PURPOSE: To reduce the coherence of output light and to reduce modal noises and distortion during the analog modulation of a light source, by coupling numbers of optical fibers which differ in length between the light source and an output optical fiber and generating delay difference.
CONSTITUTION: Light from an LD1 is incident to input terminals L1INWLnIN of respective optical fibers forming a fiber bundle 5 while diverged from a bundling part L01 into light beams L1, L2WLn through the lens 2. Those light beams are converged at a bundling part L02 again and projected dispersedly to output terminals L1OUTWLnOUT, entering a lens 3. The projected light from the lens 3 is coupled with an output optical fiber 4 and transmitted. In this case, respective optical fibers L1WLn are slightly different in length, so the projected light beams are slightly out of phase with one another; even when the emitted light of the LD1 has good coherence, the light incident to the optical fiber 4 has no coherence.
HANANO NAOMASA
FUKUGAHARA TSUTOMU
FUJINO SHIYOUJI
