A Monolithic O-Band Coherent Optical Receiver for Energy-Efficient Links

A 1310-nm (O-band) coherent optical Link is demonstrated for short-range optical interconnects that operate to 56-GBd symbol rate (SR) (112 Gbps) with FEC-acceptable BER. The coherent optical receiver (CORX) leverages a monolithic 45-nm CMOS SOI photonic-enabled process to realize an energy-efficient quadrature phase shift keying (QPSK) demodulation. Co-design of the optical and electronic circuit elements supports high-speed operation and low-power consumption. The coherent link is demonstrated with an optical transmitter photonic IC (PIC) fabricated in silicon photonic (SiPh) process with laser diodes wirebonded to a 90-nm SiGe driver electronic RFIC. The transmitter operates at 5.9-pJ/bit energy efficiency (EE) while the receiver achieves 0.73 pJ/bit and, to our knowledge, is the best EE reported for a coherent optical receiver.