Single optical carrier 200G DP-QPSK transmitter using RF sub-banding with integrated ultra-wide band IQ mixers

Employing RF sub-band multiplexing with the aid of ultra-wide band RF IQ mixers, we demonstrated a 200G DP-QPSK transmitter using two RF sub-bands and a single optical carrier. The novel technique is readily applicable to current commercial coherent DSP designed for 100G without the need for high baud-rate generation electrically. The 200G DP-QPSK transmitter, implemented using the fabricated ultra-wide band mixers, was shown to have great OSNR tolerance as it suffers only 0.5~1-dB OSNR penalty when compared to a standard 100G Nyquist DP-QPSK transmitter. The proposed RF sub-banding architecture could potentially reduce the cost and power consumption at the transmitter side for coherent optics design, without suffering the transmission penalty associated with high baud-rate generation and/or complex modulation format.