On-chip self-injection-locked gain-switched combs for flexible RF signal generation via photon–photon resonance
Loading...
Date
2026-07-27
Authors
Dominguez-Castillejo, Diego
Venkatasubramani, Lakshmi Narayanan
Rajeswari, Gayatri Vasudevan
Prasad, Deepa
Atar, Fatih Bilge
Moehrle, Martin
Barry, Liam
Corbett, Brian
Journal Title
Journal ISSN
Volume Title
Publisher
Institute of Electrical and Electronics Engineers Inc.
Published Version
Abstract
Gain switching enables directly modulated lasers to generate ultrashort pulses with flexible repetition frequencies. By preserving pulse to pulse coherence, optical frequency combs can be generated. At high frequency repetition rates, external optical injection has proven to be effective in enhancing the spectral purity of these combs. However, the integration of such architectures remains challenging, and the maximum operating rate that these devices can reach is still limited by the relaxation oscillation frequency. In this study, we present a three-section laser that exploits photon–photon resonance as a mechanism to overcome these limitations. The laser includes an integrated external cavity that provides optical feedback to the gain section. This allows frequency combs to be generated with a flexible line spacing up to 30 GHz, limited by the equipment. Optical feedback drives the laser to operate in a self-injection locking regime, removing any need for optical external injection. An additional phase expansion scheme demonstrates the generation of frequency combs with a maximum spectral width of 150 GHz for a flatness window of 10 dB and a repetition rate of 30 GHz. Finally, frequency upconversion of a 2 GHz intermediate frequency signal to 28 GHz using a 30 GHz spaced comb is shown, demonstrating the potential of the proposed device as a flexible radio-frequency generator.
Description
Keywords
Frequency combs , Integrated photonics , Photon-photon resonance , Self-injection locking , [TyndallPhotonics]
Citation
Dominguez-Castillejo, D, Venkatasubramani, L N, Rajeswari, G V, Prasad, D, Atar, F B, Moehrle, M, Barry, L & Corbett, B 2026, 'On-chip self-injection-locked gain-switched combs for flexible RF signal generation via photon–photon resonance', Journal of Lightwave Technology, vol. 44 , no. 18, pp. 8036-8045. https://doi.org/10.1109/JLT.2026.3717253