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We present analysis and proof-of-concept field demonstration of an incoherent optical code-division multiple access over an optical time-division multiple access system. The performance analysis which includes power budget and scalability calculations show scalability improvements without any significant system performance degradation.Index Terms-Optical code-division multiple access (OCDMA), optical networks, optical time-division multiple access (OTDMA).

A novel approach for improving the number of simultaneous users in a hybrid OCDMA-OTDMA network is proposed and analysed. OCDMA system is based on twodimensional wavelength-hopping time-spreading codes with multi-wavelengths picosecond carriers. The scalability increase was achieved by adding a third dimension to separate OCDMA user groups within OTDMA time slots by assigning them into different wavelength bands. We have shown this will scale-up the system capacity proportionally to the number of assigned wavelength bands. A self-clocking all-optical time gate was then demonstrated as an effective means for suppressing the growing detrimental multi access interference noise resulted from this capacity increase.

A receiver that incorporates an all-optical clock recovery approach for synchronisation suitable for use in incoherent OCDMA transmission is demonstrated. The developed solution was implemented and tested in a multiuser environment using the 2D-WHTS coding scheme on incoherent OCDMA transmission with 2.5 Gbit/s data rate. The receiver with built-in all-optical clock recovery was tested by taking the BER for the received data when synchronised with the all-optically recovered clock from the incoming OCDMA traffic and when an RF synthesiser was used to the generate the clock. Improvement of ∼7.5 dBm was observed with the all-optical clock recovery approach. The related eye diagrams and the wavelength spectrum were also recorded

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