Optical signal to noise ratio (OSNR) monitoring device and monitoring method

The invention discloses an optical signal to noise ratio (OSNR) monitoring device and monitoring method, comprising an optical amplifier (1), a first polarization control element (2), a circulator (3), a coupler (4), a nonlinear optical element (5), an attenuator (6), a second polarization control element (7), a first power meter (8) and a second power meter (9). The invention further discloses an OSNR monitoring method using the device, comprising the following steps: optimizing the polarization control elements to obtain working conditions of the linear area of the device; describing the power transmittance ratio of a transmission end to a reflection end of the monitoring device; fitting the relation between an OSNR and an output power by using a least square method; and back-calculating the OSNR by the output power according to the relation. The device and method disclosed by the invention are suitable for high-speed optical communication system. The device and method are compared with the prior scheme, the flexibility and monitoring range are improved obviously.