Design of narrow channel spacing photonic wire AWG on SOI with three stigmatic points

Abstract

In this paper, an accurate Fourier Optics method of designing AWG demultiplexer based on high-index-contract Silicon-on-Insulator (SOI) materials is presented. The typical SOI photonic wire waveguide has a cross section of 400×340nm 2 satisfying single-mode condition, and operating central wavelength is 1.5500μm. A three-stigmatic-points method is also applied in order to improve the accuracy, considering the aberration theory. Furthermore, our AWG has another important characteristic--the flat field of the output ports. In the example presented here, we design a 1×256 channel AWG with 0.1-nm channel spacing. The simulation result shows that the insert loss is almost 0dB for the central and peripheral output ports as well, representing a good uniformity. Meanwhile, the crosstalk to the adjacent channel is 14.4dB. Free spectral region (FSR) equals to 30nm as designed.

Design, simulation and characterization of integrated photonic spectrographs for Astronomy II: Low-aberration Generation-II AWG devices with three stigmatic points

“…An elegant alternative is provided through the three-stigmatic-point geometry, which achieves field-flattening by modifying the grating shape and array waveguide lengths [7][8][9]. Working field-flattened devices using three stigmatic points have been demonstrated on polymer and SOI platforms [10,11]. This work is the second paper in a series covering the design of integrated diffractive elements for the "Potsdam Arrayed Waveguide Spectrograph" (PAWS) [12], a semi-integrated photonic spectrograph using various AWG designs as well as photonic echelle gratings (PEGs) with a modified focal plane using two stigmatic points.…”