W911NF-12-R-0012-03: Hybrid Quantum Cascade Lasers on Silicon-on-sapphire
Abstract
The objective is to investigate epitaxial quantum cascade laser wafer bonding and efficient light coupling into silicon on sapphire wafers. The goal is to explore the efficiency of such processes for potential use in mid-infrared integrated photonics. Propagation loss of mid-infrared radiation in silicon-on-sapphire waveguides will be measured to accurately account for loss mechanisms to estimate the actual light coupling efficiency. The proposed investigation of a mid-infrared integrated photonics materials platforms will proceed as follows: Phase l : Design of the quantum cascade laser (QCL) epilayer with gain at 4.5 microns for AdTech Optics growth. Experimentally investigate and optimize the QCL to silicon-on-sapphire (SOS) bonding procedure using devices with gain peak at wavelengths of 8-10 micron รก currently available in the PI s laboratory (these samples will only be mechanically tested; no optical testing will be performed). Phase II: Receive 4.5 micron QCL wafer from AdTech Optics. Transfer the 4.5 micron QCL epi-layer to the SOS platform. Fabricate and test 4.5 micron QCL devices on SOS platform. Design and theoretically optimize QCL-to-SOS mode coupler. Phase III: Fabricate mode-coupled QCL on SOS. Measure QCL-to-SOS mode coupling efficiency and SOS waveguide loss. Demonstrate room-temperature operation of electrically-pumped QCL-SOS PI Cs. The approach is centered on research related to optimizing the bonding and coupling of light from the QCL to the silicon. Several alternatives using the Applied Microengineering, Ltd. aligner-wafer bonder are presented. Preliminary results also point to potential success, but the real value of the research is to measure the coupling efficiency of light. Such data will be valuable to assess the usefulness of optimized bonding processes for future mid-IR integrated photonics use with coherent beam combining or other uses with arrays of lasers (and uses in sensors where efficiency of the device is important). Optimization will include different sample cleaning methods and bonding conditions to create robust direct QCL epilayer transfer to SOS platfonn. Alternate approaches may include use of elastomeric (PDMS) stamp for the initial QCL epilayer transfer, followed by bonding the epilayer to the SOS wafer. Adhesive bonding of QCL and SOS wafers will be used as a backup option. In this case, a thin {I 00-200 nm thick) layer of SU-8 epoxy or benzocyclobutene (BCB) will be spin-coated on both QCL and SOS wafers prior to bonding. The two wafers will be thermocompressively bonded at 150-2000 Kand the SU-8 epoxy or BCB will be cured during the bonding process, providing strong bond.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1510630
Entities
People
- Mikhail A. Belkin
Organizations
- Army Contracting Command
- United States Army
- University of Texas at Austin