On-chip gain elements for integrated photonics

Albeladi, F. T., Gillgrass, S., Mishra, P., Allford, C. P. ORCID: https://orcid.org/0000-0002-3798-9014, Shutts, S. ORCID: https://orcid.org/0000-0001-6751-7790 and Smowton, P. M. ORCID: https://orcid.org/0000-0002-9105-4842 2025. On-chip gain elements for integrated photonics. Optics Express 33 (25) , pp. 52356-52372. 10.1364/OE.573505

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Abstract

The design of gain chips for hybrid integration with photonic integrated circuits (PICs) is studied and highlights the benefits of incorporating at least one reflector in the III-V gain material. Quantum dot (QD)-based gain chips with a multi-mode interference (MMI) reflector (MMIR) offer fabrication simplicity and good performance in the O-band. The inclusion of an MMIR in a ridge waveguide (RWG) laser reduces the threshold current by 87% (6 mA vs 46 mA for 1 mm length) and leads to higher slope efficiency, indicating over 90% mirror reflectivity, as compared to Fabry-Perot structures. Both 1- and 2-port designs will simplify alignment of active and passive waveguides for hybrid integration and are strong candidates for large-scale PIC applications.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Physics and Astronomy
Publisher:	Optica Publishing Group
ISSN:	1094-4087
Date of First Compliant Deposit:	7 January 2026
Date of Acceptance:	12 November 2025
Last Modified:	07 Jan 2026 15:45
URI:	https://orca.cardiff.ac.uk/id/eprint/183696

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