Determining the stable injection locking of a Fabry-Pérot laser by observing the RF spectral components generated by a low-reflectivity external cavity

Ratkoceri, Jakup (author), Batagelj, Boštjan (author)

A novel approach to monitoring the laser injection-locking (IL) state is proposed and verified using the side-mode suppression ratio (SMSR). In a photonics experiment for laser IL, an optical spectrum analyzer with the conventional criterion of a 35-dB SMSR is conventionally used to detect the locking state of a Fabry–Pérot (FP) laser with multiple longitudinal modes to an external master laser with one longitudinal mode. Since the 35-dB criterion is not always a sufficient locking condition, we propose a microwave-photonic technique to determine the stable-locking regime based on the observation of the radio-frequency (RF) components. A novel approach to monitoring the generated additional spectral components uses the well-known delayed-self-homodyne technique and the RF spectrum analyzer. For the novel generation of additional longitudinal groups on each FP laser’s resonator mode in the optical spectrum and consequently the overlapping RF components in the RF spectrum, an additional external resonator with low reflectivity was connected to the slave FP laser. The novel monitoring approach was experimentally verified by connecting a 1-m-long external cavity with 0.5% reflectivity and observing the optical IL phenomenon of a 1550-nm FP semiconductor laser.

• Language: English
• Keywords: Fabry–Pérot laser diode, semiconductor laser, injection locking, microwave photonics, mode-locked laser, locking range, linewidth, self-homodyne technique, external cavity
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2021
• Number of pages: 13 str.
• Numbering: Vol. 8, iss. 11, art. 487
• PID: 20.500.12556/RUL-136423
• UDC: 621.39
• ISSN on article: 2304-6732
• DOI: 10.3390/photonics8110487
• COBISS.SI-ID: 83025667
• Publication date in RUL: 03.05.2022

Record is a part of a journal

• Title: Photonics
• Shortened title: Photonics
• Publisher: MDPI AG
• ISSN: 2304-6732
• COBISS.SI-ID: 523331609

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 01.11.2021

Secondary language

• Language: Slovenian
• Keywords: Fabry-Pérotova laserska dioda, polprevodniški laser, rodovna vklenitev, mikrovalovna fotonika

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0246
• Name: ICT4QoL - Informacijsko komunikacijske tehnologije za kakovostno življenje

• Funder: Other - Other funder or multiple funders
• Funding programme: COST
• Project number: CA16220
• Name: European Network for the High-Performance Integrated Microwave Photonics
• Acronym: EUIMWP