Self-imaging phenomena in multi-mode photonic crystal line-defect waveguides: application to wavelength de-multiplexing

Abstract

We show that the self-imaging principle still holds true in multimode photonic crystal (PhC) line-defect waveguides just as it does in conventional multi-mode waveguides. To observe the images reproduced by this self-imaging phenomenon, the finite-difference time-domain computation is performed on a multi-mode PhC line-defect waveguide that supports five guided modes. From the computed result, the reproduced images are identified and their positions along the propagation axis are theoretically described by self-imaging conditions which are derived from guided mode propagation analysis. We report a good agreement between the computational simulation and the theoretical description. As a possible application of our work, a photonic crystal 1-to-2 wavelength demultiplexer is designed and its performance is numerically verified. This approach can be extended to novel designs of PhC devices.

Beaming effect in multimode photonic crystal by using coupled waveguides

“…1(b)]. According to the self-imaging principle in PCs [18,19], if the normalized frequency is chosen to be about a/λ = 0.425 (λ is the wavelength in free space), the minimal length of the multimode structure to achieve beam splitting is approximately 3π…”

“…For the beam-splitting function, it can also be achieved by means of multimode PCs [18]. As we know, the self-imaging principle still holds true in multimode PCs just as it does in conventional multimode waveguides [19]. And multimode PCs have been successfully applied in designing optical switches, power splitters, optical demultiplexers [20,21].…”

Theoretical modelling of one dimensional photonic crystal based optical demultiplexer

“…Traditional WDM components are realized using arrayed waveguide gratings, thin-film filters and fibre Bragg gratings. Utilizing the extraordinary properties of PhCs many ideas including directional couplers, optical microcavities, multimode self-imaging waveguides, super-prisms and optical logic gates have been proposed [5][6][7][8][9][10]. In the near future, all these will be important components of logical processors for telecommunication networks and proper alternatives for electronic logic gates [11][12][13][14][15].…”

A Compact Polarization Beam Splitter Based on a Multimode Photonic Crystal Waveguide With an Internal Photonic Crystal Section

“…Kim et al reported that the self-imaging phenomenon is still available in a multimode PhC waveguide [13] as in a conventional multimode waveguide. A device based on the MMI effect in PhC can be much smaller than a conventional MMI device due to the large dispersion of a PhC structure.…”