Advanced GaAs Based Laser Fabrication (Feasibility Study)
Lead Research Organisation:
University of Sheffield
Department Name: Electronic and Electrical Engineering
Abstract
GaAs materials research has extended the operating wavelengths of devices to those used in telecommunications and medical diagnostic applications, and offers a number of advantages over incumbent InP based devices. These revolve around the use of larger substrates leading to cost reductions, and greater band offsets allowing higher temperature (or uncooled) operation of a device through improved carrier confinement. However, GaAs based device fabrication is rather immature, with GaAs lasers typically only available as Fabry-Perot ridge structures, which exhibit highly asymmetric output, surface recombination, and broad emission spectra. Technologies such as distributed feedback (for single mode operation) and buried heterostructure lasers (symmetric output, reduced surface losses) are commonplace in commercial InP devices. The development of GaAs based buried heterostructure devices in this proposal relies upon a novel approach in circumventing deleterious regrowth upon exposed AlGaAs, allowing buried heterostructure technology for GaAs based materials. GaAs based buried heterostructure lasers will be developed and assessed in terms of electrical and optical performance, in particular the spatial profile of the optical emission using far field analysis techniques. Solid source and gaseous epitaxial overgrowth methods will be assesed and compared under various conditions. Buried gratings (distributed feedback) will be developed, initially for use in a single mode ridge laser, before ultimately incorporation in a buried heterostructure distributed feedback laser.
Organisations
Publications
Groom K
(2009)
Quantum Well and Dot Self-Aligned Stripe Lasers Utilizing an InGaP Optoelectronic Confinement Layer
in IEEE Journal of Selected Topics in Quantum Electronics
Groom K
(2008)
GaAs-based self-aligned laser incorporating InGaP opto-electronic confinement layer
in Electronics Letters
K Groom
(2008)
GaAs-Based Self-Aligned Laser Incorporating an
Stevens B
(2009)
Operating Characteristics of GaAs/InGaP Self Aligned Stripe Lasers
in Japanese Journal of Applied Physics
Stevens B
(2010)
Distributed feedback laser employing buried GaAs/InGaP index-coupled grating
in Electronics Letters
Description | follow on fund |
Amount | £113,986 (GBP) |
Funding ID | EP/H029508/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 05/2010 |
End | 07/2011 |
Description | normal response |
Amount | £167,100 (GBP) |
Funding ID | EP/J004898/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 04/2012 |
End | 02/2015 |
Title | Semiconductor light source |
Description | A method of fabricating a semiconductor light source structure for super-luminscent diodes (SLDs) or semiconductor optical amplifiers (SOAs), comprising providing a GaAs substrate; forming an A1xGa1-xAs, a lower cladding layer above the substrate; forming a GaAs separate confinement heterostructure as an active region above the lower cladding layer; and forming an upper cladding layer above the active region, the upper cladding layer comprising an elongate stripe of A1xGa1-xAs bounded on either side by an InGaP current-blocking layer, the elongate stripe defining an index-guided optical waveguide. The stripe is formed such that at least one free end of the stripe is spaced apart from an edge of the substrate and a portion of the lower cladding layer, active region, current blocking layer and upper cladding layer extend beyond the stripe thereby to provide an unpumped and laterally unguided window region. The advantages of this are reduced reflectivity at the stripe/window boundary, this advantage is increased further by tapering the edge of the stripe. The stripe may be formed via etching or cleaving. |
IP Reference | GB2471266 |
Protection | Patent granted |
Year Protection Granted | 2010 |
Licensed | No |
Impact | IP Group are presently investigating the case for spin-out new company based on this and related IP and know how. |