A Design Method for Broadband Direct Modulation Laser

Aiming at the technical problems of low output optical power and small bandwidth of direct modulation laser, a design method for broadband direct modulation laser is proposed, and the design principle and internal structure of direct modulation laser are also presented. The effects of collimator lens and focusing lens on optical coupling efficiency are compared and analyzed by optical simulation software, the simulation results show that the coupling efficiency will be significantly affected by the small radial displacement of the collimating lens, which in turn affects the output optical power of the laser. Compared to collimating lens, the coupling efficiency is less affected by the radial offset of the focusing lens. The impedance matching of a broadband laser is designed and simulated using microwave simulation software, and the key indicators are also tested. The test results show that 3 dB bandwidth, output optical power, insertion loss, and noise figure of the designed broadband direct modulation laser are 18 GHz, 10.5 dBm, -25 dB, and 45 dB respectively, reaching the international level of similar products.