A NOVEL HIGH GAIN AND WIDE BAND HYBRID AMPLIFIER DESIGNED WITH A COMBINATION OF EYDFA AND DISCRETE RAMAN AMPLIFIER

摘要

In an optical communication network, over a broad range of spectrum, gain of the amplifier must be flattened in order to increase the bandwidth utilization of the network. Here we analyse a novel approach of designing a hybrid amplifier with a combination of Single mode Erbium Ytterbium co-doped fibre amplifier and discrete Raman amplifier to flatten its gain over the optical spectrum of C and L bands, which is about 90 nm of spectral width. This hybrid amplifier requires only 5 optimal pump signals in RA and there is no need of any gain flattening filter in it. The performance of thus simulated hybrid amplifier is analysed with the help of 110*40 Gb/s non return to zero dense wavelength division multiplexed signals as the input. They cover the entire C and L bands and the presence of dense channels also ensures the accurate measurement of important parameters of hybrid amplifier such as maximum gain, gain ripple, noise figure and optical signal to noise ratio (OSNR). The five pump signals of RA are spaced equally, unequally and semi-unequally in order to attain the objective. The least gain ripple is obtained for semi-unequal pump frequency spacing. The length of SM EYDFA, RA, power of pump signals and power of DWDM input signals are optimized through Multi-parameter multi-target optimization tool of Optisystem simulation software. The five pumping signals of RA are tested with Forward, Backward and both Forward and Backward schemes in order to analyse the performance of the hybrid amplifier. Out of all experiments, SM EYDFA+RA Forward Pumping scheme offers superior performances such as maximum gain of 31.2 dB, very low gain ripple of 2.09 dB (6.7% of maximum gain), maximum noise figure of 4.68 dB and maximum OSNR of 34.23 dB. This new design of hybrid amplifier with superior gain flattening performance will be very much useful for cable television or community antenna television (CATV) and telecommunication networks.