Real-time 938-Gb/s polarization-multiplexed OFDM transmitter with 1024-point IFFT

We demonstrate a 93.8-Gb/s real-time optical OFDM transmitter with 1024-point IFFT using polarization-multiplexing and 4-QAM modulation. This is the highest IFFT size implemented for OFDM to our knowledge. The limited resources of FPGA make it challenging to place and route such a high size IFFT. The implementation penalty of the real time transmitter compared to the case where FPGAs are used as an arbitrary waveform generators increases up to 2 dB for BER of 7x10(-4). An optical back-back measurement showed required OSNR of 26.5 dB for a BER of 10(-3).