Abstract:
Space Division Multiplexing (SDM) technology in relation to optical fiber focusing on single-mode multi-core fiber (SM-MCF) as spatial multiplexing strategy to meet the rapidly increasing transmission bandwidth demand is explained in this research work. Analysis of crosstalk due to inter-core coupling in a 7-core heterogeneous and homogeneous multi-core optical fiber (MCF) based communication system with a direct detection receiver and optical preamplifier is presented. The expression for Optical Signal to Crosstalk plus Noise Ratio (OSCNR) is developed, and Bit Error Rate (BER) performance is evaluated with respect to various system parameters. Coupling coefficients due to inter-core coupling are evaluated numerically as functions of core pitch and relative refractive index contrast. The results show that there is mentionable deterioration in BER performance due to coupling induced crosstalk, and system suffers distinct power penalty at a given BER. For example, power penalty at BER of 10E-9 is found to be 4.0 dB and 4.3 dB for a MCF link of 10km corresponding to relative refractive index difference of 0.0036 and 0.0030 respectively for a pitch value of 30µm and core radius of 4.5µm. Inter-core coupling coefficients in a 9-core homogeneous MCF are evaluated and investigated analytically for the first time. Results show that the coupling coefficients are inversely related to the core pitch and relative index contrast, but it increases with the increase of core radius. Wavelength dependence of coupling coefficients and inter-core crosstalk in a 9-core homogeneous MCF are investigated analytically. The variation of mean crosstalk power with respect to the operating wavelength as well as with propagation length is investigated using coupled power theory (CPT). The results show that mean crosstalk power is linearly dependent on wavelength and propagation distance. Analytical modeling and evaluation of inter-channel and inter-core induced crosstalk including amplified spontaneous emission (ASE) noise in a single mode 7-core homogeneous MCF based Space Division Multiplexed-Wavelength Division Multiplexing (SDM-WDM) communication system with distributed Raman amplifier is presented. The BER performance results are evaluated for different system parameters, viz. number of WDM channels, channel spacing, propagation distance, pump power etc. It is noticed that BER deteriorates with Raman amplifier induced crosstalk, which is worsened further by the effect of inter-core coupling induced crosstalk of the MCF. The obtained results are compared with the similar results of published research literatures.
