Efficient Photonic Crystal Cavity-Waveguide Couplers

Stanford University, Palo Alto, California, United States
Applied Physics Letters (Impact Factor: 3.3). 11/2006; 90(7). DOI: 10.1063/1.2472534
Source: arXiv


Coupling of photonic crystal (PC) linear three-hole defect cavities (L3) to
PC waveguides is theoretically and experimentally investigated. The systems are
designed to increase the overlap between the evanescent cavity field and the
waveguide mode, and to operate in the linear dispersion region of the
waveguide. Our simulations indicate increased coupling when the cavity is
tilted by 60 degrees with respect to the waveguide axis, which we have also
confirmed by experiments. We obtained up to 90% coupling efficiency into the

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Available from: Dirk Englund, Dec 28, 2012
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    • "vice was designed such that the metal electrode, located within ∼ 1µm from the center of the resonator, had a minimum overlap with the optical mode. The fundamental mode of the resonator extends mainly in a direction that makes an angle of ∼ 30 o with the cavity axis (x) and has a small extent in the y direction[16]. To minimize the optical loss, the electrode was brought in the proximity of the resonator along the y direction and no significant degradation of the quality factor was observed. "
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    • ". (For higher input coupling efficiency, the cavity could be integrated with photonic crystal waveguide couplers[18].) A typical reflectivity spectrum measured with a tungsten halogen white light source is shown in Figure 3a; the measured quality factor is 5600. "
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    • "Chalcogenide glasses quasi-permanently change their optical properties when illuminated with light above their band gap, and have been used to tune optical devices as quantum cascade lasers [5] The tuning of PCs devices directly fabricated in chalcogenide glasses has already been shown in Ref.[6], but many other applications rely on PC fabricated in other materials such as group IV and III-V semiconductors . One such application is quantum information with InAs quantum dots (QDs) embedded in GaAs photonic crystal structures [7] [8] [9]. The performance of these devices relies on precise wavelength-matching of the cavity to embedded QDs. "
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