Chapter 11 - Pump Laser Diodes

Abstract

Pump laser diodes, essentially, deliver the raw power to regenerate optical signals along the network. The design and performance of pump laser diodes for coherent amplification of signals within a wavelength range of around 1550nm, in particular, the 980 and 1480 nm pump lasers, has been reviwed in the chapter. It also compares devices at the two wavelengths, and discusses pump reliability and diode packaging. The pump laser diodes in optical communication systems have the characteristics of a generic power supply. They exhibit high conversion efficiency to generate minimum amount of heat and be highly reliable, even though the power and current densities are pushed to their physical limits. The availability of reliable, high–power 980 nm pump lasers play a major role in enabling the commercialization of the high–bandwidth Dense Wavelength Division Multiplexing (DWDM) systems. Raman amplification is the key to solve system reach and capacity demands in the long-haul optical networks. The pump lasers that are stable enough to operate in an uncooled low-cost package open the opportunity for truly low–cost erbium–doped optical amplifiers.