| 摘要 |
PURPOSE:To make it possible to transmit and receive light beams having different wavelengths simultaneously by one piece of optical fiber and one light coupling path without noise and to avoid a large configuration and a high cost, by coupling the two light emitting and receiving devices, in which first - third semiconductor light emitting and receiving elements are arranged, by optical fiber, and shorting the electrode of one light emitting and receiving element and a common electrode. CONSTITUTION:The wavelength of light beams L1-L3, which can be emitted or received by first - third semiconductor light emitting and receiving elements are made to have relationship of lambda1<l2<lambda3. Two semiconductor light emitting and receiving devices are used as U1 and U2. The U1 and U2 are coupled by one piece of transmitting and receiving optical fiber. Therefore, two light coupling paths are not required for the optical fiber for transmission and reception, and only one path is enough. When the light L1 is emitted by the first light emitting and receiving element M1 and the light L3 is simultaneously received by the third light receiving element M3, an electrode E2 of the second light emitting and receiving element M2 and an electrode E0 are shorted. Thus light emission and light reception can be performed without substantially accompanying noises. |
