Optical isolators and circulators are extremely valuable components to have in photonic integrated circuits, but their integration with lasers poses significant design and fabrication challenges. These challenges largely stem from the incompatibility of magnetooptic material with the silicon or III-V platforms commonly used today for photonic integration. Heterogeneous integration using wafer bonding can overcome many of these challenges, and provides a promising path towards integrating isolators with lasers on the same silicon chip. An optical isolator operating for TE mode with 25 dB of isolation, 6.5 dB of insertion loss, and tunability over 40nm is demonstrated and a path towards integrating this isolator with the heterogeneous silicon/III-V laser is described.
