Fast LOS detection in a coherent optical modem

A coherent optical modem comprising:

• an Intradyne Coherent Receiver (ICR) with input power reporting circuitry configured to monitor one or more received optical signals;
• and
• processing circuitry communicatively coupled to the ICR and configured to
• receive a first interrupt from the input power reporting circuitry based on the input power reporting circuitry monitoring the one or more received optical signals,
• responsive to the first interrupt, prioritize detection of Loss of Signal (LOS) in the processing circuitry, including detecting the LOS on a main detection path, which is after Analog-to-Digital Conversion (ADC) and with communication over a bus, the first interrupt from the input power reporting circuitry providing a parallel detection path that is faster than the main detection path, and
• responsive to the detection of the LOS, provide a second interrupt to a host device associated with the coherent optical modem.