Short linear cavity laser using high concentration erbium-doped fiber co-doped with Bi3+Ga3+Al3+

A simple and effective short linear cavity erbium-doped fiber laser was presented. The laser consisted of an optical circulator (OC), a segment of self-made high concentration erbium-doped fiber co-doped with Bi3+Ga3+Al3+(BiGaAl-EDF), a uniform fiber Bragg grating (UFBG), and a wavelength division multiplexing(WDM). By using the OC as an all-reflection mirror and the UFBG written directly in the G652 fiber as a partial-reflection mirror and a wavelength selector, a stable wavelength oscillation with a center wavelength of 1 544.31 nm and a side mode suppression ratio (SMSR) of about 57 dB is achieved at room temperature. The impact of the length of BiGaAl-EDF on the laser’s output characteristic was analyzed. With a 12 cm long BiGaAl-EDF as the gain medium