Optimal design of linear tapered double S-shaped arrayed waveguide grating for broad channel spacing on silicon-on-insulator

Abstract

A linear tapered double S-shaped arrayed waveguide grating (AWG) was designed as an alternative to a U-shaped AWG, and a complete transmission spectrum for 18 channels of coarse wavelength-division multiplexing (CWDM) was demonstrated. The silicon-on-insulator based AWG with a rib waveguide structure with a broad channel spacing of 20 nm was designed to serve as a multiplexer/demultiplexer. A beam propagation method modeling simulation under transverse electric mode polarization over a free spectrum range of 700 nm was used for the design process. The geometrical dimensions of the AWG rib structure were optimized to achieve the lowest reported insertion loss of 1.07 dB and adjacent crosstalk of −38.83 dB. The influence of different etching depths on the top Si layer of the AWG for a constant core width of 0.6 μm as well as birefringence effects were also investigated. A transmission spectrum response at the output port close to the standard CWDM wavelength grid range of 1271 to 1611 nm with an average channel spacing of 2485 GHz was obtained. IntroductionSilicon-on-insulator (SOI) has become a popular choice of material in recent years because of its potential for use in the photonics components manufacturing industry, which uses a monolithic or hybrid integration assembly. Arrayed waveguide gratings (AWG)-based silicon waveguide structures functioning as multiplexers/demultiplexers (mux/ demux) are being widely employed in wavelength-division multiplexing (WDM) systems. There are several advantages in using SOI as a platform for photonics integration, such as low manufacturing costs due to the use of existing complementary metal oxide semiconductor fabrication technology, 1 compact devices, and high confinement of the optical mode. 2 Further, silicon has a high index contrast (Δn) and is transparent at infrared wavelengths, making it suitable for optical communication applications. By using these features of SOI materials, we designed and analyzed an SOI-based AWG mux/demux capable of splitting or combining the multiple signals in a single fiber utilized in coarse wavelength-division multiplexing (CWDM) systems.In this work, we optimized the geometrical rib waveguide structure and characterized the ideal parameters of a linear tapered double S-shaped AWG on an SOI platform to mitigate insertion loss (IL) and adjacent crosstalk (XT) in an 18-channel CWDM device with a channel spacing of 20 nm. The investigations were carried out by selecting the dimensions of the rib waveguide, which allows a single-mode condition where the ratio of the slab height (h) to the thickness of the top silicon (Si) guiding layer (H) or h∕H was in the range

Performance on optical properties of AWG based on SOI demultiplexer and receiver sensitivity in CWDM system

“…For broad channel spacing or CWDM channel spacing, the large FSR was produced with smallest ΔL = 1.284 µm. Hence, due to smallest ΔL and limitation on AWG tools [9] it makes individual waveguide at arrays region becomes intercept. To overcome this issue, broad channel spacing device was suitable when double S-shape pattern used at arrays waveguide region compared to U-shaped pattern.…”