| 摘要 |
PURPOSE:To change only a stimulated light frequency or phase almost without a change in the strength of the stimulated light with respect to a change in a minute injection current by using an electrode split type distribution feedback semiconductor laser and an electrode split type reflection semiconductor laser. CONSTITUTION:The transmitter is provided with an electrode split DFB-LD 41, an FM modulation drive circuit 42, a semiconductor laser optical amplifier 43 and a polarization maintaining optical fiber 44. A polarizer 45 is arranged so as to pass only a light having a polarization of 45 deg. with respect to the main axis of the fiber 44 as shown in an English caption B. The fiber 44 and the polarizer 45 form an FM-AM conversion optical circuit. In the FM-AM conversion optical circuit, the polarization plane of the incident light is set with an angle of 45 deg. with respect to the major axis of the fiber 44 and the incident optical power is separated into two major axes of the fiber 44. a mutual time delay tau with points of a distance L is expressed as tau=L/C(n1-n2) to receive different refractive indexes of n1, n2 in the input lights separated into two, where C is the velocity of light in vacuum. An electrode split DBR-LD may be used in place of the electrode split DFB-LD 41. |
