| 摘要 |
PROBLEM TO BE SOLVED: To stably measure the wavelength of a slave station optical signal by providing a polarized wave scrambler that brings a polarized wave of a variable wavelength optical signal outputted from a variable wavelength optical signal transmitter into a random state to the master station so as to make a beat level constant. SOLUTION: A plurality of slave stations 5, 6 connecting to the master station 4 via photocouplers 1, 2 and an optical fiber 3 send an optical signal modulated by a transmission signal from an optical transmitter 21 to the master station. Part of an optical signal 32c is given to an optical receiver 24 via photocouplers 22, 23, a variable wavelength optical signal 31a sent from a variable wavelength optical transmitter 19 of the master station and whose polarized wave is set to a random state by a polarized wave scrambler 33 is given to an optical receiver 24 as an optical signal 31f via photocouplers 17, 7, 2, 22, 23. A beat by optical signals 31f, 32c is sent to the master station, and the master station observes a wavelength of the slave station optical signal through detection of the beat and wavelength measurement of the variable wavelength optical signal by a wavelength counter 16. Since the polarized wave of the optical signal 31f is at random and the slave station optical signal is a linearly polarized light, a beat level by a phase difference of the polarized wave is not fluctuated. |
