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.

Publications

10 25 50
 
Description follow on fund
Amount £113,986 (GBP)
Funding ID EP/H029508/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
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 Academic/University
Country United Kingdom
Start 04/2012 
End 02/2015
 
Title Semiconductor light source and method of fabrication thereof 
Description The invention takes a self-aligned stripe configuration enabled to create buried stripe lasers within the GaAs/AlGaAs materials system to superluminescent diodes and semiconductor optical amplifiers, where termination of the stripe prior to the cleaved optical facet allows ultra low effective facet reflectivity. Such low reflectivities are required to suppress optical feedback in the cavity and enable high power, low noise components covering wavelengths accessed on GaAs. 
IP Reference GB2471266 
Protection Patent granted
Year Protection Granted 2009
Licensed No
Impact IP Group are presently investigating the case for spin-out new company based on this and related IP and know how.