Gain and noise characteristics of single-mode Er3+/Yb3+ Co-doped phosphate glass fibers

Single-mode highly Er³⁺/Yb³⁺ co-doped phosphate glass-fiber has been fabricated by rod-in-tube technique. Gain and noise measurements of the phosphate glass fiber have been performed by dual-pump configure with two 976 nm fiber-pigtail LDs using a highly Er³⁺/Yb³⁺ co-doped phosphate fiber with a length of 5.0 cm. Gain spectra and noise figures with different input signal powers of -30, -10, and -1 dBm have been investigated when the signal wavelength was tuned from 1525 to 1565 nm. A peak net gain of 16.5 dB at 1534 nm with a -30 dBm input signal from a micro erbium-doped fiber amplifier (EDFA) based on the 5.0-cm-long phosphate fiber has been achieved, that is, a net gain coefficient as high as 3.3 dB/cm, which is to the best of our knowledge, the highest from this kind of fiber amplifiers reported to-date. At the -30, -10, and -1 dBm input signal levels, less than 8.0 dB noise figures over the whole C-band have been obtained.