US 6,154,480 A · Vertical-cavity laser and laser array incorporating guided-mode resonance effects and method for making the same

Abstract

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.

Claims32

Dependent claims

A vertical-cavity laser (VCL) supported on a substrate and having a resonant cavity, comprising:

a first mirror overlying the substrate for reflecting light during laser operation;
an active region overlying the first mirror, the active region including means for photon emission during laser operation;
a guided-mode resonance (GMR) mirror overlying the active region and having at least one resonant waveguide grating, the GMR mirror reflecting light at a resonance wavelength, and diffractively coupling oscillating laser light to a leaky waveguide mode propagating along the active region to provide optical power flow, and attendant photon gain path, both across and along the active region;
at least one spacer layer overlying the GMR mirror for optical confinement;
and
first and second contact layers positioned on top and bottom surfaces of the vertical cavity laser for electrical contacts, one of said contact layers having an aperture for outputting a laser beam that is normal to the substrate.

3 more elements

A vertical-cavity laser (VCL) supported on a substrate and having a resonant cavity, comprising:

a multilayer Bragg-stack mirror overlying the substrate for reflecting light during laser operation;
an active region overlying the multilayer Bragg-stack mirror for photon emission during laser operation, the active region having at least one quantum well surrounded by appropriate barrier layers;
a guided-mode resonance (GMR) mirror overlying the active region and having at least one resonant waveguide grating, the GMR mirror reflecting light at a specific wavelength, and diffractively coupling oscillating laser light to a leaky waveguide mode propagating along the active region to provide optical power flow, and attendant photon gain path, both across and along the active region;
at least one spacer layer overlying the GMR mirror for optical confinement;
and
first and second contact layers positioned on top and bottom surfaces of the vertical cavity laser for electrical contacts, one of said contact layers having an aperture for outputting a polarized single-mode laser beam that is normal to the substrate.

3 more elements

Dependencies are inferred from the claim text.

Vertical-cavity laser and laser array incorporating guided-mode resonance effects and method for making the same

Life of this patent

Vertical-cavity laser and laser array incorporating guided-mode resonance effects and method for making the same

Life of this patent

Abstract

Claims32