Wavelength tunable single longitudinal mode fiber laser pinned to 25 GHz spacing

ABSTRACT A wavelength tunable single longitudinal mode (SLM) fiber laser is demonstrated with a high power Er‐Yb codoped fiber amplifier (EDFA) used as gain medium. A fiber Fabry‐Perot filter and a bandpass filter ensure single wavelength lasing. To realize SLM operation, a section of unpumped EDF in a Sagnac loop is adopted as a saturable absorber, which results in a self‐induced FBG (frequency band gap) with an ultranarrow bandwidth. The proposed laser is very stable and in SLM operation. The signal to noise ratio is measured about 65 dB. The output laser has a tuning range over 30 nm from 1535 to1565 nm. The tuning step of the proposed laser is 0.20 nm pinned to the ITU grid. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2404–2406, 2014