Monolithically integrated polarisation mode convertor with a semiconductor laser

Naeem, Muhammad Azhar (2013) Monolithically integrated polarisation mode convertor with a semiconductor laser. PhD thesis, University of Glasgow.

Abstract

In this thesis, the design, optimisation, fabrication and operation of waveguide based semiconductor lasers, integrated with polarisation mode convertors (PMCs), is described. Devices are fabricated in the GaAs/AlGaAs and InP/AlGaInAs material systems, using two types of structures; single PMC and back-to-back PMCs. The convertor designs are based upon air trenches, of sub-wavelength dimensions, being introduced into waveguide structures in order to achieve an asymmetric cross-sectional profile, resulting in wave-pate functionality.
The GaAs/AlGaAs PMCs are fabricated using reactive ion etching (RIE), and the phenomena of RIE lag technique is also exploited for obtaining the required asymmetric waveguide profile in a single etch step. These are then integrated with semiconductor lasers. The InP/AlGaInAs PMCs are fabricated using a combination of RIE and inductively coupled plasma (ICP) etching and are integrated with semiconductor lasers and also differential phase shifter (DPS) sections to realise devices with active polarisation control.
Integrated devices fabricated on InP/AlGaInAs material system with a semiconductor laser, a PMC followed by a DPS section yields ~40 % polarisation mode conversion whilst the DPS section is held at the transparency condition. Greater than 85 % polarisation mode conversion was also obtained with back to back PMCs, which was complement to the devices fabricated with a single PMC.
Furthermore, a first active polarisation controller, monolithically integrated with a semiconductor laser is reported. High speed modulation of the integrated device with 300 Mbps is also demonstrated via current injection to the phase shifter section of the device.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: polarisation mode convertor, integrated devices, semiconductor laser, modulator, high speed polarisation switching
• Subjects: T Technology > T Technology (General); T Technology > TK Electrical engineering. Electronics Nuclear engineering
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Supervisor's Name: Holmes, Mr. Barry Michael and Kelly, Mr. Anthony Edward
• Date of Award: 2013
• Depositing User: Mr Muhammad Azhar Naeem
• Unique ID: glathesis:2013-4419
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 27 Jun 2013 10:25
• Last Modified: 24 Jun 2016 13:43
• URI: https://theses.gla.ac.uk/id/eprint/4419