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Fabrication and experimental characterisation of multiple quantum well semiconductor laser amplifier with integrated saturable absorber.

Kong, S.F.; (2005) Fabrication and experimental characterisation of multiple quantum well semiconductor laser amplifier with integrated saturable absorber. Masters thesis , University of London. Green open access

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Abstract

The demand for high capacity, long-haul telecommunication systems is increasing at a steady rate, and will be expected to accelerate in the coming decade. At the same time, communication networks that cover long distances and serve large areas with a large information capacity are also in increasing demand. To satisfy the requirements on long distances and low cost, the communication channel must have a very low loss and low component count. A large information capacity can only be achieved with a wide system bandwidth which can support a high data rate (> 40 Gbits/s). Therefore it is important to increase the bandwidth of the communication network whilst also limiting the loss through the system. A way to achieving this is represented by the so-called all-optical signal processing. This thesis investigates the practical realisation of an all-optical 2R (Re-amplification, and Re-shaping) regenerator, employing an InGaAsP/InGaAsP multiple quantum wells (MQW) semiconductor laser amplifier (SLA) integrated with a passive saturable absorber (SA) device with recovery time made short by means of ion- implantation. The saturable absorber should have strong non-linearity to the input signal, to suppress low-power noise accumulated in long-haul optical systems, whereas the waveguide amplifier will provide the signal re-amplification function in the system. This work focuses on the fabrication process and experimental analysis of the semiconductor laser amplifier/saturable absorber (SLA/SA) devices. In particular we investigate the SLA and SA characteristics separately for simplicity. The design and fabrication issues encountered during the fabrication process are discussed, and the key characteristics that determine the SLA behaviour such as the amplified spontaneous emission (ASE), the gain, the output saturation power, and gain recovery time will be covered and for the SA, characteristics such as the non-linearity and recovery time. In addition, the use of ion implantation to create electrically isolated InGaAsP devices is studied. The work presented although not yet demonstrating a fully functional integrated SLA/SA for use as a regenerator in an all-optical system offering channel rates > 40 Gb/s and higher, offers a tool towards the determination of the best device and material design parameters to achieve the desired functionality for the SLA/SA.

Type: Thesis (Masters)
Title: Fabrication and experimental characterisation of multiple quantum well semiconductor laser amplifier with integrated saturable absorber.
Identifier: PQ ETD:594090
Open access status: An open access version is available from UCL Discovery
Language: English
Additional information: Thesis digitised by Proquest
UCL classification: UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng
URI: https://discovery.ucl.ac.uk/id/eprint/1446375
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