Closely spaced dual-wavelength fiber laser using an ultranarrow bandwidth optical filter for low radio frequency generation

• Main Authors: Ahmad, H., Razak, Nor Farhah, Zulkifli, Mohd. Zamani, Muhammad, Farah Diana, Munajat, Yusof, Harun, Sulaiman Wadi
• Format: Article
• Published: OSA - The Optical Society 2014
• Subjects: QC Physics
• Online Access: http://eprints.utm.my/id/eprint/52127/; http://dx.doi.org/10.1364/AO.53.004123

A dual-wavelength (DW) fiber laser with a closely spaced single longitudinal mode (SLM) output is proposed and demonstrated. The proposed fiber laser utilizes a conventional fiber Bragg grating with a center wavelength of about 1546.8 nm in conjunction with an ultranarrow bandwidth tunable optical filter to generate the desired DW SLM output. Observations with a very high resolution optical spectrum analyzer, which was capable of achieving resolutions up to 0.16 pm, revealed detailed spectral characteristics not characteristically seen before. A channel spacing of up to 58 nm was realized, and spacing as small as 2 pm was achieved. The minimum channel spacing and its resulting beat frequency are the narrowest observed yet to the best of our knowledge for a DW fiber laser at room temperature.