| 摘要 |
PROBLEM TO BE SOLVED: To provide a signal to noise ratio monitoring method that is easily made small in size and has high reliability in an optical direct amplification relay transmission system employing an optical amplifier and to provide an optical receiver. SOLUTION: In a signal to noise ratio monitoring method for a optical direct amplification relay transmission system, an optical receiver 100 provided with a light receiving device 1 and an equalization amplifier 2 is employed and a ratio of a mean optical current of an optical signal photoelectric-converted by the light receiving device 1 to a signal level of an output signal of the equalization amplifier 2 is detected in the signal to noise ratio monitoring method for the optical direct amplification relay transmission system, and a receiver operated according to this method is provided. |
