Abstract

The majority of recent work on erbium-doped fiber amplifiers has been centered on the choice of the pumping source, especially with regards to scalability in ultrahigh output erbium power amplifiers. There have been high-output power erbium amplifiers demonstrated using multiple pump diodes both at 980 and 1480 nm.¹ However, there are serious questions regarding power scalability when more than two pump diodes are required. We have chosen to pump on the long-wavelength tail of the Yb⁺³ absorption at 1064 nm in Er/Yb co-doped fibers using a diode-pumped Nd:YAG laser (DPL). The advantages of using a DPL are the use of mature, efficient, and high-power AlGaAs diode laser arrays, the high output beam quality, and power scaling advantage. We utilize the DPL as a brightness convener and have been able to couple >300 mW from a single DPL into single-mode fiber. Unlike direct diode excitation, this approach is nearly arbitrarily scalable in power with increasing nondiffraction-limited pump array or bar size.

© 1992 Optical Society of America