Dynamic control over group speed of light in plasma cladded optical fiber: An analytical approach

Abstract

The ability of plasma frequency to tune the guiding properties of plasma cladded optical fiber is explored and numerically investigated. The identified parameter to manipulate the propagation characteristics of the investigated structure is electron–ion density which can be controlled by varying electric potential. It is shown that the curve of group index vs optical signal frequency can be manipulated significantly by manipulating plasma frequency. Judicious consideration of fiber's parameters and the values of plasma frequency allow for obtaining minimum or desired group velocity dispersion at a desired optical frequency. Further, ability of manipulation of the slope of group index vs signal frequency curve allows for dispersion management. Possibility of significant variation in group-index is the highlight of the present work and the most impressive feature is that it could be achieved in online condition (by varying plasma frequency with the help of tuning electric field). Since, ratio of plasma to signal frequency is the only important factor in manipulating the propagation properties, the idea presented here can be extended to frequency domains in the range of Terahertz, Microwaves etc. An optical modulator is proposed in the last section on the basis of present investigation. © 2021 The Authors