Application of a semiconductor laser diode as an optical radiation source in a fiber-optic gyroscope

Subject of study . The feasibility of utilizing a frequency-modulated semiconductor laser diode, with distributed feedback, as an optical radiation source in a fiber-optic gyroscope (FOG) is investigated. Aim of study. The aim of this study is to improve the long-term stability of the scale factor of an FOG while preserving the size and weight parameters of the semiconductor laser diode integrated into the system. Method. Frequency–pulse current modulation was applied to reduce the coherence length of the semiconductor laser diode emission. The coherence length of the radiation was evaluated using broadband interferometry, and optimal parameters of the FOG’s photodetection scheme were selected. The proposed configuration was tested on an open-loop FOG prototype, and the metrological characteristics of a configuration employing a laser source were compared with those of a configuration utilizing a superluminescent diode (SLD). Main results . The obtained results demonstrated the effectiveness of the proposed scheme. The long-term instability of the central wavelength and the angular random walk were reduced to 1.3 ppm and 0.002 ∘ /h 1/2 , respectively (compared with 17 ppm and 0.004 ∘ /h 1/2 for the configuration with an SLD). The bias drift (0.05°/h) is comparable to that of the reference configuration (0.01°/h). Further reduction of this parameter remains a subject for future investigations. Practical significance . The experimental results obtained in this study demonstrate the potential applicability of frequency-modulated distributed-feedback semiconductor laser diodes as light sources in next-generation compact, high-precision FOGs.