Influence of the transmitting spectra of fiber coupler on the SNR of FOGs

The output spectra of fiber source, which transmitted through a single-mode (SM) fiber coupler, were measured by changing temperature. When the input wave of the fiber optical gyroscope (FOG) from the fiber coupler were transmitting wave and coupling wave, respectively, the temperature characteristics of signal-to-noise ratios (SNR) of FOG were simulated. The above experimental results demonstrate that the output power, mean-wavelength and spectral width of the spectra traveling through the arm of directly-transmission and that of the coupling of coupler will change when the temperature changes, and the temperature-stability of output power, mean-wavelength and spectral width of the directly-transmission arm is higher than that of the coupling arm. And the simulated results demonstrate that the errors of FOG's caused by the light wave outputting from the coupling arm of SM fiber coupler are almost 4 times of that from the directly-transmission arm.