Discretizing light behaviour in linear and nonlinear waveguide lattices

Abstract

Light propagating in linear and nonlinear waveguide lattices exhibits behaviour characteristic of that encountered in discrete systems. The diffraction properties of these systems can be engineered, which opens up new possibilities for controlling the flow of light that would have been otherwise impossible in the bulk: these effects can be exploited to achieve diffraction-free propagation and minimize the power requirements for nonlinear processes. In two-dimensional networks of waveguides, self-localized states--or discrete solitons--can travel along 'wire-like' paths and can be routed to any destination port. Such possibilities may be useful for photonic switching architectures.

Fractional Bloch oscillations in photonic lattices

“…In our experiments, singleparticle hopping dynamics in the square lattice of Fig. 1e has been simulated by discretized spatial light transport in an engineered 2D square lattice of evanescently coupled optical waveguides 29 . This lattice has been fabricated in a fused silica substrate by direct waveguide writing with femtosecond lasers [30][31][32][33][34] , taking advantage of the 3D capabilities of this technology.…”

“…This lattice has been fabricated in a fused silica substrate by direct waveguide writing with femtosecond lasers [30][31][32][33][34] , taking advantage of the 3D capabilities of this technology. The spatial propagation of the light intensity in the generic (m,n)-th lattice site maps the temporal evolution of the two-particle probability distribution j c m;n ðtÞj 2 in Fock space 29,33 . In the photonic simulator of Ĥ EBH , the role of the hopping coefficients k and r is played by the evanescent coupling constants between first-and secondneighbouring waveguides (k and r), respectively.…”

High-density waveguide superlattices with low crosstalk

“…By introducing optical nonlinearity, waveguide superlattices may provide a playground for studying a rich spectrum of phenomena in nonlinear optics, disordered systems and their interplay 27,45,46 . For example, with nonlinear selffocusing in a discrete system, we can further enhance light 'localization' in each 'atom' (waveguide), which will effectively reduce crosstalk and may enable even smaller pitches.…”

“…The latter is more common for optical device applications of interest here. Also note that the structures considered in this study resemble an insulator with hoppingtype transport and are better described on the basis of individual waveguide modes rather than periodic Bloch modes 27,47 .…”

“…For example, waveguide arrays are widely used in emerging applications such as optical-phased arrays [18][19][20][21] , space-division multiplexing 22 and chip-scale optical interconnects 23,24 , and conventional applications such as wavelength-division multiplexers 25,26 . On the other hand, a waveguide array or a waveguide lattice can also be viewed 27 as fully analogous to a periodic chain of atoms, which lends itself to a broad spectrum of fascinating scientific possibilities ranging from Anderson localization of light 28,29 to parity-time symmetric effects 30 . Thus far, in most studies, the pitch associated with such relatively simple waveguide arrays/lattices has been typically large, ranging from a few micrometres to tens of micrometres (or a multiple of wavelengths) 18,19,21,31,32 .…”