Mode scrambler for optical fibers.

Mode conversion at a splice was measured. Even the best splice, whose transmission loss was less than 0.01 dB, caused a mode conversion equaling about 11% of the total power. Spliced fiber transmission characteristics were influenced by the splicing conditions. To avoid deviations in characteristics due to splices a simple and effective mode scrambler was fabricated. Its insertion loss was less than 0.3 dB for a laser diode. Each mode's output waveform was found to be the same as the total output waveform.