Highly scalable integrated discrete fourier transformation filter in silicon-on-insulator for next generation WDM systems

The network traffic is estimated to be quadrupled by the year 2016 and will enter the “zettabyte” era. This ever increasing traffic demands more bandwidth and capacity in future from the long haul optical fiber transmission systems. The deployment of single carrier coherently detected 100 Gbps Polarization Multiplexed Quadrature Phase Shift Keying Wavelength Division Multiplexed (PM-QPSK WDM) systems is expected in the near future. Beyond that, the next generation 400 Gbps WDM systems are gaining lot of attention recently to sustain the traffic growth for the next years [1]. To make such systems spectrally efficient with low price per bit, multiple carrier Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM) is considered as one of the most attractive options. It allows the packing of multiple PM-QPSK carriers in a super-channel delivering high data rates. An all-optical implementation of the CO-OFDM receiver for systems operating at 400Gbps and beyond leads to an energy efficient solution and overcomes the speed limits of electronics.