| 摘要 |
In an non-polarized pump light source (5), a laser light source (1) transmits a virtually linearly-polarized light beam that has plural mode components arranged at an interval of an almost equal angular frequency. The transmitted light beam of the laser light source (1) is connected with a polarization dispersion device (3) in such a way that the polarization axes of the transmitted light beam and the polarization dispersion device (3) meet to form a 45° angle. In the polarization dispersion device (3), when the mode interval angular frequency is considered to be Deltaomega, the polarization mode dispersion that is not in the vicinity of (2pi/Deltaomega) is effected on the incident light from the laser light source (1). As a result, though the optical path difference between the two polarization modes becomes less than the coherent length, an effectively non-polarizing light is transmitted as a pump light from the non-polarized pump light source (5). Consequently, in an optical fiber (7), which is a Raman-amplifying medium and into which the non-polarized pump light is input, the polarization-dependency of a Raman gain reduces.
|
