The present invention is directed to an optoelectronic transmission-reception device that, in particular, can be utilized as transmission-reception transducer for half-duplex operation.
Since the medium of optical fiber (light waveguide) has largely replaced the copper cable in the long-distance network and trunk line network in communications transmission technology, the introduction of optical fiber technology in the subscriber circuit domain is an important task in coming years. The subscriber circuit domain represents the most cost-intensive domain of the telecommunication networks. This fact leads to efforts on the part of the network operators to find a solution that is cost-neutral and future-proof compared to the copper line. Different design possibilities for a transmission architecture in the subscriber circuit domain are being currently investigated. In one architecture considered to possibly have good prospects, the transmission between a terminal equipment at the exchange side (OLT=optical line termination) and a plurality of network termination at the subscriber side (ONU=optical network unit) ensues in the form of a star network with passive distribution that, given a realizable subscriber line length of about 10 km, represents an advantageous concentration of the number of subscribers at a switching center. In this design possibility for a point-to-multipoint connection, the optical fiber can be conducted up to the home of the subscriber in a preferred distribution structure (FTTH, fiber to the home, i.e. the network termination ONU of the subscriber side is located in the home). What is referred to as the TDM/TDMA method (time division multiplexing/time division multiple access), for example, is a suitable transmission method given such an architecture. A time-division multiplex frame is transmitted to all ONUs in the direction to the subscriber (downstream) (TDM). The individual ONUs then access their channels in the completely received frame. In the direction from the subscriber (upstream), the individual ONUs transmit their data bursts to the OLT in a predetermined sequence (TDMA).
Half-duplex operation wherein transmission or, respectively, reception is carried out in chronological succession at one end of the light waveguide is advantageous for data rates into the range of 150 and more megabits per second. Optoelectronic transmission-reception transducers for operation at the end of a light waveguide are still in an early stage of employment. Their costs, however, are of critical significance for the spread of the concept of fiber to the home (FTTH). Particularly for data rates in the indicated range, half-duplex operation or, respectively, what is referred to as ping-pong operation wherein transmission or, respectively, reception is carried out in chronological succession at one end possibly allows a more cost-beneficial structure of the transmission-reception module than given full-duplex operation.