Abstract
We study the coupling between the fundamental guided modes of two identical parallel nanofibers analytically and numerically. We calculate the coefficients of directional coupling, butt coupling, and self coupling as functions of the fiber radius, the light wavelength, and the fiber separation distance. We show that, due to the symmetry of the system, a mode of a nanofiber with the principal quasilinear polarization aligned along the axis joining the nanofibers or the perpendicular axis is coupled only to the mode with the same corresponding principal polarization of the other nanofiber. We find that the effects of the butt coupling and the self coupling on the power transfer are significant when the fiber radius is small, the light wavelength is large, or the fiber separation distance is small. We show that the power transfer coefficient may achieve a local maximum or become zero as the fiber radius, the light wavelength, or the fiber separation distance varies.
Highlights
Optical nanofibers are vacuum-clad, ultrathin optical fibers [1] that allow tightly radially confined light to propagate over a long distance and to interact efficiently with nearby atoms, molecules, quantum dots, or nanoparticles [2, 3, 4]
We show that the effects of the butt coupling and the mode energy changes on the power transfer are significant when the fiber radius is small, the light wavelength is large, or the fiber separation distance is small
We have calculated the coefficients of directional coupling, butt coupling, and mode energy changes as functions of the fiber radius, the light wavelength, and the fiber separation distance
Summary
Optical nanofibers are vacuum-clad, ultrathin optical fibers [1] that allow tightly radially confined light to propagate over a long distance (the range of several millimeters is typical) and to interact efficiently with nearby atoms, molecules, quantum dots, or nanoparticles [2, 3, 4]. Photonic structures composed of coupled micro- and nanofibers have been proposed, fabricated, and investigated [30, 31, 32, 33, 34, 35] Such structures have been used to build miniaturized ring interferometers and knot resonators in the visible light wavelength range in recent work by Ding et al [35]. They used the linear coupling theory [26, 27, 28, 29, 36, 37, 38, 39, 40, 41, 42, 43, 44] to calculate the directional coupling coefficient for different fiber radii and different polarization angles.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
