| 摘要 |
PURPOSE:To realize the optical communication system in which homodyne detection is easily attained in a station without need of a device having a stable absolute wavelength and a light source at a terminal equipment. CONSTITUTION:Light sources 31-3n for wavelength multiplex light are provided to a station 2 only in the communication method in which one wavelength of a wavelength multiplex light is allocated as a channel tying one terminal equipment and a station, and the light is sent to terminal equipments 11-1n through an optical fiber 9 from a station 2. The terminal equipments 11-1n use wavelength variable filters 111 11n to select one idle wavelength among wavelength multiplexer lights and modulators 121-12n are used to modulate the light from the station 2 by using a signal and the signal is returned to the station 2 for the transmission of the signal. Moreover, as the selection method of an idle wavelength, the sweeping by using the selected wavelength is implemented with the use of the filters 111-112 based on the shortest wavelength, the longest wavelength of the wavelength multiplex light or a reference wavelength including an identification signal and the method recognizing the relative wavelength from the wavelength detected at first is used. Thus, the same light as the incoming signal light from the terminal equipment to the station is easily obtained. |
