SPECTRUM-SLICED FIBER AMPLIFIER LIGHT-SOURCE FOR MULTICHANNEL WDM APPLICATIONS

We propose a potentially inexpensive light source for multichannel WDM applications. The high-power amplified spontaneous emission (ASE) from an erbium-doped fiber amplifier (EDFA), which is already in the single-mode fiber, can be efficiently divided into many channels by using an integrated optic WDM demultiplexer. This ''spectrum-sliced'' ASE can be used as light sources for WDM systems rather than several wavelength-selected DFB lasers. To demonstrate the principle, we sliced a 40-nm wide ASE spectrum of an EDFA with a narrow optical filter (3 dB bandwidth: 1.3 nm) and used the resulting source for the transmission of up to 1.7 Gb/s of data. These incoherent light sources suffer from the spontaneous-spontaneous beat noise. Thus, it is necessary to increase the optical bandwidth and/or decrease the electrical bandwidth (bit rate) to improve the signal-to-noise ratio, which, in turn, determines the transmission capacity of a WDM system using the proposed light source. We estimate that the total capacity would be about 40 Gb/s, realistically, since the channel spacing should be at least three times the optical bandwidth of each channel to avoid crosstalk.