Optical free space signalling system

A signalling system according to any preceding claim, wherein said data received by said receiving means of the first signalling device for transmission to the second signalling device is up-link data, wherein the second signalling device further

• comprises:
• i) receiving means for receiving down-link data for transmission to the first signalling device;
• ii) means for modulating one or more light beams in accordance with the down-link data to generate a plurality of modulated light beams;
• and iii) one or more lenses arranged so that the plurality of modulated light beams are output from the second signalling device towards the first signalling device as substantially collimated, spatially-separated, parallel, free-space light beams,
• and wherein the first signalling device further comprises:
• i) a plurality of detectors operable to detect respective ones of said plurality of modulated light beams output by the second signalling device and to convert the respective modulated light beams into corresponding electrical signals;
• and ii) means for processing the corresponding electrical signals to recover the down-link data.

An optical signalling device comprising:

• at least one input port for receiving data;
• a modulator operable to modulate at least one infrared light beam in accordance with the received data to generate a plurality of modulated infra-red light beams;
• and
• at least one optical element arranged so that the plurality of modulated infra-red light beams are output by the optical signalling device as substantially collimated, spatially-separated, parallel, free-space light beams.

An optical signalling device comprising:

• a plurality of spatially-separated detectors operable to convert respective incident light beams into corresponding electrical signals;
• and
• at least one optical element operable to direct a plurality of substantially collimated, spatially-separated, parallel, free-space light beams incident on the optical signalling device onto respective ones of the plurality of spatially-separated detectors,
• wherein said free-space light beams are modulated to convey information and the optical signalling device further comprises a circuit operable to process said corresponding electrical signals to recover said conveyed information.

An optical signalling device comprising:

• means for receiving data;
• means for modulating one or more light beams in accordance with the received data so as to generate a plurality of modulated light beams;
• a plurality of spatially-separated detectors;
• and
• at least one optical element arranged so that:
• i) the plurality of light beams modulated by the modulating means are output from the optical signalling device as substantially collimated, spatially-separated, parallel, free-space light beams;
• and ii) a plurality of substantially collimated, spatially-separated, parallel, free-space light beams incident on the optical signalling device are directed onto respective ones of the plurality of spatially-separated detectors,
• wherein said incident free-space light beams are modulated to convey information and the optical signalling device further comprises a circuit operable to process said corresponding electrical signals to recover said conveyed information.

An optical signalling device comprising:

• means for receiving data;
• means for modulating one or more light beams in accordance with the received data so as to generate a plurality of modulated light beams;
• a plurality of spatially-separated detectors;
• and
• at least one optical element operable:
• i) to output the plurality of light beams modulated by the modulating means are output from the optical signalling device in a predetermined direction as substantially collimated, spatially-separated, parallel, free-space light beams;
• and ii) to direct a plurality of substantially collimated, spatially-separated, parallel, free-space light beams incident on the optical signalling device from the predetermined direction onto respective ones of the plurality of spatially-separated detectors.