High Speed Directly Modulated Fabry-Perot Lasers with an Ultra-Short Cavity Length

In this paper, a novel method used for Fabry-Perot cavity length's demodulation in high-speed and large scope measurement was proposed. Principle of the method is based on uniqueness of intensity of multiple wavelengths in the scope of Fabry-Perot vibration. This technique offers flexibility of selecting incident wave length and enhances the scope of demodulation of cavity length, compared with that popular triple wave length demodulation. In experiment, multi-wavelength demodulation is demonstrated for measurement of cavity length varying from 110um to 115um and the strain resolution was higher than 0.1um.

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A High-Speed Demodulation Technology of Fiber Optic Extrinsic Fabry-Perot Interferometric Sensor Based on Coarse Spectrum

Sensors ◽

10.3390/s21196609 ◽

2021 ◽

Vol 21 (19) ◽

pp. 6609

Author(s):

Peng Zhang ◽

Ying Wang ◽

Yuru Chen ◽

Xiaohua Lei ◽

Yi Qi ◽

...

Keyword(s):

Real Time ◽

High Speed ◽

Cavity Length ◽

Fiber Optic ◽

Likelihood Estimation ◽

Time Dynamic ◽

Wavelength Division ◽

Broadband Spectrum ◽

Fabry Perot ◽

Interferometric Sensor

A fast real-time demodulation method based on the coarsely sampled spectrum is proposed for transient signals of fiber optic extrinsic Fabry-Perot interferometers (EFPI) sensors. The feasibility of phase demodulation using a coarse spectrum is theoretically analyzed. Based on the coarse spectrum, fast Fourier transform (FFT) algorithm is used to roughly estimate the cavity length. According to the rough estimation, the maximum likelihood estimation (MLE) algorithm is applied to calculate the cavity length accurately. The dense wavelength division multiplexer (DWDM) is used to split the broadband spectrum into the coarse spectrum, and the high-speed synchronous ADC collects the spectrum. The experimental results show that the system can achieve a real-time dynamic demodulation speed of 50 kHz, a static measurement root mean square error (RMSE) of 0.184 nm, and a maximum absolute and relative error distribution of 15 nm and 0.005% of the measurement cavity length compared with optical spectrum analyzers (OSA).

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Wideband fiber-optic Fabry-Perot acoustic sensing scheme using high-speed absolute cavity length demodulation

Optics Express ◽

10.1364/oe.415750 ◽

2021 ◽

Vol 29 (5) ◽

pp. 6768

Author(s):

Yang Yang ◽

Ya Wang ◽

Ke Chen

Keyword(s):

High Speed ◽

Cavity Length ◽

Fiber Optic ◽

Acoustic Sensing ◽

Fabry Perot

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Fabry–Perot Cavity Sensing Probe with High Thermal Stability for an Acoustic Sensor by Structure Compensation

Sensors ◽

10.3390/s18103393 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3393 ◽

Cited By ~ 4

Author(s):

Jin Cheng ◽

Yu Zhou ◽

Xiaoping Zou

Keyword(s):

Thermal Stability ◽

Thermal Expansion ◽

Cavity Length ◽

High Reliability ◽

Simple Approach ◽

High Thermal Stability ◽

Acoustic Sensor ◽

Practical Applications ◽

Fabry Perot ◽

Expansion Model

Fiber Fabry–Perot cavity sensing probes with high thermal stability for dynamic signal detection which are based on a new method of structure compensation by a proposed thermal expansion model, are presented here. The model reveals that the change of static cavity length with temperature only depends on the thermal expansion coefficient of the materials and the structure parameters. So, fiber Fabry–Perot cavity sensing probes with inherent temperature insensitivity can be obtained by structure compensation. To verify the method, detailed experiments were carried out. The experimental results reveal that the static cavity length of the fiber Fabry–Perot cavity sensing probe with structure compensation hardly changes in the temperature range of −20 to 60 °C and that the method is highly reproducible. Such a method provides a simple approach that allows the as-fabricated fiber Fabry–Perot cavity acoustic sensor to be used for practical applications, exhibiting the great advantages of its simple architecture and high reliability.

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Fiber Fabry-Perot tunable filter for high-speed optical packet switching

10.2172/439008 ◽

1997 ◽

Author(s):

N.L. Taranenko ◽

S.C. Tenbrink ◽

K. Hsu ◽

C.M. Miller

Keyword(s):

High Speed ◽

Packet Switching ◽

Tunable Filter ◽

Optical Packet Switching ◽

Fabry Perot

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Two-Parameter Elliptical Fitting Method for Short-Cavity Fiber Fabry–Perot Sensor Interrogation

Sensors ◽

10.3390/s19010036 ◽

2018 ◽

Vol 19 (1) ◽

pp. 36 ◽

Cited By ~ 1

Author(s):

Xiongxing Zhang ◽

Wei Wang ◽

Haibin Chen ◽

Ying Tang ◽

Zhibo Ma ◽

...

Keyword(s):

White Light ◽

Cavity Length ◽

Processing Method ◽

Light Sources ◽

Fitting Method ◽

Data Processing Method ◽

Fabry Perot ◽

Gap Sensors ◽

Two Parameter ◽

Better Than

To solve the cavity interrogation problem of short cavity fiber Fabry–Perot sensors in white light spectral interrogation with amplified spontaneous emissions (ASEs) as the white light sources, a data processing method, using an improved elliptical fitting equation with only two undetermined coefficients, is proposed. Based on the method, the cavity length of a fiber Fabry–Perot sensor without a complete reflection spectrum period in the frequency domain can be interrogated with relatively high resolution. Extrinsic fiber Fabry–Perot air-gap sensors with cavity lengths less than 30 μm are used to experimentally verify the method, and are successfully interrogated with an accuracy better than 0.55%.

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Cryogenic servo-stabilized Fabry-Perot interferometers for imaging at 3-5 and 8-13 microns

International Astronomical Union Colloquium ◽

10.1017/s0252921100022673 ◽

1995 ◽

Vol 149 ◽

pp. 60-68

Author(s):

N. K. Reay ◽

K.A.R.B. Pietraszewski

Keyword(s):

Response Time ◽

Spectral Region ◽

Feedback Loop ◽

Tuning Range ◽

Cavity Length ◽

Operating Temperature ◽

Piezoelectric Actuators ◽

Servo Control ◽

Fabry Perot ◽

Mirror Spacing

AbstractThe performance of a new liquid Nitrogen cooled Fabry-Perot etalon for imaging at 3-5µm is described. Capacitance sensors monitor the etalon mirror spacing and parallelism, and error signals produced as a consequence of changes in these parameters are used in a feedback loop with piezoelectric actuators for active cavity control. These new cryogenic etalons are designed to be compatible with the Queensgate Instruments Ltd CS100/ET servo-stabilized Fabry-Perot system.The cryogenic etalon has a clear aperture of 50mm and a nominal mirror spacing of between 5 and 60µm. It is coated for the 3 - 5µm spectral region, although coatings are also available for the 2 - 2.5µm and 8 - 13µm regions. Under servo-control at operating temperature the etalon has a response time of 30 msec and a minimum cavity tuning range of ±3µm about the nominal cavity length, corresponding to approximately 3 orders of interference at the midrange wavelength of 4µm.

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