Exceeding 25 dB Gain Broad-Spectrum Amplification in L-Band Based on a Bi/Er/La Co-Doped Silica Fiber

We fabricate two Bi/Er/La co-doped silica fibers (BELDFs). With the high-concentration doped BELDF, the fluorescence-spectrum bandwidth of the intensity >−35 dBm reaches 75 nm (1548-1623 nm), and based on a dual-pump system, the gain-spectrum bandwidth of the gain >17 dB is up to 58 nm (1565-1623 nm). Then, a dual-stage triple-pump amplification is investigated, from which the gain bandwidth of L-band could be extended to 1625 nm with gain over 16 dB, and reach 58 nm (1562-1620 nm) with the gain of >25 dB. The results indicate that utilizing the homemade BELDF can become an effective way to solve the transmission capacity bottleneck of silica optical fiber communication system in the future, and has great potential applications for optical amplifiers, fiber sensors, fiber lasers, etc.