DETECTING MAGNETOOPTIC AND INTENSITY-MODULATED OPTICAL SIGNALS WITH THE SAME DETECTOR

摘要

The present invention relates to an optical detection circuit comprising detecting means for detecting signals representing both polarisation modulation and intensity modulation in a received light beam. According to the invention the device is characterised in that the detecting means comprises polarisation modulation detection means (32, 33) for detecting two forms of polarisation, and conversion means (40) for selectively inhibiting the portion of the polarisation modulation detection means which detects one of the forms of polarisation so as to convert the polarisation modulation detection means into intensity modulation detection means when required.