A Novel Optical Path for Enhancing the Performance of High-Power Semiconductor Laser in Packaging

Abstract

High-power semiconductor laser has more significant applications in long distance and high-reliability optical communication systems. It is noticed that the packaging plays an important role in the performance of high-power semiconductor laser, including high output power, high coupling efficiency, low relative intensity noise (RIN), and so on. Usually, in a symmetrical optical path, the light, which incident directly parallel to the optical axis of the lens, will be partially reflected back to the laser and cause noise. To solve this problem, a novel asymmetric optical path is designed and implemented to meet the requirement of using a high-power laser with low RIN in this work. By employing an isolator between the first and second lens, the laser with high beam quality and low reflection of the signal was achieved. Moreover, the optical focal length of the collimating lens and the angle of the inclined lens were optimized by simulation. The proposed laser exhibited high coupling efficiency with a RIN of −168.89 dB/Hz. According to theoretical and experimental analysis, the performance of the laser will be helpful in fabricating a high-power laser with low RIN for next-generation optical communication.