A Switchable Multi-wavelength Erbium-Doped Photonic Crystal Fiber Laser with Linear Cavity Configuration

A switchable multi-wavelength erbium-doped photonic crystal fiber laser with a linear cavity configuration based on a Sagnac loop mirror is proposed and demonstrated experimentally. The laser is based on saturated spectral hole burning and the polarization hole burning effects can be switched among single-wavelength, dual-wavelength, triple-wavelength and quadruple-wavelength outputs at room temperature. The wavelength period of the output spectrum is easily varied by using polarization maintaining fibers of different lengths. The proposed fiber laser has a signal-to-noise ratio of higher than 30 dB and achieves a low threshold power of 37 mW. The power fluctuations of the lasing lines are less than 0.54 dB,1.7 dB and 2.9 dB when the laser operates at single-wavelength, dual-wavelength and triple-wavelength for one hour.