Erbium/Ytterbium Co-Doped Fiber

 DF1500Y has been used in amplifiers for the Cable TV Industry since 1993. These 'YEDFAs' have delivered output powers as high as +30 dBm and have been deployed in quantity throughout the USA, Europe and the Far East. DF1500Y is a fully commercial product, manufactured to a tried-and-tested commercial design. The key features of DF1500Y are its exceptionally high ytterbium concentration (~ 1000 dB/m at 975 nm) and its patented, phosphorus-doped core. The ytterbium level creates a very broad and intense pump-band - enabling the use of a wide range of high power pump sources. The phosphate host-glass of the core facilitates efficient energy transfer from the ytterbium ions to the erbium ions to produce the desired output within the 1550 nm window. The 'indirect' nature of this pumping process means that optical-optical conversion efficiencies can never approach those of more conventional, erbium doped fibers, but in practical, commercial applications, this relative inefficiency has been by far outweighed by the pump power available at alternative wavelengths. Two-stage YEDFAs pumped at 1047 nm by micro-YLF lasers have delivered +30dBm reliably - indicating optical-optical conversion efficiencies of around 35%.