Abstract: An optical system may include an optical radiation source, an optical device, an optical reference device, an optical detector, and a processing module. The optical radiation source may provide an optical input signal. The optical device may provide one or more of a first band-pass output associated a first band-pass wavelength response and a first band-stop output associated with a first band-stop wavelength response. The optical reference device may provide one or more of a second band-pass output associated with a second band-pass wavelength response and a second band-stop output associated with a second band-stop wavelength response. The optical devices may be coupled together and may provide an optical output signal. The optical detector may convert the optical output signal into an electrical measurement signal. The processing module may evaluate deviations between the band-pass responses and the band-stop responses.

Abstract: An ADD/DROP filter and an optical add/drop multiplexer are disclosed. An ADD/DROP filter includes an input port, an output port, an add port connecting to a modulator, and a drop port. The modulator is configured to load a pilot signal to a first optical signal to obtain a second optical signal, and transmit the second optical signal to the add port. A third optical signal is input to the input port. A wavelength difference between the second optical signal and the third optical signal is an integral multiple of a free spectral range. A power detector is connected to the output port and/or the drop port. The power detector is configured to obtain an output optical signal from the output port or the drop port and detect an optical power of the output optical signal.

Abstract: An ADD/DROP filter and an optical add/drop multiplexer are disclosed. An ADD/DROP filter includes an input port, an output port, an add port connecting to a modulator, and a drop port. The modulator is configured to load a pilot signal to a first optical signal to obtain a second optical signal, and transmit the second optical signal to the add port. A third optical signal is input to the input port. A wavelength difference between the second optical signal and the third optical signal is an integral multiple of a free spectral range. A power detector is connected to the output port and/or the drop port. The power detector is configured to obtain an output optical signal from the output port or the drop port and detect an optical power of the output optical signal.