A 300-mm Silicon Photonics Platform for Large-Scale Device Integration

A 300-mm silicon photonics platform for large-scale device integration was developed, leveraging 40-nm complementary metal-oxide-semiconductor technology. Through fabrication using this technology platform, wire waveguides were obtained with low propagation losses for the C-band (0.4 dB/cm) and O-band (1.3 dB/cm). Several types of wavelength filters, including a coupled resonator optical waveguide (CROW), an arrayed waveguide grating, and a cascaded Mach-Zehnder interferometer, were also demonstrated, with low crosstalk and low insertion loss. A polarization rotator Bragg grating with multiple reflection peaks having polarization independence was also obtained. In terms of wafer-scale uniformity, a small standard deviation of 0.7 nm in resonant wavelength for the CROW was confirmed. A grating coupler also exhibited low wafer-scale variations in the maximum coupling efficiency and the diffraction wavelength in optical coupling with a single-mode fiber. Extraction of fabrication deviations for the waveguides was performed using the spectral variation of microring resonators and grating couplers. The extracted wafer-scale variations in waveguide width and height and grating depth well reproduced the results of physical measurements, with subnanometer-level accuracy. The developed technology can thus enable manufacturing of high-speed, low-power optical interconnects.