OPTICAL MULTIPLEXING BY IMAGING CHARGE TRANSFER DEVICE

摘要

1470480 Optical multi-plexing system INTERNATIONAL STANDARD ELECTRIC CORP 6 May 1975 [14 May 1974] 18924/75 Heading G1A [Also in Divisions H3 and H5] In an optical multi-plexing system utilizing an image charge transfer device (CTD) 14, the intensity modulated light signals carried by light fibres 12a, b .... n and emerging from a planar end 13, are imaged on to the light-sensitive areas of a CTD array 14 in a one to one correspondence. A charge transfer device, CTD, comprises a series of semi-conductor regions, Fig. 1 (not shown), which each store a charge proportional to the incident light on it during a given period and the regions are serially "read-out" by way of electrodes associated with each region. Each fibre 12a, b .... n corresponds to an information channel 1, 2, .... n with its associated signal generator G 1 , G 2 .... G n and light emitting diode (LED) or laser diode d 1 d 2 ... dn. The serial electrical output 20 of the CT device 14 is a time division multi-plexed signal (T.D.M.) which is used to directly modulate a further LED or laser diode 21, thereby directing a T.D.M. signal via a single optical fibre 23. The T.D.M. signal is detected at the other end by a high speed avalance photo-diode 24 whose output is amplified and fed to a de-multiplexer 26. The description refers to a series of waveforms Figs. 3A-3E (not shown).