| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical transmission/reception circuit using components commonly inputting/outputting an optical signal of the same wavelength and moreover, sufficiently increasing sensitivity of a photo-detector. SOLUTION: The optical transmission/reception circuit 101 is provided with a Si substrate 103 forming a Y-shaped optical wave-guide 102, a semiconductor laser 104 and the photo-detector 105, and a wavelength conversion element 106 arranged on the way of the optical wave-guide 102, and for converting the wavelength λ1 to another wavelength #2. The optical signal of the wavelength λ1 is inputted from the semiconductor laser 204 to the PD port 114 of the optical wave-guide 102 to be outputted from the common port 111 with the wavelength as it is. The optical signal of the same wavelength inputted to the common port 111 is inputted to the wavelength conversion element 106, and is converted into the wavelength λ2 there to be outputted from the PD port 114. Since the photo-detector 105 is provided with a wavelength selective transmissive filter 107 for making transmit only the optical signal of the wavelength λ2 in a light receiving side, the reflection beam 118 of the wavelength λ1 and a stray beam 119 are cut off, and the sensitivity of the photo-detector is increased sufficiently. |
