Abstract:
Multicore Fiber (MCF) is found to be a promising candidate to replace Single Mode
Fiber (SMF) in order to increase the capacity of an optical fiber link. In this thesis,
investigations are carried out to find out the limitations imposed by crosstalk due to
coupling between the cores of an MCF on the Bit Error Rate (BER) performance of a
MCF optical link. Analysis is carried out for single mode multicore fiber (MCF) to find
the electric fields and power induced from one fiber to another for a given structure of a
MCF, number of cores, refractive index profile etc. The expressions of the signal power
at the output of the different cores of the MCF with excitation to any one of the cores is
found out along with the crosstalk. The expression for the crosstalk power due to
coupling among the cores is also determined. The analysis is extended to optical MCF
link with an optical pre-amplifier followed by direct detection receiver. Finally, the
expression for Signal to Crosstalk plus Noise Ratio (SCNR) at the output of the excited
fiber core is found. Computations are carried out for signal power of the desired
channel and crosstalk power due to other channels. The BER for a given data rate is
then determined numerically for different MCF parameters and transmission distance.
The optimum system design parameters like coupling co-efficient between cores of
MCF, BER, transmission distance, input power range, gain of the optical pre-amplifier
etc, is determined for a given data rate. The outcome of this research work will be
useful to design fiber optic system with Multi-core single-mode fiber running at BER
comparable to multi-mode fiber links. The proposed system may be a potential
candidate for future MIMO fiber optic communication system.
