Phase-demodulation error of a fiber-optic Fabry–Perot sensor with complex reflection coefficients

Kilpatrick, James; MacPherson, William N.; Barton, James S.; Jones, Julian D. C.

doi:10.1364/ao.39.001382

Cited by 9 publications

(10 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Note that unlike figure 8 however, the signal amplitude dv ac is lower when the slope of V dc is positive compared to when it is negative. This is due to asymmetry in the intensity-phase ITF due to absorption in the aluminium coatings used to fabricate the mirrors of this particular FPI [8]: an indication of this asymmetry can be seen in the reflected interference fringes in figure 2(a) which were obtained using the same FPI. The derivative of the ITF and hence the phase sensitivity, and thus the signal amplitude, are therefore dependent upon the sign of the slope for this FPI.…”

Section: Continuous Phase Bias Scanningmentioning

confidence: 92%

See 1 more Smart Citation

Interrogation of free-space Fabry–Perot sensing interferometers by angle tuning

Beard

2003

Meas. Sci. Technol.

View full text Add to dashboard Cite

A method of interrogating a free-space Fabry-Perot sensing interferometer (FPI) by angle tuning the incident beam in order to vary the optical pathlength is described. A system based on a PC controlled precision galvanometer and a 1-1 beam expander that enabled the angle of incidence to be rapidly and continuously varied without translation is described. This system was used to demonstrate that the transfer functions (ITF) of low finesse FPIs of optical thicknesses in the range 80-200 µm could be accurately recovered by tuning the angle of incidence over less than 9 •. Two sensor interrogation schemes are described. One involves scanning through the ITF in constant phase steps by applying an arcosine voltage waveform to the galvanometer and then returning to the angle at which the ITF phase derivative is a maximum. The other uses a mirror continuously rotating through 360 • to repetitively scan through the ITF in constant angular steps. The signal is then recovered at the instant in time that the maximum value of the ITF derivative occurs. It is considered that angle tuning offers a flexible and inexpensive alternative to interrogating free-space FP sensors by wavelength tuning.

show abstract

Section: Continuous Phase Bias Scanningmentioning

confidence: 92%

“…(a) Galvanometer mirror rotated in constant angular steps according to equation(8) producing the FPI output shown in (b). (c) Mirror rotated according to the arcosine angle function of equation(9) and resulting in the FPI output sampled in steps of constant phase shown in (d).…”

mentioning

confidence: 99%

Interrogation of free-space Fabry–Perot sensing interferometers by angle tuning

Beard

2003

Meas. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…3 is not the usual symmetrical Airy function characteristic of an FPI. Its asymmetric sawtooth shape is due to the fact that the reflection coefficients of the aluminium coatings used to form the FPI mirrors are complex due to absorption [16], [17].…”

Section: Active Phase Bias Controlmentioning

confidence: 99%

Two-dimensional ultrasound receive array using an angle-tuned Fabry-Perot polymer film sensor for transducer field characterization and transmission ultrasound imaging

Beard

2005

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

View full text Add to dashboard Cite

Abstract-A 2-D optical ultrasound receive array has been investigated. The transduction mechanism is based upon the detection of acoustically induced changes in the optical thickness of a thin polymer film acting as a FabryPerot sensing interferometer (FPI). By illuminating the sensor with a large-area laser beam and mechanically scanning a photodiode across the reflected output beam, while using a novel angle-tuned phase bias control system to optimally set the FPI working point, a notional 2-D ultrasound array was synthesized. To demonstrate the concept, 1-D and 2-D ultrasound field distributions produced by planar 3.5-MHz and focused 5-MHz PZT ultrasound transducers were mapped. The system was also evaluated by performing transmission ultrasound imaging of a spatially calibrated target. The "array" aperture, defined by the dimensions of the incident optical field, was elliptical, of dimensions 16 12 mm and spatially sampled in steps of 0.1 mm or 0.2 mm. Element sizes, defined by the photodiode aperture, of 0.8, 0.4, and 0.2 mm were variously used for these experiments. Two types of sensor were evaluated. One was a discrete 75-m-thick polyethylene terephthalate FPI bonded to a polymer backing stub which had a wideband peak noise-equivalent pressure of 6.5 kPa and an acoustic bandwidth 12 MHz. The other was a 40-m Parylene film FPI which was directly vacuum-deposited onto a glass backing stub and had an NEP of 8 kPa and an acoustic bandwidth of 17.5 MHz. It is considered that this approach offers an alternative to piezoelectric ultrasound arrays for transducer field characterization, transmission medical and industrial ultrasound imaging, biomedical photoacoustic imaging, and ultrasonic nondestructive testing.

show abstract

“…phase algorithms (two [9], three [10], four [11] and five [12] wavelength techniques), FFT algorithm [13], [14] and its improved algorithms [1], [2], [15], DTG algorithm [9], wavelet phase extracting (WPE) algorithm [16], and Least-Squares fitting (LSF) [17] and its improved algorithms [18]. Yet, the models of the above-mentioned algorithms were all established on the static FP spectrum.…”

Section: Introductionmentioning

confidence: 99%

A Demodulation Model of Dynamic Low-Finesse Fabry-Perot Cavity Based on the Instantaneous Frequency

Zhang

Xiong²,

Shao

et al. 2020

IEEE Access

View full text Add to dashboard Cite

If the measurand changes during the spectrum acquisition process, it easily leads to the failure of the classic demodulation algorithms of low-finesse optical fiber Fabry-Perot (FP) sensors. To address this problem, a novel demodulation model is proposed based on the definition of the instantaneous frequency. The proposed model establishes the relationship between the optical path length (OPL) of the FP cavity and the instantaneous frequency distribution of the FP interference spectrum. The link between the classic FFT algorithm and this model is discussed, and it is found that this model can be viewed as a generalized form of the FFT algorithm. Based on this model, the Doppler-induced demodulation error is analyzed. The analysis uncovers that the average frequency of the FP interference spectrum should be used for the evaluation of the error, and the error is proportional to the variation of OPL during the spectrum acquisition period. Further, numerical simulation and an experiment were carried out to verify the proposed model, and results show that the proposed model is effective for the dynamic low-finesse FP cavity. It is the first time that the idea of instantaneous frequency is introduced for the FP demodulation, and this model provides us a new way to cope with the FP sensing signal.

show abstract

Phase-demodulation error of a fiber-optic Fabry–Perot sensor with complex reflection coefficients

Cited by 9 publications

References 13 publications

Interrogation of free-space Fabry–Perot sensing interferometers by angle tuning

Interrogation of free-space Fabry–Perot sensing interferometers by angle tuning

Two-dimensional ultrasound receive array using an angle-tuned Fabry-Perot polymer film sensor for transducer field characterization and transmission ultrasound imaging

A Demodulation Model of Dynamic Low-Finesse Fabry-Perot Cavity Based on the Instantaneous Frequency

Contact Info

Product

Resources

About