Code flexibility of 2-D time-spreading wavelength-hopping in OCDMA systems

The potential performance and successful experimental demonstrations of two-dimensional time-spreading wavelength-hopping (TW) optical code-division multiple access systems have motivated a large volume of research into the development of new TW codes. The choice of the code is crucial in network design since the code not only affects the overall system performance but also sets limits on the physical implementation of the encoding-decoding process. In this paper, ldquoflexibilityrdquo of TW codes is investigated, providing clarity on the tradeoff between key code factors, specifically the number of available wavelengths and time chips. Network performance is evaluated by taking into consideration multiple access interference and beat noise at both the physical and link layers. Furthermore, a general formula describing the impact of the extinction ratio (ER) on the bit-error probability is explored. The results indicate the importance of code flexibility and ER in system performance optimization.