| 摘要 |
PURPOSE:To attain two-way optical communication by coupling optically a received optical input to a photocoupler and an optical output modulated by an external optical modulator with a transmission optical fiber via an optical signal insertion device so as to use efficiently the light source. CONSTITUTION:A received light sent from a 2-way communication section 502 via a constant deviation optical fiber 521 is made incident in a half mirror 41 through a lens 82 and a half mirror 81. Since a local oscillation light is made incident in the half mirror 41 via a laser module 61 and a lens 62, both lights are superimposed by the half mirror 41 and an IF light is radiated. Moreover, a data desired to be sent to the 2-way communication section 502 from the 2-way communication section 501 is inputted to a modulator driver circuit 23 and a corresponding voltage signal is fed to a modulation electrode of a phase modulator 21. Thus, the light inputted from the laser module 61 to the phase modulator 21 via lenses 63, 22 is modulated according to the sent data and then radiated. |
