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ABSTRACT: A compact directional coupler fabricated on a silicon photonic platform is presented, with a power-splitting ratio that can be tuned through a transverse temperature gradient induced by a laterally shifted integrated heater. The tuning mechanism exploits the thermally induced phase velocity mismatch between the coupled modes of the silicon waveguides. The positions of the integrated heater and the waveguide design are optimized to maximize the tuning range and to reduce electric power consumption. Asynchronous devices with an intrinsic phase mismatch are demonstrated to be more efficient, providing a tunable coupled power from 0.7 to 0.01 with 36 mW maximum power dissipation.
Optics Letters 03/2013; 38(6):863-5. · 3.40 Impact Factor
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ABSTRACT: We present the design and the fabrication of compact tunable silicon-on-insulator bandpass filters based on the integration of a Mach-Zehnder interferometer with ring resonators and activated via thermo-optic phase shifters. The proposed architecture provides wide filter bandwidth tunability from 10% to 90% of the free spectral range preserving the filter off-band rejection. Possible applications are channel subset selection in wavelength division multiplexing optical systems, adaptive filtering to signal bandwidth, and reconfigurable filters for gridless networking.
Optics Letters 09/2012; 37(17):3669-71. · 3.40 Impact Factor
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ABSTRACT: A chalcogenide-assisted silicon waveguide is realized by depositing a thin layer of A(2)S(3) glass onto a conventional silicon on insulator optical waveguide. The photosensitivity of the chalcogenide is exploited to locally change the optical properties of the waveguide through exposure to visible light radiation. Waveguide trimming is experimentally demonstrated by permanently shifting the resonant wavelength of a microring resonator by 6.7 nm, corresponding to an effective index increase of 1.6·10(-2). Saturation effects, trimming range, velocity and temporal stability of the process are discussed in details. Results demonstrate that photo-induced treatments can be exploited for a post-fabrication compensation of fabrication tolerances, as well as to set and reconfigure the circuit response.
Optics Express 07/2012; 20(14):15807-17. · 3.59 Impact Factor
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ABSTRACT: We show that optical signal propagation in a coupled resonator optical waveguide (CROW) does not introduce additional performance penalties with respect to propagation in a conventional optical waveguide. The result is demonstrated in a low-loss (1 dB) eight-ring silicon CROW by means of bit error rate measurements performed over the whole telecommunication C-band. An extensive characterization of the CROW parameters in terms of insertion loss, bandwidth, in-band intensity ripple, crosstalk, and sensitivity to thermal drifts is presented.
Optics Letters 10/2011; 36(19):3948-50. · 3.40 Impact Factor
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ABSTRACT: Wave mixing inside optical resonators, while experiencing a large enhancement of the nonlinear interaction efficiency, suffers from strong bandwidth constraints, preventing its practical exploitation for processing broad-band signals. Here we show that such limits are overcome by the new concept of travelling-wave resonant four-wave mixing (FWM). This approach combines the efficiency enhancement provided by resonant propagation with a wide-band conversion process. Compared with conventional FWM in bare waveguides, it exhibits higher robustness against chromatic dispersion and propagation loss, while preserving transparency to modulation formats. Travelling-wave resonant FWM has been demonstrated in silicon-coupled ring resonators and was exploited to realize a 630-μm-long wavelength converter operating over a wavelength range wider than 60 nm and with 28-dB gain with respect to a bare waveguide of the same physical length. Full compatibility of the travelling-wave resonant FWM with optical signal processing applications has been demonstrated through signal retiming and reshaping at 10 Gb s(-1).
Nature Communications 01/2011; 2:296. · 7.40 Impact Factor
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ABSTRACT: In this Letter, we report group index measurements of the supermodes of an array of two strongly coupled silicon-on-insulator waveguides. We observe coupling-induced dispersion that is greater than the material and waveguide dispersion of the individual waveguides. We demonstrate that the system transforms from supporting the two supermodes associated with two coupled waveguides to the single mode of a slot waveguide within the investigated spectral range. During the cutoff of the antisymmetric supermode, an anti-crossing between the symmetric TM and antisymmetric TE supermodes has been observed.
Optics Letters 12/2010; 35(23):3925-7. · 3.40 Impact Factor
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ABSTRACT: We report on experimental demonstration of all-optical switching in a silicon-on-insulator photonic wire nanocavity operating at telecom wavelengths. The switching is performed with a control pulse energy as low as approximately 0.1 pJ on a cavity device that presents very high signal transmission, an ultra-high quality-factor, almost diffraction-limited modal volume and a footprint of only 5 microm(2). High-speed modulation of the cavity mode is achieved by means of optical injection of free carriers using a nanosecond pulsed laser. Experimental results are interpreted by means of finite-difference time-domain simulations. The possibility of using this device as a logic gate is also demonstrated.
Optics Express 01/2010; 18(2):1450-61. · 3.59 Impact Factor
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ABSTRACT: We present experimental results on photonic crystal/photonic wire micro-cavity structures that demonstrate further enhancement of the quality-factor (Q-factor)--up to approximately 149,000--in the fibre telecommunications wavelength range. The Q-values and the useful transmission levels achieved are due, in particular, to the combination of both tapering within and outside the micro-cavity, with carefully designed hole diameters and non-periodic hole placement within the tapered section. Our 2D Finite Difference Time Domain (FDTD) simulation approach shows good agreement with the experimental results.
Optics Express 09/2008; 16(16):12084-9. · 3.59 Impact Factor
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Richard De La Rue,
Harold Chong,
Marco Gnan,
Nigel Johnson,
Iraklis Ntakis,
Pierre Pottier, Marc Sorel,
Ahmad Md Zain,
Hua Zhang,
Edilson Camargo,
Chongjun Jin,
Mario Armenise,
Caterina Ciminelli
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ABSTRACT: Silicon-on-insulator (SOI) is a strong candidate for application in future planar waveguide integration technology, whether or not luminescence is extracted from the silicon. We review recent research on photonic devices based on silicon-on-insulator. These devices exploit either photonic crystal or photonic wire concepts—or combinations of both. Aspects of the technologies used that are particularly critical for successful implementation of SOI-based photonics are addressed.
New Journal of Physics 10/2006; 8(10):256. · 4.18 Impact Factor
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M Richard, Marc Sorel,
Antonio Samarelli,
Philippe Velha,
Michael Strain,
Nigel P Johnson,
Graham Sharp,
Faiz Rahman,
Ali Z Khokhar,
Douglas S Macintyre,
others
Photonics and Micro-and Nano-structured Materials 2011; 01/1899
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ABSTRACT: This paper describes the realization of high quality-factor (Q-factor) and high transmission photonic crystal micro-cavity and extended cavity structures embedded in photonic wire waveguides. Q-factor of as much as 16600 have been achieved in micro-cavities with transmission of more than 80%. We have also fabricated an 8 μm long extended cavity with a measured Q-factor of 5100 with normalised transmission of around 67%. Three-dimensional (3D) Finite Difference Time Domain (FDTD) computation has been used to simulate the devices. Comparison of the simulation and measured result shows reasonably good agreement.
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Proceedings of SPIE.
