Multifunction Thin-Film Lithium Niobate Chip for an Interference Optical Gyroscope

A thin-film lithium niobate (TFLN) chip for an interferometric optical gyroscope (IOG), which integrates various passive and active functional devices such as a coupler, polarization beam splitter, and phase modulator on the chip, is proposed in this work. The measured modulation efficiency of the chip is as high as 1.8 V·cm, the modulation nonlinear coefficient is less than 1‰, and the residual intensity modulation coefficient is approximately 2.2‰, which are all excellent in the same material and similar functional devices. Welded into the IOG system, the bias instability of the system is measured to be 0.125°/h and angular random walk is 0.0048°/√h. It is verified that the multifunction TFLN chip has the potential to replace traditional bulk devices. The test process of the chip performance is described in this work, the current state is analyzed, and the future development direction is proposed.