Misalignment-Tolerant Silicon Optical Modulator With Surface-Normal Optical Interface

Compared with the performance evolution of silicon optical modulators, photonic packaging problem deserves more attention as a big obstacle of commercial applications. Edge couplers only have submicron-misalignment tolerance, while conventional grating couplers need angle polishing in fiber packaging. To achieve low-cost fiber packaging, a strong misalignment-tolerant optical modulator is proposed and demonstrated with surface normal optical interface. Benefit from the particular characteristics of the bidirectional grating structure, the silicon optical modulator can operate under ±2-μm fiber misalignment with clear open eyes.