Towards higher scalability of hybrid optical CDMA network

Ivan Glesk,Wing C Kwong,Tolulope B Osadola

doi:10.1007/s11082-017-1101-9

Ivan Glesk, Wing C Kwong + Show 1 more

Open Access

https://doi.org/10.1007/s11082-017-1101-9

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Abstract

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 two-dimensional 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.

Highlights

Recent advances in information technology have increased the demand for large communications bandwidth (Berthold 1998)
We showed that the scalability of such hybrid system is increased by a factor of M 9 N where N is the number of optical time division multiplexing (OTDM) channels and M is the number of simultaneous Optical code division multiple access (OCDMA) users per the OTDM channel
We propose and analyze a novel approach that will further increase the scalability of the OCDMA-OTDMA system we originally reported in Osadola et al 2012

Summary

Introduction

Recent advances in information technology have increased the demand for large communications bandwidth (Berthold 1998). Osadola et al (2012) proposed and demonstrated a novel architecture for increasing the scalability of an incoherent OCDMA system by employing the technique of OCDMA code reuse that enables different groups of OCDMA users to transmit in separate OTDMA channels. We propose and analyze a novel approach that will further increase the scalability of the OCDMA-OTDMA system we originally reported in Osadola et al 2012 In this new approach, a third dimension is being added to the original OCDMA-OTDMA architecture by allowing multiple OCDMA user groups assigned to different wavelength bands to transmit simultaneously within each OTDM channel. Our analysis and discussions in this paper assumes the use of multiwavelength two dimensional wavelength-hopping time-spreading (2D-WH/TS) OCDMA codes in all OCDMA sub-systems operating in OTDM channels. In support of building such system we demonstrate an all-optical self-clocking method for multiaccess interference suppression by using an all-optical time gating technique with a semiconductor optical amplifier -based Mach–Zehnder interferometer (MZI-SOA)

Design of a highly scalable OCDMA over OTDMA hybrid system

Scalability calculations

Findings

Conclusions