Design optimization of a silica based short length multifunctional Dual-core photonic crystal fiber

Abstract

A systematic study implementing numerical analysis has been presented in this work in order to design a hexagonal lattice dual core photonic crystal fiber (DC-PCF) which will be simple to fabricate but possesses very good values of optical properties for supercontinuum generation (SCG). By utilizing a full vectoral finite element method with perfectly matched boundary conditions, important propagation properties are nu- merically evaluated and tuned to desired value through the optimization of structural parameters. Finally, it is found that the optimized PCF structure exhibits very low con- finement loss (in the order of 10−7dB/km), high birefringence (in the order of 10−4), effective mode area of 17.1125µm2 while maintaining negative chromatic dispersion of −8.3138 ps/km.nm pumping at 1060 nm wavelength. The fiber when excited by a hyperbolic secant pulse having a full-width at half-maximum (FWHM) of 50 fs and a relatively low energy of 4 nJ generates a SC spectrum spanning 600nm to 1600nm. The effect of altering the pump power and other parameters on the generated spectra is also explored. Furthermore, the input noise effects on generated SCs have been ana- lyzed through the inclusion of different types of noise. It is found that the generated SC demonstrates excellent coherence property (average coherences varies from 98.77% to 92.095%) over the entire band extended from visible to the near-IR region and thus it may find applications in lasing, biological imaging, and telecommunication. In addition to these,we have also analyzed various properties of the PCF which are important and significant for optical communications and optimized the design for ef- ficient polarization and wavelength splitting. An efficient polarization splitter with a small device length and extremely low loss which is capable of decoupling two orthog- onal polarized modes with a length of 2.33 mm at a wavelength of 1550 nm has been obtained. Finally, the proposed design can also be used as a demultiplexer where at a ultra-short device length of 0.334 mm, x-polarized modes with wavelengths of 1550 nm and 1000 nm can be separated and the y-polarized modes with wavelengths of 1550 nm and 1000 nm can be separated at a device length of 0.341 mm. This short-length polarization and wavelength splitter with low loss is well-suited for applications in in- tegrated optical communications systems.