| 摘要 |
PURPOSE:To decrease the number of parts, and to enable integration easily by a method wherein a first semiconductor laser device oscillating on non-modulation is modulated by an electric signal, signal beams are obtained, and transmitted by an optical fiber, beams injected from one end of a second semiconductor laser device conducting single longitudinal mode oscillation by the same wavelength and emitted from the other end are detected by a photodetector, and the modulation components of signal beams are regenerated as an electric signal. CONSTITUTION:Intensity-modulated or frequency-modulated signal beams transmitted by an optical fiber 2 from a distributed feedback semiconductor laser device 1 performing single longitudinal mode oscillation at a wave length lambda0O on non-modulation are guided in a semiconductor laser device 3 without having an effect on the laser oscillation of the semiconductor laser device 3, and synthesized with output beams conducting single longitudinal mode oscillation at a wavelength nearby to the wavelength lambda0 of the semiconductor laser device 3, thus acquiring laser beams 4 in which laser beam components, intensity of which is modulated or frequency of which is modulated centering around the wavelength lambda0, and laser beam components at the wavelength nearby to the wavelength lambda0 are synthesized. All electric signal output 7 at intermediate frequency is regenerated in a photodetector 5. Accordingly, the number of parts is decreased, and integration can be facilitated. |
