Optimal Design of High-Speed Electro-Absorption Modulated Laser Based on Double Stack Active Layer Structure

This paper aims to further improve the response speed of the selective area growth double-stack active layer structure electro-absorption modulated laser (SAG-DSALEML) in a high-frequency modulation environment and improve the far-field divergence angle characteristics of the laser. We present a new structure of SAG-DSAL-EML. The new structure SAG-DSAL-EML active area into mesa structure and adopts iron-doped buried technology to complete the waveguide structure design. Iron-doped InP layers are grown on both sides of the active zone, which can effectively improve the high-speed frequency response characteristics of the modulator while improving the far-field divergence angle characteristics of the chip. In this paper, the Advanced Laser Diode Simulation (ALDS) software is used for simulation analysis, and it is compared and verified with the fabricated high-speed electro-absorption modulated laser sample chip with double active area laminated structure. Software analysis shows that compared with the ridge waveguide structure, the iron-doped buried structure has a smaller difference between the lateral and longitudinal angles of the far-field divergence angle, and the optical field coupling efficiency is better. Experiments show that the threshold current of the laser is 14.5mA at room temperature, and the side-mode suppression ratio of the laser at 1310nm is 45.64dB. The extinction ratio of the modulator under 3v reverse bias exceeds 16dB, and when the bias voltage is 0.9V, the modulation bandwidth under -3dB exceeds 40Ghz, which meets the basic requirements of high-speed laser communication.