Locking a polarization-insensitive optical receiver

Abstract

An optical receiver is described. Using silicon-photonic components that support a single polarization, the output of an optical receiver is independent of the polarization of an optical signal. In particular, using a polarization-diversity technique, the two orthogonal polarizations in a single-mode optical fiber are split in two and processed independently. For example, the two optical signals may be provided by a polarization-splitting grating coupler. Subsequently, a redistribution element provides mixtures of the two optical signals. Next, a wavelength channel in the two mixed optical signals is selected using a wavelength-selective filter (for example, using ring-resonator drop filters or an echelle grating) and converted into an electrical signal at an optical detector (such as a photodetector) to achieve polarization-independent operation.