| 摘要 |
PURPOSE:To eliminate waveform deterioration, crosstalk, etc., by composing the optical trans mitter of polarization modulators which modulate the polarization state of signal light outputted from a transmitting light source according to a modulating signal, an optical ampli fier, and a polarizer which extracts only a specific polarized light component from the signal light output from the optical amplifier. CONSTITUTION:The signal light 2 output from the signal light source 1 is collimated by a lens 3 into collimated light, which passes through a polarization modulator 4 and is then made incident on a polarization modulator 5. In the polarization modulator 5, the modulating signal 6 with a bit rate of 100Mb/s is applied to KDP crystal to generate a phase difference between polarized light components in the direction of an ordinary and an extraordinary optical axis and the polarization state of the signal light 2 at the time of the output of the polarization modulator 5 changes. The signal 2 which is output by the polarization modulator 5 is converged by a lens 7 and inputted to an optical amplifier 8, the signal light 2 output by the optical amplifier 8 has its modulation in the polarization state converted into intensity modulation by the polarizer 9, and the signal light 2 passed through the polarizer 9 is con verged by a lens 10 and made incident on an optical fiber 11. Consequently, even when the intensity of the signal light is large, neither waveform distortion nor crosstalk is caused. |
