| 摘要 |
PURPOSE:To generate the difference frequency signal of a short optical pulse with remarkably high frequency with a simple constitution system by using a semiconductor modulator as a light receiving means, and obtaining the difference frequency signal from a photoelectric current when the semiconductor modulator is modulated by an electric oscillator. CONSTITUTION:The difference frequency signal is outputted from the photoelectric current of the semiconductor modulator 11 as receiving an optical pulse string 1 by the semiconductor modulator 11 and modulating the semiconductor modulator 11 by the electric oscillator 3. When the optical pulse string 1 is made incident on the semiconductor modulator 11 and no voltage is applied to the semiconductor modulator 11, the optical pulse is not absorbed, and when the voltage is applied, light absorptive characteristic is wavelength-shifted to a long wavelength side, and the optical pulse is absorbed, thereby, intensity modulation is performed. Also, an effect can be increased by quantum Stark effect (QCSE) by employing superlattice (MQW) structure in the structure of the optical waveguide part of the semiconductor modulator 11. |
