Beam shaping for ultra-compact waveguide crossings on monolithic silicon photonics platform

A beam shaping approach has been implemented to realize high-performance waveguide crossings based on cosine tapers. Devices with a compact footprint of 4.7 mu m x 4.7 mu m were fabricated on the GLOBALFOUNDRIES 45 nm monolithic silicon photonics platform (45 CLO technology). Fabricated devices are found to be nearly wavelength independent (+/- 0.035 dB for 1260 nm <= lambda <= 1360 nm) with low insertion loss (similar to 0.2 dB) and crosstalk (-35 dB). The measured response of the devices is consistent with the three-dimensional finite-difference time-domain simulation results. The design stability is validated by measuring the device insertion loss on eight chips, which is found to be 0.197 +/- 0.017 dB at the designed center wavelength of 1310 nm. (C) 2020 Optical Society of America