Compact photonic crystal demultiplexers and spectrometers

Abstract

Compact on-chip wavelength demultiplexers and spectrometers are essential components for a variety of applications including integrated optical information processing devices, optical communications, and integrated optical sensing. Implementation of such devices requires strong dispersion in the optical materials, which can be realized using unique dispersive properties of photonic crystals (PCs). Possibility of integration, compactness, and compatibility with different host materials are the main advantages of PC based demultiplexers and spectrometers compared to other techniques. Here, we show an implementation of superprism-based photonic crystal devices (using a diffraction compensation scheme) that improves the performance of these devices compared to the conventional implementation. Structures obtained through optimization have been fabricated in SOI wafers using e-beam writing and ICP etching, and spatial separation of channels (with good isolation) in these superprism devices is experimentally demonstrated. The performance of these superprism devices as general-purpose spectrometers and for locating spectral features in a sensing platform will be also demonstrated and discussed. Further steps for improvement of these devices are considered and the related implementation issues are investigated.