Polarization-independent wavelength demultiplexer based on a single etched diffraction grating device

Abstract

Polarization-compatible receivers are indispensable in transceivers used for wavelength division multiplexing optical communications, as light polarization is unpredictable after transmission through network fibers. However, the strong waveguide birefringence makes it difficult to realize a polarization-independent wavelength demultiplexer in a silicon photonic receiver. Here, we utilized the birefringence effect for simultaneously demultiplexing wavelengths and polarizations, and experimentally demonstrated a polarization-independent wavelength demultiplexer with a single device on a SiPh platform. The principle was validated on an etched diffraction grating, which successfully split the arbitrarily polarized light containing four wavelengths into eight channels with single-polarization and single-wavelength signals. Polarization-dependent losses of 0.5–1.8 dB, minimum insertion loss of 0.5 dB, and crosstalks lower than −30 dB were experimentally measured for the fabricated etched diffraction grating. Thus, a promising general solution was developed for implementing polarization-independent wavelength division multiplexing receivers and other polarization-independent devices on photonics platforms with birefringent waveguide devices.

Post-Processing Trimming of Silicon Photonic Devices Using Femtosecond Laser

“…Therefore, for platforms with the cladding of silica such as SOI and silicon nitride on the insulator [ 49 , 54 ], this method can be considered to compensate for phase-sensitive devices or systems, such as optical computing chips for the photonic neural network [ 13 ], optical modulators [ 55 ], wavelength division (de) multiplexers [ 14 ], and beam splitter devices like directional couplers [ 56 ]. Unfortunately, the trimming accuracy of laser trimming in batches has not yet been tested, because deviations in the relative focus position and the output power exist in the experiments, which must be improved in subsequent experiments.…”

“…Recently, silicon photonic integrations, based on complementary metal oxide semiconductor (CMOS)-compatible processes, have shown great application prospects in optical communications, optical interconnections, optical sensing, and optical computing because of their compact size, low power consumption, and low cost [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. The process nodes used by mainstream silicon photonic manufacturers are usually 130 nm or 180 nm for low-cost production, which inevitably introduces fabrication errors in the devices.…”

Silicon-Nanowire-Based 100-GHz-Spaced 16λ DWDM, 800-GHz-Spaced 8λ LR-8, and 20-nm-Spaced 4λ CWDM Optical Demultiplexers for High-Density Interconnects in Datacenters

“…As mentioned earlier, it is worth noting that the reason for the inferior IL and PDL observed in the proposed device scheme integrated with TM 00 -mode rejection filters was primarily due to fabrication imperfections rather than the integration of the TM 00 -mode rejection filters. As indicated in Table 3, a SiN-based optical DeMUX based on Echelle grating was also reported [72]. Based on different propagation constants and diffraction conditions for TE 00 -mode and TM 00 -mode input signals in the Echelle grating region, the diffracted CWDM output signals were filtered out to spatially separated output channels.…”

Silicon-Based Polarization and Wavelength Synchronous Demultiplexing Arrayed Waveguide Grating

“…However, these strategies invite complexity due to the incorporation of the PSR and additional TE-dependent AWGs or phase shifters. In pursuit of system simplification, we present an EDG-based polarization and wavelength synchronous demultiplexing device as a novel and practical solution to the wavelength division multiplexing (WDM) polarization issue [17].…”