Evaluation of Polarization Characteristics of the Fiber-Pigtailed Waveguide-Type Ring Resonator and Implications for Resonant Micro-Optic Gyroscopes

A group of misaligned angles is proposed to describe the polarization characteristics of the fiber-pigtailed waveguide-type ring resonator (WRR). With these angles, a polarization analysis model is then set up using the Jones matrix method. The output polarization extinction ratios (PERs) of the WRR are obtained through measuring resonant curves under different input PERs. Though multiple numerical groups of solutions for misaligned angles can be obtained by substituting these input-output PERs into the polarization analysis model, we are delighted to find that different groups of misaligned angles do not affect the polarization analysis of the WRR. Thus, the output PER can be pre-evaluated by selecting any group of misaligned angles. The PER improvements of the output light from the WRR are compared both theoretically and experimentally when polarizers are added at the input and output ports of the cavity, as well as employing an intracavity polarizer. The influences of misaligned angles are also discussed.