High-Power Tunable GaAs Distributed Feedback Lasers

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Photonics is a key enabling technology with far reaching applications. In this project we will realise a new generation of enhanced-functionality GaAs-based lasers for the 300 to 1300nm wavelength range. These devices, based on a new monolithic integration scheme, will impact upon existing applications in display, printing, absorption spectroscopy and telecoms, whilst enabling new applications in astrophotonics, sensing, biomedical imaging, photodynamic therapy, fluorescence spectroscopy, cosmetic and clinical surgery procedures, process control, agriculture, defence and security. Monolithic integration on GaAs has previously been impeded due to the requirement for overgrowth upon aluminium containing layers. We will capitalise on approaches demonstrated in the investigator's previous EPSRC feasibility study into advanced discrete GaAs components to investigate the potential for true monolithic integration. We will realise a distributed feedback (DFB) laser monolithically integrated with a power amplifier within a continuous buried waveguide. As an extra proof of flexibility, there will be a heater element adjacent to the DFB for both wavelength stabilisation and tuning. This disruptive new technology will enable low cost, highly efficient, high power, wavelength agile lasers, in the range from 600 to 1300nm. Additionally, inherent high power and spectral purity are favourable for frequency doubling to extend the range down to 300nm. Specific objectives of this project will be a proof of concept demonstration of these integrated devices, backed up with reliability statistics at 760nm (based on quantum wells) and 1180nm (based on quantum dots), i.e. covering the short and long wavelength regions readily available in this technology.