Research On Mold Selector For External Cavity Narrow Linewidth Semi-conductor Laser

With the rapid development of 5G,autopilot and big data technology,the global data flow has increased explosively,which puts forward higher requirements for the high-speed transmission of information and data.In the communication system,the laser light source plays a key role in the quality and speed of information transmission.The external cavity semiconductor laser reduces the linewidth of the laser by increasing the laser cavity length,realizes the high power output and the fast tuning of the light source,which can well meet the needs of various fields.For the external cavity laser,the performance of the external cavity mode selector largely determines the output linewidth,output power and tuning range of the laser.Therefore,the research on the mode selector of external cavity laser has been a research hotspot in the optical communication industry all over the world.In this paper,the waveguide Bragg grating and the double-ring resonator in the external cavity mode selector are optimized and designed,the external cavity laser is tuned,and the designed double-ring resonator is manufactured and tested.The research contents of the full text are summarized as follows:(1)The external cavity narrow linewidth laser and its mode selector are analyzed.The basic performance of the external cavity narrow linewidth semiconductor laser is analyzed,and the narrowing effect of the external cavity mode selector on the linewidth is verified.The basic structures of Bragg grating and ring resonator are introduced,and the working principles of these two structures are analyzed by coupled mode theory and transfer matrix method respectively,and the theoretical formulas of the main optical performance indexes are obtained.(2)The uniform waveguide grating is optimized.The influence law and degree of the parameters of the grating on the optical performance are mainly studied.on this basis,the waveguide grating is optimized.the minimum linewidth of the optimized strip waveguide grating is 0.124 nm,and the maximum edge mode suppression ratio is 11.3dB,while the minimum linewidth of the ridge waveguide grating is 0.085 nm and the maximum side mode rejection ratio is 11 dB.The manufacturing error of the optimized waveguide grating is analyzed by Monte Carlo analysis method.(3)The cascaded double-ring resonator is optimized.The structure and Vernier effect of cascaded double-ring resonators are introduced.The mechanism of the influence of various structural parameters on the optical performance of the cascaded double-ring resonator is analyzed.The tuning range of the optimized double-ring resonator can reach 35 nm,the maximum side-mode rejection ratio can reach 9.2dB,and 19 wavelengths can be tuned by injecting current into ring 2.The optimized cascade double-ring resonator is used as the external cavity mode selection device of the gain chip,and the single-mode output and tuning of the external cavity narrow linewidth semiconductor laser are realized.(4)The fabrication process of the cascaded double-ring resonator is introduced,and the cascaded double-ring resonator is designed and fabricated based on the planar optical waveguide loop process.Build a test platform and test the chip.