Fig. 1. Integrated fiber optic gyroscope system based on Si₃N₄ optical engine chip

Fig. 2. High aspect ratio Si₃N₄ waveguide structure and mode field distribution diagrams. (a) Cross sectional view; (b) TE mode; (c) TM mode;(d) TM mode at bend waveguide

Fig. 3. MMI structure

Fig. 4. Simulation of the length L₂ of the multimode interference zone of MMI beam splitter. (a) The relationship between length L₂ length and MMI transmission loss; (b) the relationship between L₂ length and MMI splitting ratio

Fig. 5. Simulation of the optimal position point for the output waveguide. (a) Output waveguide transmission loss of MMI beam splitter at different points; (b) MMI beam splitter splitting ratio

Fig. 6. Simulation of the output Taper waveguide W₄ width. (a) The relationship between the width of output waveguide W₄ and MMI transmission loss; (b) the relationship between the width of output waveguide W₄ and MMI splitting ratio

Fig. 7. Simulate the length of the output Taper waveguide L₃. (a) the relationship between the length of the output Taper waveguide L₃ and the MMI transmission loss; (b) the relationship between output Taper waveguide L₃ length and MMI splitting ratio

Fig. 8. Optical field transmission diagram of MMI beam splitter

Fig. 9. Inverted spot-size converter. (a) Structural diagram; (b) transmittance under different Taper lengths

Fig. 10. Mode field transmission diagram of the Taper spot converter

Fig. 11. Processing flow chart of Si₃N₄ optical engine chip