| 摘要 |
<p>When converting an FSK output from an injection laser (2) into 1M (intensity modulation) by passage of the light through a Mach Zehnder interferometer (5), the conversion efficiency is regulated using a first feedback loop (7) to stablilise the laser's centre frequency at a half-intensity point on the spectral characteristic of the interferometer, and optionally a second loop (31) to regulate the frequency difference of the FSK so that the two FSK frequencies reside respectively at a maximum and a minimum of the characteristic. The first loop uses a low frequency modulation of the FSK frequency difference to derive its error control signal. <IMAGE></p> |
