Method for improving extinction ratio of Y-waveguide chip for fiber-optic gyroscope

The invention provides a method for improving an extinction ratio of a Y-waveguide chip for a fiber-optic gyroscope. The method for improving the extinction ratio of the Y-waveguide chip for the fiber-optic gyroscope comprises the Y-waveguide chip which is formed by a waveguide chip and a Y-shaped waveguide arranged on the waveguide chip. The input end of the waveguide chip is connected with an input optical fiber, and the output end of the waveguide chip is connected with an output optical fiber. The method for improving the extinction ratio of the Y-waveguide chip for the fiber-optic gyroscope is characterized in that a physical isolation area is formed in the middle portion of the Y-waveguide chip to interdict the transmission of emitted light in the waveguide chip. The method for improving the extinction ratio of the Y-waveguide chip for the fiber-optic gyroscope has the advantages that the extinction ratio of the waveguide chip can be greatly improved to meet the requirements of a high-precision fiber-optic gyroscope system, a modulation structure does not need to be arranged on the waveguide chip, and the method hardly has any influence on a structure size.