Superluminescent Diodes and Semiconductor Amplifiers Based on GaAs Window Structures - Follow-on-Fund

Lead Research Organisation: University of Sheffield
Department Name: Electronic and Electrical Engineering


Two main material platforms covering the spectrum from 650nm to 1650nm: InP covering 1200nm to 1650nm and GaAs covering 650nm to ~1310nm. GaAs offers a number of advantages over InP such as lower cost and higher performance in addition to accessing wavelengths unattainable in InP. However GaAs devices are typically only available as simple ridge waveguides. InP devices are also available as more complex buried waveguides which are more easily integrated and offer flexibility not found in ridge waveguides whilst they also offer improved heat dissipation, permit higher current densities for smaller active volume and have controllable optical beam profiles. These were successfully developed in the GaAs materials system in EPSRC grant EP/E001017, offering the best materials and best device architectures for future incorporation in opto-electronic integrated circuits, allowing technologically advanced device architectures to be developed at wavelengths not presently covered by such devices. IP was generated in applying our novel technique for buried GaAs waveguides to the case of the superluminescent diode (SLD) and semiconductor optical amplifier (SOA), whose operation relies upon attainment of an ultra-low reflectivity mirror at one or more ends of an optical cavity (unlike the case of a laser in which high mirror reflectivities are required). Application of our technique has enabled attainment of mirror reflectivities which are orders of magnitude lower than the lowest reported using alternative techniques, and has allowed a step change in the performance of SLDs incorporating this design, with our unoptimised proof-of-principle devices offering world-leading performance.Whilst this technology is capable of extension across the complete range of wavelengths and associated applications accessed by GaAs, we will first address a large burgeoning market for SLDs and SOAs in the field of optical coherence tomography - a medical imaging technology rolling out across the global healthcare market. Slight modification to the materials and device designs will be made, and the funding will also allow both the commercial packaging of prototype devices for beta testing modules in the field and the reliability testing necessary for convincing users and/or licensees of the technology.

Planned Impact

The initial programme of work that this funding will allow will address the optical coherence tomography (OCT) optical component market at 1050nm. World-leading superluminescent diode (SLD) performance will allow improvement to the resolution, contrast and penetration of low-cost OCT systems for diagnosis in a range of applications including ophthalmology and oncology. Hence in addition to capitalising on our demonstrated potential to fill the gap in the market for high performance and low-cost 1050nm light sources, which is estimated at $18m in 2009, our work will also directly lead to improvements in healthcare screening and diagnosis, and hence improving quality of life, through proliferation of low-cost OCT systems throughout the world. Commercialisation of 1050nm semiconductor optical amplifiers (SOAs) will also lead directly to improvements in healthcare screening and diagnosis since they will permit the realisation of ultra-high-resolution real-time 3D OCT offering the ultimate in in-vivo non-contact imaging. Academic beneficiaries include those working in all aspects of OCT imaging, and in optical communications in the longer term when the technology is extended to SOAs at 1310nm, and to more exotic active media (beyond the immediate scope of the follow-on-funding). Additionally, the outcomes of reliability testing may have consequences for the development of GaAs based opto-electronic integrated circuits incorporating this invention such as monolithically integrated widely tuneable lasers. The partnership of Fusion IP with the technology transfer office at The University of Sheffield offers a support network to identify and protect IP, and to identify and promote spin-out companies and/or license opportunities. We will explore licensing opportunities and formation of a spin-out company, both of which will add value to the UK economy in terms of income and the later resulting in job creation. In the first instance the post doctoral research associate working on the project will gain experience in product development and commercial activity. Indeed the principal investigator will also gain valuable first hand experience of the commercialistion process. In the longer term, it is hoped to secure funding to extend the product portfolio across the range of wavelengths accessed by GaAs, chiefly to target the component market for fibre optic gyroscopes used in defence and aviation (representing ~35% of the total SLD market), and the 1310nm telecoms market. Our main social and economic impacts will be in OCT components with global healthcare improvements not possible without our products, however there is income to be made for the UK economy, and further job creation through entry to the aviation/defence and telecomms markets. OCT, aviation/defence, and telecoms represent approximately equal value markets for our proposed devices.
Description EPSRC
Amount £1,048,360 (GBP)
Funding ID EP/I018328/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 07/2011 
End 06/2015
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.