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TABLE OF VARIABLES
| a(z) | arbitrary function |
| A 0 | fiber elongation corresponding to 1 rad of phase shift |
| A(z, t) | output of DAS |
| A1(z) | output of DAS with first order algorithm |
| A2(z) | output of DAS with second order algorithm |
| b(z) | arbitrary function |
| c | optical speed of light in fiber |
| C | speed of sound |
| D | DAS dynamic range |
| e(t′) | optical field of coherent input pulse |
| E(t′) | optical field on photodetector |
| ℑ(K, F) | Fourier transforms of seismic signal |
| ℑ | Fourier transform symbol |
| F | frequency of sound |
| F MAX | maximum frequency of sound |
| F S | pulse repetition rate or sampling frequency |
| G(z) | geophone antenna response |
| hυ | energy quant |
| Im Z | imaginary part of interference output |
| Ij (z, t) | intensity trace for different interferometric output |
| I(z, t) | photodetector intensity trace |
| j | integer number |
| K | acoustic angular wavenumber |
| K z | acoustic angular wavenumber along fiber |
| K e | ratio of optical to physical length of fiber |
| L | fiber length |
| L P | integration length |
| L 0 | interferometer length also known as gauge length |
| L S | scattering zones spacing |
| M | number of scattering zones |
| n eff | fiber effective refractive index |
| N F | noise figure of amplifier |
| N | number of photons per second |
| p(z) | averaging function |
| P 0 | input peak power |
| P | number of different interferometric ports or pulses |
| R BS | backscattering coefficient of fiber |
| r0(z) |
distribution
|
