Method, device, and system for evaluating characteristics of optical fiber transmission line

摘要

An optical amplifier including a pumping source for supplying pump light to an optical fiber transmission line is provided so that at least a part of the optical fiber transmission line produces Raman amplification to an optical signal. An optical filter unit for selectively switching between a first condition where the optical signal and the pump light are passed and a second condition where the optical signal is passed and the pump light is not passed is connected between the optical fiber transmission line and the optical amplifier. The power of the optical signal in the first condition is compared with that in the second condition, and the characteristics of the optical fiber transmission line, such as a splice loss therein, is evaluated according to the result of this comparison. In the second condition, the residual pump light is not supplied to the optical fiber transmission line, so that a measurement error due to Raman amplification can be eliminated to thereby allow accurate evaluation of the characteristics of the optical fiber transmission line.