ABSTRACT
An optical coupling method with high alignment tolerance by self-written waveguide (SWW) formation is a promising candidate for co-packaged optics (CPO) by silicon photonics (SiPh). However, conventional SWWs cannot be used with Si waveguides because visible light for SWW formation cannot radiate from the waveguide facet. Here, we devised a new, to the best of our knowledge, optical circuit with SiOxNy waveguides for SWW formation from an SiPh chip. With our circuit, we achieved optical coupling between an SiPh chip and a standard single-mode fiber (SSMF) with a tapered SWW (TSWW). The lowest excess coupling loss compared to butt coupling with a high-numerical aperture (NA) fiber is approximately 0.6â dB over the C-band with the TSWW. In addition, our coupling method has higher alignment tolerances than butt coupling with a high-NA fiber (HNF).
ABSTRACT
We propose a waveguide frontend with integrated polarization diversity optics for a wavelength selective switch (WSS) array with a liquid crystal on silicon switching engine to simplify the free space optics configuration and the alignment process in optical modules. The polarization diversity function is realized by the integration of a waveguide-type polarization beam splitter and a polarization rotating half-wave plate in a beam launcher using silica-based planar lightwave circuit technology. We confirmed experimentally the feasibility of using our proposed waveguide frontend in a two-in-one 1 × 20 WSS. The experimental results show that the fabricated waveguide frontend provides a polarization diversity function without any degradation in optical performance.
ABSTRACT
We demonstrate bidirectional transmission over 450 km of newly-developed dual-ring structured 12-core fiber with large effective area and low crosstalk. Inter-core crosstalk is suppressed by employing propagation-direction interleaving, and 409-Tb/s capacities are achieved for both directions.
