| 摘要 |
PURPOSE:To enable measurement of a wavelength of a local oscillation light source of a receiver by a method wherein a transmission light is switched over to an output light of a variable wavelength light source and a wavelength of the output light is scanned to measure an output light wavelength of the variable wavelength light source when the receiver is tuned. CONSTITUTION:Transmission light transmitted with an optical fiber 101 is subjected to a light heterodyne detection with an output light of a local oscillation light source 107 with a receiving section 106 to demodulate. Under a normal receiving condition, an output wavelength of the light source 107 is controlled to a wavelength displaced with a wavelength control circuit 12 by a fixed frequency from a communication wavelength using a frequency discrimination output of the receiving section 106. An optical connector 103 of a light input section of the receiving section 106 is switched over to a variable wavelength light source 110 to scan an output light wavelength of the light source 110. Thus, the output light wavelength of the light source 107 can be obtained by measuring the output light wavelength of the light source 110 as given when the receiving section 106 is detected to be tuned to the output light of the light source 110 with a tuning detection circuit 109. Here, a wavelength of the light source 110 coincides with that resulted when the output light wavelength of the light source 110 is displaced by an intermediate frequency portion. |
