On-Chip Optical Isolation for Integrated Photonics

An on-chip optical isolator is needed for integration of a laser diode with other PIC components. On-chip isolators and circulators are critical to PSI technology roadmap of PIC realization of our tunable optical paired source (TOPS). Herein, PSI propose an on-chip optical isolator architecture that is applicable for different material systems utilizing the nonlinear property of a phase modulator and a high extinction ratio microring drop filter. In phase I, we will conduct proof-of-concept demonstrations for on-chip isolator in both LNOI platform and Si PIC platform. We will develop mathematical models to evaluate device performances for different isolator designs and provide specification requirements for individual components. We will develop the key LNOI isolator components leveraging our expertise on LNOI modulators, tunable microring resonators (MRRs) and heterogeneous LNOI integrations. We will design a Si-based isolator and include it in one of our quarterly AIM MPW tape-outs. In phase I option period, both the LNOI and the Si on-chip isolators will be experimentally characterized. In addition, an InP foundry, preferably a domestic vendor, will be identified for demonstration of a system-on-chip PIC with fully integrated laser diodes and isolators in phase II. In phase II, we will improve on-chip isolator designs based on phase I results and develop PIC solutions for our TOPS system where both isolators and a circulator are required. Solutions based on heterogeneous integration of laser diodes with LNOI and Si PICs and a solution based on a fully integrated InP PIC will be investigated and compared. The goal of this SBIR effort is to develop and demonstrate a general isolator architecture that can be applied for many popular PIC platforms, and to develop a PIC version of our TOPS system for microwave photonic applications. Based on our rich experiences in LNOI PIC development, long history of using PIC foundry services and existing commercial products and system applications that will greatly benefit from an on- chip isolator technology, PSI is uniquely qualified for this work.