Publication

Abstract : A digital to analog converter is proposed and analyzed, based on carrier reservoir semiconductor optical amplifier –Mach-Zehnder (CR-SOA-MZI) configuration at 120 Gb/s. Digital to analog converter is realized by generating optical intensity based on weights of bit positions and adding to get the corresponding analog output. A CR-SOA has been used as a nonlinear element implemented in MZI configuration. It is a modified form of conventional semiconductor optical amplifier in which a wetting layer is grown in the vicinity of the active layer whose dedicated role is to replenish carriers in the active region (AR) after stimulated emission depletes available carriers. Due to this feature, CR-SOA overcomes the drawback of inherent slow carrier recovery which is prevalent in conventional SOA and therefore cannot be operated beyond 80 Gb/s. The proposed digital to analog has a resolution of 4 bits, with extinction ratio of more than 16 dB and absolute error of 1.58% only.