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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    ABSTRACT: The resonance frequency of an InAs quantum dot strongly coupled to a GaAs photonic-crystal cavity was electrically controlled via the quadratic quantum confined Stark effect. Stark shifts up to 0.3 meV were achieved using a lateral Schottky electrode that created a local depletion region at the location of the quantum dot. We report switching of a probe laser coherently coupled to the cavity up to speeds as high as 150 MHz, limited by the RC constant of the transmission line. The coupling strength g and the magnitude of the Stark shift with electric field were investigated while coherently probing the system.
    Physical Review Letters 01/2010; 104(4):047402. DOI:10.1103/PhysRevLett.104.047402 · 7.51 Impact Factor
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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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    ABSTRACT: We demonstrate second harmonic generation in photonic crystal nanocavities fabricated in the semiconductor gallium phosphide. We observe second harmonic radiation at 750 nm with input powers of only nanowatts coupled to the cavity and conversion efficiency $P_{\rm out}/P_{\rm in, coupled}^2 = 430%/{\rm W}$. The large electronic band gap of GaP minimizes absorption loss, allowing efficient conversion. Our results are promising for integrated, low-power light sources and on-chip reduction of input power in other nonlinear processes.
    Optics Express 12/2009; 17(25):22609-15. DOI:10.1364/OE.17.022609 · 3.49 Impact Factor
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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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    ABSTRACT: We demonstrate a method to locally change the refractive index in planar optical devices by photodarkening of a thin chalcogenide glass layer deposited on top of the device. The method is used to tune the resonance of GaAs-based photonic crystal cavities by up to 3 nm at 940 nm, with only 5% deterioration in cavity quality factor. The method has broad applications for postproduction tuning of photonic devices. Comment: 3 pages, 2 figures
    Applied Physics Letters 11/2007; 92(4). DOI:10.1063/1.2839308 · 3.30 Impact Factor
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