WAVELENGTH SELECTIVE AUXILIARY C-BAND ASE PUMPING FOR L-BAND EDFA

Abstract

The variation of Gain and Noise Figure (NF) at 1580 nm with length of Erbium doped fiber (EDF) for two auxiliary pumping schemes employing narrowband Amplified Spontaneous Emission (ASE) and ASE filtered up to a particular wavelength in C-band, by considering a serially cascaded two stage wideband amplifier model are investigated. It is shown that indeed, there exists a wavelength range of ASE for achieving maximum gain. The gain can be increased by 14 dB if wavelength bandwidth of 1480–1554 nm is selected instead of pumping with the broadband ASE (1480–1700 nm). By auxiliary pump using ASE sliced in the 1533 nm window, gain as high as 28 dB and NF as low as 5.5 dB can be achieved for shorter fiber length. To achieve gain of 25–30 dB for the L-band signal only a EDF length of 30 m is required in the case of tuned ASE launching at 1533 nm as compared to 40 m and 65 m by optimized ASE bandwidth and broadband. The values of noise figure do not show significant variation in any of the three configurations. It is apparent that using single wavelength ASE pumping at 1533 nm reduces the fiber length by 10 m (compared to optimized ASE bandwidth pumping) and by 32 m (compared to broadband ASE bandwidth pumping), when L-band EDFA is designed for 25–30 dB signal gain and NF less than 6 dB. These results will be important in designing cascaded wideband EDFA for Optical Fiber Communication (OFC) systems.