Resonant Fiber-Optic Gyroscope Driven by Broadband Source with Low Cost and High Accuracy

Objective Low-cost, high-precision gyroscopes have significant potential applications across various fields, including miniaturized unmanned aerial vehicles (UAVs), micro satellites, and autonomous driving. Traditional interferometric fiber-optic gyroscopes (IFOGs) have reached a relatively mature stage of development and are widely used. However, the accuracy of these system is directly proportional to the length of the fiber-optic ring. Consequently, higher accuracy requires increased gyroscope volume and cost, making the system more susceptible to environmental factors. As an alternative, resonant fiber-optic gyroscopes (RFOGs) driven by broadband sources offer the potential to achieve the same accuracy as IFOGs with shorter fiber lengths. This enables miniaturization while maintaining low cost and high precision. However, current implementations of broadband source-driven RFOGs typically reply on high-power light sources (tens of milliwatts), LiNbO3 phase modulators, and polarization-maintaining fiber-optic ring resonators (PM-FRRs), which drive up costs. In this paper, we propose a novel RFOG design that significantly reduces costs by employing a low-power (several mW) broadband light source, a piezoelectric transducer (PZT) phase modulator, and a single-mode fiber-optic ring resonator (SM-FRR) as the core optical path components. We hope that the strategies and findings presented here will contribute to the next generation of RFOG development. Methods In this paper, we undertake a comprehensive analysis and experimental investigation of broadband source-driven RFOGs, focusing on balancing cost-effectiveness and accuracy. A mathematical model of sinusoidal modulation and demodulation is developed based on the characteristics of the PZT phase modulator and the SM-FRR to validate the feasibility of the proposed design. A theoretical model is then constructed using SM-FRR parameters to analyze the shot noise-limited theoretical sensitivity and optimize key modulation parameters, including the modulation frequency and index, to maximize the demodulation slope. In addition, a self-heterodyne system is built to investigate the relationship between the half-wave voltage of the PZT phase modulator and the modulation frequency, ensuring optimal modulation parameters. Finally, a broadband source-driven RFOG system is constructed and tested in a static environment at room temperature. An Allan deviation analysis is conducted to evaluate the gyroscope's precision and bias stability. Results and Discussions An RFOG system is constructed, featuring a 39-m-long SM-FRR with a definition of 58.5 as the core sensitive element. The optimal modulation parameters are determined to be a modulation index of 1.3 and a modulation frequency of 69 kHz, yielding a theoretical sensitivity of 0.0025 (degrees)/h(1/2), limited by the photodetector's shot noise. The developed RFOG, incorporating a low-power broadband light source, a PZT phase modulator, and an FPGA for data processing, demonstrates outstanding performance in experimental testing. The measured angular random walk (ARW) is 0.0219 (degrees )/h(1/2), and the bias instability (BI) is 0.031 (degrees )/h (Fig. 10). These results confirm that the proposed broadband source-driven RFOG design significantly reduces system costs while maintaining high performance. Conclusions We demonstrate a novel RFOG driven by a broadband light source. The system's optical path features a low-power broadband light source, a PZT phase modulator, and an SM-FRR. Through optimized modulation parameters, the gyroscope operates at the maximum demodulation slope, achieving optimal performance. This innovative approach provides a promising path toward integrated, cost-effective medium- and high-precision fiber-optic gyroscope technology.