Dsp based chromatic dispersion equalization techniques in PDM-QPSK receivers

Digital filters can be implemented to reduce chromatic dispersion occur in time & the frequency domain. Generally dispersion compensation fiber (DCF) is used to compact the fiber dispersion. But different algorithms like adaptive least mean square (LMS) and constant modulus algorithm (CMA) can be adopted in time domain as dispersion compensator. This paper implies a scrutinization of digital filter to reduce intra-modal dispersion, an schematic assessment of filter characteristics based on digital equalization methods and short analysis raised cosine filter. Simulation results show that the suggested algorithm is an adequate method to estimate intra-modal dispersion in dispersionless light wave propagation of 112 gbps PDM-QPSK.