Experimental Demonstration of Optical Fast Frequency Hopping-CDMA Communications

Code division multiple access (CDMA) is a highly flexible multiple access protocol, however, significant signal bandwidth expansion is required. Given the Terahertz pass band of optical fiber, the frequency spreading of the CDMA signal is no impediment, provided it can be accomplished optically. Among wide variants of optical CDMA techniques, only a spectral encoding based approach [1] has penetrated the market. CDMA techniques based on in-fiber signal processing are the most promising due to the complexity and coupling loss reduction. In [2-4], we proposed fast frequency hopped CDMA (FFH-CDMA) based on all-fiber multiple Bragg gratings (MBGs). Theoretical analysis and numerical simulation showed that the system could accommodate a large number of users at bit rates exceeding the 1 Gbit/sec [2,4]. In this paper, we report an experimental demonstration of the optical FFH-CDMA encoding/decoding system, including a single receiver and two transmitters at bit rates varying from 100Mb/s to 1.6 Gb/s.