Chip-Scale WDM Devices Using Photonic Crystals

: This AFOSR-supported research was aimed at realizing several chip-scale optical devices needed as building blocks for implementing integrated optical systems. To achieve this, we developed several theoretical, fabrication, and characterization tools and procedures for photonic crystals. Some of the main achievements of the previous AFOSR-funded research at the device level are as follows: (1) Photonic crystal waveguides (PCWs) with low loss, large transmission bandwidth, and very low dispersion and distortion in their pass-band for efficient guiding of light; the bi-periodic PCW proposed and demonstrated in our research has shown the best performance among all proposed PCW structures in terms of low propagation loss and available guiding bandwidth; (2) Photonic crystal superprism-based demultiplexers for compact separation of spectral channels in an integrated platform; the focusing superprism idea proposed and experimentally demonstrated for the first time within this program carries the world record on PC demultiplexing in integrated platforms with at least two orders of magnitude smaller size (while having the same performance) compared to all existing implementations of the same structure; (3) Theoretical prediction of very compact photonic crystal couplers with performance that cannot be achieved in other integrated platforms; (4) Theoretical investigation and demonstration of optical cavities with high quality factors. The fabrication techniques to reliably make these structures have also been optimized.