| EPSRC Reference: |
GR/J14967/01 |
| Title: |
FAST TUNABLE SEMICONDUCTOR LASERS USING REVERSE BIASED QUANTUM WELL STRUCTURES |
| Principal Investigator: |
Seeds, Professor AJ |
| Other Investigators: |
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| Department: |
Electronic and Electrical Engineering |
| Organisation: |
UCL |
| Scheme: |
Standard Research (Pre-FEC) |
| Starts: |
01 October 1993 |
Ends: |
30 September 1996 |
Value (£): |
58,461
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| EPSRC Research Topic Classifications: |
| Optoelect. Devices & Circuits |
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Summary on Grant Application Form |
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To fabricate a quantum well laser having a reverse biased tuning section and to compare its tuning performance and output power variation with forward bias techniques. To measure the attainable speed of tuning. To investigate the application of reverse bias tuning techniques to grating filters and other structures.Progress:Lasers having uniform frequency modulation response are key components in angle modulated optical communication systems. With forward bias current injection tuning of semiconductor lasers the frequency response tends to be highly non-uniform, due to the combination of thermal and carrier density effects. We have developed a novel tuning technique based on the refractive index changes resulting from the quantum confined Stark effect in reverse biased quantum well structures. This approach has the advantage that thermal effects are absent and the large electric field results in extremely fast (fs) response, the main practical limitation to device response resulting from junction and parasitic capacitance. We have demonstrated this approach experimentally in an external cavity laser system and have achieved a bandwidth of 20 kHz -1.3 GHz +/- 1.6 dB, without any equalisation, the upper limit being due to device parasitic capacitance (1). We have now fabricated GaAs/AlGaAs quantum well lasers having CW threshold currents of20-35 mA and are working on a number of approaches to offset the tuning section absorption characteristics by the optimum amount for a fully integrated structure. 1. Cai, B., Seeds, A.J. and Roberts, J.S.: MQW tuned semiconductor lasers with uniform frequency response ,Photonics Tech. Lett., 1994, 4, pp.6-8.
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Key Findings |
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
| Summary |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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