University of Texas System

Dongho Shin

Robert Magnusson

Preston P Young

A new class of vertical-cavity lasers (VCLs) is disclosed. Conventional VCLs contain an active region enclosed by Bragg-mirror stacks of 30-100 quarter-wave layers. The new VCLs can be fabricated without Bragg mirrors by replacing them with efficient diffractive (guided-mode resonance (GMR)) mirrors with much fewer layers, for example, two or three layers. This application provides optical power flow across and along the VCL gain region, thereby greatly increasing the laser efficiency and reducing the threshold mirror reflectance needed for lasing, relative to conventional VCLs. Theoretical and experimental results show that GMR mirrors exhibit high reflectance (theoretically, 100%; experimentally, in excess of 90%) in a narrow spectral band with well-defined polarization states. When incorporated in VCLs, the GMR mirrors yield single-mode, narrow-line, highly-polarized output light. The GMR-VCL is independent of any particular material system. An example fabrication process of GaAs-based VCLs includes molecular-beam epitaxial growth of the basic planar structure and multiple-quantum-well (InGaAs/GaAs for 980 nm wavelength) active layers, interferometric recording of the GMR grating, lithographic and reactive-ion-etch definition of individual VCL elements, and metallization and contacting. GMR-VCL arrays can also be fabricated; the diffractive element will phase-lock the individual lasers to produce exceptionally high optical power and coherence. GMR-VCL technology holds high potential to provide low-cost, high-speed sources for fiber optic communications and other applications.

Growing community of inventors

Arlington, TX, United States of America

Dongho Shin