| 摘要 |
PURPOSE:To secure conversion for the incident laser beam into the short wavelength by using the detector operating at the normal temperatures and using no cooling-type detector for the incident laser beam supplied to the reception side from the transmission side in the optical communication system utilizing the infrared rays. CONSTITUTION:For the receiver which receives laser beam 2 of a fixed wavelength and containing the signal component given from transmission part 1, incident rays 4 passed through fixed space 3 are applied to reception part 5 containing the optical mixer composed of the nonlinear medium. Furthermore, near infrared rays 7 emitted from local oscillation light source 6 are led in and mixed along with rays 4 in order to convert rays 4 into the short wavelength. Thus the near infrared rays equivalent to the sum of the difference of the laser beams or coherent beam 8 featuring the wavelength within the visible band is obtained, and this beam 8 is supplied to photoelectric conversion element 9 operating at the normal temperatures. Thus, prescribed output 10 is delivered. |
