The technique introduced has relatively simple encoding and decoding procedures which can be implemented at the high bit rates used in optical fiber communication systems. Because it is similar to the established technique of self-synchronizing scrambling but is also capable of guiding the scrambling process to produce a balanced encoded bit stream, the technique is called guided scrambling, (GS). The concept of GS coding is explained, and design parameters which ensure good line code characteristics are discussed. The performance of a number of guided scrambling configurations is reported in terms of maximum consecutive like-encoded bits, encoded stream disparity, decoder error extension, and power spectral density of the encoded signal. Comparison of guided scrambling with conventional line code techniques indicates a performance which approaches that of alphabetic lookup table codes with an implementation complexity similar to that of current nonalphabetic coding techniques.>

A classification scheme is suggested here for matrix switches that use photonic principles, generally for broadband signal routing. The classification considers three independent properties, providing for a large number of categories with properties that differ in identifiable ways. Salient properties of each class are noted. Matrices are classified in the following ways: according to the switching principles used i.e. optical or optoelectronic; according to the multiplexing system used in the switch i.e. space division, modulation division or carrier division; and according to the optical configuration of the switched systems, i.e. centrally switched, optically extended or distributed. Examples of the various types are given.>

The use of optoelectric switching matrices in digital networks is examined. The possibility of large very compact arrays is demonstrated. Design considerations are discussed for a switching node for broad-band digital signals at rates of 100 and 500 Mbits/s, with 100 inputs and 103outputs. A novel feature of optoelectronic switching is that power consumption tends to scale approximately linearly with array dimension, leading to potential advantages over electronic alternatives in large dimension high-rate switching matrices.