Line code for very high-speed optical transmission systems

This paper presents line code for high-speed optical systems, called 2mB1I1C. The code enables simple error monitoring and has a good balance of marks ('1') and spaces ('0'). The total disparity of coded words is always less than or equal to that of the input code sequence. This causes the suppression of low frequency components in the power spectrum. Descriptions of the coder and the decoder are given, and some performance parameters are also determined (power spectrum, error multiplication factor, the maximum number of consecutive identical digits, error monitoring function). The comparison with the existing codes for high-speed optical systems is also included.