In multi-chip integrated photonic micro-systems, it is important to protect the laser source from reflection because the semiconductor laser is sensitive to the back reflection induced by the roughness of the waveguide sidewall or other on-chip optical structures. In order to maintain the stable operation of the light source, an additional micro-ring resonator coupled with the laser source is design before the optical circuit which enables the laser diode to enter a self-injection locking state and improves the reflection tolerance. It is experimentally demonstrated in the hybrid system that by tuning the phase shifter and the micro-ring resonate wavelength, the distributed feedback (DFB) laser enters a self-injection locking state, resulting significant improvement of the critical reflection ratio from −18.69 dB to −4.31 dB. The method can isolate the external reflection of laser diode without using heterogeneous integration, which provides a new idea for on-chip source isolation. The parameters design of the micro-ring and the coupling method with the laser are also introduced in the letter.

中文翻译：

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一种提高混合光子封装微系统中激光源反射容忍度的方法

在多芯片集成光子微系统中，保护激光源免受反射非常重要，因为半导体激光器对波导侧壁或其他芯片上光学结构的粗糙度所引起的背反射敏感。为了保持光源的稳定运行，在光路之前设计了一个附加的与激光源耦合的微环谐振器，使激光二极管进入自注入锁定状态并提高了反射容限。在混合系统中通过实验证明，通过调整移相器和微环谐振波长，分布式反馈（DFB）激光器进入自注入锁定状态，从而将临界反射率从-18.69 dB显着提高到了18.69 dB。 −4.31 dB。该方法可以在不使用异质积分的情况下隔离激光二极管的外部反射，这为片内源隔离提供了新思路。文中还介绍了微环的参数设计以及与激光的耦合方法。