Coherent/IM-DD dual operation optical transceiver

A method of operating comprising:

• providing a source configured for generating optical signals;
• providing a transceiver comprising:
• a receiver section configured to receive both coherently modulated and intensity modulated optical signals and to be optically switched between a first receiver mode and a second receiver mode, and
• a transmitter section comprising a nested Mach-Zehnder Modulator or a polarization multiplexed quad Mach-Zehnder Modulator configured to be operated in a first transmission mode and a second transmission mode;
• transmitting, via the transmitter section, in the first transmission mode an intensity modulated optical signal or in the second transmission mode a coherently modulated optical signal;
• and
• receiving an optical signal, via the receiver section, in the first receiver mode for direct detection or in the second receiver mode for coherent detection.

A transceiver comprising:

• a receiver section configured to receive both coherently modulated and intensity modulated optical signals and to be optically switched between a first receiver mode for direct detection and a second receiver mode for coherent detection;
• a transmitter section comprising an optical modulator configured to be operated in a first transmission mode to output an intensity modulated optical signal and a second transmission mode to output a coherently modulated optical signal;
• and
• a digital signal processor (DSP) for decoding the received coherently modulated and intensity modulated optical signals.