DAC-less amplifier-less generation and transmission of QAM signals using sub-volt silicon-organic hybrid modulators

We demonstrate generation and transmission of optical signals by directly interfacing highly efficient silicon-organic hybrid (SOH) modulators to binary output ports of an FPGA. Using an SOH Mach-Zehnder modulator (MZM) and an SOH IQ modulator we generate on-off-keying (OOK) and binary phase shift keying (BPSK) signals as well as quadrature phase shift keying (QPSK) and 16-state quadrature amplitude modulation (16QAM) formats. Peak-to-peak voltages amount to only 0.27 Vpp for driving the MZM and 0.41 Vpp for the IQ modulator. Neither digital-to-analog converters (DAC) nor drive amplifiers are required, and the RF energy consumption in the modulator amounts to record-low 18 fJ/bit for 16QAM signalin