| 摘要 |
PURPOSE: To obtain an optical transmitter of simple constitution which can reduce the relative intensity noise of light signals by putting light signals outputted by plural light sources together and imposing intensity modulation with a sent signal. CONSTITUTION: This light signals outputted by the light sources 10a-10n which outputs the light signals having different wavelengths is composited into on light signal by a photos compositing unit 11. Then an external modulator 12 imposes intensity modulation on the composite light signal with its sent signal. Because of this constitution, noise electric power after the composite light signal is received is the result of voltage addition of noises because noises of the respective light signals inputted to the optical modulator 11 have no correlation; and a mean electric power is the addition of DC lights and the result of voltage addition. Consequently, the S/N of the light signal can be made large by reducing the relative intensity noise of the composite light signal. The external modulator 12 inputs the sent signal through a driving circuit 13 and preferably impose intensity modulation on the composite signal with the sent signal. |
