On-chip integratable all-optical quantizer using cascaded step-size MMI

We propose a novel all-optical phase shifted quantizer using cascade step-size MMI. The operation principle has been derived in detail. A 3-bit quantizer and a 5-bit quantizer are designed and simulated based on 220-nm SOI platform to verify the feasibility of the scheme, of which the lengths are all below 200 mu m. To the best of our knowledge, they have the most compact footprint compared to the existing all-optical quantizers. In the end, the fabrication error analyses of the proposed quantizers are carried out to verify their stability. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement