Supermode dispersion and waveguide-to-slot mode transition in arrays of silicon-on-insulator waveguides

Abstract

In this Letter, we report group index measurements of the supermodes of an array of two strongly coupled silicon-on-insulator waveguides. We observe coupling-induced dispersion that is greater than the material and waveguide dispersion of the individual waveguides. We demonstrate that the system transforms from supporting the two supermodes associated with two coupled waveguides to the single mode of a slot waveguide within the investigated spectral range. During the cutoff of the antisymmetric supermode, an anti-crossing between the symmetric TM and antisymmetric TE supermodes has been observed.

Design and Dispersion Control of Microstructured Multicore Tellurite Glass Fibers with In-Phase and Out-of-Phase Supermodes

“…In addition, the supermode dispersion can vary significantly compared to the dispersion for a one-core fiber. For example, for nano-sized photonic wires, it has been shown theoretically that the dispersion of waveguide arrays can vary dramatically between different supermodes, and anomalous dispersion can be attained in coupled waveguides while a single waveguide has normal dispersion [47], which was also confirmed experimentally [48].…”

“…More complicated fiber coupling devices, such as fan-in/fan-out fiber couplers, allowing access to one or more cores, can also be used [50]. An out-of-phase supermode can be excited with free-space objective lenses [48] or spatial light modulators [43].…”

Modulated coupled nanowires for ultrashort pulses

“…In particular optical chips based on silicon sub-wavelength waveguides allow for efficient frequency conversion [3,4], all-optical pulse control [5] and all-optical switching [6]. Furthermore, couplers [7] and arrays of coupled nanowire waveguides [8,9] open possibilities for efficient spatio-temporal shaping of optical pulses. In order to harness these opportunities, it is essential to develop approaches to simultaneously and independently control temporal and spatial dispersion, as these characteristics can be strongly connected in nanophotonic structures.…”

“…We choose a bending profile according to Eq. (7). We vary the bending amplitude A and search for the minima of the coupling dispersion ∂C ef f /∂ω in the vicinity of λ 0 .…”

Modulated nanowire couplers for ultrashort pulses

“…Furthermore, arrays of coupled nanowire waveguides [2][3][4] open possibilities for efficient spatio-temporal shaping and switching of optical pulses. In order to harness these opportunities, it is essential to develop approaches to simultaneously control temporal and spatial dispersion, as these characteristics can be strongly connected in nanophotonic structures.…”