Scalable photonic crystal waveguides with 2 dB component loss

Periodic or gradient subwavelength structures are basic configurations of photonic crystals and metamaterials. The measured linear losses of those nanophotonic devices are well-beyond theoretical predictions. Nanofabrication related geometric inhomogeneity is considered as the primary cause of the deleterious performance. The deep-UV photolithography in CMOS foundry is a large-scale parallel processing, which can significantly suppress the random offsets and thus the optical linear loss. Here we demonstrate ultra-low loss photonic crystal waveguides with a multi-project wafer run through AIM photonics and post-processing. For sub-millimeter long photonic crystal waveguides, 2 dB total loss and 40 dB extinction ratio are observed across dies.