C-band 41-wavelength-switchable single-longitudinal-mode fiber laser with sub-kHz linewidth and high stability using a wide-band chirped Moire fiber Bragg grating

摘要

A high-performance wavelength-switchable single-longitudinal-mode (SLM) fiber laser with ultra-narrow linewidth and high stability in C-band was proposed and demonstrated, mainly benefiting from the use of a wide-band chirped Moire fiber Bragg grating (WB-CM-PBG) with 41 ultra-narrow channels. By combining the WB-CM-FBG with a manual tunable bandpass filter and using a subring cavity with a length of only 34cm to efficiently stabilize the SLM lasing, we achieved switchable lasing operation among 41 wavelengths, with a switching-step of similar to 0.96nm from 1526.592nm to 1565.126nm, covering the whole C-band, and obtained sub-kHz linewidth at every lasing wavelength. The high stability was validated by the measured slight fluctuations of lasing wavelength and optical power of 0.004nm and 0.113 dB, respectively, in 1.5 h. To the best of authors' knowledge, this is the state-of-the-art CM-FBG-based fiber laser reported with the greatest number of switchable-wavelengths covering C-band, and, what's more, each switchable lasing wavelength was with sub-kHz linewidth. The performance of the proposed fiber laser can be improved further with good temperature compensation and vibration isolation packaging for practical applications.