The optical backplane bus as the interconnection network of a switch

The construction of very large switches will require the interconnection of very large numbers of cards. The limitations of optical bus architectures for such configurations are the dynamic range and component losses. To reduce the dynamic range of the signals produced by an array of transmitters and allow many outlets, a small number of taps/array is required. In the case of the discrete amplifier system this corresponds to many amplifiers and the use of EFDA between a few taps will result in long lengths of fibre in the backplane. The use of the distributed EDFA within the bus is a very attractive option in terms of the low dynamic range expected and potential for many tapping positions. It is therefore a promising technology for allowing the development of terabit switching platforms