Optical signal detection system, optical signal detection device, and optical signal detection method

An optical signal detection system comprising:

• a nonlinear converter that nonlinearly converts a plurality of first optical signals into a plurality of second optical signals, and also a third optical signal into a fourth optical signal, the plurality of first optical signals being predetermined and different from each other in at least one of temporal waveform, intensity, amplitude, or phase;
• a spectrometer that obtains each of a plurality of first spectral data items from a different one of the plurality of second optical signals, and also a third spectral data item from the fourth optical signal;
• and
• a detection device that detects the third optical signal and outputs a detection result, wherein
• the detection device includes:
• an analyzer that performs sparse principal component analysis on the plurality of first spectral data items to generate a plurality of second spectral data items, each of the plurality of second spectral data items having less frequency components than a corresponding one of the plurality of first spectral data items;
• and
• a detector that compares the third spectral data item with each of the plurality of second spectral data items, and detects the third optical signal based on a result of the comparison.