| 摘要 |
PURPOSE:To obtain an optical transmission equipment with a large capacity for a long range by obtaining a sufficient optical output while suppressing the spread of an oscillation wavelength of a semiconductor laser at modulation known as chirping. CONSTITUTION:An optical signal is formed at the state of points A, B and a difference PB-PA of optical outputs corresponding to both the points is a signal level. In changing the laser drive current between IA and IB, the optical output changes between P'A and PB. In extracting only the optical output where the polarized wave front of the laser light is in the TE mode by a polarizer 3, the optical output change is PB-PA, then a large output change is obtained. Since both the points A, B are in the laser oscillating state and the value IB-IA is small, the chirping due to an injected carrier change is reduced remarkably. In observing the transmission and reception waveform being the shape of the optical signal at the incident and irradiated ends of an optical fiber 4, the deterioration in the waveform by the optical transmission using an optical fiber is suppressed considerably. |
