An optical transmission system, in which an optical transmission apparatus and an optical reception apparatus are provided, includes a coefficient determination unit configured to optimize, based on a reception signal received by the optical reception apparatus, a coefficient to be used to compensate for deterioration according to characteristics of each device configuring a transmission path between the optical transmission apparatus and the optical reception apparatus, and a device characteristic estimation unit configured to estimate the characteristics of each device by using the optimized coefficient.

An optical receiver includes an optical amplifier that amplifies a received optical signal containing multiple wavelengths, a monitor circuit that monitors light intensities of the demultiplexed optical signal, a processor, and a memory having information representing a relationship between a total incident light intensity of the optical signal incident onto the optical amplifier and gains of the optical amplifier for the respective wavelengths. The processor repeats first calculation for determining the gains of the respective wavelengths from the memory, based on a drive current for driving the optical amplifier and an estimation value of the total incident light intensity of the optical signal, second calculation for calculating the incident light intensities of the respective wavelengths of the optical signal based on the gains and the monitored light intensities, and third calculation to calculate the total incident light intensity of the optical signal, until the total incident light intensity converges.