Development of Sapphire based Integrated Microwave Photonics
Abstract
Microwave photonics (MWP) not only marries the fields of the radiofrequency (RF) engineering and optoelectronics but also brings in a considerable added value to traditional microwave and RF systems. Adding to its initial huge success in defense applications, MWP has also penetrated to a variety of civilian applications such as cellular, wireless, and satellite communications, cable television, distributed antenna systems, optical signal processing and medical imaging systems using THz waves and optical coherence tomography techniques. The future driving forces for MWP are expected to be broadband wireless access networks, the demand for more efficient wireless infrastructures due to the blooming of mobile device platforms and future wearable electronics, and emerging direct fiber link to home and in-home networks. Integrated Microwave Photonics (IMWP) incorporates the functions of MWP components /subsystems in monolithic or hybrid photonic circuits with a goal of meeting the future needs. Integrated microwave-photonic circuits on a chip offer the promise of reduced size-weight-andpower (SWAP) at very low cost when manufactured in a foundry. The chips enable the prospect of sophisticated microwave functionality that is often not available within the solely microwave domain. In 2018, Air Force Office of Scientific Research (AFOSR) has invested a research of Middle-Infrared Si-photonics for IMWP (grant No.: FA9550-18-1-0361) to University of Arkansas at Pine Bluff (UAPB), which enables UAPB to conduct a basic research to investigate the feasibility of obtaining a fully IMWP platform on Si substrate. The goal of this project is to investigate an alternative solution: IMWP on sapphire platform. We propose to utilize sapphire as a transformative high-performance self-consistent IMWP platform. Specifically, the III-V based laser and modulator on sapphire will be focused for proof-of- concept. The close match for the coefficients of thermal expansion (CTE) between sapphire and GaAs or GaSb enables the monolithic growth of high quality III-V on sapphire for active optoelectronics using the mature lattice mismatch growth technique. Furthermore, for the future development of a fully integrated solution to include a complete set of components with light source, analog signal processing, light detection, CMOS control circuit, and silicon on sapphire (SOS) circuit, the significant intellectual merit of the proposed sapphire platform includes: i) it utilizes the mature SOS CMOS and RF high frequency circuit technology featuring low power consumption; ii) sapphire has a lower refractive index with an index difference of 0.3 with Si3N4 and therefore it could leverage the mature TriPleXª technology to produce similar low loss waveguide based passive components by drop-in replacing quartz wafers with sapphire wafers; iii) for RF applications, sapphire platform has a potential to obtain much higher dynamic range due to low loss waveguide while the competing Si-photonics platform combined with off-chip 1.55 µm laser suffers from the strong two-photon absorption and therefore has limited dynamic range; iv) Sapphire as a transparent substrate would enable a versatile 3D photonics/electronics integration architecture; v) the combination of the proposed passive and active components provides broad wavelength coverage of 600-2500 nm far beyond that of typical Si photonics, which also enables on-chip sensing applications; and last but not the least, as a silicon-on-insulator (SOI) technology, SOS not only embraces all the features of Si photonics but also offer additional technology advantages such as radiation hardness. This platform could have broad applications for harsh environments (space and nuclear).
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 31, 2020
- Source ID
- W911NF2010270
Entities
People
- Aboozar Mosleh
Organizations
- Army Contracting Command
- Office of the Secretary of Defense
- University of Arkansas at Pine Bluff