LAUSR

Abstract. A hybrid optical amplifier, using a combination of Er–Yb codoped waveguide amplifier (EYDWA) and Raman amplifier, is presented. The proposed scheme is investigated for 116  ×  10  Gb  /  s dense wavelength-division multiplexed (DWDM) system at 0.2-nm channel spacing. The parameters are optimized using a hybrid genetic algorithm to achieve a flat gain of >25  dB, with a gain ripple of 2.78 dB. This is obtained over a wavelength range of 1539.7 to 1562.7 nm at 1 mW optimum input power per channel, without using any costly gain flattening scheme. An increase in gain ripple from 2.78 to 6.95 dB is observed for higher input powers up to 10 mW. The obtained noise figure (NF) is <6  dB for the given wavelength range. The effects of Er/Yb concentrations on the gain of EYDWA alone and the proposed hybrid amplifier are also investigated. The obtained high and flat gain along with low NF, lesser bit error rate (<10  −  20), and high Q-factor (>10  dB) confirm the feasibility of the proposed amplifier for broadband long-haul DWDM systems.