Hybrid pulse position modulation/ultrashort light pulse code-division multiple-access systems - Part II: Time-space processor and modified schemes

In Part I of this two-part paper, we proposed and investigated a hybrid pulse position modulation/ultrashort light pulse code-division multiple-access (PPM/ULP-CDMA) system for ultrafast optical communication networks. In the proposed scheme, the large bandwidth of an ULP is efficiently utilized by virtue of the very high time resolution of a time-space processor. In this paper, more detailed analysis and discussion on the receiver scheme using the time-space, processor is presented; nonideal performance of the time-space processor, including the reference pulse realization problem, as well as amplifier and detector noise, are taken into account. Discussions on physically achievable ranges of the system parameters that determine the performance of the proposed PPM/ULP-CDMA system are also made based upon current, state of the art technology. As remedies to overcome the physical limitations on the system parameters, two modified modulation/demodulation schemes are proposed and investigated to enhance the performance of the hybrid PPM/ULP-CDMA system.