Bilayer dispersion-flattened waveguides with four zero-dispersion wavelengths

Abstract

We propose a new type of bilayer dispersion-flattened waveguides that have four zero-dispersion wavelengths. Low and flat dispersion can be achieved by using two different material combinations, with a much smaller index contrast as compared to the previously proposed slot-assisted dispersion-flattened waveguides. Without using a nano-slot, dispersion becomes less sensitive to waveguide dimensions, which is highly desirable for high-yield device fabrication. Ultra-low dispersion, high nonlinearity, and fabrication-friendly design would make it promising for practical implementation of nonlinear photonic functions. The proposed waveguide configuration deepens our understanding of the dispersion flattening principle.

Designing Optical Waveguides: Myth and Reality

“…Optical pulses with less sequential widths demonstrate shorter HoD length. Optical waveguides are being engineered to demonstrate nearly zero second-order dispersion [69], do experience obvious effects from HoD. It is also being learnt that, if waveguide length is greater than HoD length than, HoD values are to be included in the combined effect of dispersion on the propagating optical signal, which thus provides significance of the dispersion engineering in optical waveguides and presenting as a concluding paragraph of this section.…”

Ultra-flat dispersion in an integrated waveguide with five and six zero-dispersion wavelengths for mid-infrared photonics

“…In recent years, dispersion engineering with multiple ZDWs has been proposed in various types of optical devices, such as photonic crystal fibers [8][9][10][11][12] and integrated waveguides [13][14][15][16][17][18][19][20][21][22][23][24][25][26]. In fibers, saddle-shaped dispersion curves with three and four ZDWs can be obtained by complicated geometry profiles, as a result of balanced waveguide dispersion and material dispersion.…”

“…Different material combinations are proposed to achieve low and flat dispersion in single-slot and dual-slot waveguides [18,19,21,22]. Bilayer waveguides have been proposed to flatten dispersion with four ZDWs with the slot layer removed [24]. Compared to slot-assisted waveguides, these waveguides can be formed with a relatively low index contrast, making choices of materials more flexible and more fabricationfriendly.…”

Dispersion control of silicon nanophotonic waveguides using sub-wavelength grating metamaterials in near- and mid-IR wavelengths

“…The control of the dispersion in nanophotonic waveguides has been recognized as an essential ingredient to exploring a broad range of emerging linear and nonlinear optical applications [3][4][5][6][7][8][9], including parametric optical processes, frequency combs, or supercontinuum generation, to name a few. More recently, substantial research efforts have been put forward to engineering dispersion properties in a variety of structures and material platforms [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In a particular case of the dominant SOI platform, indeed, the dispersion can be readily controlled by adjusting cross-sectional dimensions of the waveguide [10][11][12][13], because of the high modal confinement offered by the high index contrast system.…”

“…In a particular case of the dominant SOI platform, indeed, the dispersion can be readily controlled by adjusting cross-sectional dimensions of the waveguide [10][11][12][13], because of the high modal confinement offered by the high index contrast system. Apart from this straightforward approach, several different techniques have been explored, both theoretically and experimentally [14][15][16][17][18][19][20], allowing for variable dispersion engineering. This primarily includes the slot-assisted waveguide structure with horizontal and vertical geometries [14][15][16], conformal dielectric overlayers [17], multilayer guiding structures [18], double-and multi-cladded waveguides [19], or photonic crystal waveguides [20].…”