Realization of Hollow-Core Photonic-Crystal Fiber Optic Gyro Based on Low-Noise Multi-Frequency Lasers with Intermediate-Frequency Difference.

Hongchen Jiao,Lishuang Feng,Qingjun Zhang,Xindong Cui,Chunqi Zhang,Tao Wang,Xiaoning Ji,Jie Liu,Ning Liu

doi:10.3390/s20102835

Abstract

Mainly focusing on the demand for a novel resonator optic gyro based on a hollow-core photonic-crystal fiber (HC-RFOG), we achieve a multi-frequency lasers generation with low relative phase noise via an acousto-optic modulation of light from a single laser diode. We design a homologous heterodyne digital optical phase-locked loop (HHD-OPLL), based on which we realize the low-noise multi-frequency lasers (LNMFLs) with an intermediate frequency difference. The noise between the lasers with a 20 MHz difference is 0.036 Hz, within the bandwidth of 10 Hz, in a tuning range of 120 kHz, approximately 40 dB lower than that produced without the HHD-OPLL. Finally, based on the LNMFLs, an HC-RFOG is realized and a bias stability of 5.8 °/h is successfully demonstrated.

Highlights

Resonator fiber optic gyros (RFOGs) based on the hollow-core photonic-crystal fiber (HC-RFOGs), combining the miniaturization of RFOGs and the environmental stability of hollow-core photonic-crystal fibers (HCPCFs), are considered as potential alternates for navigation grade optic gyros [1,2,3].As reported, the differential detection scheme is one of the most promising solutions for suppressing nonreciprocal noises in HC-RFOGs [4,5,6]
Mainly focusing on the demand of the novel HC-RFOG, we suggest a method to generate low-noise multi-frequency lasers (LNMFL) with an intermediate frequency (IF) difference based on a single laser diode
In order to reduce the laser frequency noise in the HC-RFOG, we presented a method to the LNMFL based on the acousto-optic modulator (AOM) and HHD-optical phase-locked loop (OPLL)

Summary

Introduction

Resonator fiber optic gyros (RFOGs) based on the hollow-core photonic-crystal fiber (HC-RFOGs), combining the miniaturization of RFOGs and the environmental stability of hollow-core photonic-crystal fibers (HCPCFs), are considered as potential alternates for navigation grade optic gyros [1,2,3].As reported, the differential detection scheme is one of the most promising solutions for suppressing nonreciprocal noises in HC-RFOGs [4,5,6]. The generation of multiple-frequency lasers with low relative phase noise and radio wavelength frequency differences is the key requirement for the differential detection scheme [7,8]. The most widely used low-noise multi-frequency lasers generation method is the optical sideband modulation (OSBM) [12,13,14]. This method produces a series of optical sideband signals with a fixed frequency difference by an external modulation of the laser (amplitude modulation or phase modulation). These sideband signals have the same random phase. To obtain multi-frequency lasers with clean spectrums, researchers have proposed the optical injection locking (OIL) method [15], the optical phase-locked loop (OPLL)

Methods

Results

Conclusion