| 摘要 |
PURPOSE:To obtain an equipment wherein the waveform distortion due to wavelength dispersion is very hard to be generated, by installing a semiconductor laser, a bias circuit, a modulation circuit, a Mach-Zehnder interferometer, and a periodic signal superposing circuit. CONSTITUTION:The following are provided; a semiconductor laser 2, a bias circuit 4 for supplying a bias current to the semiconductor laser 2, a modulation circuit 6 which superposes modulation current pulses corresponding with an input signal on the bias current, and makes the integrated value of the oscillation frequency of the semiconductor laser 2, which frequency is changed by the modulation current pulses, become pi or -pi as phase quantity, and a Mach- Zehnder interferometer 6 having delay time difference corresponding to one time slot of the modulation current pluses which converts the light from the semiconductor laser 2 into an intensity modulated light. Further a periodic signal superposing circuit 10 which superposes a periodic signal having a period corresponding to the one time slot of the aboved-mentioned modulation current pulses on the above-mentioned bias current is provided. |
