Extended band erbium amplified spontaneous emission source

Summary form only given. Wavelength division multiplexed (WDM) optical comunications systems rely on wavelength selective components, fibers and other devices that must be specified in the transmission band. Currently available broadband sources for characterization in the 1.5 /spl mu/m region are based on tungsten lamp, EELED´s or Er-amplified spontaneous emission (ASE). We propose a very simple broadband source suited for characterization of optical components in the 1500 mn to 1640 nm range. The extended band ASE source is realized by combining the forward ASE in a long erbium fiber with backward ASE. As in L-band amplifiers, the input portion of the fiber absorbs the pump laser while the far end of the fiber strongly absorbs the ASE emitted in the first portion. The output ASE spectrum is thus shifted to longer wavelengths. The set-up used for the demonstration comprises of a 10 m Er-doped fiber (EDF) section followed by an isolator and then a 90 m EDF section. The isolator in between the fiber sections ensures that backward L-band ASE from the long fiber does not shifts the ASE spectrum of the short fiber section. Without this isolator the backward ASE from the longer section would compete against the c-band ASE in the shorter section. The two sections were of the same aluminosilicate Er-codoped fiber having a peak absorption at 1530 nm of 4.1 dB/m, core diameter 2.2 /spl mu/m and measured mode field diameter (Peterman II) of 4.5 /spl mu/m.