Local area network with optical transmission

A local area network with optical transmission including:

• a plurality of terminal sets (P1-1 . . . P4-16) for transmitting and receiving optical signals;
• a plurality of nodes (N1 . . . N4), connected to respective ones of said terminal sets, for transmitting and receiving said optical signals;
• a plurality of primary fibers (FP1-1 . . . FP1-16) optically connecting each of said nodes (N1) to a respective one of said terminal sets (P1-1 . . . P1-1);
• a plurality of secondary fibers (FN1-4) optically connecting each of said nodes (N1) to others of said nodes such that each of said nodes is connected at least indirectly to all of the others of said nodes;
• each of said nodes (N1) receiving an incoming optical signal (S2, T1), carrying data via one of said primary or said secondary fibers, and responding by transmitting corresponding outgoing optical signals (S8, S11, T8, T10) carrying data to all the respective terminal sets (P1-1 . . . P1-16) and to all of the others of said nodes (N2, N4) connected directly thereto, said node comprising:
• a receive transducer (2, 6) for transforming said incoming optical signal into an electrical reception signal (S4, T4);
• an amplifier (8, 10) for amplifying said electrical reception signal (S4, T4) and producing an amplified electrical signal (S5, T5);
• and
• a transmit transducer (4) for transforming the amplified electrical signal (S5, T5) into an outgoing transmitted optical signal (T6, S6), each said receive transducer (2, 6, 104) or said transmit transducer (4, 102, 106) being a receive primary transducer (2, 104) or transmit primary transducer (4, 102), respectively, if the optical signal is transmitted via one of said primary fibers, each said receive transducer or said transmit transducer being a receive secondary transducer (6, 104) or transmit secondary transducer (4, 106), respectively, if the signal is transmitted via one of said secondary fibers;
• wherein the receive primary transducers (2, 104) and the transmit primary transducers (4, 102) are tuned to two different respective wavelengths;
• a single one of said primary fibers (FP1-1) connects each said terminal set (P1-1) to its associated node (N1);
• said receive secondary transducers (6, 104) and said transmit secondary transducers (4, 106) are tuned to one of said two different respective wavelengths, said one of said two different respective wavelengths constituting a common wavelength;
• a single secondary fiber (FN1-2) interconnects two of said nodes (N1, N2) when said two of said nodes are connected together directly;
• said network further including means for preventing interference so that, when a first one of said nodes (N1) transmits an optical signal over a respective one of said secondary fibers (FN1-2, FN1-4), a further optical signal transmitted in response by a second one of said nodes (N2) cannot interfere with the operation of said first one of said nodes.