Design and realisation of InP and InAsP QDs passively monolithic Mode-locked lasers

Alharbi, Reem 2023. Design and realisation of InP and InAsP QDs passively monolithic Mode-locked lasers. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

This thesis examines the feasibility of using Indium Phosphide and Indium Arsenide Phosphide Quantum Dots for passive mode-locking through modal gain and absorption under forward and reverse bias, a novel semi-empirical approach and experimental work on fabricated passively monolithic mode-locked lasers (MLLs). There are two device configurations used in this work. The first device is a non-lasing segmented edge-emitting laser. The device’s contact width is 50 m, and its section length is 300 m. This device is used to characterise the modal gain and modal absorption of two studied materials. The second set of devices are fabricated passively monolithic MLLs with a shallow ridge of 2 m and total cavity length of 3 mm, gain-section length of 2400 m and saturable absorber-section length of 600 m. These second set of devices are used to measure and characterise the MLLs and to evaluate the reliability of the semi-empirical approach. Both devices are broad-area lasers with cleaved facets. A novel semi-empirical approach has been established to simulate the conditions of mode-locking regimes; and accordingly, design the best-performing Indium Phosphide and Indium Arsenide Phosphide mode-locked lasers in terms of absorber-to-gain length ratio. The approach used the combination of modal gain under forward bias and modal absorption under reverse bias, with particular attention paid to absorber-to-gain length ratio. The ratios investigated are 1:4, 3:17, 1:9 and 1:19. This approach enabled the prediction that both materials with a total cavity length of 3 mm will not provide mode-locking regime or lasing when the ratio of the saturable absorber length exceeds 20%. However, InP QDs are predicted to produce ML regimes only for device designs of 1:4, 3:17 and 1:9, while InAsP QDs are predicted to produce ML for device designs of 1:4, 3:17 ,1:9 and 1:19.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Physics and Astronomy
Subjects:	Q Science > QC Physics
Uncontrolled Keywords:	Compound Semiconductors, Mode-Locked Lasers, Self-assembled Quantum Dots
Funders:	Self funded
Date of First Compliant Deposit:	30 May 2023
Last Modified:	31 May 2023 09:23
URI:	https://orca.cardiff.ac.uk/id/eprint/160002

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