A receiver module comprising: a detector circuit configured to: receive an optical signal with a plurality of different optical channels of different frequencies including an optical channel with an amplitude modulated channel identification trace tone frequency, scan the optical signal for the optical channel with the amplitude modulated channel identification trace tone frequency, and identify the optical channel with the amplitude modulated channel identification trace tone frequency; and a receiver configured to: receive the optical signal with the plurality of different optical channels including the optical channel with the amplitude modulated channel identification trace tone frequency; receive information identifying the amplitude modulated channel identification trace tone frequency from the detector circuit, filter the optical signal, by setting a local oscillator of the receiver module to a predetermined optical frequency for the optical channel identified by the identified amplitude modulated channel identification trace tone frequency, to receive the optical channel with the amplitude modulated channel identification trace tone frequency, and process the optical channel with the amplitude modulated channel identification trace tone frequency to output a data stream. a detector circuit configured to: receive an optical signal with a plurality of different optical channels of different frequencies including an optical channel with an amplitude modulated channel identification trace tone frequency, scan the optical signal for the optical channel with the amplitude modulated channel identification trace tone frequency, and identify the optical channel with the amplitude modulated channel identification trace tone frequency; and receive an optical signal with a plurality of different optical channels of different frequencies including an optical channel with an amplitude modulated channel identification trace tone frequency, scan the optical signal for the optical channel with the amplitude modulated channel identification trace tone frequency, and identify the optical channel with the amplitude modulated channel identification trace tone frequency; and a receiver configured to: receive the optical signal with the plurality of different optical channels including the optical channel with the amplitude modulated channel identification trace tone frequency; receive information identifying the amplitude modulated channel identification trace tone frequency from the detector circuit, filter the optical signal, by setting a local oscillator of the receiver module to a predetermined optical frequency for the optical channel identified by the identified amplitude modulated channel identification trace tone frequency, to receive the optical channel with the amplitude modulated channel identification trace tone frequency, and process the optical channel with the amplitude modulated channel identification trace tone frequency to output a data stream. receive the optical signal with the plurality of different optical channels including the optical channel with the amplitude modulated channel identification trace tone frequency; receive information identifying the amplitude modulated channel identification trace tone frequency from the detector circuit, filter the optical signal, by setting a local oscillator of the receiver module to a predetermined optical frequency for the optical channel identified by the identified amplitude modulated channel identification trace tone frequency, to receive the optical channel with the amplitude modulated channel identification trace tone frequency, and process the optical channel with the amplitude modulated channel identification trace tone frequency to output a data stream. <EOS>