A beat-frequency tunable dual-mode fiber-Bragg-grating external-cavity laser

• Published in: IEEE photonics technology letters Vol. 17; no. 11; pp. 2436 - 2438
• Main Authors: Wei Wang, Cada, M., Seregelyi, J., Paquet, S., Mihailov, S.J., Ping Lu
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-11-2005; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: External cavity lasers (ECLs); External-cavity lasers; Feedback; fiber Bragg gratings (FBGs); Fiber lasers; Laser feedback; Lasers; microwave photonics and beat signals; Noise levels; Optical feedback; Optical fiber polarization; Optical noise; Photonics; Polarization; Radio frequencies; Radio frequency; RF signals; Signal generators; Stimulated emission; Tunable circuits and devices; Tuning
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2005.858140

A dual-mode external cavity laser employing two spatially separated fiber Bragg gratings has been investigated. We experimentally demonstrated that, without utilizing polarization separation techniques, a closely spaced (/spl sim/0.3 nm) dual-mode emission can be stabilized if a specific in-phase relation between the external feedbacks and the gain chip facet residual feedback is satisfied at both lasing wavelengths. The radio-frequency (RF) beat signal generated by the dual-mode optical signal had a typical extinction ratio of 25 dB above the noise floor and a 3-dB linewidth of approximately 2 MHz. The RF beat signal had a frequency tuning range of 200 MHz, where the dual-single-mode spectrum can be maintained.