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Sample records for active fabry-perot semiconductor

  1. Modally Resolved Fabry-Perot Experiment with Semiconductor Waveguides

    Pressl, B; Laiho, K; Geßler, J; Kamp, M; Höfling, S; Schneider, C; Weihs, G

    2015-01-01

    Based on the interaction between different spatial modes, semiconductor Bragg-reflection waveguides provide a highly functional platform for non-linear optics. Therefore, the control and engineering of the properties of each spatial mode is essential. Despite the multimodeness of our waveguide, the well-established Fabry-Perot technique for recording fringes in the optical transmission spectrum can successfully be employed for a detailed linear optical characterization when combined with Fourier analysis. A prerequisite for the modal sensitivity is a finely resolved transmission spectrum that is recorded over a broad frequency band. Our results highlight how the features of different spatial modes, such as their loss characteristics and dispersion properties, can be separated from each other allowing their comparison. The mode-resolved measurements are important for optimizing the performance of such multimode waveguides by tailoring the properties of their spatial modes.

  2. Construction of an optical semiconductor amplifier starting from a Fabry-Perot semiconductor laser

    A methodology to convert a semiconductor laser Fabry-Perot (SL-FP) in a semiconductor optical amplifier (SOA) is presented. In order to suppress the cavity resonant an optical thin film coating was deposited on the facets of the SL-FP. The experiment was carried out putting on service a new monitoring technique that consist in the observation of the laser power spectrum during the antireflection coatings deposition. This allows to determine the moment were the facets reflectivity is minimum. The SOA obtained was characterized for different polarization currents. (Author)

  3. Faraday-Active Fabry-Perot Resonator: Transmission, Reflection, and Emissivity

    Liptuga, Anatoliy; Morozhenko, Vasyl; Pipa, Viktor; Venger, Evgen; Kostiuk, Theodor

    2011-01-01

    The propagation of light within a semiconductor Faraday-active Fabry-Perot resonator (FAFR) is investigated theoretically and experimentally. It is shown that an external magnetic field radically changes the angular and spectral characteristics of transmission, reflection and emissivity of the resonator not only for polarized, but also for unpolarized light. Suppression of interference patterns and phase inversion of the interference extrema were observed in both monochromatic and polychromatic light. The investigations were carried out for the plane-parallel plates of n-InAs in the spectral range of free charge carrier absorption. The results can be used to create new controllable optical and spectroscopic devices for investigation of Faraday-active material properties and for control of parameters of plane-parallel layers and structures.

  4. A novel scheme of label abstraction and erasion based on Fabry-Perot semiconductor optical amplifier

    Wei Zhang; Kun Qiu; Yun Ling; Ying Pang

    2007-01-01

    A novel label abstraction and erasion scheme based on a Fabry-Perot semiconductor optical amplifier (FP-SOA) is proposed for all-optical separation of the bit-serial label from payload and its performance is investigated by simulation. Important features of this scheme are that it does not make use of any high-speed electronics and only one device is needed. Using this scheme, label abstraction and erasion can be realized with the extinction ratio of 9.72 and 7.05 dB, respectively.

  5. Construction of an optical semiconductor amplifier starting from a Fabry-Perot semiconductor laser; Construccion de un amplificador optico de semiconductor a partir de un laser de semiconductor Fabry-Perot

    Garcia, E.; Soto, H.; Marquez, H.; Valles V, N. [Departamento de Electronica y Telecomunicaciones, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada. Km. 107, Carretera Tijuana-Ensenada, 22860 Ensenada, Baja California (Mexico)

    2000-07-01

    A methodology to convert a semiconductor laser Fabry-Perot (SL-FP) in a semiconductor optical amplifier (SOA) is presented. In order to suppress the cavity resonant an optical thin film coating was deposited on the facets of the SL-FP. The experiment was carried out putting on service a new monitoring technique that consist in the observation of the laser power spectrum during the antireflection coatings deposition. This allows to determine the moment were the facets reflectivity is minimum. The SOA obtained was characterized for different polarization currents. (Author)

  6. Performance improvement and characterization activities for an imaging Fabry-Perot interferometer

    Larar, Allen M.; Cook, William B.; Flood, Michael A.; Campbell, Joel F.; Boyer, Charles M.

    2008-10-01

    Risk mitigation activities for a prototype imaging Fabry-Perot Interferometer (FPI) system, development originating within NASA's Instrument Incubator Program (IIP) for enabling future space-based atmospheric composition missions, are continuing at NASA Langley Research Center. The system concept and technology are focused on observing tropospheric ozone around 9.6 micron, but also have applicability toward measurement of other trace species in different spectral regions and other applications. The latest results from performance improvement and laboratory characterization activities will be reported, with an emphasis placed on testing performed to evaluate system-level radiometric, spatial, and spectral measurement fidelity.

  7. A novel time-to-live countdown scheme based on asymmetric Mach-Zehnder interferometer and Fabry-Perot semiconductor optical amplifier

    Ying Pang; Kun Qiu; Yun Ling; Wei Zhang

    2007-01-01

    We propose a novel optical time-to-live (TTL) processing scheme using asymmetric Mech-Zehnder interferometer (AMZI) and Fabry-Perot semiconductor optical amplifier (FP-SOA). AMZI transfers M TTL pulses into M - 1 pulses and two residual pulses with 6-dB power difference. FP-SOA enhances the power difference between the M- 1 pulses to the residual pulses to more than 10 dB. A numerical model is established for verifying the feasibility of this scheme.

  8. Active Q-switching of a fiber laser using a modulated fiber Fabry-Perot filter and a fiber Bragg grating

    Martínez Manuel, Rodolfo; Kaboko, J. J. M.; Shlyagin, M. G.

    2016-02-01

    We propose and demonstrate a simple and robust actively Q-switched erbium-doped fiber ring cavity laser. The Q-switching is based on dynamic spectral overlapping of two filters, namely a fiber Bragg grating-based filter and a fiber Fabry-Perot tunable filter. Using 3.5 m of erbium-doped fiber and a pump power of only 60 mW, Q-switched pulses with a peak power of 9.7 W and a pulse duration of 500 ns were obtained. A pulse repetition rate can be continuously varied from a single shot to a few KHz.

  9. Fabry-Perot-like interference security image structures: From passive to active

    Counterfeiting of products and important documents is at an all-time high and is costing the world economy hundreds of billions of dollars yearly as well as posing significant safety and health hazards through the production of uncertified goods, e.g., pharmaceutical products. To limit these effects, interference-based optical security devices offering an angular color shift are still widely in use. Unfortunately, commercial iridescent materials are now readily available and represent a potential source of counterfeiting. In this short review, we first describe the basic principles behind passive interference security image structures (ISIS) and the qualities which have resulted in their integration into most important documents. Various features which have been added to ISIS in order to make them harder to duplicate yet simpler to authenticate are also presented (metamerism, magnetic materials, diffraction, etc.). We then address the implementation of active materials, mainly electrochromic WO3 as a means of generating two-level authentication devices. Finally, we discuss some general considerations to keep in mind when developing features for security applications. - Highlights: • We review Fabry–Perot-like metal-dielectric filters used in optical security. • We discuss/demonstrate recent additions: metamerism, magnetism and diffraction. • We demonstrate a feature based on the use of thin metallic mirrors. • We cover recent developments in the use of active materials. • We demonstrate an electrochromic feature with two levels of authentication

  10. Measurements of the phase shift on reflection for low-order infrared Fabry-Perot interferometer dielectric stack mirrors.

    Mielke, S L; Ryan, R E; Hilgeman, T; Lesyna, L; Madonna, R G; Van Nostrand, W C

    1997-11-01

    A simple technique based on a Fizeau interferometer to measure the absolute phase shift on reflection for a Fabry-Perot interferometer dielectric stack mirror is described. Excellent agreement between the measured and predicted phase shift on reflection was found. Also described are the salient features of low-order Fabry-Perot interferometers and the demonstration of a near ideal low-order (1-10) Fabry-Perot interferometer through minimizing the phase dispersion on reflection of the dielectric stack. This near ideal performance of a low-order Fabry-Perot interferometer should enable several applications such as compact spectral imagers for solid and gas detection. The large free spectral range of such systems combined with an active control system will also allow simple interactive tuning of wavelength agile laser sources such as CO(2) lasers, external cavity diode lasers, and optical parametric oscillators. PMID:18264347

  11. An Archetype Semi-Ring Fabry-Perot (SRFP) Resonator

    Taghavi-Larigani, Shervin; VanZyl, Jakob

    2009-01-01

    We introduce and demonstrate the generation of a novel resonator, termed Semi-Ring Fabry-Perot (SRFP), that exhibits unique features, such as, its use of one plane mirror, allowing the SRFP to be easily fabricated as a symmetrical device. In addition to its unique features, it exhibits advantages of ring and Fabry-Perot resonators: 1) compared to a ring resonator that only allows a transmitted intensity, the Semi-Ring Fabry-Perot (SRFP) supports standing waves, allowing both a reflected and transmitted intensity; 2) the reflected light spectrum of the SRFP resonator is much narrower than similar Fabry-Perot, implying higher finesse.

  12. Tilted short base Fabry-Perot interferometer with inverted resonances in feedback system of widely tunable linear laser

    The method of spectral selection based on weak coupling between a tilted short Fabry-Perot interferometer and a semiconductor optical amplifier has been proposed. An unusual effect was discovered at a certain inclination. Narrowband spectral maxima are observed in the light backreflected from a tilted short base Fabry-Perot interferometer at natural resonances. To demonstrate possible use of this effect for creation of selective feedback in a laser, a semiconductor laser with wavelength tuning range of ±10 nm at central wavelength 1290 nm and coherence length 8 mm has been developed

  13. Influence of laser frequency noise on scanning Fabry-Perot interferometer based laser Doppler velocimetry

    Rodrigo, Peter John; Pedersen, Christian

    2014-01-01

    n this work, we study the performance of a scanning Fabry-Perot interferometer based laser Doppler velocimeter (sFPILDV) and compare two candidate 1.5 um single-frequency laser sources for the system – a fiber laser (FL) and a semiconductor laser (SL). We describe a straightforward calibration pr...... procedure for the sFPI-LDV and investigate the effect of different degrees of laser frequency noise between the FL and the SL on the velocimeter’s performance...

  14. Integrated Fabry-Perot optical space switches

    Menard, Michael

    As information technologies are adopted by more people to accomplish a greater variety of tasks, the need for optical telecommunication networks with higher capacity and flexibility grows. In addition to improving throughput by increasing transmission rates and the number of wavelength channels, novel network architectures using optical burst or packet based switching are investigated because they allow a more efficient use of transmission capacity and they enable the reorganisation of wavelength connections according to traffic demands. The implementation of such networks requires fast, broadband, transparent, and scalable optical space switches. Although research on optical space switches has been on going for decades, no solution that meets all of the above requirements has been reported yet. The work presented in this thesis introduces a novel optical space switch configuration based on tunable integrated Fabry-Perot filters working at oblique incidence and investigates their performance. A design method to implement this new switch concept is described and demonstrated with the fabrication and characterisation of optical prototypes. The prototypes are implemented in GaAs/AlGaAs planar waveguides and they are designed to be operated using the electro-optic effect. Deep etching is used to create the switch features and a comprehensive optimization of the waveguide structure is conducted to minimize radiation losses. To maximize the number of wavelength channels that can be controlled with a small refractive index modulation, the switches have a 200 GHz comb frequency response that transmits/reflects one out of every two channels on the ITU 100 GHz grid. Thus, shifting their frequency response by one channel spacing is sufficient to change the state of every channel. Furthermore, four Fabry-Perot cavities are coupled to obtain a flat and wide theoretical passband of more than 50 GHz. A Gaussian beam propagation analysis is performed to determine the minimum beam

  15. Feedback stabilized tandem Fabry-Perot interferometer

    A new system for measuring the isotopic ratio of uranium, in which two plane-type Fabry-Perot interferometers (tandem FP) are connected in series. The parallelism between the two FPs is achieved automatically by a feedback control mechanism based on laser interference fringe monitoring. The structure of the tandem FP, feedback control system, automatic parallelism adjustment mechanism and wavelength synchronization mechanism are described in detail. For experiments, a hollow cathode discharge tube of a pulse discharge type is employed. Measurements are made to determine the effects of pulse width on the 238U peak height of 502.7 nm line, recorder traces of 235U and 238U lines, half width for 238U component of the 502.7 nm line, SN ratio, reproducibility of the 235U/238U peak height ratio and 235U/238U intensity ratio. Considerations are made on the spectral line width, contrast, transmission factor, and stability of automatic parallelism control and wavelength synchronization. Results obtained indicates that a single-type interferometer would serve adequately for measuring the 235U/238U ratio if the automatic parallelism control developed here is used. The ultimate object of the tandem system is to make measurement of 236U. Satisfactory results have not obtained as yet, but most likely the present system would make it possible if a light source of a higher intensity and advanced photometric techniques are developed. (Nogami, K.)

  16. Deep Fabry-Perot imaging of NGC 6240: Kinematic evidence for merging galaxies

    The authors have observed the superluminous, infrared galaxy NGC 6240 (z = 0.025) at H alpha with the Hawaii Imaging Fabry-Perot Interferometer (HIFI - Bland and Tully 1989). During the past decade, observational evidence from all wavebands indicates that the unusual appearance of NGC 6240 has resulted from a collision between two gas-rich systems, a view which is supported by our spectrophotometric data. However, the origin of the enormous infrared luminosity (4 times 10(exp 11) solar luminosity) detected by the Infrared Astronomy Satellite (IRAS) remains highly controversial, where opinions differ on the relative roles of large-scale shocks, massive star formation or a buried active nucleus. These mechanisms are discussed in the light of the author's Fabry-Perot observations

  17. Calibrating echelle spectrographs with Fabry-Perot etalons

    Bauer, Florian F; Reiners, Ansgar

    2015-01-01

    Over the past decades hollow-cathode lamps have been calibration standards for spectroscopic measurements. Advancing to cm/s radial velocity precisions with the next generation of instruments requires more suitable calibration sources with more lines and less dynamic range problems. Fabry-Perot interferometers provide a regular and dense grid of lines and homogeneous amplitudes making them good candidates for next generation calibrators. We investigate the usefulness of Fabry-Perot etalons in wavelength calibration, present an algorithm to incorporate the etalon spectrum in the wavelength solution and examine potential problems. The quasi periodic pattern of Fabry-Perot lines is used along with a hollow-cathode lamp to anchor the numerous spectral features on an absolute scale. We test our method with the HARPS spectrograph and compare our wavelength solution to the one derived from a laser frequency comb. The combined hollow-cathode lamp/etalon calibration overcomes large distortion (50 m/s) in the wavelengt...

  18. Atmospheric temperature sensing with a multiorder Fabry-Perot interferometer.

    Wang, J; Drayson, S R; Hayes, P B

    1989-12-01

    A Fabry-Perot interferometer has a periodic response. By matching the free spectral range of a Fabry-Perot interferometer (FPI) with the period of the CO(2) spectrum, considerable advantages of throughput and spectral resolution can be achieved, leading to high spectral resolution and vertical resolution for atmospheric temperature sounders. In this paper, the concept of a high resolution multiorder Fabry-Perot interferometer using portions of the 15-microm and 4.3-microm bands of CO(2)for the purpose of atmospheric temperature sounding is discussed. Suitable sounding spectral positions, FPI free spectral range, and weighting functions are calculated. An effective spectral resolution of 0.02 cm(-1) can be achieved by the proposed sounder with a FPI finess of ~100 which is within the present state-of-the-art technology in the infrared region, leading to considerable improvement in the vertical resolution of the atmospheric temperature sounder. PMID:20555996

  19. Time Delay Properties of a Fabry-Perot Interferometer

    YUAN Shi; MAN Wei-Ning; YU Jin; GAO Jin-Yue

    2001-01-01

    The time delay properties of a Fabry-Perot interferometer are investigated. We found that the group velocity of light through a Fabry-Perot interferometer can be reduced to 10-4 of the light speed in vacuum and the time delay is 210ns, when the reflectivity is 0.999 and the distance between two mirrors is 1 cm. The system is analogous to the recently proposed one-dimensional photonic band-gap structures with a defect [Zhu et al. Opt.Commun. 174(2000)139].

  20. Fabry-Perot Interferometer-Based Electrooptic Modulator using LiNbO3 and Organic Thin Films

    Banks, C.; Frazier, D.; Penn, B.; Abdeldayem, H.; Sharma, A.; Yelleswarapu, C.; Leyderman, Alexander; Correa, Margarita; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    We report the study of a Fabry-Perot electro-optical modulator using thin crystalline film NPP, and Crystalline LiNbO3. We are able to observe 14, and 60 percent degree of modulation. Measurements were carried using a standard lock-in amplifier with a silicon detector. The proposal to design a Fabry-Perot electro-optic modulator with an intracavity electro-optically active organic material was based on the initial results using poled polymer thin films. The main feature of the proposed device is the observation that in traditional electrooptic modulators like a Packets cell, it requires few kilovolts of driving voltage to cause a 3 dB modulation even in high figure-of-merit electrooptic materials like LiNbO3. The driving voltage for the modulator can be reduced to as low as 10 volts by introducing the electrooptic material inside die resonant cavity of a Fabry-Perot modulator. This is because the transmission of the Fabry-Perot cavity varies nonlinearly with the change of refractive index or phase of light due to applied electric field.

  1. GREGOR Fabry-Perot Interferometer - status report and prospects

    Puschmann, Klaus G; Beck, Christian; Louis, Rohan E; Popow, Emil; Seelemann, Thomas; Volkmer, Reiner; Woche, Manfred; Denker, Carsten

    2012-01-01

    The GREGOR Fabry-Perot Interferometer (GFPI) is one of three first-light instruments of the German 1.5-meter GREGOR solar telescope at the Observatorio del Teide, Tenerife, Spain. The GFPI allows fast narrow-band imaging and post-factum image restoration. The retrieved physical parameters will be a fundamental building block for understanding the dynamic Sun and its magnetic field at spatial scales down to 50 km on the solar surface. The GFPI is a tunable dual-etalon system in a collimated mounting. It is designed for spectropolarimetric observations over the wavelength range from 530-860 nm with a theoretical spectral resolution of R ~ 250,000. The GFPI is equipped with a full-Stokes polarimeter. Large-format, high-cadence CCD detectors with powerful computer hard- and software enable the scanning of spectral lines in time spans equivalent to the evolution time of solar features. The field-of-view of 50" x 38" covers a significant fraction of the typical area of active regions. We present the main characteri...

  2. Silicon Carbide Mounts for Fabry-Perot Interferometers

    Lindemann, Scott

    2011-01-01

    Etalon mounts for tunable Fabry- Perot interferometers can now be fabricated from reaction-bonded silicon carbide structural components. These mounts are rigid, lightweight, and thermally stable. The fabrication of these mounts involves the exploitation of post-casting capabilities that (1) enable creation of monolithic structures having reduced (in comparison with prior such structures) degrees of material inhomogeneity and (2) reduce the need for fastening hardware and accommodations. Such silicon carbide mounts could be used to make lightweight Fabry-Perot interferometers or could be modified for use as general lightweight optical mounts. Heretofore, tunable Fabry-Perot interferometer structures, including mounting hardware, have been made from the low-thermal-expansion material Invar (a nickel/iron alloy) in order to obtain the thermal stability required for spectroscopic applications for which such interferometers are typically designed. However, the high mass density of Invar structures is disadvantageous in applications in which there are requirements to minimize mass. Silicon carbide etalon mounts have been incorporated into a tunable Fabry-Perot interferometer of a prior design that originally called for Invar structural components. The strength, thermal stability, and survivability of the interferometer as thus modified are similar to those of the interferometer as originally designed, but the mass of the modified interferometer is significantly less than the mass of the original version.

  3. A Coaxial Cable Fabry-Perot Interferometer for Sensing Applications

    Ming Luo

    2013-11-01

    Full Text Available This paper reports a novel coaxial cable Fabry-Perot interferometer for sensing applications. The sensor is fabricated by drilling two holes half-way into a coaxial cable. The device physics was described. The temperature and strain responses of the sensor were tested. The measurement error was calculated and analyzed.

  4. Statistical analysis of thermospheric gravity waves from Fabry-Perot Interferometer measurements of atomic oxygen

    E. A. K. Ford; A. L. Aruliah; Griffin, E. M.; I. McWhirter

    2008-01-01

    Data from the Fabry-Perot Interferometers at KEOPS (Sweden), Sodankyla (Finland), and Svalbard (Norway), have been analysed for gravity wave activity on all the clear nights from 2000 to 2006. A total of 249 nights were available from KEOPS, 133 from Sodankyla and 185 from the Svalbard FPI. A Lomb-Scargle analysis was performed on each of these nights to identify the periods of any wave activity during the night. Comparisons between many nights of data allow the general characteristics of the...

  5. Statistical analysis of thermospheric gravity waves from Fabry-Perot Interferometer measurements of atomic oxygen

    E. A. K. Ford; A. L. Aruliah; Griffin, E. M.; I. McWhirter

    2008-01-01

    Data from the Fabry-Perot Interferometers at KEOPS (Sweden), Sodankylä (Finland), and Svalbard (Norway), have been analysed for gravity wave activity on all the clear nights from 2000 to 2006. A total of 249 nights were available from KEOPS, 133 from Sodankylä and 185 from the Svalbard FPI. A Lomb-Scargle analysis was performed on each of these nights to identify the periods of any wave activity during the night. Comparisons between many nights of data allow the general char...

  6. Fiber optic, Fabry-Perot high temperature sensor

    James, K.; Quick, B.

    1984-01-01

    A digital, fiber optic temperature sensor using a variable Fabry-Perot cavity as the sensor element was analyzed, designed, fabricated, and tested. The fiber transmitted cavity reflection spectra is dispersed then converted from an optical signal to electrical information by a charged coupled device (CCD). A microprocessor-based color demodulation system converts the wavelength information to temperature. This general sensor concept not only utilizes an all-optical means of parameter sensing and transmitting, but also exploits microprocessor technology for automated control, calibration, and enhanced performance. The complete temperature sensor system was evaluated in the laboratory. Results show that the Fabry-Perot temperature sensor has good resolution (0.5% of full seale), high accuracy, and potential high temperature ( 1000 C) applications.

  7. Shot noise in carbon nanotube based Fabry-Perot interferometers

    Herrmann, L.G.; Delattre, T.; Morfin, P.; Berroir, J. -M.; Plaçais, B.; Glattli, D.C.; Kontos, T.

    2007-01-01

    We report on shot noise measurements in carbon nanotube based Fabry-Perot electronic interferometers. As a consequence of quantum interferences, the noise power spectral density oscillates as a function of the voltage applied to the gate electrode. The quantum shot noise theory accounts for the data quantitatively. It allows to confirm the existence of two nearly degenerate orbitals. At resonance, the transmission of the nanotube approaches unity, and the nanotube becomes noiseless, as observ...

  8. Fabry-Perot interferometer utilized for displacement measurement in a large measuring range

    The optical configuration of a Fabry-Perot interferometer is uncomplicated. This has already been applied in different measurement systems. For the displacement measurement with the Fabry-Perot interferometer, the result is significantly influenced by the tilt angles of the measurement mirror in the interferometer. Hence, only for the rather small measuring range, the Fabry-Perot interferometer is available. The goal of this investigation is to enhance the measuring range of Fabry-Perot interferometer by compensating the tilt angles. To verify the measuring characteristic of the self-developed Fabry-Perot interferometer, some comparison measurements with a reference standard have been performed. The maximum deviation of comparison experiments is less than 0.3 μm in the traveling range of 30 mm. The experimental results show that the Fabry-Perot interferometer is highly stable, insensitive to environment effects, and can meet the measuring requirement of the submicrometer order.

  9. Displacement Interferometry within a Passive Fabry-Perot Cavity

    Holá, Miroslava; Hrabina, Jan; Fejfar, A.; Kočka, J.; Stuchlík, J.; Číp, Ondřej; Oulehla, Jindřich; Lazar, Josef

    Berlin: Springer-Verlag, 2014, s. 891-894. ISBN 978-3-642-36358-0. [International Workshop on Advanced Optical Imaging and Metrology /7./. Nürtingen (DE), 08.09.2013-11.09.2013] R&D Projects: GA ČR GPP102/11/P820; GA MŠk ED0017/01/01; GA MŠk EE2.4.31.0016; GA TA ČR TA02010711; GA TA ČR TE01020233 Institutional support: RVO:68081731 Keywords : interferometry * Fabry-Perot Cavity * transparent photodetector * standing wave Subject RIV: BH - Optics, Masers, Lasers

  10. GREGOR Fabry-Perot Interferometer - status report and prospects

    Puschmann, Klaus G.; Balthasar, Horst; Beck, Christian; Louis, Rohan E.; Popow, Emil; Seelemann, Thomas; Volkmer, Reiner; Woche, Manfred; Denker, Carsten

    2012-01-01

    The GREGOR Fabry-Perot Interferometer (GFPI) is one of three first-light instruments of the German 1.5-meter GREGOR solar telescope at the Observatorio del Teide, Tenerife, Spain. The GFPI allows fast narrow-band imaging and post-factum image restoration. The retrieved physical parameters will be a fundamental building block for understanding the dynamic Sun and its magnetic field at spatial scales down to 50 km on the solar surface. The GFPI is a tunable dual-etalon system in a collimated mo...

  11. Hydrocarbon gas detection with microelectromechanical Fabry-Perot interferometer

    Mannila, Rami; Tuohiniemi, Mikko; Mäkynen, Jussi; Näkki, Ismo; Antila, Jarkko

    2013-05-01

    VTT Technical Research Centre of Finland has developed microelectromechanical (MEMS) Fabry-Perot interferometer (FPI) for hydrocarbon measurements. Fabry-Perot interferometer is a structure where is two highly reflective surfaces separated by a tunable air gap. The MEMS FPI is a monolithic device, i.e. it is made entirely on one substrate in a batch process, without assembling separate pieces together. The gap is adjusted by moving the upper mirror with electrostatic force, so there are no actual moving parts. The manufactured MEMS FPIs have been characterized. The tuning wavelength range of the MEMS FPI is 2.8-3.5 μm and its spectral resolution is 50-60 nm. VTT has designed and manufactured a handheld size demonstrator device based on the technology presented in this abstract. This device demonstrates gas detecting by measuring cigarette lighter gas and various plastic materials transmission spectra. The demonstrator contains light source, gas cell, MEMS FPI, detector and control electronics. It is connected to a laptop by USB connection, additional power supply or connection is not needed.

  12. Advancement of Optical Component Control for an Imaging Fabry-Perot Interferometer

    Larar, Allen M.; Cook, William B.; Flood, Michael A.; Campbell, Joel F.; Boyer, Charles M.

    2009-01-01

    Risk mitigation activities associated with a prototype imaging Fabry-Perot Interferometer (FPI) system are continuing at the NASA Langley Research Center. The system concept and technology center about enabling and improving future space-based atmospheric composition missions, with a current focus on observing tropospheric ozone around 9.6 micron, while having applicability toward measurement in different spectral regions and other applications. Recent activities have focused on improving an optical element control subsystem to enable precise and accurate positioning and control of etalon plates; this is needed to provide high system spectral fidelity critical for enabling the required ability to spectrally-resolve atmospheric line structure. The latest results pertaining to methodology enhancements, system implementation, and laboratory characterization testing will be reported

  13. A novel Michelson Fabry-Perot hybrid interference sensor based on the micro-structured fiber

    Zhang, Yaxun; Zhang, Yu; Wang, Zhenzhen; Liu, Zhihai; Wei, Yong; Zhao, Enming; Yang, Xinghua; Zhang, Jianzhong; Yang, Jun; Yuan, Libo

    2016-09-01

    We propose and demonstrate a novel Michelson Fabry-Perot hybrid fiber interference sensor. By integrating a Michelson interferometer in a two-core fiber and a Fabry-Perot interferometer in a micro silica-capillary, we produce the Michelson Fabry-Perot hybrid interference sensor. Owing to the structure characteristic of the micro-structured fiber, this hybrid fiber interference sensor can achieve the measurement of the axial strain and radial bending simultaneously. The measurement sensitivity of the axial train is 0.015 nm/με and the measurement sensitivity of the radial bending is 1.393 nm/m-1.

  14. Millimeter-long Fiber Fabry-Perot cavities

    Ott, Konstantin; Kohlhaas, Ralf; Schüppert, Klemens; Rosenbusch, Peter; Long, Romain; Reichel, Jakob

    2016-01-01

    We demonstrate fiber Fabry-Perot (FFP) cavities with concave mirrors that can be operated at cavity lengths as large as 1.5mm without significant deterioration of the finesse. This is achieved by using a laser dot machining technique to shape spherical mirrors with ultralow roughness and employing single-mode fibers with large mode area for good mode matching to the cavity. Additionally, in contrast to previous FFPs, these cavities can be used over an octave-spanning frequency range with adequate coatings. We also show directly that shape deviations caused by the fiber's index profile lead to a finesse decrease as observed in earlier attempts to build long FFP cavities, and show a way to overcome this problem.

  15. Electrically tuneable micromachined fabry-perot interferometer in gas analysis

    Blomberg, M.; Torkkeli, A.; Lehto, A.; Helenelund, Ch; Viitasalo, M.

    1997-01-01

    This paper describes an optical gas concentration measurement system, which is based on an electrically tuneable micromachined Fabry-Perot interferometer (FPI). The operating principle of the system is NDIR Single-Beam Dual-Wavelength measurement. The FPI is tuned so that the pass band coincides with the absorption band of the measured gas; a detector records the strength of the signal getting through the measurement chamber. The pass band of the FPI is then shifted to either side of the absorption band; the detected signal constitutes the reference signal. The ratio of these two signals indicates the degree of light absorption and so the gas concentration. Properties of the FPI are discussed, as well as the performance of the measurement system.

  16. Superconducting electromagnetic actuators for astronomical Fabry-Perot interferometers

    Nishimura, T.; Low, F. J.; Shivanandan, K.

    1985-01-01

    Two types of superconducting electromagnetic actuators linear and angular - for precise control of Fabry-Perot spectrometer etalons at liquid helium temperature were manufactured and tested successfully. The linear displacement unit (45 Newtons/Amp) has maximum travel of + or - 44 microns with off-axis deviation of less than 1.5 arcseconds for 15 microns path. The angular unit has maximum tilt of + or - 8 arcminutes and can maintain parallelism of two etalons to better than 0.3 arcsecond of angle by compensating the differential contraction upon cooling and off-axis deviation of the linear displacement unit. These actuators are proving especially useful in low temperature infrared instrumentation where other choices, such as piezoelectric crystals, fail and where essentially zero power dissipation permits low infrared backgrounds to be maintained along with long cryogenic lifetimes.

  17. Micromachined fiber optic Fabry-Perot underwater acoustic probe

    Wang, Fuyin; Shao, Zhengzheng; Hu, Zhengliang; Luo, Hong; Xie, Jiehui; Hu, Yongming

    2014-08-01

    One of the most important branches in the development trend of the traditional fiber optic physical sensor is the miniaturization of sensor structure. Miniature fiber optic sensor can realize point measurement, and then to develop sensor networks to achieve quasi-distributed or distributed sensing as well as line measurement to area monitoring, which will greatly extend the application area of fiber optic sensors. The development of MEMS technology brings a light path to address the problems brought by the procedure of sensor miniaturization. Sensors manufactured by MEMS technology possess the advantages of small volume, light weight, easy fabricated and low cost. In this paper, a fiber optic extrinsic Fabry-Perot interferometric underwater acoustic probe utilizing micromachined diaphragm collaborated with fiber optic technology and MEMS technology has been designed and implemented to actualize underwater acoustic sensing. Diaphragm with central embossment, where the embossment is used to anti-hydrostatic pressure which would largely deflect the diaphragm that induce interferometric fringe fading, has been made by double-sided etching of silicon on insulator. By bonding the acoustic-sensitive diaphragm as well as a cleaved fiber end in ferrule with an outer sleeve, an extrinsic Fabry-Perot interferometer has been constructed. The sensor has been interrogated by quadrature-point control method and tested in field-stable acoustic standing wave tube. Results have been shown that the recovered signal detected by the sensor coincided well with the corresponding transmitted signal and the sensitivity response was flat in frequency range from 10 Hz to 2kHz with the value about -154.6 dB re. 1/μPa. It has been manifest that the designed sensor could be used as an underwater acoustic probe.

  18. Compact High-Resolution Broad-Band Terahertz Fabry-Perot Spectrometer Project

    National Aeronautics and Space Administration — Our objective is to develop a compact scanning Fabry-Perot spectrometer, for satellite far-infrared astronomy and Earth remote sensing, that operates at wavelengths...

  19. Calibration of Fabry-Perot interferometers for electron cyclotron emission measurements on the Tore Supra tokamak

    The electron temperature is routinely measured on TORE SUPRA using Fabry-Perot cavities. These have been calibrated using a technique involving coherent addition and Fourier analysis of a chopped black-body source. Comparison with conventional techniques is reported

  20. Rugged Low Temperature Actuators for Tunable Fabry Perot Optical Filters Project

    National Aeronautics and Space Administration — During our Phase I SBIR research, we propose to integrate a novel low-temperature large-strain actuator technology into Fabry-Perot optical filters. The resulting...

  1. Fabry-Perot Based Ranging Interferometer Receiver for High Spectral Resolution Lidar Project

    National Aeronautics and Space Administration — Michigan Aerospace Corporation (MAC) is pleased to present the following Phase II proposal for a Fabry-Perot Based Interferometer Receiver for the High Spectral...

  2. Fabry-Perot observations of [FeX] in the Cygnus Loop and IC443

    The authors present the first results of an observational program of SNRs in the coronal lines of [FeX] and [FeXIV] using Fabry--Perot spectrophotometer. These support previously published brightnesses

  3. Tunable Fabry-Perot filter and grating hybrid modulator to improve dispersive spectrometer resolution

    Fang, Liang; Li, Guojun; Yang, Huan; Zhou, Chongxi

    2016-05-01

    We describe a tunable Fabry-Perot filter and grating hybrid modulator to achieve a higher spectral resolution compared with that produced by a single grating with the same period. In the hybrid modulator, a tunable Fabry-Perot filter is designed with a long cavity to accommodate a multi-order narrowband pre-filter. A grating is then utilized to separate these multi-orders spatially. Scanning the air gap of the tunable Fabry-Perot filter within 1/2 wavelength, the entire spectrogram can be achieved by compositing each group of transmitted multi-orders. Light passes first through the Fabry-Perot cavity and then into the grating. Thus, all of the light is incident on the Fabry-Perot cavity at a given angle, which can reduce the requirement for incident beam alignment and simplify the operation of the hybrid modulator. The structural matching conditions of the tunable Fabry-Perot filter and grating were presented based on the operating law of the hybrid modulator. In terms of the Rayleigh criterion, the practical spectral resolution of the hybrid modulator can be increased by at least twice that of the single grating. Experiments with a neon lamp revealed that the spectral resolution of the hybrid modulator was nearly double that of a single grating.

  4. 1064-nm Fabry-Perot transmission filter laser damage competition

    Stolz, Christopher J.; Caputo, Mark; Griffin, Andrew J.; Thomas, Michael D.

    2014-10-01

    Narrow-bandwidth Fabry-Perot transmission filters are used in telecommunications, fiber lasers1, and for diode pumped alkali lasers (DPAL)2. Because of their interference properties, extremely high standing-wave electric fields occur at peak transmission. For this study, the filters met a minimum transmission of 90% and were spectrally centered within an angle tuning range of 10-30 degrees. A blind laser damage test assured sample and submitter anonymity. The participants selected the coating materials, design, spectral bandwidth, cleaning method, and deposition method. Laser damage testing was performed at a wavelength of 1064 nm using a raster scan method on a single testing facility to enable a direct comparison among the participants. Pulse length scaling relationships were explored by laser damage testing at a 3.5-ns and 18-ns pulse length. The results show that the spectral bandwidth had the strongest relationship to the laser damage threshold. Other parameters such as deposition processes, cleaning method, coating materials, and layer count were also explored.

  5. Performance of a dual Fabry-Perot cavity refractometer.

    Egan, Patrick F; Stone, Jack A; Hendricks, Jay H; Ricker, Jacob E; Scace, Gregory E; Strouse, Gregory F

    2015-09-01

    We have built and characterized a refractometer that utilizes two Fabry-Perot cavities formed on a dimensionally stable spacer. In the typical mode of operation, one cavity is held at vacuum, and the other cavity is filled with nitrogen gas. The differential change in length between the cavities is measured as the difference in frequency between two helium-neon lasers, one locked to the resonance of each cavity. This differential change in optical length is a measure of the gas refractivity. Using the known values for the molar refractivity and virial coefficients of nitrogen, and accounting for cavity length distortions, the device can be used as a high-resolution, multi-decade pressure sensor. We define a reference value for nitrogen refractivity as n-1=(26485.28±0.3)×10(-8) at p=100.0000  kPa, T=302.9190  K, and λ(vac)=632.9908  nm. We compare pressure determinations via the refractometer and the reference value to a mercury manometer. PMID:26368682

  6. Optical fiber Fabry-Perot interferometer for microorganism growth detection

    Liu, Xiaohui; Jiang, Mingshun; Sui, Qingmei; Luo, Shuyang; Geng, Xiangyi

    2016-07-01

    An optical fiber Fabry-Perot interferometer (FPI) based on hollow-core photonic crystal fiber (HCPCF) for microorganism growth detection is proposed and demonstrated. The FPI is formed by splicing both ends of a short section of HCPCF to SMFs and cleaving the SMF pigtail to a proper length. By measuring the fringe contrast of interference pattern, the refractive index (RI) changes of analyte during microorganism growth can be obtained. RI response of the sensor was investigated theoretically and experimentally. It shows linear response with sensitivity of -136 dB/RIU and good repeatability. Temperature response was also tested and the result confirms the low temperature cross-sensitivity of the sensor. Detection of yeast growth in liquid medium by the FPI sensor was conducted and the result shows the characteristic of typical yeast growth curve. With its advantages of high RI sensitivity, low temperature cross-sensitivity, capability for real-time measurement and so on, this FPI sensor has great potential in biosensing.

  7. Demonstration of Fabry-Perot interferometric spectrometry technology

    Petersen, T. V.; Makel, D. B.; Thurman, C.

    1993-01-01

    As rocket engine components experience wear or failure, anomalous materials may be entrained in the plume. Historically, visible plume anomalies have preceded many rocket engine failures, some of which have been catastrophic. Development of a small, rugged, high-speed, high resolution Fabry-Perot interferometer (FPI) based spectrometer capable of detecting the spectral signatures of eroding engine components during rocket engine test and/or flight operations is described. An operational plume spectrometer fabricated with miniaturized optics has been successfully tested. An extensive test series was conducted to define the limits of the spectrometer with respect to time-response and resolution. The data collected during testing were correlated with measurements obtained using sensitive ground equipment in order to benchmark the spectrometer's performance against a known device. The FPI demonstrated the reliability required for a flight instrument by functioning satisfactorily at or near the rocket engine test stand environment. Several of the optical components are interchangeable, allowing collection of a greater variety of plume signals. Also, the FPI's high resolution capabilities suggest it is suitable for application to both absorption and emission spectroscopy.

  8. Study on the structure of bridge surface of the micro Fabry-Perot cavity tunable filter

    Micro Fabry-Perot cavity tunable filters are widely applied in the area of Pushbroom Hyperspectral imaging, DWDM optical communication system and self-adaptive optics. With small volume, lower consumption and cost, the Micro Fabry-Perot cavity tunable filter can realize superior response speed, large spectral range, high definition and high reliability. By deposition metal membrane on silicon chip by MEMS technology, the micro Fabry-Perot cavity has been achieved, which is actuated by electrostatic force and can realize the function of an optical filter. In this paper, the micro-bridge structure of the micro Fabry-Perot cavity tunable filter has been studied. Finite element analysis software COMSOL Multiphysics has been adopted to design the structure of the micro-bridge of the micro filter. In order to simulate the working mechanism of the micro Fabry-Perot cavity and study the electrical and mechanical characteristics of the micro tunable filter,the static and dynamic characteriastics are analyzed, such as stress, displacement, transient response, etc. The corresponding parameters of the structure are considered as well by optimizition the filter's sustain structure.

  9. Resolution improvement of grating spectrometer by using a tunable Fabry-Perot filter

    Fang, Liang; Shi, Zhendong; Qiu, Chuankai; Zhou, Chongxi

    2015-10-01

    Aiming at the problem of the resolution reduction in a miniaturized grating spectrometer, we presented a method to improve its spectral resolution by inserting a tunable Fabry-Perot filter into its optical path before the grating. The Fabry-Perot filter was designed to filter out a partial spectrogram and separate the original undistinguishable spectral lines so as to make their actual wavelengths can be detected. The different cavity length of the Fabry-Perot filter is corresponding to the different separated partial spectrogram. Combining all the separated partial spectrograms, an entire spectrogram with improved resolution can be achieved. Experimentally, the spectral resolution of a grating dispersive system was improved from 2 nm to 1.2nm in a broad spectral range by insetting a homemade tunable Fabry-Perot filter, which demonstrated the feasibility of this scheme. The tunable Fabry-Perot filter is fit for miniaturization by using MEMS technology and is able to work as an independent module. The method proposed provides a potential way to improve the spectral resolution without reducing the spectral range of the existing miniaturized grating spectrometers.

  10. Wavelength calibration with Fabry Perot Interferometers - yes we can!

    Franziskus Bauer, Florian; Zechmeister, Mathias; Reiners, Ansgar

    2015-08-01

    Hollow-cathode lamps (HCLs) are used as default wavelength standard for spectroscopic measurements but have a number of well-known shortcomings. Advancing to cm/s precision in radial velocity experiments requires more stable calibration sources with more uniform line distributions. Fabry Perot Interferometers (FPI) are a practical alternative with a well-suited line distribution at relatively low cost. We present a simple method to characterize FPIs using standard HCLs and including the FPI spectrum in the wavelength calibration process. We propose to use the HCL wavelength solution to define a rough wavelength scale that is used to approximate the FPI peak positions. We assume that the FPI mirror distance is a smooth function of wavelength and utilize the large number of FPI peaks (typically 10^4) to consistently model all FPI peak wavelengths. With this approach, we anchor the dense FPI lines with the absolute HCL-scale combining their precision and accuracy. We test our method with the HARPS spectrograph and compare our wavelength calibration to one derived from a laser frequency comb (LFC) spectrum. Our combined HCL/FPI wavelength calibration removes the known, large-amplitude distortions of 50 m/s that occur in the HCL solution. Direct comparison with the LFC solution bears only small differences between the LFC and the HCL/FPI solutions and demonstrates that the HCL/FPI solution can overcome the most important shortcomings in HCL wavelength solutions. An FPI can provide an economical alternative to LFCs in particular for smaller projects.

  11. Gamma radiation resistant Fabry-Perot fiber optic sensors

    Liu, Hanying; Miller, Don W.; Talnagi, Joseph

    2002-08-01

    The Nuclear Regulatory Commission (NRC) in 1998 completed a study of emerging technologies that could be applicable to measurement systems in nuclear power plants [H. M. Hashemian [et al.], "Advanced Instrumentation and Maintenance Technologies for Nuclear Power Plants," NUREG/CR-5501 (1998)]. This study concluded that advanced fiber optic sensing technology is an emerging technology that should be investigated. It also indicated that there had been very little research related to performance evaluation of fiber optic sensors in nuclear plant harsh environments, although substantial research has been performed on nuclear radiation effects on optical fibers in the last two decades. A type of Fabry-Perot fiber optic temperature sensor, which is manufactured by Fiso Technologies in Canada, is qualified to be a candidate for potential applications in nuclear radiation environment due to its unique signal processing technique and its resistance to power loss. The gamma irradiation effects on this type of sensors are investigated in this article. Two sensors were irradiated in a gamma irradiation field and one of them was irradiated up to a total gamma dose of 133 Mrad. The sensor on-line performance was monitored during each gamma irradiation test. Furthermore, the sensor static and dynamic performance before and after each irradiation test were evaluated according to the Standard ISA-dS67.06.01 ("Performance Monitoring for Nuclear Safety-Related Instrument Channels in Nuclear Power Plants", Standard ISA-dS67.06.01, Draft 7, Instrument Society of America, 1999). Although several abnormal phenomena were observed, analysis shows that gamma irradiation is not accredited to the abnormal behavior, which implies that this type of sensor is suitable to a gamma irradiation environment with a high gamma dose.

  12. Fiber Fabry-Perot interferometer with controllable temperature sensitivity.

    Zhang, Xinpu; Peng, Wei; Zhang, Yang

    2015-12-01

    We proposed a fiber taper based on the Fabry-Perot (FP) interferometer structure with controllable temperature sensitivity. The FP interferometer is formed by inserting a segment of tapered fiber tip into the capillary and subsequently splicing the other end of the capillary to a single-mode fiber (SMF), the tapered fiber endface, and the spliced face form the FP cavity. Through controlling the inserted tapered fiber length, a series of FP interferometers were made. Because the inserted taper tip has the degree of freedom along the fiber axial, when the FP interferometer is subjected to temperature variation, the thermal expansion of the fiber taper tip will resist the FP cavity length change caused by the evolution of capillary length, and we can control the temperature sensitivity by adjusting the inserted taper length. In this structure, the equivalent thermal expansion coefficient of the FP interferometer can be defined; it was used to evaluate the temperature sensitivity of the FP interferometer, which provides an effective method to eliminate the temperature effect and to enhance other measurement accuracy. We fabricated the FP interferometers and calibrated their temperature characters by measuring the wavelength shift of the resonance dips in the reflection spectrum. In a temperature range of 50°C to 150°C, the corresponding temperature sensitivities can be controlled between 0 and 1.97 pm/°C when the inserted taper is between 75 and 160 μm. Because of its controllable temperature sensitivity, ease of fabrication, and low cost, this FP interferometer can meet different temperature sensitivity requirements in various application areas, especially in the fields which need temperature insensitivity. PMID:26625075

  13. First Light from Triple-Etalon Fabry-Perot Interferometer for Atmospheric OI Airglow (6300 A)

    Watchorn, S.; Noto, J.; Pedersen, T.; Betremieux, Y.; Migliozzi, M.; Kerr, R. B.

    2006-05-01

    Scientific Solutions, Inc. (SSI) has developed a triple-etalon Fabry-Perot interferometer (FPI) to observe neutral winds in the ionosphere by measuring neutral oxygen (O I) emission at 630.0 nm during the day. This instrument is to be deployed in the SSI airglow building at the Cerro Tololo observatory (30.17S 70.81W) in Chile, in support of the Comm/Nav Outage Forecast System (C/NOFS) project. Post-deployment observation will be made in conjunction with two other Clemson University Fabry-Perots in Peru, creating a longitudinal chain of interferometers for thermospheric observations. These instruments will make autonomous day and night observations of thermospheric dynamics. Instruments of this type can be constructed for a global chain of autonomous airglow observatories. The FPI presented in this talk consists of three independently pressure-controlled etalons, fed collimated light by a front optical train headed by an all-sky lens with a 160-degree field of view. It can be controlled remotely via a web-based service which allows any internet-connected computer to mimic the control computer at the instrument site. In fall 2005, the SSI system was first assembled at the Millstone Hill Observatory in Westford, Massachusetts, and made day and evening observations. It was then moved to the High-frequency Active Auroral Research Project (HAARP) site in Gakona, Alaska, to participate in joint optical/ionospheric heating campaigns. Additionally, natural airglow observations were made, both locally and remotely via the internet from Massachusetts. The Millstone and HAARP observations with two etalons yielded strong 630-nm atmospheric Fraunhofer absorption lines, with some suggestion of the Ring effect. By modeling the atmospheric absorption line as the constant times the corresponding solar absorption -- itself modeled as a Gaussian plus a polynomial -- the absorption feature is subtracted, leaving only the emission feature. Software ring-summing tools developed at the

  14. High Finesse Fiber Fabry-Perot Cavities: Stabilization and Mode Matching Analysis

    Gallego, Jose; Alavi, Seyed Khalil; Alt, Wolfgang; Martinez-Dorantes, Miguel; Meschede, Dieter; Ratschbacher, Lothar

    2015-01-01

    Fiber Fabry-Perot cavities, formed by micro-machined mirrors on the end-facets of optical fibers, are used in an increasing number of technical and scientific applications, where they typically require precise stabilization of their optical resonances. Here, we study two different approaches to construct fiber Fabry-Perot resonators and stabilize their length for experiments in cavity quantum electrodynamics with neutral atoms. A piezo-mechanically actuated cavity with feedback based on the Pound-Drever-Hall locking technique is compared to a novel rigid cavity design that makes use of the high passive stability of a monolithic cavity spacer and employs thermal self-locking and external temperature tuning. Furthermore, we present a general analysis of the mode matching problem in fiber Fabry-Perot cavities, which explains the asymmetry in their reflective line shapes and has important implications for the optimal alignment of the fiber resonators. Finally, we discuss the issue of fiber-generated background ph...

  15. Rayleigh Scattering Measurements Using a Tunable Liquid Crystal Fabry-Perot Interferometer

    Mielke-Fagan, Amy F.; Clem, Michelle M.; Elam, Kristie A.

    2010-01-01

    Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous density, velocity, and temperature measurements. The Fabry-Perot interferometer or etalon is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating these flow properties. This paper investigates the use of a tunable liquid crystal (LC) Fabry-Perot etalon in Rayleigh scattering experiments at NASA Glenn Research Center. The LC etalon provides a robust interferometry system that can be tuned rapidly by adjusting the voltage applied to the liquid crystal interface. Tuning the interferometer is often necessary to control the physical locations of the concentric interference fringes when Rayleigh light is imaged through the LC etalon. The LC etalon diagnostic system was tested in a 1-cm diameter nozzle flow in two different scattering configurations to evaluate its usefulness for Rayleigh measurements compared to a traditional non-tunable fused silica Fabry-Perot etalon.

  16. Silk fibroin diaphragm-based fiber-tip Fabry-Perot pressure sensor.

    Cheng, Linghao; Wang, Cengzhong; Huang, Yunyun; Liang, Hao; Guan, Bai-Ou

    2016-08-22

    A miniature fiber-optic Fabry-Perot is built on the tip of a single mode fiber with a thin silk fibroin film as the diaphragm for pressure measurement. The silk fibroin film is regenerated from aqueous silk fibroin solution obtained by an environmentally benign fabrication process, which exhibits excellent optical and physicochemical properties, such as transparency in visible and near infrared region, membrane-forming ability, good adhesion, and high mechanical strength. The resulted Fabry-Perot pressure sensor is therefore highly biocompatible and shows good airtightness with a response of 12.3 nm/kPa in terms of cavity length change. PMID:27557238

  17. Flat top liquid crystal tunable filter using coupled Fabry-Perot cavities.

    Alboon, Shadi A; Lindquist, Robert G

    2008-01-01

    In this paper, a coupled Fabry-Perot cavities filter, using the liquid crystal as the tunable medium, is investigate to achieve tunable flat top filtering performance across the C and L bands. A tandem coupled Fabry-Perot is presented for a tunable passband filter with flat top and minimum ripple in the passband. The overall tuning range of the filter is 172 nm. Several designs are shown with comparable performance to the commercial available 100 GHz fixed single channel filters. PMID:18521153

  18. Extrinsic fiber-optic Fabry-Perot interferometer sensor for refractive index measurement of optical glass

    A simple fiber-optic sensor based on Fabry-Perot interference for refractive index measurement of optical glass is investigated both theoretically and experimentally. A broadband light source is coupled into an extrinsic fiber Fabry-Perot cavity formed by the surfaces of a sensing fiber end and the measured sample. The interference signals from the cavity are reflected back into the same fiber. The refractive index of the sample can be obtained by measuring the contrast of the interference fringes. The experimental data meet with the theoretical values very well. The proposed technique is a new method for glass refractive index measurement with a simple, solid, and compact structure.

  19. Solar CIV Vacuum-Ultraviolet Fabry-Perot Interferometers

    Gary, G. Allen; West, Edward A.; Rees, David; McKay, Jack A.; Zukic, Maumer; Herman, Peter

    2006-01-01

    Aims: A tunable, high spectral resolution, high effective finesse, vacuum ultraviolet (VUV) Fabry-Perot interferometer (PPI) is designed for obtaining narrow-passband images, magnetograms, and Dopplergrams of the transition region emission line of CIV (155 nm). Methods: The integral part of the CIV narrow passband filter package (with a 2-10 pm FWHM) consists of a multiple etalon system composed of a tunable interferometer that provides high-spectral resolution and a static low-spectral resolution interferometer that allows a large effective free spectral range. The prefilter for the interferometers is provided by a set of four mirrors with dielectric high-reflective coatings. A tunable interferometer, a VUV piezoelectric-control etalon, has undergone testing using the surrogate F2 eximer laser line at 157 nm for the CIV line. We present the results of the tests with a description of the overall concept for a complete narrow-band CIV spectral filter. The static interferometer of the filter is envisioned as being hudt using a set of fixed MgF2 plates. The four-mirror prefilter is designed to have dielectric multilayer n-stacks employing the design concept used in the Ultraviolet Imager of NASA's Polar Spacecraft. A dual etalon system allows the effective free spectral range to be commensurate with the prefilter profile. With an additional etalon, a triple etalon system would allow a spectrographic resolution of 2 pm. The basic strategy has been to combine the expertise of spaceflight etalon manufacturing with VUV coating technology to build a VUV FPI which combines the best attributes of imagers and spectrographs into a single compact instrument. Results. Spectro-polarimetry observations of the transition region CIV emission can be performed to increase the understanding of the magnetic forces, mass motion, evolution, and energy release within the solar atmosphere at the base of the corona where most of the magnetic field is approximately force-free. The 2D imaging

  20. Enhanced bulk-edge Coulomb coupling in Fractional Fabry-Perot interferometers

    von Keyserlingk, C. W.; Simon, S. H.; Rosenow, Bernd

    2014-01-01

    We study the effects of bulk-edge Coulomb coupling on quantum Hall Fabry-Perot interferometers. We find that these effects can be appreciable in devices which would not usually be associated with strong bulk-edge Coulomb coupling, provided the devices in question exhibit certain fractional plateaus. With this in mind, we analyze recent experiments at $\

  1. APPLICATION OF A FABRY-PEROT INTERFEROMETRY TO REMOTE SENSING OF GASEOUS POLLUTANTS

    A method for the remote sensing of molecular species via the rotational Raman effect was developed. The method uses the properties of a scanning Fabry-Perot interferometer to multiplex the spectra in a manner specific for a given species. Furthermore, the method allows the 'in pr...

  2. Large-area Fabry-Perot modulator based on electro-optic polymers

    Benter, Nils; Bertram, Ralph Peter; Soergel, Elisabeth;

    2006-01-01

    We present a large-area electro-optic Fabry-Perot modulator utilizing a photoaddressable bis-azo polymer placed between two dielectric mirrors with an open aperture of 2 cm. A modulation efficientcy of 1% at an effective modulation voltage of 20 V for a wavelength of 1.55 mymeter is demonstrated...

  3. High-finesse fiber Fabry-Perot cavities: stabilization and mode matching analysis

    Gallego, J.; Ghosh, S.; Alavi, S. K.; Alt, W.; Martinez-Dorantes, M.; Meschede, D.; Ratschbacher, L.

    2016-03-01

    Fiber Fabry-Perot cavities, formed by micro-machined mirrors on the end-facets of optical fibers, are used in an increasing number of technical and scientific applications, where they typically require precise stabilization of their optical resonances. Here, we study two different approaches to construct fiber Fabry-Perot resonators and stabilize their length for experiments in cavity quantum electrodynamics with neutral atoms. A piezo-mechanically actuated cavity with feedback based on the Pound-Drever-Hall locking technique is compared to a novel rigid cavity design that makes use of the high passive stability of a monolithic cavity spacer and employs thermal self-locking and external temperature tuning. Furthermore, we present a general analysis of the mode matching problem in fiber Fabry-Perot cavities, which explains the asymmetry in their reflective line shapes and has important implications for the optimal alignment of the fiber resonators. Finally, we discuss the issue of fiber-generated background photons. We expect that our results contribute toward the integration of high-finesse fiber Fabry-Perot cavities into compact and robust quantum-enabled devices in the future.

  4. A Novel Extrinsic Fiber-Optic Fabry-Perot Strain Sensor System Based on Optical Amplification

    2003-01-01

    A novel extrinsic fiber-optic Fabry-Perot interferometric strain sensor system is demonstrated based on the simultaneous use of the amplified spontaneous emission and optical amplification. The improvement of 3~4 orders of magnitude in signal level can be achieved.

  5. Characterization of a Fabry--Perot interferometer and a dc arc plasma jet for spectrochemical analysis

    A system involving the use of a Fabry--Perot interferometer in combination with a dc arc plasma jet has been constructed and characterized for spectrochemical analysis. Parameters such as flow rate ratio, observation region, electrode composition and orifice size have been considered. Improvements such as noise reduction and dry aerosol introduction of samples were suggested

  6. Development of tunable Fabry-Perot spectral camera and light source for medical applications

    Kaarre, M.; Kivi, S.; Panouillot, P. E.; Saari, H.; Mäkynen, J.; Sorri, I.; Juuti, M.

    2013-05-01

    VTT has developed a fast, tunable Fabry-Perot (FP) filter component and applied it in making small, lightweight spectral cameras and light sources. One application field where this novel technology is now tested is medical field. A demonstrator has been made to test the applicability of FP based spectral filtering in the imaging of retina in visible light wavelength area.

  7. A new fiber-tip Fabry-Perot interferometer and its application for pressure measurement

    Wang, Guanjun; Liu, Shen; Zhao, Jing; Liao, Changrui; Xu, Xizhen; Wang, Yiping

    2015-07-01

    This paper reports a new silica fiber-tip Fabry-Perot interferometer with thin film and large surface area characteristic for high pressure and vacuum degree detection simultaneously, which is fabricated by etching a flat fiber tip into concave surface firstly, with subsequent arc jointing the concave fiber into a inline Fabry-Perot cavity, then drawing one surface of the F-P cavity into several micrometers scale by arc discharge and finally etching the surface into sub-micrometer scale integrally. As the silica fiber-tip Fabry-Perot interferometer film thickness could be tailored very thinly by HF acid solution, plus the surface area of thin film could be expanded during the chemical etching process, the variation of the bubble cavity length is very sensitive to the inner/outer pressure difference of the fiber-tip Fabry-Perot interferometer. Experimental result shows an high sensitivity of 780nm/MPa is feasible. Such configuration has the advantages of lowcost, ease of fabrication and compact size, which make it a promising candidate for pressure and vacuum measurement.

  8. Transmission of few-cycle pulses by Fabry-Perot interferometer

    We theoretically model the transmission of ultra-short optical pulses by Fabry- Perot interferometer, taking into account multiple waves re-reflection inside interferometer by examination of two superimposed waves. Based on the analytical and numerical analysis, we calculate the transformations of the optical electric field profiles and optical spectra of the pulses at the output of the interferometer

  9. All-Optical Switching Using Fabry-Perot Laser Diodes (Invited paper)

    P.; K.; A.; Wai; L.; Y.; Chan; H.; Y.; Tam

    2003-01-01

    In this paper, we investigate all-optical packet switching using a multi-wavelength mutual injection-locked Fabry-Perot laser diode. We observe error-free packet-switching of a 10 Gb/s signal with an extinction ratio of 16.9.

  10. A Ray-tracing Method to Analyzing Modulated Planar Fabry-Perot Antennas

    Hougs, Mikkel Dahl; Kim, Oleksiy S.; Breinbjerg, Olav

    2015-01-01

    A new approach for fast modelling of Fabry-Perot antennas with modulated partially reflective surfaces (PRS) using ray-tracing is proposed. For validation of the method, a configuration is introduced which consists of a cavity with a modulated PRS, fed internally by a magnetic dipole. The PRS...

  11. Fast charge exchange spectroscopy using a Fabry-Perot spectrometer in the JIPP TII-U tokamak

    A new charge exchange spectroscopic technique using a Fabry-Perot spectrometer has been developed to increase the photon flux at the detector and improve the time resolution of ion temperature and plasma rotation velocity measurements. The spectral resolution is obtained by arranging two dimensional fiber optics and a two dimensional detector at the focal plane of a coupled lens located on both sides of a Fabry-Perot spectrometer. The effective finesse of the Fabry-Perot interferometer in this system is 14. The time evolution of the ion temperature is obtained with a time resolution of 125 μs and with the spatial resolution of 3 cm (8 channels). (author)

  12. A laser-lock concept to reach cm/s-precision in Doppler experiments with Fabry-Perot wavelength calibrators

    Reiners, A; Ulbrich, R G

    2014-01-01

    State-of-the-art Doppler experiments require wavelength calibration with precision at the cm/s level. A low-finesse Fabry-Perot interferometer (FPI) can provide a wavelength comb with a very large bandwidth as required for astronomical experiments, but unavoidable spectral drifts are difficult to control. Instead of actively controlling the FPI cavity, we propose to passively stabilize the interferometer and track the time-dependent cavity length drift externally. A dual-finesse cavity allows drift tracking during observation. The drift of the cavity length is monitored in the high-finesse range relative to an external standard: a single narrow transmission peak is locked to an external cavity diode laser and compared to an atomic frequency. Following standard locking schemes, tracking at sub-mm/s precision can be achieved. This is several orders of magnitude better than currently planned high-precision Doppler experiments. It allows freedom for relaxed designs rendering this approach particularly interesting...

  13. Recent Progress in Multiparameter Measurement Based on Extrinsic Fiber-Optic Fabry-Perot Interferometers and Fiber Gratings

    2003-01-01

    This paper presents a review of recent progress in simultaneous measurement of multiparameters including strain, temperature, vibration, transverse load, based on the combinations of extrinsic fiber-optic Fabry-Perot interferometers and fiber gratings.

  14. High time resolution measurements of the thermosphere from Fabry-Perot Interferometer measurements of atomic oxygen

    E. A. K. Ford

    2007-06-01

    Full Text Available Recent advances in the performance of CCD detectors have enabled a high time resolution study of the high latitude upper thermosphere with Fabry-Perot Interferometers (FPIs to be performed. 10-s integration times were used during a campaign in April 2004 on an FPI located in northern Sweden in the auroral oval. The FPI is used to study the thermosphere by measuring the oxygen red line emission at 630.0 nm, which emits at an altitude of approximately 240 km. Previous time resolutions have been 4 min at best, due to the cycle of look directions normally observed. By using 10 s rather than 40 s integration times, and by limiting the number of full cycles in a night, high resolution measurements down to 15 s were achievable. This has allowed the maximum variability of the thermospheric winds and temperatures, and 630.0 nm emission intensities, at approximately 240 km, to be determined as a few minutes. This is a significantly greater variability than the often assumed value of 1 h or more. A Lomb-Scargle analysis of this data has shown evidence of gravity wave activity with waves with short periods. Gravity waves are an important feature of mesosphere-lower thermosphere (MLT dynamics, observed using many techniques and providing an important mechanism for energy transfer between atmospheric regions. At high latitudes gravity waves may be generated in-situ by localised auroral activity. Short period waves were detected in all four clear nights when this experiment was performed, in 630.0 nm intensities and thermospheric winds and temperatures. Waves with many periodicities were observed, from periods of several hours, down to 14 min. These waves were seen in all parameters over several nights, implying that this variability is a typical property of the thermosphere.

  15. Fiber Optic Fabry-Perot Current Sensor Integrated with Magnetic Fluid Using a Fiber Bragg Grating Demodulation

    Ji Xia; Qi Wang; Xu Liu; Hong Luo

    2015-01-01

    An optical fiber current sensor based on Fabry-Perot interferometer using a fiber Bragg grating demodulation is proposed. Magnetic fluid is used as a sensitive medium in fiber optical Fabry-Perot (F-P) cavity for the optical characteristic of magnetic-controlled refractive index. A Fiber Bragg grating (FBG) is connected after the F-P interferometer which is used to reflect the optical power at the Bragg wavelength of the interference transmission spectrum. The corresponding reflective power o...

  16. Hydrogen production rates from ground-based Fabry-Perot observations of comet Kohoutek

    Scherb, F.

    1981-01-01

    The only ground-based observations of a cometary hydrogen corona that have been obtained up to the present were carried out during the appearance of comet Kohoutek (1973 XII). Hydrogen Balmer alpha (H-alpha) emission from the gas cloud surrounding the comet was detected using a Fabry-Perot spectrometer at Kitt Peak National Observatory. These observations have been reexamined using (1) recently obtained solar full-disk Lyman beta emission line profiles, (2) a new calibration of the absolute sensitivity of the Fabry-Perot spectrometer based on comparison of NGC 7000 with standard stars and the planetary nebula NGC 7662, and (3) corrections for atmospheric extinction instead of the geocoronal H-alpha comparison method used previously to obtain comet H-alpha intensities. The new values for hydrogen production rates are in good agreement with results obtained from Lyman alpha observations of comet Kohoutek.

  17. Testing and characterization of a multispectral imaging Fabry-Perot interferometer for tropospheric trace species detection

    Larar, Allen M.; Cook, William B.; Mills, Carl S.; Flood, Michael A.; Burcher, Ernest E.; Boyer, Charles M.; Puschell, Jeffrey J.

    2006-12-01

    The Tropospheric Trace Species Sensing Fabry-Perot Interferometer (TTSS-FPI) was a NASA Instrument Incubator Program (IIP) project for risk mitigation of enabling concepts and technology applicable to future NASA Science Mission Directorate atmospheric chemistry measurements. Within IIP an airborne sensor was developed and laboratory-tested to demonstrate the instrument concept and enabling technologies that are also applicable to the desired geostationary-based implementation. The concept is centered about an imaging Fabry-Perot interferometer (FPI) observing a narrow spectral interval within the strong 9.6 micron ozone infrared band with a spectral resolution ~0.07 cm -1, and also has applicability to and could simplify designs associated with sensors targeting measurement of other trace species. Results of testing and characterization of enabling subsystems and the overall instrument system are reported; emphasis is placed on recent laboratory testing performed to evaluate system-level radiometric, spatial, and spectral measurement fidelity.

  18. Electric field sensor based on cholesteric liquid crystal Fabry-Perot etalon

    Ko, Myeong Ock; Kim, Sung-Jo; Kim, Jong-Hyun; Lee, Bong Wan; Jeon, Min Yong

    2015-09-01

    We propose an electric field sensor using a cholesteric liquid crystal (CLC) Fabry-Perot etalon and a broadband optical source. The CLC cell consists of glass substrates, polyimide layers, electrodes, and CLC layer. There is a threshold behavior for CLC cell and no change in the transmitted wavelength occurs until a threshold value. The threshold value is 0.8 V/μm for fabricated CLC cell in this experiment. The transmitted or reflected wavelength from the CLC Fabry-Perot etalon depends on the applied electric field. The valley wavelengths of the transmitted light from the CLC device are linearly increased from 1303 nm to 1317 nm as the applied electric field to the CLC device is increased from 0.8 V/μm to 1.9 V/μm.

  19. Coherent electron transparent tunneling through a single barrier within a Fabry-Perot cavity

    Stolle, Jason; Baum, Chaz; Amann, Ryan; Haman, Ryan; Call, Tanner; Li, Wei

    2016-07-01

    Electromagnetic wave and quantum DeBroglie wave have many parallels between each other. We investigate the quantum mechanical counterpart of electromagnetic resonant tunneling through a non-absorbing metal layer. It is confirmed that an electron also has transparent transmission through a single barrier within a Fabry-Perot like cavity. This tunneling structure is actually a distortion of the Fabry-Perot echelon. We find that for a specific resonant electron energy, the cavity length is related to the electron's DeBroglie wavelength; and the single barrier can be located at a series positions with an interval equal to a half of the DeBroglie wavelength, not just at the center of the cavity. This tunneling phenomenon will have novel applications in quantum devices such as the resonant tunneling diode and scanning tunneling microscope. The results of this paper should also have impact on related electromagnetic research and application.

  20. Optical Analog-to-digital Conversion Scheme Based on Tunable Fabry-Perot Resonator

    LI Zheng

    2007-01-01

    Proposed is an interference type of optical analog-to-digital conversion(ADC). The refractive index of Fabry-Perot cavity changes with different voltages. The Fabry-Perot resonator converts electronic intensity into light wavelength through selecting lights of different wavelengthes. The parameters of the scheme are acquired with the transmission matrix of optical element and the time of steady-state light field. The maximum sampling speedes of 4-bit, 6-bit, 7-bit, 8-bit and 9-bit(ADC) are 1.695×1010 count/s, 4.33×109 count/s, 2.38×109 count/s, 1.24×109 count/s and 5.9×108 count/s, respectively.

  1. Chronology of Fabry-Perot Interferometer Fiber-Optic Sensors and Their Applications: A Review

    Md. Rajibul Islam

    2014-04-01

    Full Text Available Optical fibers have been involved in the area of sensing applications for more than four decades. Moreover, interferometric optical fiber sensors have attracted broad interest for their prospective applications in sensing temperature, refractive index, strain measurement, pressure, acoustic wave, vibration, magnetic field, and voltage. During this time, numerous types of interferometers have been developed such as Fabry-Perot, Michelson, Mach-Zehnder, Sagnac Fiber, and Common-path interferometers. Fabry-Perot interferometer (FPI fiber-optic sensors have been extensively investigated for their exceedingly effective, simple fabrication as well as low cost aspects. In this study, a wide variety of FPI sensors are reviewed in terms of fabrication methods, principle of operation and their sensing applications. The chronology of the development of FPI sensors and their implementation in various applications are discussed.

  2. Optical gas sensors based on correlation spectroscopy using a Fabry-Perot interferometer

    Vargas-Rodríguez, Everardo

    2007-01-01

    In this work we present an analysis of gas sensors based on correlation spectroscopy with a Fabry-Perot interferometer (FPI). In this technique the spectral FPI transmission fringe pattern is matched with ro-vibrational absorption lines. To produce the cross correlation principle the FPI fringe pattern must be shifted along the frequency axis. Hence as the spectral FPI fringes are equidistant and symmetric therefore the ro-vibrational absorption lines of the target molecule must be almost equ...

  3. Diode laser frequency stabilization using a low cost, low finesse Fabry-Perot cavity

    Hastings, Hannah; Jaber, Noura B.; Piatt, Georgia; Gregoric, Vincent C.; Carroll, Thomas J.; Noel, Michael W.

    2016-05-01

    Our lab employs low cost, low finesse Fabry-Perot cavities to stabilize the frequency of diode lasers used in ultra-cold Rydberg atom experiments. To characterize the stability of this technique, we perform a self-heterodyne linewidth measurement. For comparison, we also measure the linewidth when using a saturated absorption spectrometer to provide frequency stability. This work is supported by the National Science Foundation under Grants No. 1205895 and No. 1205897.

  4. Phase Space of Tristability in Dual Injection-Locked Fabry-Perot Laser Diodes

    R. V. Pajković; M. M. Krstić; J. V. Crnjanski; A. R. Totović; D. M. Gvozdić

    2015-01-01

    We investigate theoretically the case of dual injection-locking, in which the two light signals are simultaneously externally injected into the cavity of a slave Fabry-Perot laser diode. We show that dual injection-locking leads to formation of new stationary points, and potentially to optical tristability of the slave laser. We show that a region in which the slave laser exhibits three stable steady-states occurs only for sufficiently different frequency detunings of the two injection signal...

  5. Electron density and temperature study of plasmas using a millimeter-wave Fabry-Perot interferometer

    The contents of this article, which have been used as a basis for a State doctorate thesis, deal with research into focussing systems of the Fabry-Perot, millimetre wave type. With the help of this equipment, measurements have been made of the electronic density using interferometry in the range from 109 to 1014 electrons/cm3, and of the electron temperature by Thomson diffusion, of plasmas formed by laser ionisation and by high frequency. (author)

  6. Linear FBG Temperature Sensor Interrogation with Fabry-Perot ITU Multi-wavelength Reference

    Minho Song; Hyoung-Jun Park

    2008-01-01

    The equidistantly spaced multi-passbands of a Fabry-Perot ITU filter are used as an efficient multi-wavelength reference for fiber Bragg grating sensor demodulation. To compensate for the nonlinear wavelength tuning effect in the FBG sensor demodulator, a polynomial fitting algorithm was applied to the temporal peaks of the wavelength-scanned ITU filter. The fitted wavelength values are assigned to the peak locations of the FBG sensor reflections, obtaining constant accuracy, regardless of th...

  7. Reduction of CCD observations made with a scanning Fabry--Perot interferometer. III. Wavelength scale refinement

    Moiseev, A V

    2015-01-01

    We describe the recent modifications to the data reduction technique for observations acquired with the scanning Fabry-Perot interferometer (FPI) mounted on the 6-m telescope of the Special Astrophysical Observatory that allow the wavelength scale to be correctly computed in the case of large mutual offsets of studied objects in interferograms. Also the parameters of the scanning FPIs used in the SCORPIO-2 multimode focal reducer are considered.

  8. Comparing Finesse simulations, analytical solutions and OSCAR simulations of Fabry-Perot alignment signals

    Ballmer, Stefan; Freise, Andreas; Fulda, Paul

    2014-01-01

    This document records the results of a comparison of the interferometer simulation Finesse against an analytic (MATLAB based) calculation of the alignment sensing signals of a Fabry Perot cavity. This task was started during the commissioning workshop at the LIGO Livingston site between the 28.1. and 1.02 2013 with the aim of creating a reference example for validating numerical simulation tools. The FFT based simulation OSCAR joined the battle later.

  9. Differential Radiometers Using Fabry-Perot Interferometric Technique for Remote Sensing of Greenhouse Gases

    Georgieva, Elena M.; Heaps,William S.; Wilson, Emily L.

    2007-01-01

    A new type of remote sensing radiometer based upon the Fabry-Perot interferometric technique has been developed at NASA's Goddard Space Flight Center and tested from both ground and aircraft platform. The sensor uses direct or reflected sunlight and has channels for measuring column concentration of carbon dioxide at 1570 nm, oxygen lines sensitive to pressure and temperature at 762 and 768 nm, and water vapor (940 nm). A solid Fabry-Perot etalon is used as a tunable narrow bandpass filter to restrict the measurement to the gas of interest's absorption bands. By adjusting the temperature of the etalon, which changes the index of refraction of its material, the transmission fringes can be brought into nearly exact correspondence with absorption lines of the particular species. With this alignment between absorption lines and fringes, changes in the amount of a species in the atmosphere strongly affect the amount of light transmitted by the etalon and can be related to gas concentration. The technique is applicable to different chemical species. We have performed simulations and instrument design studies for CH4, "Cot isotope, and CO detection. Index Terms- Absorbing media, Atmospheric measurements, Fabry-Perot interferometers, Optical interferometry, Remote sensing.

  10. A compact Fourier transform imaging spectrometer employing a variable gap Fabry-Perot interferometer

    Lucey, Paul G.; Akagi, Jason; Bingham, Adam L.; Hinrichs, John L.; Knobbe, Edward T.

    2014-05-01

    Fourier transform spectroscopy is a widely employed method for obtaining visible and infrared spectral imagery, with applications ranging from the desktop to remote sensing. Most fielded Fourier transform spectrometers (FTS) employ the Michelson interferometer and measure the spectrum encoded in a time-varying signal imposed by the source spectrum interaction with the interferometer. A second, less widely used form of FTS is the spatial FTS, where the spectrum is encoded in a pattern sampled by a detector array. Recently we described using a Fabry-Perot interferometer, with a deliberately wedged gap geometry and engineered surface reflectivities, to produce an imaging spatial FTS. The Fabry-Perot interferometer can be much lighter and more compact than a conventional interferometer configuration, thereby making them suitable for portable and handheld applications. This approach is suitable for use over many spectral regimes of interest, including visible and infrared regions. Primary efforts to date have focused on development and demonstration of long wave infrared (LWIR) spectral imagers. The LWIR version of the miniaturized Fabry-Perot has been shown to be effective for various applications including spectral imaging-based chemical detection. The compact LWIR spectral imager employs uncooled optics and a microbolometer camera; a handheld version is envisioned for future development. Recent advancements associated with the spatial Fourier Transform imaging spectrometer system are described.

  11. FABSOAR--A Fabry-Perot Spectrometer for Oxygen A-band Research Final Technical Report

    Watchorn, Steven

    2010-09-10

    Because this was a Phase I project, it did not add extensively to the body of A-band knowledge. There was no basic research performed on that subject. The principal addition was that a mechanical and optical design for a triple-etalon Fabry-Perot interferometer (FABSOAR) capable of A-band sensing was sketched out and shown to be within readily feasible instrument fabrication parameters. The parameters for the proposed triple-etalon Fabry-Perot were shown to be very similar to existing Fabry-Perots built by Scientific Solutions. The mechanical design for the FABSOAR instrument incorporated the design of previous Scientific Solutions imagers, condensing the three three-inch-diameter etalons into a single, sturdy tube. The design allowed for the inclusion of a commercial off-the-shelf (COTS) filter wheel and a thermocooled CCD detector from Andor. The tube has supports to mount to a horizontal or vertical opticaltable surface, and was to be coupled to a Scientific Solutions pointing head at the Millstone Hill Observatory in Massachusetts for Phase II calibration and testing.

  12. Statistical analysis of thermospheric gravity waves from Fabry-Perot Interferometer measurements of atomic oxygen

    E. A. K. Ford

    2008-02-01

    Full Text Available Data from the Fabry-Perot Interferometers at KEOPS (Sweden, Sodankylä (Finland, and Svalbard (Norway, have been analysed for gravity wave activity on all the clear nights from 2000 to 2006. A total of 249 nights were available from KEOPS, 133 from Sodankylä and 185 from the Svalbard FPI. A Lomb-Scargle analysis was performed on each of these nights to identify the periods of any wave activity during the night. Comparisons between many nights of data allow the general characteristics of the waves that are present in the high latitude upper thermosphere to be determined. Comparisons were made between the different parameters: the atomic oxygen intensities, the thermospheric winds and temperatures, and for each parameter the distribution of frequencies of the waves was determined. No dependence on the number of waves on geomagnetic activity levels, or position in the solar cycle, was found. All the FPIs have had different detectors at various times, producing different time resolutions of the data, so comparisons between the different years, and between data from different sites, showed how the time resolution determines which waves are observed. In addition to the cutoff due to the Nyquist frequency, poor resolution observations significantly reduce the number of short-period waves (<1 h period that may be detected with confidence. The length of the dataset, which is usually determined by the length of the night, was the main factor influencing the number of long period waves (>5 h detected. Comparisons between the number of gravity waves detected at KEOPS and Sodankylä over all the seasons showed a similar proportion of waves to the number of nights used for both sites, as expected since the two sites are at similar latitudes and therefore locations with respect to the auroral oval, confirming this as a likely source region. Svalbard showed fewer waves with short periods than KEOPS data for a season when both had the same time resolution data

  13. Fabry-Perot interferometer-based remote sensing of SO2

    Kuhn, Jonas; Bobrowski, Nicole; Lübcke, Peter; Pöhler, Denis; Tirpitz, Jan-Lukas; Vogel, Leif; Platt, Ulrich

    2015-04-01

    We studied SO2 degassing from volcanoes and monitored the corresponding SO2 fluxes. Besides the effect on climate and the hazardous effects at a local scale, the absolute magnitude of SO2 fluxes or ratios of SO2 with other volcanic gases can be an indicator for volcanic activity and even help to understand and model processes in the interior of volcanoes. Due to its characteristic absorption structure, high abundance in the volcanic plume and low atmospheric background, SO2 can be easily identified and quantified by remote sensing techniques. DOAS and FTIR became standard techniques for volcanic SO2 measurements. Along with the development of portable devices they offer the advantage of simultaneous measurements of multiple gas species. However, both techniques often need complex data evaluation and observations are usually limited to a single viewing direction. Spatially resolved measurements, which are for instance required to determine gas fluxes, frequently have to be obtained sequentially leading to a relatively low time resolution. A further, today nearly established method to determine SO2 emission fluxes is the "SO2 camera". The SO2 camera has the advantage of a high spatial and temporal resolution, but is very limited in spectral information using only two wavelength channels and thus being less selective. Cross-interferences with volcanic plume aerosol, the ozone background, and other trace gases frequently cause problems in SO2 camera measurements. Here we introduce a novel passive remote sensing method for SO2 measurements in the atmosphere using a Fabry-Perot interferometer (FPI) setup. The transmission profile of this FPI consists of periodic transmission peaks that match the periodic SO2 absorption bands in the UV. In principle, this method allows imaging of two-dimensional SO2 distributions similarly to SO2 cameras. Interferences of standard SO2 cameras are greatly reduced with the FPI method. In addition, this technique can also be applied to other

  14. Study of Fabry-Perot Etalon Stability and Tuning for Spectroscopic Rayleigh Scattering

    Clem, Michelle M.; Mielke-Fagan, Amy F.; Elam, Kristie A.

    2010-01-01

    The Fabry-Perot interferometer is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating flow properties such as gas velocity and temperature. Rayleigh scattered light from a focused laser beam can be directly imaged through a solid Fabry-Perot etalon onto a CCD detector to provide the spectral content of the scattered light. The spatial resolution of the measurements is governed by the locations of interference fringes. The location of the fringes can be changed by altering the etalon?s physical characteristics, such as thickness and index of refraction. For a fused silica solid etalon the physical properties can be adjusted by changing the etalon temperature; hence changing the order of the interference pattern and the physical fringe locations. Controlling the temperature of the etalon can provide for a slow time-response spatial scanning method for this type of etalon system. A custom designed liquid crystal Fabry-Perot (LCFP) can provide for a fast time-response method of scanning the etalon system. Voltage applied to the liquid crystal interface sets the etalon?s properties allowing Rayleigh measurements to be acquired at varying spatial locations across the image of the laser beam over a very short time period. A standard fused silica etalon and a tunable LCFP etalon are characterized to select the system that is best suited for Rayleigh scattering measurements in subsonic and supersonic flow regimes. A frequency-stabilized laser is used to investigate the apparent frequency stability and temperature sensitivity of the etalon systems. Frequency stability and temperature sensitivity data of the fused silica and LCFP etalon systems are presented in this paper, along with measurements of the LCFP etalon?s tuning capabilities. Rayleigh scattering velocity measurements with both etalon systems are presented, in an effort to determine which etalon is better suited to provide optical flow

  15. High-sensitivity Fabry-Perot interferometric pressure sensor based on a nanothick silver diaphragm.

    Xu, Feng; Ren, Dongxu; Shi, Xiaolong; Li, Can; Lu, Weiwei; Lu, Lu; Lu, Liang; Yu, Benli

    2012-01-15

    We present a fiber-optic extrinsic Fabry-Perot interferometer pressure sensor based on a nanothick silver diaphragm. The sensing diaphragm, with a thickness measured in a few hundreds of nanometers, is fabricated by the electroless plating method, which provides a simple fabrication process involving a high-quality diaphragm at a low cost. The sensor exhibits a relatively linear response within the pressure variation range of 0-50 kPa, with a high pressure sensitivity of 70.5 nm/kPa. This sensor is expected to have potential applications in the field of highly sensitive pressure sensors. PMID:22854444

  16. Viability analysis of a dual gas sensor based on a single Fabry-Perot interferometer

    Vargas-Rodriguez, E.; May-Arrioja, D. A.; Estudillo-Ayala, J. M.; Rojas Laguna, R.; Mata-Chavez, R. I.; Alvarado Mendez, E.

    2009-09-01

    In this work an investigation into the viability of a dual gas sensor based on correlation spectroscopy using a single Fabry-Perot Interferometer (FPI) is presented. Here, based on sensor response simulations, it is demonstrated that the commonly considered undesirable effect due to multiple internal reflections of the FPI's mirror substrate can be used to increase the sensing capability of the system. Usually designers tend to minimize these reflections to improve the FPI transmission spectrum. However we let them to occur in order to used them as a part of the modulation system of the sensor which allows us to detect two gases simultaneously using a single FPI.

  17. A Lossy Fabry-perot Based Optical Filter for Natural Gas Analysis

    Ayerden, N.P.; Ghaderi, M.; De Graaf, G.; Wolffenbuttel, R.F.

    2014-01-01

    A set-up for optical gas composition measurement based on absorption spectroscopy is composed of a white light source, a gas cell and a spectrometer. The Fabry-Perot optical filter is suitable for miniaturization of this system, as it is composed of only two reflectors with a transparent layer in-between. Varying the width of this optical resonator to cover the wavelength range in which the components to be analyzed have specific features, gives the absorption spectrum. The gas cell remains a...

  18. Characterization of miniature fiber-optic Fabry-Perot interferometric sensors based on hollow silica tube

    Jia, Pinggang; Fang, Guocheng; Wang, Daihua

    2016-06-01

    A miniature fiber-optic Fabry-Perot interferometer (MOFPI) fabricated by splicing a hollow silica tube (HST) with inner diameter of 4 µm to the end of a single-mode fiber is investigated and experimentally demonstrated. The theoretical relationship between the free spectrum range and the length of HST is verified by fabricating several MOFPIs with different lengths. We characterize the MOFPIs for temperature, liquid refractive index, and strain. Experimental results show that the sensitivities of the temperature, liquid refractive index, and strain are 16.42 pm/℃,-118.56 dB/RIU, and 1.21 pm/µɛ, respectively.

  19. Fabry-Perot resonance enhanced electrically pumped random lasing from ZnO films

    Ni, P. N.; Shan, C. X.; Wang, S. P.; Lu, Y. J.; Li, B. H.; Shen, D. Z.

    2015-12-01

    Fabry-Perot (F-P) resonance has been introduced into Au/MgO/ZnO structure in order to improve the performance of electrically pumped random lasing in this structure. It is found that the lasing threshold of this structure is significantly reduced by introducing the F-P resonance due to the better optical confinement. Meanwhile, this structure shows improved random lasing output characteristics with less random lasing modes and strong dominant output mode due to the gain competition process. The results demonstrate that introducing F-P resonance into the random media provides an effective strategy towards controllable, high performance electrically pumped random lasers.

  20. Single-mode tunable erbium:ytterbium fibre Fabry-Perot laser

    Hsu, K; Miller, C M; Kringlebotn, J.T.; Townsend, J.E.; Payne, D. N.

    1994-01-01

    A compact tunable single-mode fiber laser is developed by using a novel combination of high-gain erbium: ytterbium (Er:Yb) phosphate fiber and fiber Fabry-Perot (FFP) cavity configurations. Experiments demonstrate the shortest Er:Yb phosphate FFP laser ever reported, which has a 100µm cavity length with a continuous wavelength tuning range over 4.52nm, as limited by the sharp fiber gain peak. In addition, an alternative 3-mirror laser design has also demonstrated single-mode lasing operation.

  1. Linear FBG Temperature Sensor Interrogation with Fabry-Perot ITU Multi-wavelength Reference

    Minho Song

    2008-10-01

    Full Text Available The equidistantly spaced multi-passbands of a Fabry-Perot ITU filter are used as an efficient multi-wavelength reference for fiber Bragg grating sensor demodulation. To compensate for the nonlinear wavelength tuning effect in the FBG sensor demodulator, a polynomial fitting algorithm was applied to the temporal peaks of the wavelength-scanned ITU filter. The fitted wavelength values are assigned to the peak locations of the FBG sensor reflections, obtaining constant accuracy, regardless of the wavelength scan range and frequency. A linearity error of about 0.18% against a reference thermocouple thermometer was obtained with the suggested method.

  2. Low-profile Circularly Polarized Antenna Exploiting Fabry-Perot Resonator Principle

    Pitra, K.; Z. Raida; J. Lacik

    2015-01-01

    We designed a patch antenna surrounded by a mushroom-like electromagnetic band-gap (EBG) structure and completed it by a partially reflective surface (PRS). EBG suppresses surface waves and creates the bottom wall of the Fabry-Perot (FP) resonator. PRS plays the role of a planar lens and forms the top wall of the FP resonator. The novel PRS consists of a two-layer grid exhibiting inductive and capacitive (LC) behavior which allows us to obtain a reflection phase between –108 and +180 degrees....

  3. Position sensing with standing wave detection within a passive Fabry-Perot cavity

    Holá, Miroslava; Hrabina, Jan; Číp, Ondřej; Oulehla, Jindřich; Lazar, Josef

    Budva: University of Montenegro, 2013. s. 148. [ALT´13. Annual International Conference on Advanced Laser Technologies /21./. 16.09.2013-20.09.2013, Budva] R&D Projects: GA ČR GPP102/11/P820; GA MŠk ED0017/01/01; GA MŠk EE2.4.31.0016; GA TA ČR TA02010711; GA TA ČR TE01020233 Institutional support: RVO:68081731 Keywords : position sensing * standing wave detection * Fabry-Perot cavity Subject RIV: BH - Optics, Masers, Lasers

  4. Electron polarization measurement using a Fabry-Perot cavity at HERA

    Zhang, Z

    2001-01-01

    A new Compton longitudinal polarimeter currently under construction for HERA is presented. The key component of the polarimeter is a Fabry-Perot cavity located around the electron beam pipe. With such an optical cavity, a continuous laser power equivalent to 5 kW, much higher than those commercially available, can be achieved, leading to one backscattered photon per bunch crossing. This ``few-photon mode'' will allow a very precise determination of the calorimeter response with little systematic uncertainty. The electron polarization measurement at the per mill level is expected.

  5. Emulation of Fabry-Perot and Bragg resonators with temporal optical solitons.

    Voytova, T; Oreshnikov, I; Yulin, A V; Driben, R

    2016-06-01

    The scattering of weak dispersive waves (DWs) on several equally spaced temporal solitons is studied. It is shown by systematic numerical simulations that the reflection of the DWs from the soliton trains strongly depends on the distance between the solitons. The dependence of the reflection and transmission coefficients on the inter-soliton distance and the frequency of the incident waves are studied in detail, revealing fascinating quasi-periodic behavior. The analogy between the observed nonlinear phenomena in the temporal domain and the usual Fabry-Perot and Bragg resonators is discussed. PMID:27244384

  6. OPTICAL FREQUENCY-LOCKING OF A NEMATIC LIQUID CRYSTAL IN A FABRY-PEROT INTERFEROMETER

    Wang, P.-Y.; Dai, J.-H.; Zhang, H.-J.

    1988-01-01

    The light-induced frequency-locking of a nematic liquid crystal in a Fabry-Perot interferometer with a periodic optical drive are studied. The frequency lockings with winding numbers 1/1, 1/2, 113, 1/4, and so on are easily observed by varying the driving amplitude Ɗ and frequency ω. Frequency lockings between the above mentioned winding numbers can only be observed occasionally due to the effect of noise. All the winding numbers of the frequency lockings belong to the Farey tree. Quasiperiod...

  7. Application of Fabry-Perot velocimeter to high-speed experiments

    The Fabry-Perot (F-P) velocimeter is a useful instrument for measuring the velocity of objects at speeds ranging from fractions of a kilometer per second to a few tens of kilometers per second and up. Because of its immunity to electromagnetic interference and its velocity resolution, it has become the prime diagnostic tool in our electric-gun facility. Examples of its application to high speed experiments are discussed, including: electric-gun flyer studies, spallation of materials under high-speed impact, momentum-transfer studies, pressure pulse created by high-velocity impact, and detonation-wave studies in high-explosive experiments

  8. Intrinsic Fabry-Perot Interferometeric Sensor Based on Microfiber Created by Chemical Etching

    Ruohui Wang

    2014-09-01

    Full Text Available An intrinsic Fabry-Perot interferometeric sensor based on a microfiber has been demonstrated. The micro-size suspended core is created by chemical etching a photonics crystal fiber, of which the cladding has a micrometer-spaced, hexagonal array of air holes. The sensing head is fabricated by chemical etching a short section of photonics crystal fiber spliced with a single mode fiber. The temperature sensing characteristic of the interferometer has also been demonstrated and a sensitivity 14.3 pm/°C is obtained.

  9. Emulation of Fabry-Perot and Bragg resonators with temporal optical solitons

    Voytova, Tanya; Yulin, Alexey; Driben, Rodislav

    2016-01-01

    The scattering of weak dispersive waves (DW) on several equally spaced temporal solitons is studied. It is shown by systematic numerical simulations that the reflection of the DWs from the soliton trains strongly depends on the distance between the solitons. The dependence of the reflection and transmission coefficients on the inter-soliton distance and the frequency of the incident waves is studied in detail, revealing fascinating quasi-periodic behavior. The analogy between the observed nonlinear phenomena in temporal domain and usual Fabry-Perot and Bragg resonators is discussed.

  10. The GREGOR Fabry Perot Interferometer (GFPI), Technical Innovations and Results achieved in 2013

    Puschmann, Klaus Gerhard

    2016-01-01

    This paper shall provide a summary of not yet published technical innovations to the GREGOR Fabry-Perot Interferometer (GFPI) at the 1.5m GREGOR Solar Telescope (Europe's largest solar telescope) that I implemented in 2013 as the Instrument Scientist of the GFPI. It also represents an overview of important and not yet published observational results that I achieved with the GFPI in 2013. The results and achievements can be considered a milestone in the further development, scientific verification and final acceptance of this instrument. The instrument is now in operation and employed by the international scientific community.

  11. A liquid helium cooled mid-infrared imaging Fabry-Perot spectrometer

    Watarai, H.; Chaen, K.; Matsuhara, H.; Matsumoto, T.; Takahashi, H.

    1994-03-01

    A liquid helium cooled mid-infrared imaging Fabry-Perot spectrometer has been under development. A Si:P 5x5 detector array is used for this instrument. Although the array system has small format, but combination with junction field effect transistor (JFET) array will provide noise equivalent line flux of 1.0 x 10-21 w/sq cm(1000 sec, 10 sigma). This sensitivity is comparable with the short wavelength spectrometer (SWS) of the Infrared Space Observatory (ISO).

  12. Subkilohertz linewidth reduction of a DFB diode laser using self-injection locking with a fiber Bragg grating Fabry-Perot cavity.

    Wei, Fang; Yang, Fei; Zhang, Xi; Xu, Dan; Ding, Meng; Zhang, Li; Chen, Dijun; Cai, Haiwen; Fang, Zujie; Xijia, Gu

    2016-07-25

    A simple and low-cost 1550 nm semiconductor laser with subkilohertz intrinsic linewidth is experimentally demonstrated. A commercial distributed feedback diode laser is self-injection locked to the resonance transmission peaks of a fiber Bragg grating Fabry-Perot cavity through a polarization-maintaining fiber ring with the optical path length of 4 m, with the laser frequency noise suppressed by over 70 dB in the Fourier frequency band from 5 Hz and 1 kHz. The laser features an intrinsic Lorentzian linewidth of 125 Hz as well as a relative intensity noise of continuous tunability, which is suitable for advanced applications requiring a narrow linewidth laser with ultralow frequency noise. PMID:27464187

  13. Generation of millimeter-wave sub-carrier optical pulse by using a Fabry-Perot interferometer

    Qing Ye; Ronghui Qu; Zujie Fang

    2007-01-01

    A novel scheme is proposed to transform a Gaussian optical pulse to a millimeter-wave (mm-wave) frequency modulation pulse by using a Fabry-Perot interferometer (FPI) for radio-over-fiber (ROF) system.It is shown that modulation frequency of mm-wave is determined by the optical path of the Fabry-Perot (F-P) cavity, and amplitude decay time and energy transfer efficiency are related to the reflectivity of the F-P cavity mirror. The effect of pulse train extension on inter-symbol interference is also discussed.

  14. Electrically tunable liquid-crystal Fabry-Perot device for terahertz radiation

    Li, Hui; Pan, Fan; Liu, Kan; Wu, Yuntao; Zhang, Yanduo; Xie, Xiaolin

    2015-11-01

    In this paper, we will present a smart structure based on an electrically controlled liquid crystal (LC) Fabry-Perot to achieve terahertz (THz) filter, which has extremely potential in THz communication. This proposed structure doesn't need any mechanical movements because of adapting LC as a key material to compose the Fabry-Perot device. The THz filter based on LC, which is smart, light and cheap, can be realized to solve that common problem of short of tunable devices in THz radiation. The chosen LC material is E7, which has very stable and good transmissions in THz range. Under the external applied voltage, the alignment of the nematic LC allows the refractive index of the device to be tuned. Because of this feature, the resonant peaks could be shifted by changing the applied voltage. Especially, when the alignment is changed from planar to phototropic, the maximum value of the shift could be realized. The simulation result of the proposed device could be got. And the optimal structural parameters could be also got. Numerical analyses results have shown that the proposed structure has a high narrow transmission band and very sharp edges. This THz filter is novel for compact and smart features, so this kind of proposed THz filter is very attractive in many applications, such as THz communication, and THz spectral imaging.

  15. Fabry-Perot Temperature Sensor for Quasi-Distributed Measurement Utilizing OTDR

    Ping Xu; Fu-Fei Pang; Na Chen; Zhen-Yi Chen; Ting-Yun Wang

    2008-01-01

    A quasi-distributed Fabry-Perot fiber optic temperature sensor array using optical time domain reflectometry (OTDR) technique is presented. The F-P sensor is made by two face to face single-mode optical fibers and their surfaces have been polished. Due to the low reflectivity of the fiber surfaces, the sensor is described as low Fresnel Fabry-Perot interferometer (FPI). The working principle is analyzed using two-beam optical interference approximation. To measure the temperature, a certain temperature sensitive material is filled in the cavity. The slight changes of the reflective intensity which is induced by the refractive index of the material was eaught by OTDR. The length of the cavity is obtained by monitoring the interference spectrum which is used for the setting of the sensor static characteristics within the quasi-linear range. Based on our design, a three point sensor array are fabricated and characterized. The experimental results show that with the temperature increasing from -30℃ to 80℃, the reflectivity increase in a good linear manner. The sensitivity was approximate 0.074 dB℃. For the low transmission loss, more sensors can be integrated.

  16. Blood pressure manometer using a twin Bragg grating Fabry-Perot interferometer

    van Brakel, Adriaan; Swart, Pieter L.; Chtcherbakov, Anatoli A.; Shlyagin, Mikhail G.

    2005-02-01

    We propose the use of optical fiber Bragg gratings in a non-invasive blood pressure waveform monitor. Bragg gratings can be written in a Fabry-Perot interferometric configuration to yield a method of strain measurement that has both a high resolution and a wide unambiguous range. This fiber Bragg grating Fabry-Perot interferometer (FBGI) can be used as a sensor to detect strain resulting from blood pressure applied to the walls of an artery situated near the patient"s skin. Strain measurements taken on the skin surface, typically over the radial artery at the wrist, are encoded as phase shifts of the FBGI signal. These phase shifts may be obtained by the analytic representation of the interferometer signal in the wavelength domain or by Fourier analysis in the frequency domain. For the proof of concept a realistic physical model was constructed to simulate pressure conditions at the actual sensor location. The operation of the device is demonstrated by measurements of pressure-pulse waveforms obtained in real-time. This sensor was also successfully tested on human patients, and these results are also presented. Since it yields continuous readings of blood pressure non-invasively, further application of the optical manometer may yield an alternative to conventional sphygmomanometry.

  17. Star formation in NGC 4449: MAMA-detector UV imagery and Fabry-Perot Balmer-line imagery

    Hill, Robert S.; Home, Allen T.; Smith, Andrew M.; Bruhweiler, Fred C.; Cheng, K.P.; Hintzen, Paul M. N.; Oliversen, Ronald J.

    1994-01-01

    Using far-ultraviolet (FUV) and Balmer-line imagery, we investigate the star formation history of 22 large OB complexes in the Magellanic irregular galaxy NGC 4449. The FUV luminosity of NGC 4449 is comparable to those of late-type spirals and is greater than that of the LMC by approximately 2.4 mag, indicating substantial star formation in the last 10(exp 8) yr. FUV data were taken using a sounding-rocket telescope with a Multianode Microchannel Array (MAMA) detector, and Balmer-line data were taken using the Goddard Fabry-Perot Imager. The resulting imagery shows bright, roughly coincident FUV and H alpha sources throughout the extent of the visible galaxy. We model these sources using cluster-evolution codes. Although all sources are a few Myr old, clear age differences are found. In particular, several of the most recently active star formation regions are located together in the galaxy's northern periphery, which is apparently coincident with a large H I reservoir. The brightest and most massive OB complexes are found along the northeast-southwest surface brightness ridgeline (the 'bar'). Over the entire galaxy, star formation rates are consistent on timescales of 10(exp 6), 10(exp 8), and 10(exp 9) yr. A history of recent star formation is suggested with two main episodes, one predominantly in the bar ending approximately 5 Myr ago, and an ongoing one associated with an observed H I cloud.

  18. The Hawaii Imaging Fabry-Perot Interferometer (HIFI)

    At Mauna Kea Observatory, researchers conducted optical, imaging spectrophotometric studies of selected active galaxies using both the Canada-France-Hawaii 3.6m and University of Hawaii 2.2m telecopes (Tully, Bland and Cecil 1988). To maximize spatial resolution, researchers select galaxies independent of luminosity but known to possess interesting morphologies or high-velocity, extranuclear ionized gas (Walker 1968; Rubin and Ford 1968). They study both the large-scale patterns produced in IR-luminous, starburst systems (e.g., M82, NGC 253, NGC 6240) and those with compact, but spatially extended, circumnuclear, narrow line regions (e.g., M51, NGC 1068, NGC 4151). Current studies are restricted to the optical (SII), (NII) and (OIII) lines and the brightest Balmer recombination lines. These lines are, in principle, sufficient to constrain the dynamical structure and dominant excitation mechanism of the ionized component

  19. The Hawaii Imaging Fabry-Perot Interferometer (HIFI)

    Bland, Jonathan; Cecil, Gerald; Tully, Brent

    1990-01-01

    At Mauna Kea Observatory, researchers conducted optical, imaging spectrophotometric studies of selected active galaxies using both the Canada-France-Hawaii 3.6m and University of Hawaii 2.2m telecopes (Tully, Bland and Cecil 1988). To maximize spatial resolution, researchers select galaxies independent of luminosity but known to possess interesting morphologies or high-velocity, extranuclear ionized gas (Walker 1968; Rubin and Ford 1968). They study both the large-scale patterns produced in IR-luminous, starburst systems (e.g., M82, NGC 253, NGC 6240) and those with compact, but spatially extended, circumnuclear, narrow line regions (e.g., M51, NGC 1068, NGC 4151). Current studies are restricted to the optical (SII), (NII) and (OIII) lines and the brightest Balmer recombination lines. These lines are, in principle, sufficient to constrain the dynamical structure and dominant excitation mechanism of the ionized component.

  20. Lineshape Engineering in an All-Pass Ring Resonator with Backreflection Coupled to a Symmetrical Fabry-Perot Resonator

    Melnikov, Vasily A.

    2012-11-10

    We derive transfer functions for an all-pass ring resonator with internal backreflection coupled to a symmetrical Fabry-Perot resonator and demonstrate electromagnetically induced transparency-like and Fano-like lineshapes tunable by backreflection in the ring resonator.

  1. Reduce of the Linewidth of a Diode Laser by Locking to a High-Finesse Fabry-Perot Cavity

    HUANG Kai-Kai; ZHANG Jian-Wei; CHEN Jing-Biao; YANG Dong-Hai

    2006-01-01

    @@ We report frequency locking of a commercial 657nm diode laser to a high finesse Fabry-Perot cavity by the Pound-Drever-Hall method. The laser linewidth relative to the cavity is estimated to be about 6 kHz.

  2. Precise monitoring of ultra low expansion Fabry-Perot cavity length by the use of a stabilized optical frequency comb

    Šmíd, Radek; Číp, Ondřej; Buchta, Zdeněk; Ježek, Jan; Mikel, Břetislav; Čížek, Martin; Lazar, Josef

    Piscataway: IEEE, 2010, s. 480-484. ISBN 978-1-4244-6399-2. ISSN 1075-6787. [2010 IEEE International Frequency Control Symposium. New Port Beach (CA), 01.07.2010-04.07.2010] Institutional support: RVO:68081731 Keywords : Bragg gratings * Fabry-Perot resonators * Global Positioning System * laser cavity resonators Subject RIV: BH - Optics, Masers, Lasers

  3. The Comparison of Environmental Effects on Michelson and Fabry-Perot Interferometers Utilized for the Displacement Measurement

    Chung-Ping Chang

    2010-03-01

    Full Text Available The optical structure of general commercial interferometers, e.g., the Michelson interferometers, is based on a non-common optical path. Such interferometers suffer from environmental effects because of the different phase changes induced in different optical paths and consequently the measurement precision will be significantly influenced by tiny variations of the environmental conditions. Fabry-Perot interferometers, which feature common optical paths, are insensitive to environmental disturbances. That would be advantageous for precision displacement measurements under ordinary environmental conditions. To verify and analyze this influence, displacement measurements with the two types of interferometers, i.e., a self-fabricated Fabry-Perot interferometer and a commercial Michelson interferometer, have been performed and compared under various environmental disturbance scenarios. Under several test conditions, the self-fabricated Fabry-Perot interferometer was obviously less sensitive to environmental disturbances than a commercial Michelson interferometer. Experimental results have shown that induced errors from environmental disturbances in a Fabry-Perot interferometer are one fifth of those in a Michelson interferometer. This has proved that an interferometer with the common optical path structure will be much more independent of environmental disturbances than those with a non-common optical path structure. It would be beneficial for the solution of interferometers utilized for precision displacement measurements in ordinary measurement environments.

  4. The technique of detecting the laser-ultrasonic vector displacement with a confocal Fabry-Perot interferometer waves in a plate

    PAN Yongdong; QIAN Menglu

    2003-01-01

    Generally, a confocal Fabry-Perot interferometer is only able to detect the out-of-plane component of a displacement field; while the in-plane component often has the information about the material which cannot be found in this out-of-plane component. In this paper, based on a confocal Fabry-Perot interferometer set-up for detecting the out-of-plane component of a laser generated acoustic field, a technique is developed to detect both the out-of-plane and inplane displacement components simultaneously with a novel two-channel confocal Fabry-Perot interferometer.

  5. A new detection method used to calibrate Fabry-Perot interferometers in the infrared range

    Fabry-Perot interferometers are routinely used in the Tore Supra Tokamak in order to measure the time evolution of the electron temperature of the confined plasmas. Calibration of such interferometers requires the detection of very low DC levels (0.1 nV) with signal-to-noise ratios less than 10-5, which is generally not compatible with standard detection methods. A new correlation method to achieve this absolute calibration is proposed. It is based on a proper noise auto-correlation technique combined with an optimized signal filtering involving Fourier analysis. The advantages of the method are detailed and experimentally compared to standard averaging techniques, such as coherent addition and synchronous detection. The method can be used in a more general context every time very small amplitude signals are to be measured

  6. Spoof surface plasmon Fabry-Perot open resonators in a surface-wave photonic crystal

    Gao, Zhen; Xu, Hongyi; Zhang, Youming; Zhang, Baile

    2016-01-01

    We report on the proposal and experimental realization of a spoof surface plasmon Fabry-Perot (FP) open resonator in a surface-wave photonic crystal. This surface-wave FP open resonator is formed by introducing a finite line defect in a surface-wave photonic crystal. The resonance frequencies of the surface-wave FP open resonator lie exactly within the forbidden band gap of the surface-wave photonic crystal and the FP open resonator uses this complete forbidden band gap to concentrate surface waves within a subwavelength cavity. Due to the complete forbidden band gap of the surface-wave photonic crystal, a new FP plasmonic resonance mode that exhibits monopolar features which is missing in traditional FP resonators and plasmonic resonators is demonstrated. Near-field response spectra and mode profiles are presented in the microwave regime to characterize properties of the proposed FP open resonator for spoof surface plasmons.

  7. An optimized strain demodulation method for PZT driven fiber Fabry-Perot tunable filter

    Sheng, Wenjuan; Peng, G. D.; Liu, Yang; Yang, Ning

    2015-08-01

    An optimized strain-demodulation-method based on piezo-electrical transducer (PZT) driven fiber Fabry-Perot (FFP) filter is proposed and experimentally demonstrated. Using a parallel processing mode to drive the PZT continuously, the hysteresis effect is eliminated, and the system demodulation rate is increased. Furthermore, an AC-DC compensation method is developed to address the intrinsic nonlinear relationship between the displacement and voltage of PZT. The experimental results show that the actual demodulation rate is improved from 15 Hz to 30 Hz, the random error of the strain measurement is decreased by 95%, and the deviation between the test values after compensation and the theoretical values is less than 1 pm/με.

  8. A simple Fabry-Perot pressure sensor fabricated on fiber optic tip

    Di Palma, Pasquale; Natale, Daniele; Campopiano, Stefania; Iadicicco, Agostino

    2016-05-01

    In this work, we demonstrate an extrinsic pressure sensor realized on single mode fiber tip by means of simple fabrication steps and with low-cost instrumentations. The sensing element consists in a Fabry-Perot cavity: one reflecting surface is the end of the optical fiber, precisely cut, and the other one is a metallic diaphragm. Under the action of the external pressure, the metallic diaphragm bends changing the optical cavity length and, consequently, the characteristics of the reflected signal. The holder structure, which allows the alignment of the fiber tip and reflecting diaphragm, consists in a commercial zirconia ferule with external diameter of Dex = 2.5 mm. Despite its simplicity and cost-effectiveness, the achieved results show performance comparable to more complex and expensive configurations. By using an aluminum plate as reflecting diaphragm. sensitivity ranging in the 70-130pm/mmHg is experimentally.

  9. Striped-double cavity fabry-perot interferometers using both glass and air cavities

    Perry, S; Steinmetz, L

    1998-07-08

    We have used piezo-driven Fabry-Perot interferometers in the past far many continuous velocity-time measurements of fast moving surfaces. In order to avoid the annoying drift of some of these devices, we have developed and used inexpensive, solid glass, striped etalons with lengths up to 64 mm. Usable apertures are 35 mm by 80 mm with a finess of 25. A roundabout technique was devised for double cavity operation. We built a passive thermal housing for temperature stability, with tilt and height adjustments. We have also developed and used our first fixed etalon air-spaced cavity with a rotatable glass double- cavity insert. The rotation allows the referee cavity fractional order to be adjusted separately from that of the main cavity. It needs very little thermal protection, and eliminates the need for a roundabout scheme for double cavity operation, but is more costly than the solid glass version I

  10. The PVLAS experiment: measuring vacuum magnetic birefringence and dichroism with a birefringent Fabry-Perot cavity

    Della Valle, Federico; Milotti, Edoardo [INFN, Trieste (Italy); Universita di Trieste, Dipt. di Fisica, Trieste (Italy); Ejlli, Aldo; Messineo, Giuseppe; Zavattini, Guido [INFN, Ferrara (Italy); Universita di Ferrara, Dipt. di Fisica e Scienze della Terra, Ferrara (Italy); Gastaldi, Ugo [INFN, Ferrara (Italy); Pengo, Ruggero; Ruoso, Giuseppe [INFN, Lab. Nazionale di Legnaro, Legnaro (Italy)

    2016-01-15

    Vacuum magnetic birefringence was predicted long time ago and is still lacking a direct experimental confirmation. Several experimental efforts are striving to reach this goal, and the sequence of results promises a success in the next few years. This measurement generally is accompanied by the search for hypothetical light particles that couple to two photons. The PVLAS experiment employs a sensitive polarimeter based on a high finesse Fabry-Perot cavity. In this paper we report on the latest experimental results of this experiment. The data are analysed taking into account the intrinsic birefringence of the dielectric mirrors of the cavity. Besides a new limit on the vacuum magnetic birefringence, the measurements also allow the model-independent exclusion of new regions in the parameter space of axion-like and milli-charged particles. In particular, these last limits hold also for all types of neutrinos, resulting in a laboratory limit on their charge. (orig.)

  11. Light trapping in an ensemble of point-like impurity centers in Fabry-Perot cavity

    Kuraptsev, A S

    2016-01-01

    We report the development of quantum microscopic theory of quasi-resonant dipole-dipole interaction in the ensembles of impurity atoms imbedded into transparent dielectric and located into Fabry-Perot cavity. On the basis of the general approach we study the simultaneous influence of the cavity and resonant dipole-dipole interaction on the shape of the line of atomic transition as well as on light trapping in dense impurity ensembles. We analyze this influence depending on the size of the ensemble, its density, as well as on r.m.s. deviation of the transition frequency shifts caused by the symmetry disturbance of the internal fields of the dielectric medium. Obtained results are compared with the case when the cavity is absent. We show that the cavity can essentially modify cooperative polyatomic effects.

  12. Embedded intrinsic Fabry-Perot optical fiber sensors in cement concrete structures

    Kim, Ki S.; Yoo, Jae-Wook; Kim, Seung Kwan; Kim, Byoung Yoon

    1996-05-01

    Intrinsic Fabry-Perot optical fiber sensors were embedded to the tensile side of the 20 cm by 20 cm by 150 cm cement concrete structures. The sensors were attached to the reinforcing steels and then, the cement concretes were applied. It took 30 days for curing the specimens. After that, the specimens were tested with 4-point bending method by a universal testing machine. Strains were measured and recorded by the strain gauges embedded near optical fiber sensors. Output data of fiber sensor showed good linearity to the strain data from the strain gauges up to 2000 microstrain. The optical fiber sensors showed good response after yielding of the structure while embedded metal film strain gauges did not show any response. We also investigated the behavior of the optical fiber sensor when the specimens were broken down. In conclusion, the optical fiber sensors can be used as elements of health monitoring systems for cement concrete infra-structures.

  13. Overview of laboratory testing results for an imaging Fabry-Perot interferometer

    Larar, Allen M.; Cook, William B.; Flood, Michael A.; Campbell, Joel F.; Boyer, Charles M.; Remus, Rubin G.; Burcher, Ernest E.; Puschell, Jeffery J.

    2007-10-01

    An airborne imaging Fabry-Perot Interferometer (FPI) system was developed within NASA's Instrument Incubator Program (IIP) to mitigate risk associated with implementation of such a device in future space-based atmospheric remote sensing missions. This system is focused on observing tropospheric ozone through measuring a narrow spectral interval within the strong 9.6 micron infrared ozone band at high spectral resolution, while the concept and technology also have applicability toward measurement of other trace species and other applications. The latest results from laboratory testing and characterization of enabling subsystems and the overall instrument system will be reported, with an emphasis placed on testing performed to evaluate system-level radiometric, spatial, and spectral measurement fidelity.

  14. Optical design and characterization of a gas filled MEMS Fabry-Perot filter

    Ayerden, N. Pelin; Ghaderi, Mohammadamir; de Graaf, Ger; Wolffenbuttel, Reinoud F.

    2015-05-01

    A concept for a highly integrated and miniaturized gas sensor based on infrared absorption, a Fabry-Perot type linear variable optical filter with integrated gas cell, is presented. The sample chamber takes up most of the space in a conventional spectrometer and is the only component that has so far not been miniaturized. In this concept the gas cell is combined with the resonator cavity of the filter. The optical design, fabrication, and characterization results on a MEMSbased realization are reported for a 24-25.5 μm long tapered resonator cavity. Multiple reflections from highly reflective mirrors enable this optical cavity to also act as a gas cell with an equivalent optical absorption path length of 8 mm. Wideband operation of the filter is ensured by fabrication of a tapered mirror. In addition to the functional integration and significant size reduction, the filter contains no moving parts, thus enables the fabrication of a robust microspectrometer

  15. Influence of the Talbot effect on the loss permutations of Fabry - Perot resonator modes

    The loss permutations of Fabry - Perot resonator modes caused by the harmonic spatial perturbation of the radiation phase on one of the mirrors are studied numerically. The periods and amplitudes of perturbations are found at which the second or third mode in the eigenvalue modulus becomes the first mode. It is shown that in the case of perturbations with the period l0, at which the Talbot length is equal to the double resonator length, the permutations are caused by an increase in the losses of the fundamental mode. It is also shown that the perturbation amplitudes with the period l0, which equalise losses of the modes, depend linearly on the inverse Fresnel number F-1. (resonators. modes)

  16. Fabry-Perot microcavity sensor for H2-breath-test analysis

    Vincenti, Maria Antonietta; De Sario, Marco; Petruzzelli, V.; D'Orazio, Antonella; Prudenzano, Francesco; de Ceglia, Domenico; Scalora, Michael

    2007-10-01

    Leak detection of hydrogen for medical purposes, based on the monitoring of the optical response of a simple Fabry-Perot microcavity, is proposed to investigate either the occurrence of lactose intolerance, or lactose malabsorption condition. Both pathologic conditions result in bacterial overgrowth in the intestine, which causes increased spontaneous emission of H2 in the human breath. Two sensitivity figures of merit are introduced to inspect changes in the sensor response, and to relate the microcavity response to a pathologic condition, which is strictly related to a different level of exhaled hydrogen. Different sensor configurations using a metal-dielectric microcavity are reported and discussed in order to make the most of the well-known ability of palladium to spontaneously absorb hydrogen.

  17. Advanced Interrogation of Fiber-Optic Bragg Grating and Fabry-Perot Sensors with KLT Analysis.

    Tosi, Daniele

    2015-01-01

    The Karhunen-Loeve Transform (KLT) is applied to accurate detection of optical fiber sensors in the spectral domain. By processing an optical spectrum, although coarsely sampled, through the KLT, and subsequently processing the obtained eigenvalues, it is possible to decode a plurality of optical sensor results. The KLT returns higher accuracy than other demodulation techniques, despite coarse sampling, and exhibits higher resilience to noise. Three case studies of KLT-based processing are presented, representing most of the current challenges in optical fiber sensing: (1) demodulation of individual sensors, such as Fiber Bragg Gratings (FBGs) and Fabry-Perot Interferometers (FPIs); (2) demodulation of dual (FBG/FPI) sensors; (3) application of reverse KLT to isolate different sensors operating on the same spectrum. A simulative outline is provided to demonstrate the KLT operation and estimate performance; a brief experimental section is also provided to validate accurate FBG and FPI decoding. PMID:26528975

  18. Gas detection with microelectromechanical Fabry-Perot interferometer technology in cell phone

    Mannila, Rami; Hyypiö, Risto; Korkalainen, Marko; Blomberg, Martti; Kattelus, Hannu; Rissanen, Anna

    2015-06-01

    VTT Technical Research Centre of Finland has developed a miniaturized optical sensor for gas detection in a cell phone. The sensor is based on a microelectromechanical (MEMS) Fabry-Perot interferometer, which is a structure with two highly reflective surfaces separated by a tunable air gap. The MEMS FPI is a monolithic device, i.e. it is made entirely on one substrate in a batch process, without assembling separate pieces together. The gap is adjusted by moving the upper mirror with electrostatic force, so there are no actual moving parts. VTT has designed and manufactured a MEMS FPI based carbon dioxide sensor demonstrator which is integrated to a cell phone shield cover. The demonstrator contains light source, gas cell, MEMS FPI, detector, control electronics and two coin cell batteries as a power source. It is connected to the cell phone by Bluetooth. By adjusting the wavelength range and customizing the MEMS FPI structure, it is possible to selectively sense multiple gases.

  19. Highly accurate spectral retardance characterization of a liquid crystal retarder including Fabry-Perot interference effects

    Vargas, Asticio [Departamento de Ciencias Físicas, Universidad de La Frontera, Temuco (Chile); Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción (Chile); Mar Sánchez-López, María del [Instituto de Bioingeniería, Universidad Miguel Hernández, 03202 Elche (Spain); García-Martínez, Pascuala [Departament d' Òptica, Universitat de València, 45100 Burjassot (Spain); Arias, Julia; Moreno, Ignacio [Departamento de Ciencia de Materiales, Óptica y Tecnología Electrónica, Universidad Miguel Hernández, 03202 Elche (Spain)

    2014-01-21

    Multiple-beam Fabry-Perot (FP) interferences occur in liquid crystal retarders (LCR) devoid of an antireflective coating. In this work, a highly accurate method to obtain the spectral retardance of such devices is presented. On the basis of a simple model of the LCR that includes FP effects and by using a voltage transfer function, we show how the FP features in the transmission spectrum can be used to accurately retrieve the ordinary and extraordinary spectral phase delays, and the voltage dependence of the latter. As a consequence, the modulation characteristics of the device are fully determined with high accuracy by means of a few off-state physical parameters which are wavelength-dependent, and a single voltage transfer function that is valid within the spectral range of characterization.

  20. Design of a reconfigurable optical add/drop multiplexer based on tunable Fabry-Perot array

    Ye, Jiansen; Wang, Xin; Li, Zhuo; Yang, Yang; Xu, Rui; Shi, Rui

    2015-08-01

    With the development of optical fiber communication, dense wavelength division multiplexing (DWDM) system is important for the rapid management of multi-wavelength in the core node of the optical transmission network. In this paper, a reconfigurable optical add-drop multiplexer (ROADM) based on the tunable Fabry-Perot (F-P) array is proposed. An optical switch with high isolation and low crosstalk is designed by using the characteristics of filtering and tuning for the F-P array. The principle, structure, and function of the tunable F-P array are introduced. The characteristics of filtering and tuning for the F-P filter are also calculated, and the factor for the isolation, crosstalk, response time and insertion loss are analyzed. A single physical channel ROADM with 16 signal channels, which operates in C-band, is designed and optimized by simulation.

  1. Enhanced Bulk-Edge Coulomb Coupling in Fractional Fabry-Perot Interferometers.

    von Keyserlingk, C W; Simon, S H; Rosenow, Bernd

    2015-09-18

    Recent experiments use Fabry-Perot (FP) interferometry to claim that the ν=5/2 quantum Hall state exhibits non-Abelian topological order. We note that the experiments appear inconsistent with a model neglecting bulk-edge Coulomb coupling and Majorana tunneling, so we reexamine the theory of FP devices. Even a moderate Coulomb coupling may strongly affect some fractional plateaus, but very weakly affect others, allowing us to model the data over a wide range of plateaus. While experiments are consistent with the ν=5/2 state harboring Moore-Read topological order, they may have measured Coulomb effects rather than an "even-odd effect" due to non-Abelian braiding. PMID:26431008

  2. Diaphragm-free fiber-optic Fabry-Perot interferometer based on tapered hollow silica tube

    Fang, Guocheng; Jia, Pinggang; Liang, Ting; Tan, Qiulin; Hong, Yingping; Liu, Wenyi; Xiong, Jijun

    2016-07-01

    A miniature fiber-optic Fabry-Perot interferometer fabricated by splicing a diaphragm-free hollow silica tube to a single-mode fiber and fusing the inner core to a taper is presented. The tapered zone forces lights to propagate from the fiber core into the silica tube, and the lights is reflected from the end faces of the optical fiber and the hollow silica tube. The contrast ratio of the interference fringe is determined by the minimum inner diameter of hollow silica tube. The responses of the proposed interferometer to high-temperature, gas refractive index, liquid refractive index and pressure were measured and were found to be linear with sensitivities of 16.26 pm/°C, 610.47 nm/RIU, -122.36 dB/RIU and 1.56 pm/kPa, respectively.

  3. Colloidal pattern replication through contact photolithography operated in a "Talbot-Fabry-Perot" regime

    Emplit, Aline; Huynen, Isabelle; Vlad, Alexandru; Sarrazin, Michael

    2014-01-01

    We detail on a continuous colloidal pattern replication by using contact photolithography. Chrome on quartz masks are fabricated using colloidal nanosphere lithography and subsequently used as photolithography stamps. Hexagonal pattern arrangements with different dimensions (980, 620 and 480 nm, using colloidal particles with respective diameters) have been studied. When the mask and the imaged resist layer were in intimate contact, a high fidelity pattern replica was obtained after photolithography exposure and processing. In turn, the presence of an air-gap in between has been found to affect the projected image onto the photoresist layer, strongly dependent on the mask feature size and air-gap height. Pattern replication, inversion and hybridization was achieved for 980 nm-period mask; no hybridization for the 620 nm; and only pattern replication for the 480 nm. These results are interpreted in the framework of a "Talbot-Fabry-Perot" effect. Numerical simulations corroborate with the experimental findings ...

  4. Advanced Interrogation of Fiber-Optic Bragg Grating and Fabry-Perot Sensors with KLT Analysis

    Daniele Tosi

    2015-10-01

    Full Text Available The Karhunen-Loeve Transform (KLT is applied to accurate detection of optical fiber sensors in the spectral domain. By processing an optical spectrum, although coarsely sampled, through the KLT, and subsequently processing the obtained eigenvalues, it is possible to decode a plurality of optical sensor results. The KLT returns higher accuracy than other demodulation techniques, despite coarse sampling, and exhibits higher resilience to noise. Three case studies of KLT-based processing are presented, representing most of the current challenges in optical fiber sensing: (1 demodulation of individual sensors, such as Fiber Bragg Gratings (FBGs and Fabry-Perot Interferometers (FPIs; (2 demodulation of dual (FBG/FPI sensors; (3 application of reverse KLT to isolate different sensors operating on the same spectrum. A simulative outline is provided to demonstrate the KLT operation and estimate performance; a brief experimental section is also provided to validate accurate FBG and FPI decoding.

  5. Thermospheric gravity waves in Fabry-Perot Interferometer measurements of the 630.0nm OI line

    E. A. K. Ford

    2006-03-01

    Full Text Available Gravity waves are an important feature of mesosphere - lower thermosphere (MLT dynamics, observed using many techniques and providing an important mechanism for energy transfer between atmospheric regions. It is known that some gravity waves may propagate through the mesopause and reach greater altitudes before eventually "breaking" and depositing energy. The generation, propagation, and breaking of upper thermospheric gravity waves have not been studied directly often. However, their ionospheric counterparts, travelling ionospheric disturbances (TIDs, have been extensively studied in, for example, radar data. At high latitudes, it is believed localised auroral activity may generate gravity waves in-situ. Increases in sensor efficiency of Fabry-Perot Interferometers (FPIs located in northern Scandinavia have provided higher time resolution measurements of the auroral oval and polar cap atomic oxygen red line emission at 630.0 nm. A Lomb-Scargle analysis of this data has shown evidence of gravity wave activity with periods ranging from a few tens of minutes to several hours. Oscillations are seen in the intensity of the line as well as the temperatures and line of sight winds. Instruments are located in Sodankylä, Finland; Kiruna, Sweden; Skibotn, Norway, and Svalbard in the Arctic Ocean. A case study is presented here, where a wave of 1.8 h period has a phase speed of 250 ms-1 with a propagation angle of 302°, and a horizontal wavelength of 1600 km. All the FPIs are co-located with EISCAT radars, as well as being supplemented by a range of other instrumentation. This allows the waves found in the FPI data to be put in context with the ionosphere and atmosphere system. Consequently, the source region of the gravity waves can be determined.

  6. Protoplanetary Disks in the Orion Nebula An H$\\alpha$ Fabry-Perot study and Astrobiological Aspects

    De la Fuente-Acosta, E; Arias, L; Throop, H B; Ambrocio-Cruz, P; Fuente, Eduardo de la; Rosado, Margarita; Arias, Lorena; Throop, Patricia Ambrocio-Cruz & Henry B.

    2002-01-01

    In this paper, we present a briefly overview of the protoplanetary disks in the Orion Nebula, incluiding some astrobiological aspects and an H$\\alpha$ Fabry-Perot study of 16 of them. We found that Fabry-Perot interferometry constitutes an effective technique for the detection of proplyds. We also report heliocentric systemic velocities for the proplyds 82-336, 158-323, 158-326, 159-350, 161-314, 161-324, 163-317, 166-316, 167-317, 168-326, 170-337, 176-325, 177-341, 180-331, 197-427 and 244-440. The velocities were measured between 22-38 km s$^{-1}$.

  7. Simplified Reflection Fabry-Perot Method for Determination of Electro-Optic Coefficients of Poled Polymer Thin Films

    Warren N. Herman

    2011-08-01

    Full Text Available We report a simplified reflection mode Fabry-Perot interferometry method for determination of electro-optic (EO coefficients of poled polymer thin films. Rather than fitting the detailed shape of the Fabry-Perot resonance curve, our simplification involves a technique to experimentally determine the voltage-induced shift in the angular position of the resonance minimum. Rigorous analysis based on optical properties of individual layers of the multilayer structure is not necessary in the data analysis. Although angle scans are involved, the experimental setup does not require a θ-2θ rotation stage and the simplified analysis is an advantage for polymer synthetic efforts requiring quick and reliable screening of new materials. Numerical and experimental results show that our proposed method can determine EO coefficients to within an error of ~8% if poled values for the refractive indices are used.

  8. An ultrahigh Finesse Fabry-Perot superconducting resonator as a photon box for cavity-QED experiments

    Kuhr, S; Guerlin, C; Bernu, J; Hoff, U B; Del'eglise, S; Brune, M; Raimond, J M; Haroche, S; Osnaghi, S; Jacques, E; Bosland, P; Visentin, B; Kuhr, Stefan; Guerlin, Christine; Bernu, Julien; Hoff, Ulrich Busk; Del\\'{e}glise, Samuel; Brune, Michel; Raimond, Jean-Michel; Haroche, Serge; Osnaghi, Stefano

    2006-01-01

    We have built a microwave Fabry-Perot resonator made of diamond-machined copper mirrors coated with superconducting niobium. Its damping time (Tc = 130 ms at 51 GHz and 0.8 K) corresponds to a finesse of 4.6 e9, the highest ever reached for a Fabry-Perot in any frequency range. We have tested this resonator by sending across it two circular Rydberg atoms, the first emitting a photon and the second absorbing it after a delay of 1/10 s. This long storage time photon box opens novel perspectives for quantum information. It can be used to perform sequences of hundreds of gate operations on individual atomic qubits. A set-up with one or two photon boxes can store mesoscopic fields made of hundreds of photons for decoherence and non-locality studies.

  9. Development of a New, Precise Near-infrared Doppler Wavelength Reference: A Fiber Fabry-Perot Interferometer

    Halverson, Samuel; Ramsey, Lawrence; Redman, Stephen; Nave, Gillian; Wilson, John C; Hearty, Fred; Holtzman, Jon

    2012-01-01

    We present the ongoing development of a commercially available Micron Optics fiber-Fabry Perot Interferometer as a precise, stable, easy to use, and economic spectrograph reference with the goal of achieving <1 m/s long term stability. Fiber Fabry-Perot interferometers (FFP) create interference patterns by combining light traversing different delay paths. The interference creates a rich spectrum of narrow emission lines, ideal for use as a precise Doppler reference. This fully photonic reference could easily be installed in existing NIR spectrographs, turning high resolution fiber-fed spectrographs into precise Doppler velocimeters. First light results on the Sloan Digital Sky Survey III (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectrograph and several tests of major support instruments are also presented. These instruments include a SuperK Photonics fiber supercontinuum laser source and precise temperature controller. A high resolution spectrum obtained using the NIST 2-m...

  10. Diphotons in a nonlinear Fabry-Perot resonator: Bound states of interacting photons in an optical ''quantum wire''

    We propose a high-Q Fabry-Perot resonator with cylindrical mirrors, operating near fundamental mode and filled with an alkali vapor, as the photonic analog to the electronic quantum wire. The internal photons constitute a 1D Bose gas with pairwise interactions. We solve for the two-photon bound state which determines a resonance for the two-photon transmission function. Emphasis is placed on the experimental feasibility of observing these quasiparticles

  11. An in-situ method for measuring the non-linear response of a Fabry-Perot cavity

    Bu, Wenhao; Liu, Mengke; Xie, Dizhou; Yan, Bo

    2016-01-01

    High finesse Fabry-Perot(FP) cavity is a very important frequency reference for laser stabiliza- tion, and is widely used for applications such as precision measurement, laser cooling of ions or molecules. But the non-linear response of the piezoelectric ceramic transducer (PZT) in the FP cav- ity limits the performance of the laser stabilization. Measuring and controlling such non-linearity are important. Here we report an in-situ, optical method to characterize this non-linearity by measuri...

  12. The Comparison of Environmental Effects on Michelson and Fabry-Perot Interferometers Utilized for the Displacement Measurement

    Chung-Ping Chang; Lih-Horng Shyu; Yung-Cheng Wang

    2010-01-01

    The optical structure of general commercial interferometers, e.g., the Michelson interferometers, is based on a non-common optical path. Such interferometers suffer from environmental effects because of the different phase changes induced in different optical paths and consequently the measurement precision will be significantly influenced by tiny variations of the environmental conditions. Fabry-Perot interferometers, which feature common optical paths, are insensitive to environmental distu...

  13. Response of a New Low-Coherence Fabry-Perot Sensor to Hematocrit Levels in Human Blood

    Małgorzata Jędrzejewska-Szczerska

    2014-04-01

    Full Text Available In this paper, a low-coherence Fabry-Perot sensor with a spectrally measured signal processing response to the refractive index of liquids is presented. Optical fiber sensors are potentially capable of continuous measuring hematocrit levels in blood. Low-coherence Fabry-Perot interferometric sensors offer a robust solution, where information about the measurand is encoded in the full spectrum of light reflected from the sensing interferometer. The first step in the research on such sensor is the assessment of its performance under favorable conditions, i.e., using blood samples from healthy volunteers tested in vitro. Such an experiment was conducted using a sensor comprising a superluminescent diode source, an optical spectrum analyzer working as the detection setup and a sensing Fabry-Perot interferometer providing high interference contrast. The response of this sensor was recorded for several samples and compared with the reference laboratory method. The coefficient of determination (R2 for a linear relationship between the results given by both methods was 0.978 and the difference between these results was less than 1%. The presented results suggest that further research into the performance of the sensor is merited.

  14. Design and performance modelling of a wavelength specific asymmetric Fabry-Perot modulator

    Asymmetric Fabry-Perot modulators (AFPM's) combine the nonlinear effects present in multiple quantum well (MQW) structures with the interferometric operation of a Fabry-Perot cavity, thus increasing the modulator performance over simple transmission or reflection devices. Parameters commonly used to evaluate the performance of a multiple quantum well optical modulator are: its contrast ratio, dynamic range, and insertion loss. We present the design analysis of a GaAs/AlGaAs AFPM for operation at 850 nm with respect to these performance parameters. The reflectivity of the Bragg stack forming the back mirror of the AFPM was found for different layer materials. The number of layers and the materials used, was determined to ensure a mirror with a high maximum reflectivity over a range of wavelengths. A high reflectivity back mirror minimises the insertion loss while a broad reflectivity maxima reduces the dependence of device operation on the growth quality of the stack. Computations of transition energies of the MQW showed that for device operation at 850 nm, a well width of 84.8 Angstroms (30 atomic monolayers) was required. Our calculations confirm those reported elsewhere, that show for this well width the barrier width may be reduced to approximately 50 Angstroms without superlattice coupling causing a serious degradation in the width of the excitonic peaks. The characteristics of the primary exciton peak have a large effect on the performance of the AFPM. Calculations indicated that narrow linewidths and large Stark shifts are required for an optimised contrast ratio, dynamic range and insertion loss. We demonstrate that with exciton linewidths of 3 nm and Stark shifts of 15 nm, contrast ratios of 900 are achievable. Of greater importance to the performance of the AFPM is the quality of the epitaxial growth and the accuracy of the cavity phase matching. It was found that if the thickness of the cavity deviates by only 10 monolayers either side of the optimum

  15. A Novel Technique to Measure Gain Spectrum for Fabry-Pérot Semiconductor Lasers

    2003-01-01

    A novel gain measurement technique based on the integration of the measured amplified spontaneous emission spectrum multiplying a phase function over one longitudinal mode interval is proposed for Fabry-Perot semiconductor lasers.

  16. High-quality far-infrared Fabry-Perot resonators with high-Tc superconducting reflectors

    We report on far-infrared Fabry-Perot resonators with high-Tc superconducting reflectors that have a high peak-transmissivity and a high quality factor. The resonators consist of two nearly plane-parallel MgO plates, with the adjacent surfaces coated with YBa2Cu3O7-δ (YBCO) thin films. The resonance frequencies are mainly determined by the distance between the films. The shapes of the resonator transmission curves are structured due to feedback of the resonances in the MgO plates with the main resonance occurring between the YBCO films. We present the transmissivity data for a series of the resonators with different film thicknesses (33, 53, and 63 nm). In our measurements, the first-order resonances are adjusted to frequencies between 50 and 80 cm-1. As expected, the largest peak-transmissivity (0.61) had the resonator with the thinnest films, while the highest finesse (120) was reached with the thickest films. (orig.)

  17. Application of High-Temperature Extrinsic Fabry-Perot Interferometer Strain Sensor

    Piazza, Anthony

    2008-01-01

    In this presentation to the NASA Aeronautics Sensor Working Group the application of a strain sensor is outlined. The high-temperature extrinsic Fabry-Perot interferometer (EFPI) strain sensor was developed due to a need for robust strain sensors that operate accurately and reliably beyond 1800 F. Specifically, the new strain sensor would provide data for validating finite element models and thermal-structural analyses. Sensor attachment techniques were also developed to improve methods of handling and protecting the fragile sensors during the harsh installation process. It was determined that thermal sprayed attachments are preferable even though cements are simpler to apply as cements are more prone to bond failure and are often corrosive. Previous thermal/mechanical cantilever beam testing of EFPI yielded very little change to 1200 F, with excellent correlation with SG to 550 F. Current combined thermal/mechanical loading for sensitivity testing is accomplished by a furnace/cantilever beam loading system. Dilatometer testing has can also be used in sensor characterization to evaluate bond integrity, evaluate sensitivity and accuracy and to evaluate sensor-to-sensor scatter, repeatability, hysteresis and drift. Future fiber optic testing will examine single-mode silica EFPIs in a combined thermal/mechanical load fixture on C-C and C-SiC substrates, develop a multi-mode Sapphire strain-sensor, test and evaluate high-temperature fiber Bragg Gratings for use as strain and temperature sensors and attach and evaluate a high-temperature heat flux gauge.

  18. Millimeter Wave Fabry-Perot Resonator Antenna Fed by CPW with High Gain and Broadband

    Xue-Xia Yang

    2016-01-01

    Full Text Available A novel millimeter wave coplanar waveguide (CPW fed Fabry-Perot (F-P antenna with high gain, broad bandwidth, and low profile is reported. The partially reflective surface (PRS and the ground form the F-P resonator cavity, which is filled with the same dielectric substrate. A dual rhombic slot loop on the ground acts as the primary feeding antenna, which is fed by the CPW and has broad bandwidth. In order to improve the antenna gain, metal vias are inserted surrounding the F-P cavity. A CPW-to-microstrip transition is designed to measure the performances of the antenna and extend the applications. The measured impedance bandwidth of S11 less than −10 dB is from 34 to 37.7 GHz (10.5%, and the gain is 15.4 dBi at the center frequency of 35 GHz with a 3 dB gain bandwidth of 7.1%. This performance of the antenna shows a tradeoff among gain, bandwidth, and profile.

  19. Analytical Modelling of a Refractive Index Sensor Based on an Intrinsic Micro Fabry-Perot Interferometer

    Everardo Vargas-Rodriguez

    2015-10-01

    Full Text Available In this work a refractive index sensor based on a combination of the non-dispersive sensing (NDS and the Tunable Laser Spectroscopy (TLS principles is presented. Here, in order to have one reference and one measurement channel a single-beam dual-path configuration is used for implementing the NDS principle. These channels are monitored with a couple of identical optical detectors which are correlated to calculate the overall sensor response, called here the depth of modulation. It is shown that this is useful to minimize drifting errors due to source power variations. Furthermore, a comprehensive analysis of a refractive index sensing setup, based on an intrinsic micro Fabry-Perot Interferometer (FPI is described. Here, the changes over the FPI pattern as the exit refractive index is varied are analytically modelled by using the characteristic matrix method. Additionally, our simulated results are supported by experimental measurements which are also provided. Finally it is shown that by using this principle a simple refractive index sensor with a resolution in the order of 2.15 × 10−4 RIU can be implemented by using a couple of standard and low cost photodetectors.

  20. Fabry-Perot Absorption Line Spectroscopy of the Galactic Bar. I. Kinematics

    Rangwala, Naseem; Stanek, K Z

    2008-01-01

    We use Fabry-Perot absorption line imaging spectroscopy to measure radial velocities using the Ca II 8542 line in 3360 stars towards three lines of sight in the Milky Way's bar: Baade's Window and offset position at (l,b) ~ (+-5.0, -3.5). This sample includes 2488 bar red clump giants, 339 bar M/K-giants, and 318 disk main sequence stars. We measure the first four moments of the stellar velocity distribution of the red clump giants, and find it to be symmetric and flat-topped. We also measure the line-of-sight average velocity and dispersion of the red clump giants as a function of distance in the bar. We detect stellar streams at the near and far side of the bar with velocity difference > 30 km/s at l = +-5, but we do not detect two separate streams in Baade's Window. Our M-giants kinematics agree well with previous studies, but have dispersions systematically lower than those of the red clump giants by ~ 10 km/s. For the disk main sequence stars we measure a velocity dispersion of ~ 45 km/s for all three li...

  1. All-fiber upconversion high spectral resolution wind lidar using a Fabry-Perot interferometer.

    Shangguan, Mingjia; Xia, Haiyun; Wang, Chong; Qiu, Jiawei; Shentu, Guoliang; Zhang, Qiang; Dou, Xiankang; Pan, Jian-Wei

    2016-08-22

    An all-fiber, micro-pulse and eye-safe high spectral resolution wind lidar (HSRWL) at 1.5 μm is proposed and demonstrated by using a pair of upconversion single-photon detectors and a fiber Fabry-Perot scanning interferometer (FFP-SI). In order to improve the optical detection efficiency, both the transmission spectrum and the reflection spectrum of the FFP-SI are used for spectral analyses of the aerosol backscatter and the reference laser pulse. Taking advantages of high signal-to-noise ratio of the detectors and high spectral resolution of the FFP-SI, the center frequencies and the bandwidths of spectra of the aerosol backscatter are obtained simultaneously. Continuous LOS wind observations are carried out on two days at Hefei (31.843 °N, 117.265 °E), China. The horizontal detection range of 4 km is realized with temporal resolution of 1 minute. The spatial resolution is switched from 30 m to 60 m at distance of 1.8 km. In a comparison experiment, LOS wind measurements from the HSRWL show good agreement with the results from an ultrasonic wind sensor (Vaisala windcap WMT52). An empirical method is adopted to evaluate the precision of the measurements. The standard deviation of the wind speed is 0.76 m/s at 1.8 km. The standard deviation of bandwidth variation is 2.07 MHz at 1.8 km. PMID:27557211

  2. Switchable single-polarization dual-wavelength TDFL using PM Fabry-Perot filter

    Liu, Shuo; Yan, Fengping; Liu, Peng; Zhang, Luna; Bai, Zhuoya; Yin, Bin; Zhou, Hong

    2016-05-01

    A switchable single-polarization (SP), dual-wavelength thulium-doped fiber laser using polarization maintaining (PM) Fabry-Perot (F-P) filter is proposed. A combination of the PM F-P filter, a polarization controller (PC) and a polarizer is used to ensure the SP lasing operation. A stable dual-wavelength lasing operation is obtained at 1941.82 nm and 1942.21 nm. By adjusting the PCs, the proposed laser can achieve SP single-wavelength lasing operation; the polarization extinction ratios are higher than 33 dB. When the pump power is higher than 2.98 W, the optical signal-to-noise ratios of the SP single-wavelength operation can reach 60 dB, and the output power variations are less than 0.32 dB (X-polarization) and 0.30 dB (Y-polarization). The slope efficiencies of SP lasing operation are 6.26% (X-polarization) and 8.79% (Y-polarization), respectively.

  3. Low-profile Circularly Polarized Antenna Exploiting Fabry-Perot Resonator Principle

    K. Pitra

    2015-12-01

    Full Text Available We designed a patch antenna surrounded by a mushroom-like electromagnetic band-gap (EBG structure and completed it by a partially reflective surface (PRS. EBG suppresses surface waves and creates the bottom wall of the Fabry-Perot (FP resonator. PRS plays the role of a planar lens and forms the top wall of the FP resonator. The novel PRS consists of a two-layer grid exhibiting inductive and capacitive (LC behavior which allows us to obtain a reflection phase between –108 and +180 degrees. Thanks to this PRS, we can control the height of the cavity in the range from lambda/2 to lambda/300. Obtained results show that the FP resonator antenna enables us to achieve a low profile and a high-gain. The patch is excited by a microstrip transmission line via the cross-slot aperture generating the circular polarization. Functionality of the described concept of the FP antenna was verified at 10 GHz. The antenna gain was 15 dBi, the impedance bandwidth 2.3% for |S11| less than –10 dB, and the axial ratio bandwidth 0.6% for AR less than 3.0 dB. Hence, the antenna is suitable for narrowband applications. Computer simulations show that the microwave FP antenna can be simply redesigned to serve as a source of circularly polarized terahertz waves.

  4. Evaluation of Fabry-Perot polymer film sensors made using hard dielectric mirror deposition

    Buchmann, Jens; Zhang, Edward; Scharfenorth, Chris; Spannekrebs, Bastian; Villringer, Claus; Laufer, Jan

    2016-03-01

    Fabry-Perot (FP) polymer film sensors offer high acoustic sensitivity, small element sizes, broadband frequency response and optical transmission to enable high resolution, backward mode photoacoustic (PA) imaging. Typical approaches to sensor fabrication involve the deposition of stacks of alternating dielectric materials to form interferometer mirrors, which are separated by a polymer spacer. If hygroscopic soft dielectric materials are used, a protective polymer layer is typically required. In this study, methods for the deposition of water-resistant, hard dielectric materials onto polymers were explored to improve the robustness and performance of the sensors. This involved the optimisation of the fabrication process, the optical and acoustic characterisation of the sensors, and a comparison of the frequency response with the output of an acoustic forward model. The mirrors, which were separated by a 20 μm Parylene spacer, consisted of eight double layers of Ta2O5 and SiO2 deposited onto polymer substrates using temperature-optimised electron vapour deposition. The free spectral range of the interferometer was 32 nm, its finesse FR = 91, and its visibility V = 0.72. The noise-equivalent pressure was 0.3 kPa (20 MHz bandwidth). The measured frequency response was found to be more resonant at 25 MHz compared to sensors with soft dielectric mirrors, which was also in good agreement with the output of a forward model of the sensor. The sensors were used in a PA scanner to acquire 3-D images in tissue phantoms.

  5. Hot-wire sandwiched Fabry-Perot interferometer for microfluidic flow rate sensing

    Li, Ying; Yan, Guofeng; Zhang, Liang; He, Sailing

    2015-08-01

    We present a Fabry-Perot interferometer for microfluidic flow rate sensing. The FPI was composed by a pair of fiber Bragg grating reflectors and a micro Co2+-doped optical fiber cavity, acting as a "hot-wire" sensor. A microfluidic channel made from commercial silica capillary was integrated with the FPIs on a chip to realize flow-rate sensing system. By utilizing a tunable pump laser with wavelength of 1480 nm, the proposed flowmeter was experimentally demonstrated. The flow rate of the liquid sample is determined by the induced resonance wavelength shift of the FPI. The effect of the pump power on the performance of our flowmeter was investigated. The dynamic response was also measured under different flow-rate conditions. The experimental results achieve a sensitivity of 70 pm/(μL/s), a dynamic range up to 1.1 μL/s and response time in the level of seconds. Such good performance renders the sensor a promising supplementary component in microfluidic biochemical sensing system.

  6. Demodulation of a fiber Fabry-Perot strain rosette using white light interferometry

    Zuliani, Gary Louis

    Fiber optic sensors are starting to be used in specialty application areas where electrical sensors are usually found, such as in aircraft and spacecraft. Fiber optic sensor technology has advantages over its electronic counterparts including small size and weight, immunity to electromagnetic interference, and ruggedness. The use of fiber interferometers as sensors is reviewed along with methods for demodulating their signals. The principles of path-matched differential interferometry and coherence multiplexing are demonstrated and applied to the design and construction of a system that simultaneously demodulates three fiber Fabry-Perot (FFP) interferometers. The FFP's formed the arms of a delta rosette which were bonded to the surface of an aluminum cantilevered beam and were illuminated with one broadband light source. The receiving interferometer consisted of a bulk Michelson interferometer with three distinct optical paths. A charge coupled device array was used as the detector allowing fringe shifts to be counted on a television monitor. Tensor measurements were made and found to be in good agreement when compared to those obtained from electrical strain gages.

  7. An optical fiber Fabry-Perot flow measurement technology based on partial bend structure

    Yang, Huijia; Jiang, Junfeng; Zhang, Xuezhi; Pan, Yuheng; Zhu, Wanshan; Zhou, Xiang; Liu, Tiegen

    2016-08-01

    An optical fiber Fabry-Perot (F-P) flow measurement technology is presented, which is based on partial bend structure. A 90° partial bend structure is designed to achieve the non-probe flow measurement with a pressure difference. The fluid simulation results of partial bend structure show that the error of the pressure difference is below 0.05 kPa during steady flow. The optical fiber F-P sensor mounted on the elbow with pressure test accuracy of 1% full scale is used to measure the fluid flow. Flow test results show that when the flow varies from 1 m3/h to 6.5 m3/h at ambient temperature of 25 °C, the response time is 1 s and the flow test accuracy is 4.5% of the F-P flow test system, proving that the F-P flow test method based on partial bend structure can be used in fluid flow measurement.

  8. Spectral imager based on Fabry-Perot interferometer for Aalto-1 nanosatellite

    Mannila, Rami; Näsilä, Antti; Viherkanto, Kai; Holmlund, Christer; Näkki, Ismo; Saari, Heikki

    2013-09-01

    The Aalto-1 is a 3U-cubesat project coordinated by Aalto University. The satellite, Aalto-1, will be mainly built by students as project assignments and thesis works. The Aalto-1 is planned to launch on 2014. VTT Technical Research Centre of Finland is developing the main Earth observation payload, a miniaturized spectral imager unit, for the satellite. The spectral imager unit contains a spectral imager, a visible RGB-camera and control electronics of the cameras. Detailed design of the spectral imager unit has been completed and assembly of the spectral imager unit will be done in the autumn 2013. The spectral imager is based on a tunable Fabry-Perot interferometer (FPI) accompanied by an RGB CMOS image sensor. The FPI consists of two highly reflective surfaces separated by a tunable air gap and it is based on a piezo-actuated structure. The piezo-actuated FPI uses three piezo-actuators and is controlled in a closed capacitive feedback loop. The spectral resolution of the imager will be 8-15 nm at full width at half maximum and it will operate in the wavelength range 500-900 nm. Imaging resolution of the spectral imager is 1024x1024 pixels and the focal length of the optics is 32 mm and F-number is 3.4. Mass of the spectral imager unit is approximately 600 grams, and dimensions are 97 mm x 97 mm x 48 mm.

  9. Fabry-Perot interferometer based on etched side-hole fiber for microfluidic refractive index sensing

    Wu, Shengnan; Yan, Guofeng; Zhou, Bin; He, Sailing

    2015-08-01

    In this paper, we present a novel fiber-optic open-cavity Fabry-Perot interferometer (FPI), which is specially designed for microfluidic refractive index (RI) sensing. An etching Side-hole fiber (SHF) was sandwiched between in two single-mode-fibers (SMF) and then a cavity was opened up by chemical etching method in the SHF. The minute order of the etching process endow such FPIs with low cost and ease of fabrication. For further microfluidic sensing test, the FPI was integrated with a cross microfluidic slit that was fabricated through photolithography. The refractive index response of the FPI was characterized using sodium hydroxide solution with RI range from 1.3400 to 1.3470. Experimental results show that FPIs with different length of open-cavity have the similar liner RI response with different RI sensitivities. The optimal RI sensitivity of more than 1138 nm/RI can be achieved with open-cavity length of 56 μm. The temperature response was also investigated, which shows that FPIs exhibit a very low temperature cross-sensitivities of 4.00 pm/ °C and 1.95 pm/ °C corresponding FPIs with cavity length of 123 μm and 56 μm, respectively. Such good performance renders the FPI a promising in-line microfluidic sensor for temperature-insensitive RI sensing.

  10. Use of a Fabry Perot Interferometer to Isolate Pure Rotational Raman Spectra of Diatomic Molecules

    Arshinov, Yuri; Bobrovnikov, Sergey

    1999-07-01

    We propose to use a Fabry Perot interferometer (FPI) as a comb frequency filter to isolate pure rotational Raman spectra (PRRS) of nitrogen molecules. In making the FPI s free spectral range equal to the spectral spacing between the lines of nitrogen PRRS, which are practically equidistant, one obtains a device with a comb transmission function with the same period. However, to match the FPI transmission comb completely with the comb of nitrogen PRRS lines one should tune the wavelength of the radiation used to excite the PRRS of nitrogen exactly to the position of any minimum in the FPI transmission comb. Thus to achieve this task for the case of nitrogen PRRS one must take the FPI s free spectral range f 4 B N 2 and the wavelength of the exciting radiation such that (1 exc ) 4 B N 2 ( k 1 2 ), where B N 2 is the rotational constant of the nitrogen molecule and k is an arbitrary integer number. In this case all (odd and even) pure rotational Raman lines of nitrogen will pass through the FPI while the line of exciting radiation is being suppressed. Additionally, a FPI cuts out the spectrally continuous sky background light from the spectral gaps between the PRRS lines.

  11. A novel fiber optic Fabry-Perot structure with a micrometric diameter tip

    Wang, Xingwei; Xu, Juncheng; Wang, Zhuang; Cooper, Kristie L.; Wang, Anbo

    2006-08-01

    This paper presents a novel fiber optic Fabry-Perot (FP) structure with a micrometric diameter tip. The fabrication of micro scale probes has become essential in intracellular surgery, in cell sensing, manipulation, and injection. It is of great importance in many fields, such as genetics, pathology, criminology, pharmacogenetics, and food safety. With such a tiny protrusion, the sensor can be inserted into micron size cells, say, for DNA analysis. With the FP cavity inside the fiber, the change of optical path difference (OPD) caused by the environment can be demodulated. In addition, the structure is intrinsically capable of temperature compensation. What's more, it is simple, cost-efficient, and compact. Last but not the least, the structure shows promise for nanometric protrusion. Once this goal is achieved, the sensor can be inserted into most cells. The sensor could pave the way for faster, more accurate medical diagnostic tests for countless conditions and may ultimately save lives by allowing earlier disease detection and intervention.

  12. CIV Vacuum Ultraviolet Fabry-Perot Interferometers for Transition-Region Magnetography

    Gary, G. Allen; West, Edward A.; Rees, David; Zukic, Maumer; Herman, Peter; Li, Jianzhao

    2006-01-01

    The vacuum ultraviolet region allows remote sensing of the upper levels of the solar atmosphere where the magnetic field dominates the physics. Obtaining an imaging interferometer that observes the transition region is the goal of this program. This paper gives a summary of our instrument development program (1998-2005) for a high-spectral-resolution, piezoelectric tunable Vacuum Ultraviolet Fabry-Perot Interferometer (VUV FPI) for obtaining narrow-passband images, magnetograms, and Dopplergrams of the transition region emission line of CN (155nm). A VUV interferometer will allow us to observe the magnetic field, flows, and heating events in the mid-transition region. The MSFC VUV FPI has measured values of FWHM approx. 9pm, FSR approx. 62pm, finesse approx. 5.3 and transmittance approx. 50% at 157nm. For the measurements, the University of Toronto's F2 eximer laser was used as an appropriate proxy for CIV 155nm. This has provided the first tunable interferometer with a FWHM compatible to VUV filter magnetograph.

  13. All-fiber upconversion high spectral resolution wind lidar using a Fabry-Perot interferometer

    Shangguan, Mingjia; Wang, Chong; Qiu, Jiawei; Shentu, Guoliang; Zhang, Qiang; Dou, Xiankang; Pan, Jian-wei

    2016-01-01

    An all-fiber, micro-pulse and eye-safe high spectral resolution wind lidar (HSRWL) at 1550nm is proposed and demonstrated by using a pair of upconversion single-photon detectors and a fiber Fabry-Perot scanning interferometer (FFP-SI). In order to improve the optical detection efficiency, both the transmission spectrum and the reflection spectrum of the FFP-SI are used for spectral analyses of the aerosol backscatter and the reference laser pulse. The reference signal is tapped from the outgoing laser and served as a zero velocity indicator. The Doppler shift is retrieved from a frequency response function Q, which is defined as the ratio of difference of the transmitted signal and the reflected signal to their sum. Taking advantages of high signal-to-noise ratio of the detectors and high spectral resolution of the FFP-SI, the Q spectra of the aerosol backscatter are reconstructed along the line-of-sight (LOS) of the telescope. By applying a least squares fit procedure to the measured Q spectra, the center fr...

  14. Development of a Fabry-Perot cavity for the Compton polarimetry

    A quick, precise and non-destructive longitudinal polarisation measurement should be a great advantage for the HAPPEX experiment at CEBAF (Jefferson Lab, USA). To achieve this, it could be possible to use a Fabry-Perot cavity to get a high photon flux at the electron-photon interaction point of a Compton polarimeter. This thesis is a first study for the design of such a system. We have shown that a 'monolithic' cavity, i.e. with mirrors mounted on fixed stage, is a good solution. My contribution for these studies is the development of a code to compute the optimum geometry of a cavity. Another of my contribution concerns the test of a cavity based on commercial mirrors with a gain > 160, using the Pound-Drever method to lock the laser frequency. My studies concern optical matching between the laser beam and the cavity, the choice of the frequency of modulation for the feed-back system and the characterization of the intracavity power. This work is a first step of the studies which will lead to the integration of a cavity based system on the CEBAF beam line. (author)

  15. Underwater blast wave pressure sensor based on polymer film fiber Fabry-Perot cavity.

    Wang, Junjie; Wang, Meng; Xu, Jian; Peng, Li; Yang, Minghong; Xia, Minghe; Jiang, Desheng

    2014-10-01

    This paper describes the theoretical and experimental aspects of an optical underwater shock wave sensor based on a polymer film optical fiber Fabry-Perot cavity manufactured by vacuum deposition technology. The transduction mechanism of the sensor involves a normally incident acoustic stress wave that changes the thickness of the polymer film, thereby giving rise to a phase shift. This transient interferometric phase is interrogated by a three-phase-step algorithm. Theoretically, the sensor-acoustic-field interaction principle is analyzed, and the phase modulation sensitivity based on the theory of waves in the layered media is calculated. Experimentally, a static calibration test and a dynamic calibration test are conducted using a piston-type pressure calibration machine and a focusing-type electromagnetic shock wave. Results indicate that the repeatability, hysteresis, nonlinearity, and the overall measurement accuracy of the sensor within the full pressure range of 55 MPa are 1.82%, 0.86%, 1.81%, and 4.49%, respectively. The dynamic response time is less than 0.767 μs. Finally, three aspects that need further study for practical use are pointed out. PMID:25322237

  16. Performance Evaluation of Fabry-Perot Temperature Sensors in Nuclear Power Plant Measurements

    The Fiso Fabry-Perot fiber-optic temperature sensor was selected for performance evaluation and for potential application in nuclear power plants because of its unique interferometric sensing mechanism and data-processing technique, and its commercial availability. It employs a Fizeau interferometer and a charge-coupled device array to locate the position of the maximum interference fringe intensity, which is directly related to the environmental temperature. Consequently, the basic sensing mechanism is independent of the absolute transmitted light intensity, which is the most likely parameter to be affected by external harsh environments such as nuclear irradiation, high pressure/temperature, and cyclical vibration.This paper reports research on the performance of two Fiso Fabry-Perot temperature sensors in environmental conditions expected in nuclear power plants during both normal and abnormal (i.e., accident) conditions. The environmental conditions simulated in this paper include gamma-only (60Co) irradiation, pressure/temperature environmental transient, and mixed neutron/gamma field, respectively.The first sensor exhibited no failure or degradation in performance during and following gamma-only irradiation in which a total dose of 15 kGy was delivered at a dose rate of 2.5 kGy/h. Following gamma irradiation, this sensor was then tested for 10.75 days in a thermohydraulic environment prescribed by the Institute of Electrical and Electronics Engineers IEEE323-1983. Intermittent behavior was observed throughout the latter portions of this test, and degradation in performance occurred after the test. Visual evaluation after opening the sensor head indicated that the internal welding methodology was the primary contributor to the observed behavior during this test. Further consultation with the vendor shows that the robustness and reliability of Fiso sensors can be substantially improved by modifying the internal welding methods.The second Fiso temperature sensor

  17. Daytime operation of a pure rotational Raman lidar by use of a Fabry-Perot interferometer

    We propose to use a Fabry-Perot interferometer (FPI) in a pure rotational Raman lidar to isolate return signals that are due to pure rotational Raman scattering from atmospheric nitrogen against the sky background. The main idea of this instrumental approach is that a FPI is applied as a frequency comb filter with the transmission peaks accurately matched to a comb of practically equidistant lines of a pure rotational Raman spectrum (PRRS) of nitrogen molecules. Thus a matched FPI transmission comb cuts out the spectrally continuous sky background light from the spectral gaps between the PRRS lines of nitrogen molecules while it is transparent to light within narrow spectral intervals about these lines. As the width of the spectral gaps between the lines of the PRRS of nitrogen molecules is ∼114 times the width of an individual spectral line, cutting out of the sky background from these gaps drastically improves the signal-to-background ratio of the pure rotational Raman lidar returns. This application of the FPI enables one to achieve daytime temperature profiling in the atmosphere with a pure rotational Raman lidar in the visible and near-UV spectral regions. We present an analysis of application of the FPI to filtering out the pure rotational Raman lidar returns against the solar background. To demonstrate the feasibility of the approach proposed, we present temperature profiles acquired during a whole-day measurement session in which a Raman lidar equipped with a FPI was used. For comparison, temperature profiles acquired with Vaisala radiosondes launched from the measurement site are also presented

  18. Deep Fabry-Perot Hα observations of two Sculptor group galaxies, NGC 247 and 300

    Hlavacek-Larrondo, J.; Marcelin, M.; Epinat, B.; Carignan, C.; de Denus-Baillargeon, M.-M.; Daigle, O.; Hernandez, O.

    2011-09-01

    It has been suggested that diffuse ionized gas can extend all the way to the end of the H I disc, and even beyond, such as in the case of the warped galaxyNGC 253 (Bland-Hawthorn et al.). Detecting ionized gas at these radii could carry significant implications as to the distribution of dark matter in galaxies. With the aim of detecting this gas, we carried out a deep Hα kinematical analysis of two Sculptor group galaxies, NGC 247 and 300. The Fabry-Perot data were taken at the 36-cm Marseille Telescope in La Silla, Chile, offering a large field of view. With almost 20 hours of observations for each galaxy, very faint diffuse emission is detected. Typical emission measures of 0.1 cm-6 pc are reached. For NGC 247, emission extending up to a radius comparable with that of the H I disc (r˜ 13 arcmin) is found, but no emission is seen beyond the H I disc. For NGC 300, we detect ionized gas on the entirety of our field of view (rmax˜ 14 arcmin), and find that the bright H II regions are embedded in a diffuse background. Using the deep data, extended optical rotation curves are obtained, as well as mass models. These are the most extended optical rotation curves thus far for these galaxies. We find no evidence suggesting that NGC 247 has a warped disc, and to account for our non-detection of Hα emission beyond its H I disc, as opposed to the warped galaxy NGC 253, our results favour the model in which, only through a warp, ionization by hot young stars in the central region of a galaxy can let photons escape and ionize the interstellar medium in the outer parts.

  19. Large-aperture MOEMS Fabry-Perot interferometer for miniaturized spectral imagers

    Rissanen, Anna; Langner, Andreas; Viherkanto, Kai; Mannila, Rami

    2015-02-01

    VTT's optical MEMS Fabry-Perot interferometers (FPIs) are tunable optical filters, which enable miniaturization of spectral imagers into small, mass producible hand-held sensors with versatile optical measurement capabilities. FPI technology has also created a basis for various hyperspectral imaging instruments, ranging from nanosatellites, environmental sensing and precision agriculture with UAVs to instruments for skin cancer detection. Until now, these application demonstrations have been mostly realized with piezo-actuated FPIs fabricated by non-monolithical assembly method, suitable for achieving very large optical apertures and with capacity to small-to-medium volumes; however large-volume production of MEMS manufacturing supports the potential for emerging spectral imaging applications also in large-volume applications, such as in consumer/mobile products. Previously reported optical apertures of MEMS FPIs in the visible range have been up to 2 mm in size; this paper presents the design, successful fabrication and characterization of MEMS FPIs for central wavelengths of λ = 500 nm and λ = 650 nm with optical apertures up to 4 mm in diameter. The mirror membranes of the FPI structures consist of ALD (atomic layer deposited) TiO2-Al2O3 λ/4- thin film Bragg reflectors, with the air gap formed by sacrificial polymer etching in O2 plasma. The entire fabrication process is conducted below 150 °C, which makes it possible to monolithically integrate the filter structures on other ICdevices such as detectors. The realized MEMS devices are aimed for nanosatellite space application as breadboard hyperspectral imager demonstrators.

  20. Short-wave infrared (SWIR) spectral imager based on Fabry-Perot interferometer for remote sensing

    Mannila, Rami; Holmlund, Christer; Ojanen, Harri J.; Näsilä, Antti; Saari, Heikki

    2014-10-01

    VTT Technical Research Centre of Finland has developed a spectral imager for short-wave infrared (SWIR) wavelength range. The spectral imager is based on a tunable Fabry-Perot interferometer (FPI) accompanied by a commercial InGaAs Camera. The FPI consists of two dielectric coated mirrors separated by a tunable air gap. Tuning of the air gap tunes also transmitted wavelength and therefore FPI acts as a tunable band bass filter. The FPI is piezo-actuated and it uses three piezo-actuators in a closed capacitive feedback loop for air gap tuning. The FPI has multiple order transmission bands, which limit free spectral range. Therefore spectral imager contains two FPI in a stack, to make possible to cover spectral range of 1000 - 1700 nm. However, in the first tests imager was used with one FPI and spectral range was limited to 1100-1600 nm. The spectral resolution of the imager is approximately 15 nm (FWHM). Field of view (FOV) across the flight direction is 30 deg. Imaging resolution of the spectral imager is 256 x 320 pixels. The focal length of the optics is 12 mm and F-number is 3.2. This imager was tested in summer 2014 in an unmanned aerial vehicle (UAV) and therefore a size and a mass of the imager were critical. Total mass of the imager is approximately 1200 grams. In test campaign the spectral imager will be used for forest and agricultural imaging. In future, because results of the UAV test flights are promising, this technology can be applied to satellite applications also.

  1. Daytime operation of a pure rotational Raman lidar by use of a Fabry-Perot interferometer

    Arshinov, Yuri; Bobrovnikov, Sergey; Serikov, Ilya; Ansmann, Albert; Wandinger, Ulla; Althausen, Dietrich; Mattis, Ina; Müller, Detlef

    2005-06-01

    We propose to use a Fabry-Perot interferometer (FPI) in a pure rotational Raman lidar to isolate return signals that are due to pure rotational Raman scattering from atmospheric nitrogen against the sky background. The main idea of this instrumental approach is that a FPI is applied as a frequency comb filter with the transmission peaks accurately matched to a comb of practically equidistant lines of a pure rotational Raman spectrum (PRRS) of nitrogen molecules. Thus a matched FPI transmission comb cuts out the spectrally continuous sky background light from the spectral gaps between the PRRS lines of nitrogen molecules while it is transparent to light within narrow spectral intervals about these lines. As the width of the spectral gaps between the lines of the PRRS of nitrogen molecules is ~114 times the width of an individual spectral line, cutting out of the sky background from these gaps drastically improves the signal-to-background ratio of the pure rotational Raman lidar returns. This application of the FPI enables one to achieve daytime temperature profiling in the atmosphere with a pure rotational Raman lidar in the visible and near-UV spectral regions. We present an analysis of application of the FPI to filtering out the pure rotational Raman lidar returns against the solar background. To demonstrate the feasibility of the approach proposed, we present temperature profiles acquired during a whole-day measurement session in which a Raman lidar equipped with a FPI was used. For comparison, temperature profiles acquired with Vaisala radiosondes launched from the measurement site are also presented.

  2. Locking IR and UV diode lasers to a visible laser using a LabVIEW PID controller on a Fabry-Perot signal

    Kwolek, J M; Goodman, D S; Smith, W W

    2015-01-01

    Simultaneous laser locking of IR and UV lasers to a visible reference laser is demonstrated via a Fabry-Perot cavity. LabVIEW is used to analyze the input and an internal PID algorithm converts the Fabry-Perot signal to an analog locking feedback signal. The locking program stabilized both lasers to a long term stability of less than 12 MHz, with the lab-built IR laser undergoing signi?cant improvement in frequency stabilization. The results of this study demonstrate the viability of a simple computer-controlled, non temperature-stabilized Fabry-Perot locking scheme for our applications, laser cooling of Ca+ ions, and its use in other applications with similar modest frequency stabilization requirements.

  3. Optical fiber Fabry-Perot interferometer cavity fabricated by femtosecond laser micromachining and fusion splicing for refractive index sensing.

    Liao, C R; Hu, T Y; Wang, D N

    2012-09-24

    We demonstrate a fiber in-line Fabry-Perot interferometer cavity sensor for refractive index measurement. The interferometer cavity is formed by drilling a micro-hole at the cleaved fiber end facet, followed by fusion splicing. A micro-channel is inscribed by femtosecond laser micromachining to vertically cross the cavity to allow liquid to flow in. The refractive index sensitivity obtained is ~994 nm/RIU (refractive index unit). Such a device is simple in configuration, easy for fabrication and reliable in operation due to extremely low temperature cross sensitivity of ~4.8 × 10(-6) RIU/°C. PMID:23037431

  4. Q-switching of a high-power solid-state laser by a fast scanning Fabry-Perot interferometer

    An investigation was made of the suitability of a Q-switch, based on a piezoelectrically scanned short-base Fabry-Perot interferometer, for an Nd3+:YAG laser with an average output radiation power up to 2 kW. The proposed switch made it possible to generate of giant pulses of 60 - 300 ns duration at a repetition rate of 20 - 100 kHz. Throughout the investigated range of the pulse repetition rates the average power was at least equal to that obtained by cw lasing. Special requirements to be satisfied by the interferometer, essential for efficient Q-switching, were considered. (control of laser radiation parameters)

  5. Monitor of mirror distance of Fabry-Perot cavity by the use of stabilized femtosecond laser comb

    Šmíd, Radek; Ježek, Jan; Buchta, Zdeněk; Čížek, Martin; Mikel, Břetislav; Lazar, Josef; Číp, Ondřej

    Žilina: Žilinská univerzita, 2010. s. 104. ISBN 978-80-554-0238-3. [Slovak-Czech-Polish Optical Conference on Wave and Quantum Aspects of Contemporary Optics /17./. 06.09.2010, Liptovsky Jan] R&D Projects: GA MPO 2A-1TP1/127; GA ČR GAP102/10/1813; GA MŠk(CZ) LC06007 Institutional research plan: CEZ:AV0Z20650511 Keywords : length standard * femtosecond laser * stabilization * Fabry-Perot cavity Subject RIV: BH - Optics, Masers, Lasers

  6. Monitor of mirror distance of Fabry-Perot cavity by the use of stabilized femtosecond laser comb

    Šmíd, Radek; Ježek, Jan; Buchta, Zdeněk; Čížek, Martin; Mikel, Břetislav; Lazar, Josef; Číp, Ondřej

    Bellingham: SPIE, 2010, 77460I: 1-8. ISBN 978-0-8194-8236-5. [Slovak-Czech-Polish Optical Conference on Wave and Quantum Aspects of Contemporary Optics /17./. Liptovsky Jan (SK), 06.09.2010] R&D Projects: GA MŠk(CZ) LC06007; GA MPO 2A-1TP1/127; GA ČR GAP102/10/1813 Institutional research plan: CEZ:AV0Z20650511 Keywords : length standard * femtosecond laser * stabilization * Fabry-Perot cavity Subject RIV: BH - Optics, Masers, Lasers

  7. A tunable electrochromic fabry-perot filter for adaptive optics applications.

    Blaich, Jonathan David; Kammler, Daniel R.; Ambrosini, Andrea; Sweatt, William C.; Verley, Jason C.; Heller, Edwin J.; Yelton, William Graham

    2006-10-01

    The potential for electrochromic (EC) materials to be incorporated into a Fabry-Perot (FP) filter to allow modest amounts of tuning was evaluated by both experimental methods and modeling. A combination of chemical vapor deposition (CVD), physical vapor deposition (PVD), and electrochemical methods was used to produce an ECFP film stack consisting of an EC WO{sub 3}/Ta{sub 2}O{sub 5}/NiO{sub x}H{sub y} film stack (with indium-tin-oxide electrodes) sandwiched between two Si{sub 3}N{sub 4}/SiO{sub 2} dielectric reflector stacks. A process to produce a NiO{sub x}H{sub y} charge storage layer that freed the EC stack from dependence on atmospheric humidity and allowed construction of this complex EC-FP stack was developed. The refractive index (n) and extinction coefficient (k) for each layer in the EC-FP film stack was measured between 300 and 1700 nm. A prototype EC-FP filter was produced that had a transmission at 500 nm of 36%, and a FWHM of 10 nm. A general modeling approach that takes into account the desired pass band location, pass band width, required transmission and EC optical constants in order to estimate the maximum tuning from an EC-FP filter was developed. Modeling shows that minor thickness changes in the prototype stack developed in this project should yield a filter with a transmission at 600 nm of 33% and a FWHM of 9.6 nm, which could be tuned to 598 nm with a FWHM of 12.1 nm and a transmission of 16%. Additional modeling shows that if the EC WO{sub 3} absorption centers were optimized, then a shift from 600 nm to 598 nm could be made with a FWHM of 11.3 nm and a transmission of 20%. If (at 600 nm) the FWHM is decreased to 1 nm and transmission maintained at a reasonable level (e.g. 30%), only fractions of a nm of tuning would be possible with the film stack considered in this study. These tradeoffs may improve at other wavelengths or with EC materials different than those considered here. Finally, based on our limited investigation and material set

  8. All-fiber upconversion high spectral resolution wind lidar using a Fabry-Perot interferometer

    Shangguan, Mingjia; Xia, Haiyun; Wang, Chong; Qiu, Jiawei; Shentu, Guoliang; Zhang, Qiang; Dou, Xiankang; Pan, Jian-wei

    2016-08-01

    An all-fiber, micro-pulse and eye-safe high spectral resolution wind lidar (HSRWL) at 1550nm is proposed and demonstrated by using a pair of upconversion single-photon detectors and a fiber Fabry-Perot scanning interferometer (FFP-SI). In order to improve the optical detection efficiency, both the transmission spectrum and the reflection spectrum of the FFP-SI are used for spectral analyses of the aerosol backscatter and the reference laser pulse. The reference signal is tapped from the outgoing laser and served as a zero velocity indicator. The Doppler shift is retrieved from a frequency response function Q, which is defined as the ratio of difference of the transmitted signal and the reflected signal to their sum. Taking advantages of high signal-to-noise ratio of the detectors and high spectral resolution of the FFP-SI, the Q spectra of the aerosol backscatter are reconstructed along the line-of-sight (LOS) of the telescope. By applying a least squares fit procedure to the measured Q spectra, the center frequencies and the bandwidths are obtained simultaneously. And then the Doppler shifts are determined relative to the center frequency of the reference signal. To eliminate the influence of temperature fluctuations on the FFP-SI, the FFP-SI is cased in a chamber with temperature stability of 0.001 during the measurement. Continuous LOS wind observations are carried out on two days at Hefei (31.843 N, 117.265 E), China. In the meantime, LOS wind measurements from the HSRWL show good agreement with the results from an ultrasonic wind sensor (Vaisala windcap WMT52). Due to the computational expensive of the convolution operation of the Q function, an empirical method is adopted to evaluate the quality of the measurements. The standard deviation of the wind speed is 0.76 m/s at the 1.8 km. The standard deviation of the retrieved bandwidth variation is 2.07 MHz at the 1.8 km.

  9. Parameter design of signal processing for transmission/reflection-type hybrid extrinsic Fabry Perot interferometric optical fiber sensors

    Kim, Sang-Hoon; Lee, Jung-Ju

    2005-02-01

    A transmission/reflection-type hybrid extrinsic Fabry-Perot interferometric (TRHEFPI) optical fiber sensor presents transmission-type and reflection-type sensor signals simultaneously, and measurement directions can be robustly distinguished with the phase lead or lag of the linear combination signal from the original sensor signal. This sensor principle compensates for the ambiguous distinction of the measurement directions and direction changes of conventional interferometric optical fiber sensors, including extrinsic Fabry-Perot interferometric optical fiber sensors, due to the exclusive use of fringe counting in signal processing. Designing a sensor coefficient in the linear combination signal is one of the most important works in signal processing for the TRHEFPI optical fiber sensor because the magnitude of the phase shifts depends on the sensor coefficient. A design method of the sensor coefficient is presented in this research. The method was verified with experimental sensor signals and applied to strain measurement experiments. A method of absolute measurement using the TRHEFPI optical fiber sensor is also presented.

  10. Frequency stabilization based on high finesse glass-ceramic Fabry-Perot cavity for a 632.8-nm He-Ne laser

    Fu, Tingting; Yang, Kaiyong; Tan, Zhongqi; Luo, Zhifu; Wu, Suyong

    2014-12-01

    A frequency stabilization technique for a 632.8nm He-Ne laser with a high finesse Fabry-Perot cavity is introduced in this paper. The resonant frequency of the cavity is taken as the frequency standard .In this system the Fabry-Perot cavity is composed of a glass-ceramic spacer, with thermal expansion coefficient smaller than 2×10-8/°C , which means an excellent thermal stabilization which greatly decreases the thermal impacts on the cavity length in the desired constant-temperature environment.The intra-cavity spherical mirror is specially designed, which makes the Fabry-cavity a sensor element in our subsequent experiments for a new practical optical accelerometer .Both cavity mirrors were custom made in our laboratory which have reflectivities greater than 99.995% at 632.8nm, so the Fabry-Perot cavity has a finesse of about 62830. The half-maximum transmission line width is about 55.48 KHz and the free spectral range is 3.5GHz .In the experimental setup, we adopt the frequency stabilization circuit with small dithering .With proper dithering voltage, the laser can be precisely locked to the Fabry-Perot cavity minimum reflection point. Theoretically the frequency stability can reach 10-10 order.

  11. Fabry-perot kinematics of hh 202-204 in the orion nebula: are they part of a big bipolar outflow?

    M. Rosado

    2002-01-01

    Full Text Available Se presenta un estudio cinem atico de los objetos HH 202, 203 y 204 usando mapas de velocidad Fabry-Perot en H y [N II]. En el caso de HH 202 se encuentran nebulosidades que podr an estar asociadas a este objeto o bien, dada sus altas velocidades (superiores a 100 km s

  12. Semiconductor Lasers and Their Application in Optical Fiber Communication.

    Agrawal, Govind P.

    1985-01-01

    Working principles and operating characteristics of the extremely compact and highly efficient semiconductor lasers are explained. Topics include: the p-n junction; Fabry-Perot cavity; heterostructure semiconductor lasers; materials; emission characteristics; and single-frequency semiconductor lasers. Applications for semiconductor lasers include…

  13. Large field enhancement obtained by combining Fabry-Perot resonance and Rayleigh anomaly in photonic crystal slabs

    Dossou, Kokou B

    2016-01-01

    By applying the properties of Fabry-Perot resonance and Rayleigh anomaly, we have showed that a photonic crystal slab can scatter the light from an incident plane wave into a diffracted light with a very large reflection or transmission coefficient. The enhanced field is either a propagating diffraction order (with a grazing angle of diffraction) or a weakly evanescent order, so it can be particularly useful for applications requiring an enhanced propagating field (or an enhanced field with a low attenuation). An efficient effective medium technique is developed for the design of the resonant photonic crystal slabs. Numerical simulations have shown that photonic crystal slabs with low index contrast, such as the ones found in the cell wall of diatoms, can enhance the intensity of the incident light by four orders of magnitude.

  14. Theoretical and experimental investigation of the mode-spacing of fiber Bragg grating Fabry-Perot cavity

    Wenhua Ren; Peilin Tao; Zhongwei Tan; Yan Liu; Shuisheng Jian

    2009-01-01

    The mode-spacing of the fiber Bragg grating Fabry-Perot(FBG F-P)cavity is calculated by using the effective cavity length which contains the effective length of the FBG.The expression of the effective length,defined by using the phase-time delay,is obtained and simplified as a function of the peak reflectivity at the Bragg wavelength,the band edges,and the first zero-reflectivity wavelength.The effective length is discussed from the energy penetration depth point of view.Three FBG F-P cavities are fabricated in order to validate the effective length approach.The experimental data fits well with the theoretical predictions.The limitation of this method is also pointed out and the improved approach is proposed.

  15. An ultra-low detection-limit optofluidic biosensor based on all glass Fabry-Perot cavity.

    Wu, Haibo; Huang, Hui; Bai, Min; Liu, Pengbo; Chao, Ming; Hu, Jie; Hao, Jian; Cao, Tun

    2014-12-29

    An all glass optofludic biosensor with high quality-factor Fabry-Perot cavity (FPC) channel was reported. The all glass sandwich structure can completely eliminate the etching roughness of the channel surface, and can extend the operating wavelength to visible and ultraviolet regions compared with that of Si-based sensor. The quality-factor of the FPC channel is 875, and the system noise can be reduced to 1.2 nV by combining optical differential detection with phase lock-in detection. A detection limit of 15ng/mL for glucose solution, which corresponds to a refractive index unit of 2.0 × 10-9, was experimentally demonstrated. The all glass FPC sensor features low cost and robust compared with surface-plasmon-resonance sensor and ring-resonator sensor. PMID:25607165

  16. Comparative assessment of the sensitivity of localized surface plasmon resonance transducers and interference-based Fabry-Perot transducers

    Localized surface plasmon resonance (LSPR) transducers have been widely investigated for use in sensing applications. An alternative approach based on interference from thin films (Fabry-Perot interferometers) has been previously advanced, offering a rather high sensitivity. Both methods involve easily produced substrates and simple optical setups. Here, the sensitivity offered by typical transducers of the two kinds in a usual sensing scenario is compared quantitatively, using experimental and simulated data, and their respective advantages are discussed. To facilitate the comparison a simple sensitivity parameter is proposed. It is concluded that LSPR transducers offer superior sensitivity for analytes and recognition interfaces of small dimensions (up to several nanometers), especially in a wet environment, while the interference transducers become advantageous for thicker layers in dry conditions. For LSPR transducers, significantly higher sensitivity is obtained by using reflection, rather than transmission, measurements. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. An in-situ method for measuring the non-linear response of a Fabry-Perot cavity

    Bu, Wenhao; Xie, Dizhou; Yan, Bo

    2016-01-01

    High finesse Fabry-Perot(FP) cavity is a very important frequency reference for laser stabiliza- tion, and is widely used for applications such as precision measurement, laser cooling of ions or molecules. But the non-linear response of the piezoelectric ceramic transducer (PZT) in the FP cav- ity limits the performance of the laser stabilization. Measuring and controlling such non-linearity are important. Here we report an in-situ, optical method to characterize this non-linearity by measuring the resonance signals of a dual-frequency laser. The di?erential measurement makes it insensitive to laser and cavity drifting, and has a very high sensitivity. It can be applied for various applications with PZT, especially in an optical lab.

  18. Evaluation of lenght of the Fabry-Perot cavity with ultra-low expansion spacer with optical frequency comb

    Šmíd, Radek; Čížek, Martin; Číp, Ondřej

    Praha: Institute of Plasma Physics, 2012 - (Vít, T.; Kovačičinová, J.; Lédl, V.), s. 132-136 ISBN 978-80-87026-02-1. [Optics and Measurement 2012. Liberec (CZ), 16.10.2012-18.10.2012] R&D Projects: GA ČR(CZ) GPP102/12/P962; GA MŠk ED0017/01/01; GA ČR GAP102/10/1813; GA ČR GPP102/11/P819 Institutional support: RVO:68081731 Keywords : Fabry-Perot cavity * ultra-low expansion * coeffiecient of thermal expansion * optical frequency comb Subject RIV: BH - Optics, Masers, Lasers

  19. Optical fiber Fabry-Perot interferometer with pH sensitive hydrogel film for hazardous gases sensing

    Zheng, Yangzi; Chen, Li Han; Chan, Chi Chiu; Dong, Xinyong; Yang, Jingyi; Tou, Zhi Qiang; So, Ping Lam

    2015-09-01

    An optical fiber Fabry-Perot interferometer (FPI) coated with polyvinyl alcohol/poly-acrylic acid (PVA/PAA) hydrogel film for toxic gases measurement has been developed. Splicing a short section of hollow core fiber between two single mode fibers forms the FPI. Dip-coated pH-sensitive PVA/PAA hydrogel film on the fiber end performs as a receptor for binding of volatile acids or ammonia, which makes the sensing film swelling or shrinking and results in the dip wavelength shift of the FPI. By demodulating the evolution of reflection spectrum for various concentrations of volatile acids, a sensitivity of 20.8 nm/ppm is achieved with uniform linearity.

  20. Differential Radiometers Using Fabry-Perot Interferometric Technique for Remote Sensing Determination of Various Atmospheric Trace Gases

    Georgieva, E. M.; Heaps, W. S.; Wilson, E. L.

    2007-01-01

    New type of remote sensing instrument based upon the Fabry-Perot inte rferometric technique has been developed at NASA's Goddard Space Flight Center. Fabry-Perot interferometry (FPI) is a well known, powerful spectroscopic technique and one of its many applications is to be use d to measure greenhouse gases and also some harmful species in the at mosphere. With this technique, absorption of particular species is me asured and related to its concentration. A solid Fabry-Perot etalon is used as a frequency filter to restrict the measurement to particular absorption bands of the gas of interest. With adjusting the thicknes s of the etalon that separation (in frequency) of the transmitted fri nges can be made equal to the almost constant separation of the gas a bsorption lines. By adjusting the temperature of the etalon, which changes the index of refi-action of its material, the transmission fring es can be brought into nearly exact correspondence with absorption li nes of the particular species. With this alignment between absorption lines and fringes, changes in the amount of a species in the atmosph ere strongly affect the amount of light transmitted by the etalon and can be related to gas concentration. The instrument that we have dev eloped detects the absorption of various atmospheric trace gases in d irect or reflected sunlight. Our instrument employing Fabry-Perot interferometer makes use of two features to achieve high sensitivity. The first is high spectral resolution enabling one to match the width of an atmospheric absorption feature by the instrumental band pass. The second is high optical throughput enabled by using multiple spectral lines simultaneously. For any species that one wishes to measure, thi s first feature is available while the use of multiple spectral features can be employed only for species with suitable spectra and freedom from interfering species in the same wavelength region. We have deve loped an instrument for use as ground based

  1. Impact of mode partition noise in free-running gain-switched Fabry-Perot laser for 2-dimensional OCDMA.

    Wang, Xu; Chan, Kam

    2004-07-26

    Free-running gain-switched Fabry-Perot laser diode is an appropriate incoherent broadband optical source for incoherent 2-dimensional optical code division multiple access. However, the mode partition noise (MPN) in the laser seriously degrades performance. We derived a bit error rate (BER) expression in the presence of MPN using the power spectra of the laser. The theory agreed with the experimental results. There was a power penalty and BER floor due to the MPN in the laser. Therefore, this scheme should be operated with a sufficiently large number of modes. At least 9 modes should be used for error-free transmission at 1 Gbit/s for the laser we investigated in this work. PMID:19483858

  2. Comparative assessment of the sensitivity of localized surface plasmon resonance transducers and interference-based Fabry-Perot transducers

    Kedem, O.; Vaskevich, A.; Rubinstein, I. [Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100 (Israel)

    2012-11-15

    Localized surface plasmon resonance (LSPR) transducers have been widely investigated for use in sensing applications. An alternative approach based on interference from thin films (Fabry-Perot interferometers) has been previously advanced, offering a rather high sensitivity. Both methods involve easily produced substrates and simple optical setups. Here, the sensitivity offered by typical transducers of the two kinds in a usual sensing scenario is compared quantitatively, using experimental and simulated data, and their respective advantages are discussed. To facilitate the comparison a simple sensitivity parameter is proposed. It is concluded that LSPR transducers offer superior sensitivity for analytes and recognition interfaces of small dimensions (up to several nanometers), especially in a wet environment, while the interference transducers become advantageous for thicker layers in dry conditions. For LSPR transducers, significantly higher sensitivity is obtained by using reflection, rather than transmission, measurements. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Amplification of the Signal Intensity of Fluorescence-Based Fiber-Optic Biosensors Using a Fabry-Perot Resonator Structure

    Meng-Chang Hsieh

    2015-02-01

    Full Text Available Fluorescent biosensors have been widely used in biomedical applications. To amplify the intensity of fluorescence signals, this study developed a novel structure for an evanescent wave fiber-optic biosensor by using a Fabry-Perot resonator structure. An excitation light was coupled into the optical fiber through a laser-drilled hole on the proximal end of the resonator. After entering the resonator, the excitation light was reflected back and forth inside the resonator, thereby amplifying the intensity of the light in the fiber. Subsequently, the light was used to excite the fluorescent molecules in the reactive region of the sensor. The experimental results showed that the biosensor signal was amplified eight-fold when the resonator reflector was formed using a 92% reflective coating. Furthermore, in a simulation, the biosensor signal could be amplified 20-fold by using a 99% reflector.

  4. Design of fiber magnetic field sensor based on fiber Bragg grating Fabry-Perot cavity ring-down spectroscopy

    Li, Qi; Chen, Haiyan

    2015-06-01

    A novel fiber magnetic sensor based on the fiber Bragg grating Fabry-Perot (FBG-FP) cavity ring-down technique with pulse laser injection is proposed and demonstrated theoretically. A general expression of the intensity of the output electric field is derived, and the effect of the external magnetic field on the ring-down time is discussed. The results show that the output light intensity and the ring-down time of the FBG-FP cavity are in the inverse proportion to the magnitude of the external magnetic field. Our results demonstrate the new concept of the fiber magnetic sensor with the FBG-FP cavity ring-down spectroscopy and the technical feasibility.

  5. A 2 by 2 wavelength tunable Fabry-Perot filter by using an electro-optic polymer film

    Xinwan Li(李新碗); Ailun Ye(叶爱伦); Jianping Chen(陈建平); Guiling Wu(吴龟灵)

    2004-01-01

    A tunable Fabry-Perot (F-P) filter by using electro-optic polymer film is proposed. The electro-optic polymer is alkoxysilane dye (ASD)/SiO2-TiO2 hybrid material, whose electro-optic coefficient γ33 is about 5 pm/V. The wavelength tuning range of 3.8 nm under 400-V DC voltage and the nonlinear characteristic with the electric field have been obtained via electro-optical properties of polymer. Both of polymer film fabrication and F-P filter design have been introduced. The tunable F-P filter is designed for the application of two-input/two-output port wavelength-selective optical switch. Also, some problems have been discussed in this letter.

  6. Coupling of a T12Ba2CaCu2O8 Thin Film Intrinsic Josephson Junction and a Fabry-Perot Resonator

    FAN Bin; WANG Zheng; YUE Hong-Wei; YAN Shao-Lin; JI Lu; HE Ming; SONG Feng-Bin; FANG Lan; ZHAO Xin-Jie

    2011-01-01

    We study the electromagnetic coupling mechanism of a T12Ba2CaCu2O8(TI-2212)thin film intrinsic Josephson junction to a hemispherical Fabry-Perot resonator. An effective model to analyze coupling mechanism is put forward. The dielectric substrate is used as a dielectric resonator antenna and the Josephson junction, and a superconducting film is used as the feed line to excite a resonance mode inside the dielectric resonator antenna.To confirm this method, two Josephson junction samples with different dimensions of substrate and shapes of superconducting film are fabricated and tested under microwave irradiations. At the same time, numerical simulations of the antenna characteristics and the field distribution of these samples are performed by numerical simulation. The different coupling intensities of the two samples with the Fabry Perot resonator fit well with the numerical simulation results. The proposed model is important for Josephson junctions used in the microwave field.

  7. Continuous-Wave Single-Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking Using Feedback from a Fiber Bragg Grating

    Duerksen, Gary L.; Krainak, Michael A.

    1998-01-01

    Single-frequency operation of uncoated Fabry-Perot laser diodes is demonstrated by phase- locking the laser oscillations through self-injection seeding with feedback from a fiber Bragg grating. By precisely tuning the laser temperature so that an axial-mode coincides with the short-wavelength band edge of the grating, the phase of the feedback is made conjugate to that of the axial mode, locking the phase of the laser oscillations to that mode.

  8. Development of a six channel Fabry-Perot interferometer for continuous measurement of electron temperature of Tokamak plasma. Application to current diffusion study

    It is shown how the properties of the electron cyclotron emission of a tokamak plasma can be used to measure the electron temperature. The design of a six channel Fabry-Perot interferometer is then described. This interferometer allows the measurement of the time evolution of the electron temperature profile of the plasma in the TFR tokamak. Using this technique interesting results have been obtained concerning the current penetration during the start up phase of a tokamak discharge

  9. Passive amplification of a fiber laser in a Fabry-Perot cavity: application to gamma-ray production by Compton backscattering

    One of the critical points of the International Linear Collider (ILC) is the polarized positrons source. Without going through further explanation on the physical process of polarized positrons production, we point out that they are produced when circularly polarized gamma rays interact with mater. Thus, the critical point is the circularly polarized gamma-ray source. A technical solution for this source is the Compton backscattering and in the end, this thesis takes place in the framework for the design of a high average power laser systems enslaved to Fabry-Perot cavities for polarized gamma-ray production by Compton backscattering. In the first part, we present this thesis context, the Compton backscattering principle and the choice for an optical architecture based on a fiber laser and a Fabry-Perot cavity. We finish by enumerating several possible applications for Compton backscattering which shows that the work presented here might benefits from technology transfer through others research fields. In the second part, we present the different fiber laser architecture studied as well as the results obtained. In the third part, we remind the operating principle of a Fabry-Perot cavity and present the one used for our experiment as well as its specificities. In the fourth part, we address the Compton backscattering experiment which enables us to present the joint utilization of a fiber laser and a Fabry-Perot cavity in a particles accelerator to generate gamma rays for the first time to our knowledge. This experiment took place in the Accelerator Test Facility (ATF). The experimental apparatus as well as the results obtained are thus presented. In the end, we summarize the results presented in this manuscript and propose different evolution possibilities for the system in a general conclusion. (author)

  10. Spectral properties of a semiconductor α-DFB laser cavity

    The experimental and theoretical investigations of spectral properties of a semiconductor α-DFB laser cavity are carried out. It is shown that in these lasers the curvature of mode gain spectra near the maximum is higher by more than two orders of magnitude than in conventional semiconductor lasers with a Fabry-Perot cavity. The distance between the adjacent axial modes of an α-DFB laser is shorter than in the case of a Fabry-Perot cavity laser of the same length, and its experimental value agrees well with the value obtained in the simple geometrical model, taking into account a zigzag propagation of radiation inside the cavity. (lasers)

  11. Fast response Fabry-Perot interferometer microfluidic refractive index fiber sensor based on concave-core photonic crystal fiber.

    Tian, Jiajun; Lu, Zejin; Quan, Mingran; Jiao, Yuzhu; Yao, Yong

    2016-09-01

    We report a fast response microfluidic Fabry-Perot (FP) interferometer refractive index (RI) fiber sensor based on a concave-core photonic crystal fiber (CPCF), which is formed by directly splicing a section CPCF with a section of single mode fiber. The CPCF is made by cleaving a section of multimode photonic crystal fiber with an axial tension. The shallow concave-core of CPCF naturally forms the FP cavity with a very short cavity length. The inherent large air holes in the cladding of CPCF are used as the open channels to let liquid sample come in and out of FP cavity. In order to shorten the liquid channel length and eliminate the harmful reflection from the outside end face of the CPCF, the CPCF is cleaved with a tilted tensile force. Due to the very small cavity capacity, the short length and the large sectional area of the microfluidic channels, the proposed sensor provides an easy-in and easy-out structure for liquids, leading to great decrement of the measuring time. The proposed sensor exhibits fast measuring speed, the measuring time is less than 359 and 23 ms for distilled water and pure ethanol, respectively. We also experimentally study and demonstrate the superior performances of the sensor in terms of high RI sensitivity, good linear response, low temperature cross-sensitivity and easy fabrication. PMID:27607621

  12. Theoretical analysis of transmission characteristics for all fiber, multi-cavity Fabry-Perot filters based on fiber Bragg gratings

    XU OU; LU ShaoHua; DONG XiaoWei; LI Bin; NING TiGang; JIAN ShuiSheng

    2008-01-01

    The characteristics of transmission spectra for the all fiber, multi-cavity FabryPerot (FP) configuration based on fiber Bragg gratings (FBG) are theoretically analyzed and modeled. The general transmission matrix function for the structure with any number of cavities is derived, and explicit expression of the power trans-mission coefficient for symmetrical two-cavity FP is presented. The general condi-tions for flat-top single resonant peak at the central wavelength in FBG stop band are derived and verified in the numerical simulation section. The transmission peaks of single-cavity and two-cavity FP structures are compared and discussed, and results show that compared to the single-cavity FP, flatness of the top and steepness at the edge of transmission peak can be improved by introducing one more cavity. The resonant transmission peak properties of two-cavity structure are investigated in detail for various values of cavity length and FBGs with different reflection characteristics, and the design guidelines for transmission-type filters are presented. The results show that the steepness of peak slope can be improved by increase of FBG reflectivities, and these kinds of filters can be used as nar-row-band single-channel selectors and multi-channel wavelength de-multiplexing by properly choosing the length of cavities and reflectivities of FBGs.

  13. Signal processing algorithm of newly developed transmission-type extrinsic Fabry-Perot interferometric optical fiber sensor

    Kim, Sang-Hoon; Lee, Jung-Ju; Kwon, Il-Bum

    2000-06-01

    The newly developed TEFPI (transmission-type extrinsic Fabry- Perot interferometric) optical fiber sensor can distinguish the direction of measurement more simply and effectively than the conventional reflection-type EFPI optical fiber sensors. The output signal of the TEFPI optical fiber sensor has the characteristics that the signal level of fringes shows a negative slope for a tensile direction and a positive slope for a compressive direction. Based on these characteristics, the direction of measurement of the TEFPI optical fiber sensor can be distinguished with ease. In this paper, the signal processing algorithm adequate to the TEFPI optical fiber sensor was developed. This algorithm can process signal with recognition of the positions of peaks, valleys and signal levels of fringes. Thus this can determine a measurement direction and the positions of direction changes by using the change trend of signal levels. The developed algorithm makes the post-process and real-time process of the signal of the TEFPI optical fiber sensor possible.

  14. Intra-Tissue Pressure Measurement in Ex Vivo Liver Undergoing Laser Ablation with Fiber-Optic Fabry-Perot Probe

    Daniele Tosi

    2016-04-01

    Full Text Available We report the first-ever intra-tissue pressure measurement performed during 1064 nm laser ablation (LA of an ex vivo porcine liver. Pressure detection has been performed with a biocompatible, all-glass, temperature-insensitive Extrinsic Fabry-Perot Interferometry (EFPI miniature probe; the proposed methodology mimics in-vivo treatment. Four experiments have been performed, positioning the probe at different positions from the laser applicator tip (from 0.5 mm to 5 mm. Pressure levels increase during ablation time, and decrease with distance from applicator tip: the recorded peak parenchymal pressure levels range from 1.9 kPa to 71.6 kPa. Different pressure evolutions have been recorded, as pressure rises earlier in proximity of the tip. The present study is the first investigation of parenchymal pressure detection in liver undergoing LA: the successful detection of intra-tissue pressure may be a key asset for improving LA, as pressure levels have been correlated to scattered recurrences of tumors by different studies.

  15. Measurement of Microvibration by Using Dual-Cavity Fiber Fabry-Perot Interferometer for Structural Health Monitoring

    Dae-Hyun Kim

    2014-01-01

    Full Text Available Extensive researches have recently been performed to study structural integrity using structural vibration data measured by in-structure sensors. A fiber optic sensor is one of candidates for the in-structure sensors because it is low in cost, light in weight, small in size, resistant to EM interference, long in service life, and so forth. Especially, an interferometric fiber optic sensor is very useful to measure vibrations with high resolution and accuracy. In this paper, a dual-cavity fiber Fabry-Perot interferometer was proposed with a phase-compensating algorithm for measuring micro-vibration. The interferometer has structurally two arbitrary cavities; therefore the initial phase difference between two sinusoidal signals induced from the interferometer was also arbitrary. In order to do signal processing including an arc-tangent method, a random value of the initial phase difference is automatically adjusted to the exact 90 degrees in the phase-compensating algorithm part. For the verification of the performance of the interferometer, a simple vibration-test was performed to measure micro-vibration caused by piezoelectric transducer (PZT. As an experimental result, the interferometer attached on the PZT successfully measured the 50 Hz-vibration of which the absolute displacement oscillated between −424 nm and +424 nm.

  16. An Imaging Fabry-Perot System for the Robert Stobie Spectrograph on the Southern African Large Telescope

    Rangwala, Naseem; Pietraszewski, Chris; Joseph, Charles L

    2007-01-01

    We present the design of the Fabry-Perot system of the Robert Stobie Spectrograph on the 11m Southern African Large Telescope and its characterization as measured in the laboratory. This system provides spectroscopic imaging at any desired wavelength spanning a bandpass 430 - 860 nm, at four different spectral resolving powers ranging from 300 to 9000. Our laboratory tests revealed a wavelength dependence of the etalon gap and parallelism with a maximum variation between 600 - 720 nm that arises because of the complex structure of the broadband multi-layer dielectric coatings. We also report an unanticipated optical effect of this multi-layer coating structure that produces a significant, and wavelength dependent, change in the apparent shape of the etalon plates. This change is caused by two effects: the physical non-uniformities or thickness variations in the coating layers, and the wavelength dependence of the phase change upon refection that can amplify these non-uniformities. We discuss the impact of the...

  17. Photometric properties of solar H alpha Fabry-Perot etalons. Application to the analysis of the chromospheric fringe

    Bazin, Cyril

    2012-01-01

    We consider the use of the commercially available Fabry-Perot etalons (FP) for the imaging of the solar chromosphere in the H line of HI. Three etalons of 40, 60 and 90 mm of diameter were evaluated and accurately analysed. At normal incidence the maximum transmission wavelength is 656.285 nm for the 60 and 40 mm etalons FP. The finesse has been evaluated at 13.3 for the FP 60mm, 8.7 for the FP 40 and 13.9 for the FP 90 mm. Shifts of the central wavelength as a function of the incidence angle were accurately measured. Polynomial curves precisely giving the transmitted central wavelength variations when using a quasi-parallel beam from a point-like source are presented. Further calibrations have been done with a photometric accuracy using i/ a 16 bits CCD camera; ii/ a Littrow spectrograph of a spectral power 110000, a linear dispersion giving a 0.0058 nm/pixel resolution and iii/ feed by an artificial Sun used as a light source and iv/ precisely adjustable in position optical components. The precise laborator...

  18. Near real-time analysis of extrinsic Fabry-Perot interferometric sensors under damped vibration using artificial neural networks

    Dua, Rohit; Watkins, Steve E.

    2009-03-01

    Strain analysis due to vibration can provide insight into structural health. An Extrinsic Fabry-Perot Interferometric (EFPI) sensor under vibrational strain generates a non-linear modulated output. Advanced signal processing techniques, to extract important information such as absolute strain, are required to demodulate this non-linear output. Past research has employed Artificial Neural Networks (ANN) and Fast Fourier Transforms (FFT) to demodulate the EFPI sensor for limited conditions. These demodulation systems could only handle variations in absolute value of strain and frequency of actuation during a vibration event. This project uses an ANN approach to extend the demodulation system to include the variation in the damping coefficient of the actuating vibration, in a near real-time vibration scenario. A computer simulation provides training and testing data for the theoretical output of the EFPI sensor to demonstrate the approaches. FFT needed to be performed on a window of the EFPI output data. A small window of observation is obtained, while maintaining low absolute-strain prediction errors, heuristically. Results are obtained and compared from employing different ANN architectures including multi-layered feedforward ANN trained using Backpropagation Neural Network (BPNN), and Generalized Regression Neural Networks (GRNN). A two-layered algorithm fusion system is developed and tested that yields better results.

  19. Intra-Tissue Pressure Measurement in Ex Vivo Liver Undergoing Laser Ablation with Fiber-Optic Fabry-Perot Probe.

    Tosi, Daniele; Saccomandi, Paola; Schena, Emiliano; Duraibabu, Dinesh Babu; Poeggel, Sven; Leen, Gabriel; Lewis, Elfed

    2016-01-01

    We report the first-ever intra-tissue pressure measurement performed during 1064 nm laser ablation (LA) of an ex vivo porcine liver. Pressure detection has been performed with a biocompatible, all-glass, temperature-insensitive Extrinsic Fabry-Perot Interferometry (EFPI) miniature probe; the proposed methodology mimics in-vivo treatment. Four experiments have been performed, positioning the probe at different positions from the laser applicator tip (from 0.5 mm to 5 mm). Pressure levels increase during ablation time, and decrease with distance from applicator tip: the recorded peak parenchymal pressure levels range from 1.9 kPa to 71.6 kPa. Different pressure evolutions have been recorded, as pressure rises earlier in proximity of the tip. The present study is the first investigation of parenchymal pressure detection in liver undergoing LA: the successful detection of intra-tissue pressure may be a key asset for improving LA, as pressure levels have been correlated to scattered recurrences of tumors by different studies. PMID:27092504

  20. Nanoantenna-induced fringe splitting of Fabry-Perot interferometer: a model study of plasmonic/photonic coupling.

    Liu, Huanhuan; Erouel, Mohsen; Gerelli, Emmanuel; Harouri, Abdelmounaim; Benyattou, Taha; Orobtchouk, Régis; Milord, Laurent; Belarouci, Ali; Letartre, Xavier; Jamois, Cécile

    2015-11-30

    In this paper, we present a simple approach to study the coupling mechanisms between a plasmonic system consisting of bowtie nanoantennas and a photonic structure based on a Fabry-Perot interferometer. The nanoantenna array is represented by an equivalent homogeneous layer placed at the interferometer surface and yielding the effective dielectric function of the NA resonance. A phase matching model based on thin film interference is developed to describe the multi-layer interferences in the device and to analyze the fringe variations induced by the introduction of the plasmonic layer. The general model is validated by an experimental system consisting of a bowtie nanoantenna array and a porous-silicon-based interferometer. The optical response of this hybrid device exhibits both the enhancement induced by the nanoantenna resonance and the fringe pattern of the interferometer. Using the phase matching model, we demonstrate that strong coupling can occur in such a system, leading to fringe splitting. A study of the splitting strength and of the coupling behavior is given. The model study performed in this work enables to gain deeper understanding of the optical behavior of plasmonic/photonic hybrid devices. PMID:26698737

  1. Switchable and multi-wavelength linear fiber laser based on Fabry-Perot and Mach-Zehnder interferometers

    Gutierrez-Gutierrez, J.; Rojas-Laguna, R.; Estudillo-Ayala, J. M.; Sierra-Hernández, J. M.; Jauregui-Vazquez, D.; Vargas-Treviño, M.; Tepech-Carrillo, L.; Grajales-Coutiño, R.

    2016-09-01

    In this manuscript, switchable and multi-wavelength erbium-doped fiber laser arrangement, based on Fabry-Perot (FPI) and Mach-Zehnder (MZI) interferometers is presented. Here, the FPI is composed by two air-microcavities set into the tip of conventional single mode fiber, this one is used as a partially reflecting mirror and lasing modes generator. And the MZI fabricated by splicing a segment of photonic crystal fiber (PCF) between a single-mode fiber section, was set into an optical fiber loop mirror that acts as full-reflecting and wavelength selective filter. Both interferometers, promotes a cavity oscillation into the fiber laser configuration, besides by curvature applied over the MZI, the fiber laser generates: single, double, triple and quadruple laser emissions with a signal to noise ratio (SNR) of 30 dB. These laser emissions can be switching between them from 1525 nm to 1534 nm by adjusting the curvature radius over the MZI. This laser fiber offers a wavelength and power stability at room temperature, compactness and low implementation cost. Moreover the linear laser proposed can be used in several fields such as spectroscopy, telecommunications and fiber optic sensing systems.

  2. Active cancellation of residual amplitude modulation in a frequency-modulation based Fabry-Perot interferometer

    Yu, Yinan; Wang, Yicheng; Pratt, Jon R.

    2016-03-01

    Residual amplitude modulation (RAM) is one of the most common noise sources known to degrade the sensitivity of frequency modulation spectroscopy. RAM can arise as a result of the temperature dependent birefringence of the modulator crystal, which causes the orientation of the crystal's optical axis to shift with respect to the polarization of the incident light with temperature. In the fiber-based optical interferometer used on the National Institute of Standards and Technology calculable capacitor, RAM degrades the measured laser frequency stability and correlates with the environmental temperature fluctuations. We have demonstrated a simple approach that cancels out excessive RAM due to polarization mismatch between the light and the optical axis of the crystal. The approach allows us to measure the frequency noise of a heterodyne beat between two lasers individually locked to different resonant modes of a cavity with an accuracy better than 0.5 ppm, which meets the requirement to further determine the longitudinal mode number of the cavity length. Also, this approach has substantially mitigated the temperature dependency of the measurements of the cavity length and consequently the capacitance.

  3. Extrinsic Fabry-Perot interferometry for noncontact temperature control of nanoliter-volume enzymatic reactions in glass microchips.

    Easley, Christopher J; Legendre, Lindsay A; Roper, Michael G; Wavering, Thomas A; Ferrance, Jerome P; Landers, James P

    2005-02-15

    Optical fiber extrinsic Fabry-Perot interferometry (EFPI) was investigated as a noncontact temperature sensor and utilized for regulating the temperature of small-volume solutions in microchips. Interference pattern analysis determined the optical path lengths (OPL) associated with reflections from various surfaces on or in the microchip, in particular, from gold sputtered on the bottom of a microchannel. Since OPL is directly proportional to refractive index, which is dependent on solution temperature, the EFPI sensor was capable of noncontact monitoring of solution temperature simply from alterations in the measured path length. Calibration of the sensor against a thermocouple was performed while heating the microchip in a noncontact manner with an IR lamp. The combination of EFPI temperature sensor, IR-mediated heating, and air cooling allowed a fully noncontact system for small-volume temperature control in microchip structures, and its utility was illustrated by optimal digestion of DNA by a temperature-dependent restriction endonuclease in 320 nL. The functionality and simplicity of the microchip EFPI temperature sensor was enhanced by replacing the prebonding sputtered gold with a tunable, chemically plated semireflective silver coating created in situ after chip fabrication. This provided an 8-fold improvement in the lowest detectable temperature change (deltaT = 0.1 degrees C), facilitated primarily by enhanced reflection from both the bottom and top surfaces of the microchannel. This approach for controlling micro- and nanoscale reactions--with heating, cooling, and temperature control being carried out in a completely noncontact fashion--provides an accurate and sensitive method for executing chemical and biochemical reactions in microchips. PMID:15858983

  4. A high power Fabry-Perot resonator for precision Compton polarimetry with the longitudinally polarised lepton beams at HERA

    Zomer, F

    2003-12-01

    The new polarimeter, currently installed at HERA and waiting for its commissioning, is the main topic of this document. In the first chapter, studies of the impact of the polarization measurement accuracy on 3 observables, the right-handed and the standard charged current cross-sections and the determination of the light quark couplings to the Z{sup 0} are presented. The main point is that, unlike small polarisation asymmetry measurements, absolute cross section measurements are very sensitive to the polarization uncertainties. In the second chapter, the beam polarization built up and the Compton polarimetry are presented. Compton polarimetry consists in measuring and analysing the energy spectrum of photons backscattered after laser-electron interactions. The proposed polarimeter upgrade is described in chapter 3. The core of this polarimeter is a high finesse Fabry-Perot cavity filled by a 750 mW ND:YaG laser. This optical resonator, made up of 2 super-mirrors located around the electron beam, provides a few kilo Watt laser beam. The mechanical implementation at HERA and the conditions to maintain the optical resonance are discussed. The chapter 4 is dedicated to the control and measurement of the laser light polarisation. This is a very important aspect of our polarimeter since the determination of the electron beam polarization depends directly on the level of the laser circular polarisation. Before reaching the final design of the cavity installed at HERA, a prototype cavity has been built and operated at Orsay. Results of the laser/cavity alignments and performances of the laser power amplification with this prototype are described in chapter 5. (A.C.)

  5. Miniaturized imaging spectrometer based on Fabry-Perot MOEMS filters and HgCdTe infrared focal plane arrays

    Velicu, S.; Buurma, C.; Bergeson, J. D.; Kim, Tae Sung; Kubby, J.; Gupta, N.

    2014-05-01

    Imaging spectrometry can be utilized in the midwave infrared (MWIR) and long wave infrared (LWIR) bands to detect, identify and map complex chemical agents based on their rotational and vibrational emission spectra. Hyperspectral datasets are typically obtained using grating or Fourier transform spectrometers to separate the incoming light into spectral bands. At present, these spectrometers are large, cumbersome, slow and expensive, and their resolution is limited by bulky mechanical components such as mirrors and gratings. As such, low-cost, miniaturized imaging spectrometers are of great interest. Microfabrication of micro-electro-mechanicalsystems (MEMS)-based components opens the door for producing low-cost, reliable optical systems. We present here our work on developing a miniaturized IR imaging spectrometer by coupling a mercury cadmium telluride (HgCdTe)-based infrared focal plane array (FPA) with a MEMS-based Fabry-Perot filter (FPF). The two membranes are fabricated from silicon-oninsulator (SOI) wafers using bulk micromachining technology. The fixed membrane is a standard silicon membrane, fabricated using back etching processes. The movable membrane is implemented as an X-beam structure to improve mechanical stability. The geometries of the distributed Bragg reflector (DBR)-based tunable FPFs are modeled to achieve the desired spectral resolution and wavelength range. Additionally, acceptable fabrication tolerances are determined by modeling the spectral performance of the FPFs as a function of DBR surface roughness and membrane curvature. These fabrication non-idealities are then mitigated by developing an optimized DBR process flow yielding high-performance FPF cavities. Zinc Sulfide (ZnS) and Germanium (Ge) are chosen as the low and the high index materials, respectively, and are deposited using an electron beam process. Simulations are presented showing the impact of these changes and non-idealities in both a device and systems level.

  6. An arrayed infrared filter based on liquid crystal Fabry-Perot effect for electrically tunable spectral imaging detection

    Lin, Jiuning; Tong, Qing; Luo, Jun; Lei, Yu; Zhang, Xinyu; Sang, Hongshi; Xie, Changsheng

    2015-12-01

    An arrayed electrically tunable infrared (IR) filter based on the key structure of liquid crystal Fabry-Perot (LC-FP) working in the wavelength range from 2.5 to 12 μm, is designed and fabricated successfully. According to the electrically controlled birefringence characteristics of nematic LC molecules, the refractive index of LC materials filled into a prefabricated microcavity can be adjusted by the spatial electric field stimulated between the top aluminum electrode patterned by conventional UV-photolithography and the bottom aluminum electrode in the LC-FP. The particular functions including key spectral selection and spectral adjustment, can be performed by the developed LC-FP filter driven and controlled electrically. Our experiments show that the maximum transmittance of the transmission peaks is ~24% and the peaks of transmission spectrum shift through applying different voltage signals with a root mean square (RMS) value ranging from 0 to ~21.7Vrms. The experimental results are consistent with the simulation according to the model constructed by us. As a 4-channel array-type IR filter, the top electrode of the device is composed of four same sub-electrodes, which is powered, respectively, to select desired transmission spectrum. Each of the units in the device is operated separately and synchronously, which means that spectral images of the same object can be obtained with different wavelengths in one shot. Without any mechanical parts, the developed LC-FP filter exhibits several advantages including ultra-small size, low cost, high reliability, high spectral selectivity, and compact integration.

  7. Characterization of the LIGO 4 km Fabry-Perot cavities via their high-frequency dynamic responses to length and laser frequency variations

    Recent measurements at the LIGO Hanford Observatory have confirmed the predicted high-frequency dynamic response of km scale Fabry-Perot cavities to length and laser frequency variations. The dynamic response functions have been exploited to determine a number of cavity parameters including the cavity length and the resonance width. A new technique based on a variation of these measurements has been utilized to measure the interferometer arm cavity lengths with a precision of 80 μm. We present an overview of these measurements and discuss how the dynamic field responses could be used to measure the cavity g factors which are related to the mirror radii of curvature

  8. A high-finesse Fabry-Perot cavity with a frequency-doubled green laser for precision Compton polarimetry at Jefferson Lab

    Rakhman, A.; Hafez, M; S. Nanda; Benmokhtar, F.; Camsonne, A.; Cates, G. D.; Dalton, M. M.; Franklin, G. B.; Friend, M.; Michaels, R. W.; Nelyubin, V.; D.S. Parno; Paschke, K. D.; Quinn, B. P.; Souder, P. A.

    2016-01-01

    A high-finesse Fabry-Perot cavity with a frequency-doubled continuous wave green laser (532~nm) has been built and installed in Hall A of Jefferson Lab for high precision Compton polarimetry. The infrared (1064~nm) beam from a ytterbium-doped fiber amplifier seeded by a Nd:YAG nonplanar ring oscillator laser is frequency doubled in a single-pass periodically poled MgO:LiNbO$_{3}$ crystal. The maximum achieved green power at 5 W IR pump power is 1.74 W with a total conversion efficiency of 34....

  9. Photonic filtering of microwave signals in the frequency range of 0.01-20 GHz using a Fabry-Perot filter

    We demonstrate experimentally the efficiency of tuning of a photonic filter in the frequency range of 0.01 to 20 GHz. The presented work combines the use of a multimode optical source associated with a dispersive optical fiber to obtain the filtering effect. Tunability effect is achieved by the use of a Fabry-Perot filter that allows altering the spectral characteristics of the optical source. Experimental results are validated by means of numerical simulations. The scheme here proposed has a potential application in the field of optical telecommunications.

  10. MWIR/LWIR filter based on Liquid-Crystal Fabry-Perot structure for tunable spectral imaging detection

    Zhang, Huaidong; Muhammad, Afzal; Luo, Jun; Tong, Qing; Lei, Yu; Zhang, Xinyu; Sang, Hongshi; Xie, Changsheng

    2015-03-01

    An electrically tunable medium-wave infrared (MWIR)/long-wave infrared (LWIR) filter based on the key structure of Liquid-Crystal (LC) Fabry-Perot (FP), which works in the wavelength range from 2.5 μm to 12 μm, is designed and fabricated successfully in this paper. According to the optical interference principle of the FP cavity and electrically controlled birefringence of nematic LC molecules, the particular functions including spectral selection and spectral staring and spectral adjustment, can be realized by the developed MWIR/LWIR filter driven and controlled electrically. As to the LC-FP filter, both planar reflective mirrors are shaped by depositing a layer of aluminum (Al) film (∼60 nm) over one side of double-side polished Zinc Selenide (ZnSe) wafer (∼1 mm), and then polyimide (PI) layer with the thickness of ∼100 nm is coated directly on Al film. With typical sandwich architecture, the depth of the cavity with nematic LC molecules sealed in is ∼7.5 μm. To make sure the LC molecules parallel aligned and twist regularly under voltage driving signal applied on Al film, which also acts as electrode, the V-grooves are formed in PI layer with the depth of ∼90 nm and the width of ∼350 nm at average by strong rubbing. The typical transmission spectrum in MWIR&LWIR wavelength range and several spectral images in MWIR wavelength range based on the fabricated LC-FP filter, have been obtained through applying a voltage driving-signal with different root-means-square (RMS) value over the electrodes of LC-FP filter in the selected voltage range from 0VRMS to 19.8VRMS. The testing result demonstrates a prospect of realization smart spectral imaging and further integrating the LC-FP filter with infrared focal plane arrays (FPAs) to achieve the purpose infrared multispectral imaging. The developed MWIR&LWIR LC-FP filters show some obvious advantages such as wide working wavelength range, electrically tunable spectral selection, ultra-compact, low cost, being

  11. Electrically tunable infrared filter based on the liquid crystal Fabry-Perot structure for spectral imaging detection.

    Zhang, Huaidong; Muhammmad, Afzal; Luo, Jun; Tong, Qing; Lei, Yu; Zhang, Xinyu; Sang, Hongshi; Xie, Changsheng

    2014-09-01

    An electrically tunable infrared (IR) filter based on the liquid crystal (LC) Fabry-Perot (FP) key structure, which works in the wavelength range from 5.5 to 12 μm, is designed and fabricated successfully. Both planar reflective mirrors with a very high reflectivity of ∼95%, which are shaped by depositing a layer of aluminum (Al) film over one side of a double-sided polished zinc selenide wafer, are coupled into a dual-mirror FP cavity. The LC materials are filled into the FP cavity with a thickness of ∼7.5  μm for constructing the LC-FP filter, which is a typical type of sandwich architecture. The top and bottom mirrors of the FP cavity are further coated by an alignment layer with a thickness of ∼100  nm over Al film. The formed alignment layer is rubbed strongly to shape relatively deep V-grooves to anchor LC molecules effectively. Common optical tests show some particular properties; for instance, the existing three transmission peaks in the measured wavelength range, the minimum full width at half-maximum being ∼120  nm, and the maximum adjustment extent of the imaging wavelength being ∼500  nm through applying the voltage driving signal with a root mean square (RMS) value ranging from 0 to ∼19.8  V. The experiment results are consistent with the simulation, according to our model setup. The spectral images obtained in the long-wavelength IR range, through the LC-FP device driven by the voltage signal with a different RMS value, demonstrates the prospect of the realization of smart spectral imaging and further integrating the LC-FP filter with IR focal plane arrays. The developed LC-FP filters show some advantages, such as electrically tunable imaging wavelength, very high structural and photoelectronic response stability, small size and low power consumption, and a very high filling factor of more than 95% compared with common MEMS-FP spectral imaging approaches. PMID:25321356

  12. Experimental determination of intracavity losses of monolithic Fabry-Perot cavities made of Pr3+:Y2SiO5.

    Goto, Hayato; Nakamura, Satoshi; Ichimura, Kouichi

    2010-11-01

    We propose an experimental method with which all the following quantities can be determined separately: the intracavity loss and individual cavity-mirror transmittances of a monolithic Fabry-Perot cavity and furthermore the coupling efficiency between the cavity mode and the incident light. It is notable that the modified version of this method can also be applied to whispering-gallery-mode cavities. Using this method, we measured the intracavity losses of monolithic Fabry-Perot cavities made of Pr3+:Y2SiO5 at room temperature. The knowledge of the intracavity losses is very important for applications of such cavities, e.g., to quantum information technologies. It turns out that fairly high losses (about 0.1%) exist even for a sample with extremely low dopant concentration (2×10(-5) at. %). The experimental results also indicate that the loss may be mainly due to the bulk loss of Y2SiO5 crystal. The bulk loss is estimated to be 7×10(-4) cm(-1) (0.003 dB/cm) or lower. PMID:21164720

  13. Generation of tunable multi-wavelength optical short pulses using self-seeded Fabry-Perot laser diode and tilted multimode fiber Bragg grating

    Tongjian Cai; Yunqi Liu; Xiaobei Zhang; Tingyun Wang

    2011-01-01

    We experimentally demonstrate the simultaneous generation of tunable multi-wavelength picosecond laser pulses using a self-seeding configuration that consists of a gain-switched Fabry-Perot laser diode (FPLD)with an external cavity formed by a tilted multimode fiber Bragg grating.Dual- and triple-wavelength pulses are obtained and tuned in a flexible manner by changing the temperature of the FPLD.The side mode suppression ratio larger than 25 dB is achieved at different dual- and triple-wavelengths and the typical pulsewidth of the output pulses is ~70 ps.In the experiment, the wavelength separation can be narrowed to 0.57 nm.%@@ We experimentally demonstrate the simultaneous generation of tunable multi-wavelength picosecond laser pulses using a self-seeding configuration that consists of a gain-switched Fabry-Perot laser diode (FPLD)with an external cavity formed by a tilted multimode fiber Bragg grating.Dual-and triple-wavelength pulses are obtained and tuned in a flexible manner by changing the temperature of the FPLD.The side mode suppression ratio larger than 25 dB is achieved at different dual-and triple-wavelength8 and the typical pulsewidth of the output pulses is~70 ps.In the experiment, the wavelength separation can be narrowed to 0.57 nm.

  14. Bidirectional Transmission in Colourless WDM-PON based on Injection-Locked Fabry-Perot Laser at 2.5 Gbit/s using Low-Cost Seeding Source

    Nguyen, Quoc Thai; Besnard, Pascal; Bramerie, Laurent; Shen, Alexandre; Duan, Guang-Hua; Kazmierski, Christophe; Simon, Jean-Claude

    2009-01-01

    Error-free transmission over 20km of 8-channels for both downstream and upstream in colourless WDM-PON based on injection-locked Fabry-Perot laser is experimentally demonstrated at 2.5Gbit/s, using a single quantum dash mode-locked laser as multi-wavelength seeding source.

  15. Precision measurements of gas refractivity by means of a Fabry-Perot interferometer illustrated by the monitoring of radiator refractivity in the DELPHI RICH detectors

    Filippas-Tassos, A; Fokitis, E; Maltezos, S; Patrinos, K

    2002-01-01

    With an updated, flexible, highly efficient and easily installed system we obtained accurate refractivity (n-1) values. This system is a refractometer based on a Fabry-Perot interferometer and was used to monitor the refractivity of DELPHI RICH Cherenkov radiators near the VUV region. By using a Pt-Ne spectral lamp and improved alignment and temperature control, the refractivities of C//5F//1//2 and C//4F//1 //0 have been monitored since 1996. With this light source, selected to have large coherence lengths, we can extract the refractivity at several wavelengths from one data set only. The estimated errors of the refractivity measurements are less than 1.2%, and depend on wavelength and the type of gas used. The various parameters affecting the accuracy of the refractometer are also discussed. Finally, results from special sample refractivity measurements of the liquid radiator (C//6F//1//4) in its gas phase, are presented.

  16. Analysis and design of tunable wideband microwave photonics phase shifter based on Fabry-Perot cavity and Bragg mirrors in silicon-on-insulator waveguide.

    Qu, Pengfei; Zhou, Jingran; Chen, Weiyou; Li, Fumin; Li, Haibin; Liu, Caixia; Ruan, Shengping; Dong, Wei

    2010-04-20

    We designed a microwave (MW) photonics phase shifter, consisting of a Fabry-Perot filter, a phase modulation region (PMR), and distributed Bragg reflectors, in a silicon-on-insulator rib waveguide. The thermo-optics effect was employed to tune the PMR. It was theoretically demonstrated that the linear MW phase shift of 0-2pi could be achieved by a refractive index variation of 0-9.68x10(-3) in an ultrawideband (about 38?GHz-1.9?THz), and the corresponding tuning resolution was about 6.92 degrees / degrees C. The device had a very compact size. It could be easily integrated in silicon optoelectronic chips and expected to be widely used in the high-frequency MW photonics field. PMID:20411021

  17. Wideband and frequency-tunable microwave generation using an optoelectronic oscillator incorporating a Fabry-Perot laser diode with external optical injection.

    Pan, Shilong; Yao, Jianping

    2010-06-01

    Wideband and frequency-tunable microwave signal generation using an optoelectronic oscillator incorporating a Fabry-Perot laser diode (FP-LD) with external optical injection is proposed and demonstrated. Through external injection, the FP-LD functions as a tunable high-Q photonic microwave filter, and the frequency tuning is realized by either tuning the wavelength of the externally injected optical light or changing the temperature to adjust the longitudinal modes of the FP-LD. An experiment is performed; a microwave signal with a frequency tunable from 6.41 to 10.85 GHz is generated. The phase noise performance of the generated microwave signal is also investigated. PMID:20517459

  18. Fabry-Perot Kinematics of HH 202, 203-204 in the Orion Nebula Are they part of a Big Bipolar Outflow?

    Rosado, M; Arias, L; Le Coarer, E; Rosado, Margarita; Fuente, Eduardo de la; Arias, Lorena

    2001-01-01

    We present a kinematic study of the Herbig-Haro objects HH 202, 203 and 204 using Halpha and [NII] Fabry-Perot velocity maps. For HH 202 we find new features that could belong to this HH object or that perhaps are associated with an outflow different from HH 202. Because of its high velocity (up to 100 km/seg) this outflow probably can be a HH flow not catalogued previously. Large internal motions are found in the fainter regions of HH 203-204, as well as evidence of transverse density gradients. We show that the apex of HH 204 is the zone of maximum velocity in agreement with bow shock models. From our studies, we find kinematic evidence that suggests that HH 203-204 and HH 202 are part of a single and large (approx 0.55 pc) HH flow.

  19. Effect of small variations in the refractive index of the ambient medium on the spectrum of a bent fibre-optic Fabry - Perot interferometer

    Kulchin, Yurii N; Vitrik, O B; Gurbatov, S O [Institute for Automation and Control Processes, Far-Eastern Branch, Russian Academy of Sciences, Vladivostok (Russian Federation)

    2011-09-30

    The phase of light propagating through a bent optical fibre is shown to depend on the refractive index of the medium surrounding the fibre cladding when there is resonance coupling between the guided core mode and cladding modes. This shifts the spectral maxima in the bent fibre-optic Fabry - Perot interferometer. The highest phase and spectral sensitivities achieved with this interferometer configuration are 0.71 and 0.077, respectively, and enable changes in the refractive index of the ambient medium down to 5 Multiplication-Sign 10{sup -6} to be detected. This makes the proposed approach potentially attractive for producing highly stable, precision refractive index sensors capable of solving a wide range of liquid refractometry problems.

  20. A New Remote Sensing Filter Radiometer Employing a Fabry-Perot Etalon and a CCD Camera for Column Measurements of Methane in the Earth Atmosphere

    Georgieva, E. M.; Huang, W.; Heaps, W. S.

    2012-01-01

    A portable remote sensing system for precision column measurements of methane has been developed, built and tested at NASA GSFC. The sensor covers the spectral range from 1.636 micrometers to 1.646 micrometers, employs an air-gapped Fabry-Perot filter and a CCD camera and has a potential to operate from a variety of platforms. The detector is an XS-1.7-320 camera unit from Xenics Infrared solutions which combines an uncooled InGaAs detector array working up to 1.7 micrometers. Custom software was developed in addition to the graphical user basic interface X-Control provided by the company to help save and process the data. The technique and setup can be used to measure other trace gases in the atmosphere with minimal changes of the etalon and the prefilter. In this paper we describe the calibration of the system using several different approaches.

  1. Tip-sensitive all-silica fiber-optic Fabry-Perot ultrasonic hydrophone for charactering high intensity focused ultrasound fields

    Wang, D. H.; Jia, P. G.; Wang, S. J.; Zhao, C. L.; Zeng, D. P.; Wang, H.; Li, F. Q.

    2013-07-01

    This Letter reports on a tip-sensitive all-silica fiber-optic Fabry-Perot (TAFOFP) ultrasonic hydrophone for measuring high intensity focused ultrasound (HIFU) fields. The all-silica fiber-optic structure ensures that the TAFOFP ultrasonic hydrophone can withstand HIFU fields and the tip-sensitive configuration ensures that the TAFOFP ultrasonic hydrophone can achieve a high spatial resolution of 125 μm. The experimental results have shown that the TAFOFP ultrasonic hydrophone could stably measure the peak positive ultrasonic pressure as high as 4.34 MPa, and the measured ultrasonic pressure distributions of the HIFU field by the fabricated TAFOFP ultrasonic hydrophone agreed well with those by the piezoceramic needle hydrophone.

  2. A Study on the Measurement of Foreign Material in Dissimilar Metal Contact Using Pulse Laser and Confocal Fabry-Perot Interferomete

    A laser ultrasonic inspection system is a non-contact inspection device which generates and measures ultrasonics by using laser beam. A laser ultrasonic inspection system provides a high measurement resolution because the ultrasonic signal generated by a pulse laser beam has a wide-band spectrum and the ultrasonic signal is measured from a small focused spot of a measuring laser beam. In this study, galvanic corrosion phenomenon was measured by non-destructive and non-contact method using the laser. The case of mixed foreign material on the part of corrosion was assumed and laser ultrasonic experiment was conducted. Ultrasonic was generated by pulse laser from the back side of the specimen and ultrasonic signal was acquired from the same location of the front side using continuous wave laser and Confocal Fabry-Perot Interferometer(CFPI). The characteristic of the ultrasonic signal of exist foreign material part was analyzed and the location and size of foreign material was measured.

  3. MEMS Fabry-Perot interferometer-based spectrometer demonstrator for 7.5 μm to 9.5 μm wavelength range

    Mäkynen, Jussi H.; Tuohiniemi, Mikko; Näsilä, Antti; Mannila, Rami; Antila, Jarkko E.

    2014-03-01

    VTT Technical research centre of Finland has developed a MEMS Fabry-Perot interferometer (FPI) for the wavelength range from 7.5 μm to 9.5 μm. The device consists of two Distributed Bragg Reflectors (DBR) manufactured with MEMS processing techniques. The full width half maximum of the transmission peak is 150nm. This transmission peak can be tuned from 7.5 μm to 9.5 μm by applying a control voltage from 0 V to 30 V. A laboratory demonstrator has been put together to show the use of this module as a part of a spectral measurement setup. Several gas samples have been measured with the setup and compared against measurement results found in literature.

  4. Photon-counting Brillouin optical time-domain reflectometry based on up-conversion detector and fiber Fabry-Perot scanning interferometer

    Xia, Haiyun; Shentu, Guoliang; Wang, Chong; Qiu, Jiawei; Xia, Xiuxiu; Chen, Chao; Zheng, Mingyang; Xie, Xiuping; Zhang, Qiang; Dou, Xiankang; Pan, Jianwei

    2015-01-01

    A direct-detection Brillouin optical time-domain reflectometry (BOTDR) is proposed and demonstrated by using an up-conversion single-photon detector and a fiber Fabry-Perot scanning interferometer (FFP-SI). Taking advantage of high signal-to-noise ratio of the detector and high spectrum resolution of the FFP-SI, the Brillouin spectrum along a polarization maintaining fiber (PMF) is recorded on a multiscaler with a small data size directly. In contrast with conventional BOTDR adopting coherent detection, photon-counting BOTDR is simpler in structure and easier in data processing. In the demonstration experiment, characteristic parameters of the Brillouin spectrum including its power, spectral width and frequency center are analyzed simultaneously along a 10 km PMF at different temperature and stain conditions.

  5. Utilizing erbium fiber ring scheme and Fabry-Perot laser diode for stable and wavelength-tunable laser in single-longitudinal-mode output

    In this investigation, we propose and demonstrate a stable and wavelength-tunable erbium-doped fiber (EDF) ring laser scheme with external-injected Fabry-Perot laser diode (FP-LD) technology, in single-longitudinal-mode (SLM) output behavior. Here, the output power and side-mode suppression ratio (SMSR) of the proposed laser scheme can be obtained between –3.9 and 1.3 dBm and 30.1 and 50.5 dB in the operating wavelengths of 1523.65 and 1561.50 nm with 1.12 nm tuning step, respectively, according to the output mode-spacing of FP-LD used. Besides, the lasing stabilities of output power and wavelength are also investigated and discussed

  6. Large-Scale Measurements of Thermospheric Dynamics with a Multisite Fabry-Perot Interferometer Network: Overview of Plans and Results from Midlatitude Measurements

    Jonathan J. Makela

    2012-01-01

    Full Text Available The North American Thermosphere Ionosphere Observing Network (NATION, comprising a new network of Fabry-Perot interferometers (FPIs, to be deployed in the Midwest of the United States of America is described. FPIs will initially be deployed to four sites to make coordinated measurements of the neutral winds and temperature in the Earth's thermosphere using measurements of the 630 nm redline emission. The observing strategy of the network will take into account local observing conditions, and common volume measurements from multiple sites will be made in order to estimate local vector wind quantities. The network described is expandable, and as additional FPI sites are installed in North America, or elsewhere, the goal of providing the upper atmospheric research community with a robust dataset of neutral winds and temperatures can be achieved.

  7. Stokes imaging polarimetry using image restoration at the Swedish 1-m Solar Telescope II: A calibration strategy for Fabry-Perot based instruments

    Schnerr, R S; van Noort, M

    2010-01-01

    Context: The combination of image restoration and a Fabry-Perot interferometer (FPI) based instrument in solar observations results in specific calibration issues. FPIs generally show variations over the field-of-view while in the image restoration process the 1-to-1 relation between pixel space and image space is lost, complicating correcting for such variations. Aims: To develop a data reduction method that takes these issues into account, and minimizes the resulting errors. Methods: By accounting for the time variations in the telescope Mueller matrix and using separate calibration data optimized for the wavefront sensing in the MOMFBD image restoration process and for the final deconvolution of the data we remove most of the calibration artifacts from the resulting data. Results: Using the presented method to reduce full Stokes data from CRISP at the SST, we find that it drastically reduces the instrumental and image restoration artifacts resulting from cavity errors, reflectivity variations and the polar...

  8. Direct-detection Doppler wind measurements with a Cabannes Mie lidar: A. Comparison between iodine vapor filter and Fabry Perot interferometer methods

    She, Chiao-Yao; Yue, Jia; Yan, Zhao-Ai; Hair, Johnathan W.; Guo, Jin-Jia; Wu, Song-Hua; Liu, Zhi-Shen

    2007-07-01

    Atmospheric line-of-sight (LOS) wind measurement by means of incoherent Cabannes-Mie lidar with three frequency analyzers with nearly the same maximum transmission of ˜80% that could be fielded at different wavelengths is analytically considered. These frequency analyzers are (a) a double-edge Fabry-Perot interferometer (FPI) at 1064 nm (IR-FPI), (b) a double-edge Fabry-Perot interferometer at 355 nm (UV-FPI), and (c) an iodine vapor filter (IVF) at 532 nm with two different methods, using either one absorption edge, single edge (se-IVF), or both absorption edges, double edge (de-IVF). The effect of the backscattered aerosol mixing ratio, Rb, defined as the ratio of the aerosol volume backscatter coefficient to molecular volume backscatter coefficient, on LOS wind uncertainty is discussed. Assuming a known aerosol mixing ratio, Rb, and 100,000 photons owing to Cabannes scattering to the receiver, in shot-noise-limited detection without sky background, the LOS wind uncertainty of the UV-FPI in the aerosol-free air (Rb=0), is lower by ˜16% than that of de-IVF, which has the lowest uncertainty for Rb between 0.02 and 0.08; for Rb>0.08, the IR-FPI yielded the lowest wind uncertainty. The wind uncertainty for se-IVF is always higher than that of de-IVF, but by less than a factor of 2 under all aerosol conditions, if the split between the reference and measurement channels is optimized. The design flexibility, which allows the desensitization of either aerosol or molecular scattering, exists only with the FPI system, leading to the common practice of using IR-FPI for the planetary boundary layer and using UV-FPI for higher altitudes. Without this design flexibility, there is little choice but to use a single wavelength IVF system at 532 nm for all atmospheric altitudes.

  9. Evaluation by a ray trace method of an asymmetric Fabry-Perot optical resonator for a monochromatic LCS gamma ray source

    Non-destructive measurement systems of nuclear material are under development in our group. The measurement systems are based on monochromatic γ-ray generated from laser Compton scattering (LCS) based on energy-recovery linac accelerator technologies. The accuracy improvement of the non-destructive measurement systems and the exploration of the precise excitation state in an atomic nucleus are attained by further developing a pure monochromatic LCS-γ-ray source. The energy spread of a mode-locked short pulse laser restricts the monochromaticity of the LCS-γ-ray source. Therefore, an ultra-narrow band width laser should be used for instead of the short pulse laser. We have proposed an asymmetric confocal Fabry-Perot optical resonator as a supercavity of the pure monochromatic LCS-γ-ray source. The influences due to the distortion and the misalignment of the mirrors were evaluated by a ray trace method. We present R and D status and the evaluation results for the optical resonator. (author)

  10. Optical simulation of three-dimensional x-ray diffraction using two-dimensional lattices and a Fabry-Perot etalon

    Sommer, W.

    2013-03-01

    The basic experimental setup of a Fabry-Perot etalon between a collimating and a focusing lens is modified by introducing 2D rectangular lattices between the etalon and the collimating lens. Consequently, the irradiance of the interference fringes on a screen in the focal plane of the focusing lens changes and is modified by the diffraction pattern of the 2D lattice. The constructive interference directions resulting from both the etalon and the diffraction by the 2D lattice have to correlate in order to obtain maximum irradiance. Considering this experiment in a didactical context and analysing how a 2D rectangular lattice is seen through the etalon, the investigation provides us with the concept of an optical space containing a row of virtual 2D lattices. Due to the partially reflecting plane surfaces of the etalon, different virtual images of the 2D lattice form a 3D lattice with a tetragonal or orthorhombic structure. As an optical interface, the simple setup with a 2D lattice and an etalon models a 3D lattice. Using a laser, the diffraction pattern of a 2D lattice and etalon can be used to optically simulate 3D x-ray diffraction. The experiments can be included wherever undergraduate or graduate students have to follow up Laue's formulation of x-ray diffraction.