摘要 |
An optical fiber (5) is coupled to an end face (5) of a semiconductor laser diode and the other end face is coupled to one end of a monomode optical waveguide. The other end of waveguide is terminated in a reflecting manner, e.g. by mirror, to reduce the coherence length of the laser. Thus, so-called "speckle patterns" are only produced in the transmission fiber over a short distance from the laser and modal noise further on in the transmission fiber can be prevented by avoiding the use of non-ideal fiber couplings or other connections having a spatial filter effect within this short distance from the laser. |