Postfabrication Phase Error Correction of Silicon Photonic Circuits by Single Femtosecond Laser Pulses

Phase errors caused by fabrication variations in silicon photonic integrated circuits are an important problem, which negatively impacts device yield and performance. This paper reports our recent progress in the development of a method for permanent, postfabrication phase error correction of silicon photonic circuits based on femtosecond laser irradiation. Using beam shaping technique, we achieve a 14-fold enhancement in the phase tuning resolution of the method with a Gaussian-shaped beam compared to a top-hat beam. The large improvement in the tuning resolution makes the femtosecond laser method potentially useful for very fine phase trimming of silicon photonic circuits. We also show that femtosecond laser pulses can directly modify silicon photonic devices through a SiO2 cladding layer, making it the only permanent post-fabrication method that can tune silicon photonic circuits protected by an oxide cladding.

硅光子集成电路制造偏差导致的相位误差是一个重要问题，它对器件的成品率和性能产生负面影响。本文报道了我们近期在基于飞秒激光照射的硅光子电路永久性制造后相位误差校正方法开发方面取得的进展。利用光束整形技术，我们使用高斯形状光束实现的该方法的相位调谐分辨率比平顶光束提高了14倍。调谐分辨率的大幅提高使得飞秒激光方法有可能用于硅光子电路非常精细的相位微调。我们还表明，飞秒激光脉冲可以通过二氧化硅包层直接修改硅光子器件，这使其成为唯一一种能够对受氧化物包层保护的硅光子电路进行调谐的永久性制造后方法。