Precision Navigation Grade Fiber-Optic Gyroscope (FOG)

The objective of the program is to develop a Precision Fiber Optic Gyro (PFOG) for the navigational grade inertial measurement units (IMUs) for use in the modern Position Navigation Time (PNT) applications. In Phase I of the program, a conceptual design of the PFOG was developed and its feasibility affirmed. The PFOG under development is a closed loop gyro. The key feature of the design is a functionally isolated multi-integrated optics chip (MIOC) mounted on a silicon substrate providing the electronics. The design incorporates a high degree of operational symmetry -- in optical, mechanical and electronic areas. The gyro operation at the highest point of sensitivity is ensured via a differential bias phase modulator (DBPM). For the closed-loop operation, a digitally synthesized phase ramp generator nulls the rotation rate induced Sagnac phase shift via a differential Sagnac phase modulator (DSPM). Six different methods of phase modulation for DBPM and DSPM were analyzed and the optimal one was selected for first fab iteration of the MIOC. The selected design yields four MIOC devices per 76mm LiNbO3 wafer. In Phase II, the PFOG prototype will be built to size using component design finalized during Phase I analysis and trade-off studies. It will be made up of a fiber spool and an electro-optics hybrid package. The hybrid package will consist of a LiNbO3 MIOC and a silicon substrate. Upon completing the development, a PFOG prototype unit will be built, tested, and delivered to AFRL at WPAFB for further evaluation.