Materials Processing for Heterogeneous Integration of Optical Isolators

ABSTRACT: This proposal develops materials processing and fabrication techniques for the heterogeneous integration of compact magneto-optical isolators. Commercially available magneto-optical materials will be tested and evaluated. The magneto-optic materials will be qualified to meet project metrics of less than 1 dB/cm bulk optical loss and Verdet constant at least -40 Rad/T.m. Both ion slicing and mechanical processes will be explored for production of magneto-optic films no more than 300 micron x 50 microns x 10 microns. Magneto-optic materials will be attached to silicon wafers to demonstrate suitability for heterogeneous integration with silicon photonics. Design and simulation efforts will focus on efficient coupling of light between attached magneto-optic films and the photonic substrate. A particularly compelling aspect of this proposal is the exploration of latching magnet-less film that do not require any external magnetic field. Magnet-less isolator device structures have the potential to be simpler and more compact relative to devices that require attachment of permanent magnets. We anticipate that the materials engineering technologies developed during this effort will be transferable to a foundry at a national facility for integration into standard silicon photonics processes.; BENEFIT: Optical isolators are used in high-speed transmitters used in long haul communications and laser based systems used in defense and aerospace applications. Optical isolator products used in todays defense and commercial systems are discrete components that are difficult and tedious to harness and maintain in the field because of the high number of optical fiber interfaces and the associated number of optical couplers and connectors. To fully enjoy the benefits of photonics technology, it is critical to integrate the various components into a single substrate to reduce size, power consumption, and cost. Heterogeneous integration of optical isolator in a silicon photonic circuit enables high level of integration, improved interconnect density and longer distance links, while making use of the mature silicon semiconductor foundry process.