| 摘要 |
PURPOSE:To produce a light pulse having a narrow width by a method wherein one end of a light film having a reflection mirror at the other end of the optical fiber is oppositely faced to a light projecting end surface of the semiconductor laser and the laser is driven. CONSTITUTION:Light pulse produced at the right end of the semiconductor laser 1 is fed to a light film 3, reflected by the reflection mirror 4 and then returned back to the semiconductor laser. The light fed again is amplified and fed again to the optical fiber 3 at the right end plane, at last a width of the light pulse is made to be narrow, the laser 1 is oscilated with a single mode. At this time, the light coming from the left end of the laser is a light pulse having a single wave length with a narrow width. The optical fiber 3 may keep a fine flux of laser and a flux of light reciprocating to and from a reflection mirror. With this arrangement, a measurement of range of the optical fiber having a range more than several GHz may be performed with a less error of measurement. |
