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We report our advances in development of subwavelength engineered metamaterial structures in silicon waveguides, specifically high-efficiency fiber-chip couplers, ultra-broadband surface grating couplers and nanophotonic beam splitters, evanescent field waveguide sensors and on-chip Fourier-transform spectrometers.
Polarization management is a key functionality in many photonic applications including telecommunications, polarization diversity circuits and sensing, to name a few. Developing integrated circuits capable of reliably controlling polarization state would result in compact and low cost circuits with improved stability, compared with fiber or bulk optics solutions. Polarization rotators are a key building...
Subwavelength engineering in silicon photonic integrated circuits is a powerful design tool that allows one to synthesize an effective photonic medium with adjustable refractive index. This creates a new degree of freedom in photonic circuit design. We present an overview of the fundamental concept and its application to address several important practical challenges in the implementation of silicon...
In a heat-assisted magnetic recording (HAMR) system, optical power is delivered by the waveguide to interact with the near-field transducer. The influence of optical properties of waveguide core on transducer efficiency has been investigated by using finitedifference time domain simulations. It is observed that the waveguide core of large refractive index can improve transducer efficiency due to more...
Polarization control is essential in applications ranging from optical communications to interferometric sensors. The implementation of integrated polarization controllers is challenging as they require polarization rotating waveguides with stringent fabrication tolerances. Here, we present a fully integrated polarization controller scheme that significantly relaxes the requirements on the rotating...
In most integrated optics platforms, including silicon-on-insulator, only minor modifications in refractive index are possible. The geometry of the waveguiding structure is thus the only degree of freedom for the design of devices. The use of sub-wavelength gratings (SWGs), i.e. structures that are small enough to suppress diffraction effects, enables local engineering of both refractive index and...
Integrated optical affinity sensors based on Mach–Zehnder interferometers (MZIs) enable sensitive and label-free detection of chemical and biological molecules. However, since MZIs transduce optical phase changes into sinusoidal intensity variations, they exhibit a variable sensitivity that vanishes at the extrema of the transmittance function. Moreover, the direction of phase change cannot be unambiguously...
Directional couplers are key building blocks for network-on-chip devices such as wavelength demultiplexers and switches. The operational bandwidth of directional couplers is, however, limited, and existing techniques to extend their bandwidth result in significantly increased device footprints and degraded phase response. Here we present a novel approach to enhance the bandwidth of directional couplers...
We demonstrate all-optical XOR logic function for 40Gb/s DPSK signals in the C-band, based on four-wave mixing (FWM) in a silicon nanowire. Error-free operation with a system penalty of ∼ 4.3dB at 10−9 BER has been achieved.
We demonstrate all-optical wavelength conversion at 10 Gb/s for differential phase-shift keyed (DPSK) data in the C-band, based on four-wave mixing (FWM) in a silicon ring resonator. Error-free operation with a system penalty of ∼ 4.1 dB at 10−9 BER is achieved.
We demonstrate all-optical XOR logic function for 40Gb/s DPSK signals in the C-band, based on four-wave mixing (FWM) in a silicon nanowire. Error-free operation with a system penalty of ∼ 4.3dB at 10−9 BER has been achieved.
A complete instrumentation system for interrogating silicon photonic wire waveguide sensor array chips has been built and demonstrated. The system is designed to read 16 or more photonic wire sensors on a single silicon chip simultaneously and in real time, while delivering sample fluid to the sensors through microfluidic channels fabricated monolithically on the chip. The chip can be inserted into...
The use of grating couplers for fiber to chip coupling is a promising technique, allowing wafer scale testing with no need for facet preparation. Albeit grating couplers have been extensively studied for Si-wire waveguides, the implementation on SOI micrometric rib waveguides remains challenging, mainly due to excitation of higher order modes. In this work we show for the first time that monomode...
In this work a fiber to chip grating coupler in micrometric SOI rib waveguides is experimentally demonstrated, for the first time, with −4dB coupling efficiency when an inverse taper is used as excitation stage.
We report a SOI ring resonator biosensor array with 1 reference ring and 4 sensing rings, using WDM as the addressing scheme. On-chip referencing and temperature shift cancellation are demonstrated, and the differential signal shows a low temperature sensitivity of ~plusmn0.8 pm/degC.
A silicon waveguide evanescent field molecular sensor interrogated by reflection from a surface grating is demonstrated. The sensor is probed by a beam of light incident at thetas = 45deg through the backside of the silicon-on-insulator (SOI) wafer. The reflected power shows a strong resonant feature near lambda = 1532 nm, arising from resonant coupling of incident beam, guided mode, and the reflected...
We show by theoretical analysis and experiments on submicrometer silicon-on-insulator channel waveguides that the optical scattering loss of high-index-contrast planar waveguides is modified significantly by a thin-film interference effect, caused by boundary reflections.
Using silicon photonic wire waveguides we demonstrate highly sensitive and ultra-compact optical circuits for molecular sensing. The high-index-contrast of these structures is exploited to fabricate new folded waveguide geometries beneficial for sensing, as well as optical switching applications.
We present the novel design of a silicon modulator with low operation voltage of les3 V by employing periodically interleaved pn junctions. Simulations predict that in depletion mode it has a high modulation efficiency of better than 1.5 Vldrcm.
We demonstrate a method of canceling the temperature dependence of ring resonator sensors using a double ring configuration. Temperature calibration curves are provided for SOI photonic wire ring sensors with air and SU8 polymer cladding.
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