losses in the 3rd dimension. To achieve a fast and optimized design an optical simulation program is used. Particular attention has to be paid to the design of the POF as a light source in the simulation program and the optimisation of the grating. The following realization of the demultiplexer is planed to be done with injection molding. This technology offers easy and very economical processing. These advantages make this technology first choice for optical components in the low-cost array.

Cascaded Mach-Zehnder wavelength filters in silicon photonics for low loss and flat pass-band WDM (de-)multiplexing.

Science.gov (United States)

Horst, Folkert; Green, William M J; Assefa, Solomon; Shank, Steven M; Vlasov, Yurii A; Offrein, Bert Jan

2013-05-20

We present 1-to-8 wavelength (de-)multiplexer devices based on a binary tree of cascaded Mach-Zehnder-like lattice filters, and manufactured using a 90 nm CMOS-integrated silicon photonics technology. We demonstrate that these devices combine a flat pass-band over more than 50% of the channel spacing with low insertion loss of less than 1.6 dB, and have a small device size of approximately 500 × 400 µm. This makes this type of filters well suited for application as WDM (de-)multiplexer in silicon photonics transceivers for optical data communication in large scale computer systems.

Long-period gratings in photonic crystal fibers operating near the phase-matching turning point for evanescent chemical and biochemical sensing

Czech Academy of Sciences Publication Activity Database

Tian, F.; Kaňka, Jiří; Du, H.

2012-01-01

Roč. 20, č. 19 (2012), s. 20952-20961 ISSN 1094-4087 R&D Projects: GA MŠk(CZ) LH11038 Institutional support: RVO:67985882 Keywords : Photonic crystal fiber * Long-period grating * Optical sensors Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.546, year: 2012

Definition, analysis and development of an optical data distribution network for integrated avionics and control systems. Part 2: Component development and system integration

Science.gov (United States)

Yen, H. W.; Morrison, R. J.

1984-01-01

Fiber optic transmission is emerging as an attractive concept in data distribution onboard civil aircraft. Development of an Optical Data Distribution Network for Integrated Avionics and Control Systems for commercial aircraft will provide a data distribution network that gives freedom from EMI-RFI and ground loop problems, eliminates crosstalk and short circuits, provides protection and immunity from lightning induced transients and give a large bandwidth data transmission capability. In addition there is a potential for significantly reducing the weight and increasing the reliability over conventional data distribution networks. Wavelength Division Multiplexing (WDM) is a candidate method for data communication between the various avionic subsystems. With WDM all systems could conceptually communicate with each other without time sharing and requiring complicated coding schemes for each computer and subsystem to recognize a message. However, the state of the art of optical technology limits the application of fiber optics in advanced integrated avionics and control systems. Therefore, it is necessary to address the architecture for a fiber optics data distribution system for integrated avionics and control systems as well as develop prototype components and systems.

Highly-stable monolithic femtosecond Yb-fiber laser system based on photonic crystal fibers

DEFF Research Database (Denmark)

Liu, Xiaomin; Lægsgaard, Jesper; Turchinovich, Dmitry

2010-01-01

in the oscillator cavity for dispersion balancing and nonlinear optical limiting, and another one is used for low nonlinearity final pulse recompression. The chirped-pulse amplification and recompression of the 232-fs, 45-pJ/pulse oscillator output yields a final direct fiber-end delivery of 7.3-nJ energy pulses......A self-starting, passively stabilized, monolithic all polarizationmaintaining femtosecond Yb-fiber master oscillator / power amplifier with very high operational and environmental stability is demonstrated. The system is based on the use of two different photonic crystal fibers. One is used...... of around 297 fs duration. Our laser shows exceptional stability. No Q-switched modelocking events were detected during 4-days long observation. An average fluctuation of only 7.85 · 10−4 over the mean output power was determined as a result of more than 6-hours long measurement. The laser is stable towards...

Stress wave propagation in thin long-fiber carbon/epoxy composite panel. Numerical and experimental solutions

Directory of Open Access Journals (Sweden)

Kroupa T.

2007-10-01

Full Text Available The article deals with experimental and numerical analysis of stress wave propagation in a thin long fiber carbon/epoxy composite material. Experiments were performed on in-plane loaded square composite panels with dimensions 501mm x 501mm x 2:2 mm. The panels have several fiber orientations (0°, 30°, 60° and 90° measured from the loaded edge. They were loaded by in-plane impact of steel sphere. The impact area was on the edge, exactly 150mm from top left corners corner of the panels. The loading force was approximated by atime dependent function. Its shape was obtained from three dimensional contact analysis, which was performed on smaller area of panel. The function was used in further plane stress analysis of the whole panels. The comparison of the numerical and experimental results was executed. An attempt at determination of velocity of propagation of Rayleigh waves on the loaded edge was performed and the results are discussed in the paper. Further directions of the research are proposed.

CO2 laser ablation of bent optical fibers for sensing applications

International Nuclear Information System (INIS)

Lévesque, L; Jdanov, V

2011-01-01

A procedure for the fabrication of a fiber optic sensor involving CO 2 laser ablation at λ = 10.6 µm is proposed. A basic system to achieve optical fiber bending and material processing on a single mode optical fiber is described and it is demonstrated that an optical fiber can be bent at a very precise angle by focusing a CO 2 beam locally near the glass cladding surface until it reaches melting temperature. A method is also described for removing material at the apex of a bent fiber to obtain a smooth and well flattened plane surface that is suitable for optical fiber sensing

Direct writing of half-meter long CNT based fiber for flexible electronics.

Science.gov (United States)

Huang, Sihan; Zhao, Chunsong; Pan, Wei; Cui, Yi; Wu, Hui

2015-03-11

Rapid construction of flexible circuits has attracted increasing attention according to its important applications in future smart electronic devices. Herein, we introduce a convenient and efficient "writing" approach to fabricate and assemble ultralong functional fibers as fundamental building blocks for flexible electronic devices. We demonstrated that, by a simple hand-writing process, carbon nanotubes (CNTs) can be aligned inside a continuous and uniform polymer fiber with length of more than 50 cm and diameters ranging from 300 nm to several micrometers. The as-prepared continuous fibers exhibit high electrical conductivity as well as superior mechanical flexibility (no obvious conductance increase after 1000 bending cycles to 4 mm diameter). Such functional fibers can be easily configured into designed patterns with high precision according to the easy "writing" process. The easy construction and assembly of functional fiber shown here holds potential for convenient and scalable fabrication of flexible circuits in future smart devices like wearable electronics and three-dimensional (3D) electronic devices.

Highly reflective Bragg gratings in slightly etched step-index polymer optical fiber.

Science.gov (United States)

Hu, Xuehao; Pun, Chi-Fung Jeff; Tam, Hwa-Yaw; Mégret, Patrice; Caucheteur, Christophe

2014-07-28

During the past few years, a strong progress has been made in the photo-writing of fiber Bragg gratings (FBGs) in polymer optical fibers (POFs), animated by the constant wish to enhance the grating reflectivity and improve the sensing performances. In this paper, we report the photo-inscription of highly reflective gratings in step-index POFs, obtained thanks to a slight etching of the cladding. We demonstrate that a cladding diameter decrease of ~12% is an ideal trade-off to produce highly reflective gratings with enhanced axial strain sensitivity, while keeping almost intact their mechanical resistance. For this, we make use of Trans-4-stilbenemethanol-doped photosensitive step-index poly(methyl methacrylate) (PMMA) POFs. FBGs are inscribed at ~1550 nm by the scanning phase mask technique in POFs of different external diameters. Reflectivity reaching 97% is achieved for 6 mm long FBGs, compared to 25% for non-etched POFs. We also report that a cladding decrease enhances the FBG axial tension while keeping unchanged temperature and surrounding refractive index sensitivities. Finally and for the first time, a measurement is conducted in transmission with polarized light, showing that a photo-induced birefringence of 7 × 10(-6) is generated (one order of magnitude higher than the intrinsic fiber birefringence), which is similar to the one generated in silica fiber using ultra-violet laser.

Bio-composites fabricated by sandwiching sisal fibers with polypropylene (PP)

Energy Technology Data Exchange (ETDEWEB)

Sosiati, H., E-mail: hsosiati@gmail.com [Nanomaterials Research Group, LPPT Universitas Gadjah Mada (Indonesia); Nahyudin, A., E-mail: ahmadnahyudin@yahoo.co.id; Fauzi, I., E-mail: ikhsannurfauzi@gmail.com; Wijayanti, D. A., E-mail: wijayantidwiastuti@gmail.com [Department of Physics, Faculty of Mathematics and Natural Sciences, Gadjah Mada University (Indonesia); Triyana, K., E-mail: triyana@ugm.ac.id [Nanomaterials Research Group, LPPT Universitas Gadjah Mada (Indonesia); Department of Physics, Faculty of Mathematics and Natural Sciences, Gadjah Mada University (Indonesia)

2016-04-19

Sisal fibers reinforced polypropylene (PP) composites were successfully fabricated using sandwiching sisal fibers with PP sheets. The ratio of fiber and polymer matrix was 50:50 (wt. %). Untreated short and long sisal fibers, and alkali treated short sisal fibers in 6% NaOH at 100°C for 1 and 3 h were used as reinforcement or fillers. A small amount (3 wt. %) of maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the surface morphology and chemical composition of the fibers, respectively. Flexural test of sisal/PP composites was done according to ASTM D 790-02. The results showed that flexural strength of untreated long fiber reinforced composite is much higher than that of the untreated and alkali treated short fibers reinforced composites with and without the addition of MAPP. Alkalization related to fiber surface modification, fiber length/fiber orientation and a composite fabrication technique are important factors in contributing to the fiber distribution within the matrix, the bonding between the fiber and the matrix and the enhancement of flexural strength of the bio-composite.

Bio-composites fabricated by sandwiching sisal fibers with polypropylene (PP)

International Nuclear Information System (INIS)

Sosiati, H.; Nahyudin, A.; Fauzi, I.; Wijayanti, D. A.; Triyana, K.

2016-01-01

Sisal fibers reinforced polypropylene (PP) composites were successfully fabricated using sandwiching sisal fibers with PP sheets. The ratio of fiber and polymer matrix was 50:50 (wt. %). Untreated short and long sisal fibers, and alkali treated short sisal fibers in 6% NaOH at 100°C for 1 and 3 h were used as reinforcement or fillers. A small amount (3 wt. %) of maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the surface morphology and chemical composition of the fibers, respectively. Flexural test of sisal/PP composites was done according to ASTM D 790-02. The results showed that flexural strength of untreated long fiber reinforced composite is much higher than that of the untreated and alkali treated short fibers reinforced composites with and without the addition of MAPP. Alkalization related to fiber surface modification, fiber length/fiber orientation and a composite fabrication technique are important factors in contributing to the fiber distribution within the matrix, the bonding between the fiber and the matrix and the enhancement of flexural strength of the bio-composite.

Bio-composites fabricated by sandwiching sisal fibers with polypropylene (PP)

Science.gov (United States)

Sosiati, H.; Nahyudin, A.; Fauzi, I.; Wijayanti, D. A.; Triyana, K.

2016-04-01

Sisal fibers reinforced polypropylene (PP) composites were successfully fabricated using sandwiching sisal fibers with PP sheets. The ratio of fiber and polymer matrix was 50:50 (wt. %). Untreated short and long sisal fibers, and alkali treated short sisal fibers in 6% NaOH at 100°C for 1 and 3 h were used as reinforcement or fillers. A small amount (3 wt. %) of maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the surface morphology and chemical composition of the fibers, respectively. Flexural test of sisal/PP composites was done according to ASTM D 790-02. The results showed that flexural strength of untreated long fiber reinforced composite is much higher than that of the untreated and alkali treated short fibers reinforced composites with and without the addition of MAPP. Alkalization related to fiber surface modification, fiber length/fiber orientation and a composite fabrication technique are important factors in contributing to the fiber distribution within the matrix, the bonding between the fiber and the matrix and the enhancement of flexural strength of the bio-composite.

Revenue-driven Lightpaths Provisioning over Optical WDM Networks Using Bee Colony Optimization

Directory of Open Access Journals (Sweden)

Goran Z. Marković

2017-01-01

Full Text Available Revenue-driven Lightpaths Provisioning over Optical WDM Networks Using Bee Colony Optimization Goran Z. Markovic University of Belgrade n Faculty of Transport and Traffic Engineering, Vojvode Stepe 305, Belgrade, 11000, Serbia E-mail: g.markovic@sf.bg.ac.rs Abstract This paper aims to study the lightpaths provisioning problem in optical WDM networks with scarce available wavelengths under the static (off-line traffic demands such that network operatorrs (NOrs revenue is maximized. To achieve this goal, a NO has to be addressed with the issue how to solve the call admission control jointly with the lightpaths routing and wavelength assignment (RWA problem in efficient manner. The improved bee colony optimization (BCOi metaheuristic is applied to solve the considered revenue maximization (Max-Rev problem. We evaluated the performances of the proposed BCOi Max-Rev framework by performing numerous simulation experiments in different realistic WDM optical network topologies. We observed that our BCOi Max-Rev algorithm is an efficient tool to produce high quality solutions within reasonable amount of CPU time. It has been proved that BCOi Max-Rev solutions just slightly deviate from optimal solutions (at most 1% and considerably outperform some heuristic algorithms, such as the Max-Profit and FCFS. In addition, our Max-Rev BCOi algorithm is able to produce better solution quality compared to the constructive BCO approach (up to 3.5% in the case of NSFNet and 5% in the case of EON. Finally, we compared the BCOi to differential evolution (DE approach in the case of more complex networks, such as the USA optical network topology. The results show that our BCOi always outperforms DE metaheuristic, whereby the profit improvement could reach up to 20 % in some instances. Keywords: bee colony optimization (BCO, lightpath, optical network, routing and wavelength assignment (RWA, revenue maximization. 1. Introduction Optical networks employing wavelength

Alternative technique for biodiesel quality control using an optical fiber long-period grating sensor

International Nuclear Information System (INIS)

Falate, Rosane; Nike, Karen; Costa Neto, Pedro Ramos da; Cacao Junior, Eduardo; Muller, Marcia; Kalinowski, Hypolito Jose; Fabris, Jose Luis

2007-01-01

We report the use of an optical fiber sensor to measure the soybean oil concentration in samples obtained from the mixture of pure biodiesel and commercial soybean oil. The operation of the device is based on the long-period grating sensitivity to the surrounding medium refractive index, which leads to measurable modifications in the grating transmission spectrum. The proposed analysis method results in errors in the oil concentration of 0.4% and 2.6% for pure biodiesel and commercial soybean oil, respectively. Techniques of total glycerol, dynamic viscosity, density, and hydrogen nuclear magnetic resonance spectroscopy were also employed to validate the proposed method. (author)

Alternative technique for biodiesel quality control using an optical fiber long-period grating sensor

Energy Technology Data Exchange (ETDEWEB)

Falate, Rosane [Universidade Estadual de Ponta Grossa, PR (Brazil). Dept. de Informatica; Nike, Karen; Costa Neto, Pedro Ramos da [Universidade Tecnologica Federal do Parana, Curitiba (Brazil). Dept. de Quimica; Cacao Junior, Eduardo; Muller, Marcia; Kalinowski, Hypolito Jose; Fabris, Jose Luis [Universidade Tecnologica Federal do Parana, Curitiba (Brazil). Dept. de Fisica]. E-mail: fabris@utfpr.edu.br

2007-07-01

We report the use of an optical fiber sensor to measure the soybean oil concentration in samples obtained from the mixture of pure biodiesel and commercial soybean oil. The operation of the device is based on the long-period grating sensitivity to the surrounding medium refractive index, which leads to measurable modifications in the grating transmission spectrum. The proposed analysis method results in errors in the oil concentration of 0.4% and 2.6% for pure biodiesel and commercial soybean oil, respectively. Techniques of total glycerol, dynamic viscosity, density, and hydrogen nuclear magnetic resonance spectroscopy were also employed to validate the proposed method. (author)

Structures and Performance of Graphene/Polyimide Composite Graphite Fibers

Directory of Open Access Journals (Sweden)

LI Na

2017-09-01

Full Text Available Dry-wet spinning process was used to gain graphene oxide/polyimide composite fibers, then graphene/polyimide composite carbon and graphite fibers were obtained through carbonized and graphitized. Different graphene oxide contents of the composite carbon and graphite fibers were measured by thermal gravimetric analysis, Raman, mechanical properties, electrical properties,SEM and so on. The results show that when the GO content is 0.3%(mass fraction,the same below, the thermal property of the graphene oxide/polyimide composite fibers is the best. The mechanical and electrical properties are obriously improved by the addition of GO, graphitization degree also increases. When the composite carbon fibers are treated at 2800℃, GO content increases to 2.0%, the thermal conductivity of the composite graphite fibers reaches 435.57W·m-1·K-1 and cross-section structures of carbon fibers are more compact.

Design and analysis of adaptive honeycomb structure with pneumatic muscle fibers

Science.gov (United States)

Yin, Weilong; Tian, Dongkui; Chen, Yijin

2012-04-01

The adaptive honeycomb structure actuated by pneumatic muscle fibers is proposed in this paper. The FE model of adaptive honeycomb structure is developed by use of ANSYS software. The elastics modulus of the developed pneumatic muscle fibers is experimentally determined and their output force is tested. The results show that the contraction ratio of the pneumatic muscle fibers with inner diameter of 2mm could reach up to 26.8% and the force could reach to a value of 27N when the applied pressure is 0.4MPa and the contraction ratio is zero. When the adaptive honeycomb has a certain load and an effective output displacement, the applied force must be greater than a certain value. The adaptive honeycomb must be consumed extra energy when the output displacement and force are produced.

VCSEL sources for optical fiber-wireless composite data links at 60GHz

DEFF Research Database (Denmark)

Vegas Olmos, Juan José; Pang, Xiaodan; Lebedev, Alexander

2013-01-01

This paper presents a performance assessment of 60-GHz mm-wave signal generation using photonic upconversion employing a VCSEL as source. The system reaches 10−9 BER over a variety of optical fibers for data rates of 1.25-Gbit/s.......This paper presents a performance assessment of 60-GHz mm-wave signal generation using photonic upconversion employing a VCSEL as source. The system reaches 10−9 BER over a variety of optical fibers for data rates of 1.25-Gbit/s....

A Multicast Sparse-Grooming Algorithm Based on Network Coding in WDM Networks

Science.gov (United States)

Zhang, Shengfeng; Peng, Han; Sui, Meng; Liu, Huanlin

2015-03-01

To improve the limited number of wavelength utilization and decrease the traffic blocking probability in sparse-grooming wavelength-division multiplexing (WDM) networks, a multicast sparse-grooming algorithm based on network coding (MCSA-NC) is put forward to solve the routing problem for dynamic multicast requests in this paper. In the proposed algorithm, a traffic partition strategy, that the coarse-granularity multicast request with grooming capability on the source node is split into several fine-granularity multicast requests, is designed so as to increase the probability for traffic grooming successfully in MCSA-NC. Besides considering that multiple destinations should receive the data from source of the multicast request at the same time, the traditional transmission mechanism is improved by constructing edge-disjoint paths for each split multicast request. Moreover, in order to reduce the number of wavelengths required and further decrease the traffic blocking probability, a light-tree reconfiguration mechanism is presented in the MCSA-NC, which can select a minimal cost light tree from the established edge-disjoint paths for a new multicast request.

Hollow Core Optical Fiber Gas Lasers: Toward Novel and Practical Systems in Fused Silica

Science.gov (United States)

2017-05-18

Hollow core Optically pumped Fiber Gas LASer’s (HOFGLAS’s) based on population inversion combine advantages of fiber lasers such as long interaction...polarization dependent fiber properties. Preliminary experiments were performed toward simultaneous lasing in the visible and near infrared; lasing in...words) Hollow core Optically pumped Fiber Gas LASer’s (HOFGLAS’s) based on population inversion combine advantages of fiber lasers such as long

Periodical rocking long period gratings in PANDA fibers for high temperature and refractive index sensing

Science.gov (United States)

Jin, Wa; Bi, Wei-hong; Fu, Xing-hu; Fu, Guang-wei

2017-09-01

We report periodical rocking long period gratings (PR-LPGs) in PANDA fibers fabricated with CO2 laser. The PR-LPGs achieve very high coupling efficiency of 19 dB with 12 periods and a 3.5° twist angle in just one scanning cycle, which is much more effective than the conventional CO2 laser fabrication technique. This type of LPGs exhibits polarization-selective resonance dips which demonstrate different sensitivities to environmental parameters. The high temperature and external refractive index sensitivities are measured simultaneously, so it can be used as a wavelength-selective polarization filter and sensor.

Fiber-integrated Brillouin microspectroscopy: Towards Brillouin endoscopy

Directory of Open Access Journals (Sweden)

Irina V. Kabakova

2017-11-01

Full Text Available Brillouin imaging (BI for micromechanical characterization of tissues and biomaterials is a fast-developing field of research with a strong potential for medical diagnosis of disease-modified tissues and cells. Although the principles of BI imply its compatibility with in vivo and in situ measurements, the integration of BI with a flexible catheter, capable of reaching the region of interest within the body, is yet to be reported. Here, for the first time, we experimentally investigate integration of the Brillouin spectroscope with standard optical fiber components to achieve a Brillouin endoscope. The performance of single-fiber and dual-fiber endoscopes are demonstrated and analyzed. We show that a major challenge in construction of Brillouin endoscopes is the strong backward Brillouin scattering in the optical fiber and we present a dual-fiber geometry as a possible solution. Measurements of Brillouin spectra in test liquids (water, ethanol and glycerol are demonstrated using the dual-fiber endoscope and its performance is analyzed numerically with the help of a beam propagation model.

Processing and Mechanical Properties of Macro Polyamide Fiber Reinforced Concrete.

Science.gov (United States)

Jeon, Joong Kyu; Kim, WooSeok; Jeon, Chan Ki; Kim, Jin Cheol

2014-11-26

This study developed a macro-sized polyamide (PA) fiber for concrete reinforcement and investigated the influence of the PA fiber on flexural responses in accordance with ASTM standards. PA fibers are advantageous compared to steel fibers that are corrosive and gravitated. The macro-sized PA fiber significantly improved concrete ductility and toughness. Unlike steel fibers, the PA fibers produced two peak bending strengths. The first-peaks occurred near 0.005 mm of deflection and decreased up to 0.5 mm of deflection. Then the bending strength increased up to second-peaks until the deflections reached between 1.0 and 1.5 mm. The averaged flexural responses revealed that PA fiber content did not significantly influence flexural responses before L /600, but had significant influence thereafter. Toughness performance levels were also determined, and the results indicated more than Level II at L /600 and Level IV at others.

Alkaline treatment on piassava (Attalea funifera martius) fiber

International Nuclear Information System (INIS)

Santos, E.B.C.; Moreno, C.G.; Barros, J.J.P.; Moura, D.A.; Fim, F.C.; Wellen, R.M.R.; Silva, L.B.

2016-01-01

Alkaline treatment on piassava fiber with size inferior to 270 mesh was performed to remove impurities. The treatments took place under magnetic stirring and Sodium Hydroxide (NaOH) solution with 2, 4, 6 and 8% of concentration; processing time ranged between 100 and 400 minutes, with intervals of 25 minutes; the main object was to reach the optimum concentration and time. The concentration 2% was used to remove efficiently the impurities without damaging excessively the fiber. The fibers were characterized by means of X-ray diffraction (XRD) and optical microscopy (OM). Fibers presented XRD diffraction peak around 22 deg, due to the crystalline structure of cellulose. By optical microscopy was observed the treatment efficacy of the 2% NaOH solution in removing surface impurities. (author)

Ontogenetic changes in skeletal muscle fiber type, fiber diameter and myoglobin concentration in the Northern elephant seal (Mirounga angustirostris

Directory of Open Access Journals (Sweden)

Colby eMoore

2014-06-01

Full Text Available Northern elephant seals (Mirounga angustirostris (NES are known to be deep, long-duration divers and to sustain long-repeated patterns of breath-hold, or apnea. Some phocid dives remain within the bounds of aerobic metabolism, accompanied by physiological responses inducing lung compression, bradycardia and peripheral vasoconstriction. Current data suggest an absence of type IIb fibers in pinniped locomotory musculature. To date, no fiber type data exist for NES, a consummate deep diver. In this study, NES were biopsied in the wild. Ontogenetic changes in skeletal muscle were revealed through succinate dehydrogenase (SDH based fiber typing. Results indicated a predominance of uniformly shaped, large type I fibers and elevated myoglobin (Mb concentrations in the longissimus dorsi (LD muscle of adults. No type II muscle fibers were detected in any adult sampled. This was in contrast to the juvenile animals that demonstrated type II myosin in Western Blot analysis, indicative of an ontogenetic change in skeletal muscle with maturation. These data support previous hypotheses that the absence of type II fibers indicates reliance on aerobic metabolism during dives, as well as a depressed metabolic rate and low energy locomotion. We also suggest that the lack of type IIb fibers (adults may provide a protection against ischemia reperfusion (IR injury in vasoconstricted peripheral skeletal muscle.

On-demand virtual optical network access using 100 Gb/s Ethernet.

Science.gov (United States)

Ishida, Osamu; Takamichi, Toru; Arai, Sachine; Kawate, Ryusuke; Toyoda, Hidehiro; Morita, Itsuro; Araki, Soichiro; Ichikawa, Toshiyuki; Hoshida, Takeshi; Murai, Hitoshi

2011-12-12

Our Terabit LAN initiatives attempt to enhance the scalability and utilization of lambda resources. This paper describes bandwidth-on-demand virtualized 100GE access to WDM networks on a field fiber test-bed using multi-domain optical-path provisioning. © 2011 Optical Society of America

Towards all-optical label switching nodes with multicast