Single-Mode, 980 nm Pump Lasers for Fiber Amplifiers,

Pump lasers for Er3-doped silica fiber optical amplifiers must demonstrate excellent spatial mode stability to high output power levels in order to achieve useful gain. 1,2 The pump band at 980 nm is the most efficient of the principle Er3 absorption bands in terms of gain per input optical power.3 Pumping at 980 nm is also preferred in comparison to pumping at 1480 nm because it reduces the noise introduced into the amplified optical signal.4 In this paper we describe the design, fabrication, and characteristics of a high power, MBE-grown 980 nm laser with a simple, weakly-index-guided structure. The geometry of the lasers lateral waveguide is carefully controlled to ensure that all of the power is in the fundamental spatial mode. Far field patterns of these devices are single lobed and stable to the highest measured powers. These Fabry-Perot lasers exhibit single frequency operation to output powers as high as 170 mW, with linewidths as narrow as 5 MHz.