Coupled-mode theory and propagation losses in photonic crystal waveguides

University of Glasgow, Glasgow, Scotland, United Kingdom
Optics Express (Impact Factor: 3.49). 07/2003; 11(13):1490-6. DOI: 10.1364/OE.11.001490
Source: PubMed

ABSTRACT Mode coupling phenomena, manifested by transmission "ministopbands", occur in two-dimensional photonic crystal channel waveguides. The huge difference in the group velocities of the coupled modes is a new feature with respect to the classical Bragg reflection occurring, e.g., in distributed feedback lasers. We show that an adequate ansatz of the classical coupled-mode theory remarkably well accounts for this new phenomenon. The fit of experimental transmission data from GaAs-based photonic crystal waveguides then leads to an accurate determination of the propagation losses of both fundamental and higher, low-group-velocity modes.

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Available from: C. Weisbuch, Jul 10, 2014
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    • "The problem of coupling between localized states in photonic crystals, i.e waveguide or surface modes, has been studied recently [9] [10] [11] [12]. In [8], Olivier et al apply the coupled mode theory (CMT) to the problem of waveguides in photonic crystals. They analyze the cases of multimode waveguides and the coupling between counter propagating waves, finding very simple analytic relations involving the basic parameters of these modes, such as the coupling coefficient for counter propagating modes. "
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    ABSTRACT: Photonic crystal waveguides are being used for different applications in sensors, lasers, interferometers, and optical circuits. The process of coupling a light beam to a waveguide presents an inherent loss of energy, particularly for monomode waveguides. In this work, we study the coupling of an interface mode in a metal-2D photonic crystal (2DPC) and a photonic crystal waveguide mode. The coupling produces a hybrid mode that presents an avoided crossing inside the photonic crystal band gap. The avoided crossing produces a mini-stop band whose frequency width is larger when the waveguide is closer to the interface. Using the finite difference time domain method (FDTD) we show that the hybrid mode can be excited by incident light normal to the interface for an appropriate thickness of the metal. For an incident light beam with a given frequency such that two hybrid modes can be excited simultaneously, the energy goes from the interface to the waveguide and vice versa, oscillating with a period given by the coupling distance, as described by coupled mode theory (CMT).
    Journal of optics 02/2014; 16(3):035501. DOI:10.1088/2040-8978/16/3/035501 · 2.01 Impact Factor
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    • "Mode conversion phenomenon is analytically and experimentally investigated in PCCW as a periodic waveguide with similar structure to the substrate integrated waveguide [7]. As it is shown, mode conversion is appeared by a dip in the transmission spectrum of the fundamental mode and energy is transferred to the higher order mode which propagates backward. "
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    ABSTRACT: Substrate integrated waveguide is a planar circuit with periodic discontinuities. Periodicity of the structure results to electromagnetic band gaps. Moreover due to higher order modes generation, mode conversion phenomenon happens in the structure at some specific frequencies. In this article, two dimensional multiport method is used to analyze substrate integrated waveguide. As the results show, mode conversion and classical electromagnetic band gaps affect propagation characteristics of substrate integrated waveguide. These phenomena are investigated by employing two simple examples of periodic structures.
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    • "These waveguides are primarily based on the in-plane photonic band gap confinement. Our main system of interest consists of heterostructure-type or ''substrate-type'' confinement in the third direction, whereby a low-index contrast material system, such as AlGaAs/GaAs or InP/ InGaAsP is exploited to confine light vertically [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]. However, membranes (i.e., thin slabs of perforated semiconductor surrounded by air) will be specifically considered in Section 6 of this paper, in the spirit of the striking results of the Kyoto group [14] [15] [16]. "
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    ABSTRACT: We review the various progresses towards light control in a series of photonic crystal waveguides we studied by the internal light source method on GaAs or InP substrates, or theoretically. We focus mostly on the canonical few-missing rows waveguides. We address physics issues, and device issues as well, looking at demultiplexing functions, gain, lasing and spontaneous emission. In the end of the paper, we briefly give some clues on our insight on ultra-slow modes and ultra-narrow confinement capabilities in the single missing row “W1” waveguide.
    Photonics and Nanostructures - Fundamentals and Applications 02/2006; 4(1-4):1-11. DOI:10.1016/j.photonics.2005.10.002 · 1.35 Impact Factor
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