Harnessing the frequency dimension in integrated photonics offers key advantages in terms of scalability, noise resilience, parallelization, and compatibility with telecom multiplexing techniques. Integrated ring resonators have been used to generate frequency-entangled states through spontaneous four-wave mixing. However, state-of-the-art integrated resonators are limited by trade-offs among size, spectral separation, and efficient photon pair generation. We have developed silicon ring resonators with a footprint below 0.05 mm2 providing more than 70 frequency channels separated by 21 GHz. We exploit the narrow frequency separation to parallelize and independently control 34 single qubit-gates with a single set of three off-the-shelf electro-optic devices. We fully characterize 17 frequency-bin maximally entangled qubit pairs by performing quantum state tomography. We demonstrate for the first time, we believe, a fully connected five-user quantum network in the frequency domain. These results are a step towards a generation of quantum circuits implemented with scalable silicon photonics technology, for applications in quantum computing and secure communications.
Fluoranthene and Pyrene (PAHs) airborne particles are well known for their mutagenic and carcinogenic properties. Manipulation of such nanoparticles below 100 nm makes it challenging due to their low polarizability and dielectric properties. Current optical nano-tweezer designs such as trench, slot and Hybrid Plasmonic Waveguides (HPWG) provides a strong gradient force for trapping, but they often have ≤ 50 nm gaps and have very low fabrication tolerances. In this work, we show the modeling of optical forces and sensitivity of different waveguide structures to sense large numbers of particles to monitor the Air Quality Index (AQI). To increase the trapping gaps and sensitivity in HPWG, we have designed them to use radiation modes of the dielectric waveguides. We call this phenomenon a “mode-lift”. Here we present the numerical and experimental results of industrially compatible integrated photonic sensors such as strip, slot, subwavelength grating (SWG) and HPWG used for measuring AQI.
Multispectral sensors such as Ambient Light sensors (ALS) are becoming increasingly popular due to growing concerns for health, environment, and safety. These sensors provide non-intrusive quantitative and qualitative information on the photonic footprints of interest. To meet the demand for mass production, CMOS image sensors (CIS) are a good basis for these devices. Commercial hyperspectral cameras use a generalization of Bayer-like matrix of Fabry-Perot cavities (FPC) as multispectral filters embedded onto a CIS. However, the delicate fabrication of these filters is tedious and leads to a pronounced surface topology. In this study, we demonstrate experimentally that multispectral sensing can be achieved using a hybrid FPC (h-FPC) which is an improved version of the regular FP cavity, that consists of two silicon mirrors, SiO2 spacer, and a sub-wavelength silicon grating at the center of the cavity. These structures were fabricated using a CMOS compatible process and can be integrated into an imager process flow. The h-FPC optical response can be tuned in the near-infrared region (750-950nm) by changing the filling factor of the grating inside the cavity without varying its height, unlike planar FPC. This feature makes the hybrid FPC a more versatile and efficient option for agile multispectral sensing.
Silicon photonics has been largely developed as a platform to address the future challenges in several applications including datacom, sensing or optical communications, among others. However, the properties of silicon itself is not enough to overcome all limitations in terms of speed, power consumption and scalability. New strategies have then been encouraged based on the hybrid integration of new materials in the silicon photonics platform. In this paper, we will introduce the recent advances in the hybrid integration of doped crystalline-oxides on silicon and silicon nitride waveguides. Especially, Yttria-stabilized zirconia (YSZ) with a lattice parameter compatible with the silicon lattice has been considered because it exhibits promising linear and nonlinear optical properties: low propagation loss, no two photon absorption (TPA) due to its large bandgap energy, a large transparency window from the ultraviolet to the mid-infrared and a good Kerr effect. Furthermore, YSZ can be doped with many dopants to develop active photonic devices with strong second- and third-order nonlinearities and light emission. We have recently demonstrated propagation loss in YSZ waveguides as low as 2dB/cm at a wavelength of 1380 nm, a nonlinear refractive index (Kerr effect) comparable with the SiN coefficient and light amplification in Er3+ doped YSZ on SiN waveguides. The recent results are very promising to pave the way for the development of low cost and low power consumption devices.
The large mode size mismatch between standard single-mode optical fibers and silicon-on-insulator (SOI) waveguides poses a significant challenge to efficiently couple light from the optical fiber to the chip, and vice versa. Surface grating couplers are often used for this purpose, however, their operational bandwidth is limited to a few tens of nanometers, as a consequence of the wavelength-dependent radiation angle. This constraint seriously hampers the use of surface grating couplers for next-generation passive optical networks (PONs), in which the wavelengths used for the upstream and downstream channels are separated more than 150 nm.
In this work, we present a dual-band grating coupler for 10 Gbit symmetric PONs. Our device operates as a wavelength multiplexer/demultiplexer, simultaneously coupling and combining/splitting two optical signals at the wavelengths of λ_1=1270 nm and λ_2=1577 nm. The coupler is based on engineering a surface grating coupler to obtain opposite radiation angles for the two respective wavelengths. To achieve a higher coupling efficiency, the material platform thicknesses were optimized as a tradeoff between the waveguide propagation loss and the substrate reflectivity. By judiciously choosing the period (Λ=500 nm) and the duty cycle (DC=55%) of the grating section, an efficient dual-band grating coupler is designed with a minimum feature size of 225 nm. The coupler was fabricated in ST Crolles using their 300 mm SOI platform and 193-nm deep-ultraviolet lithography, demonstrating that large-scale fabrication is feasible. Measured fiber-chip coupling efficiencies were -4.9 dB and -5.2 dB with a 3-dB bandwidth of >27 nm and 56 nm at λ_1=1270 nm and λ_2=1577 nm, respectively.
Silicon photonic modulators are a key component for electro-optic transmitter within data centers. Electro-refractive modulators relying on free carrier plasma dispersion in Mach-Zehnder interferometer have become the most popular solution. Accumulation–based capacitive modulators are an efficient approach, which can reduce the modulation power consumption. In this work we study the behavior of capacitive modulators with polycrystalline silicon to form the capacitance. The modulators are made within the standard fabrication flow with only few add-ons. In this work we show that furnace annealing conditions and excimer laser annealing conditions during the polycrystalline silicon formation enhance the modulator bandwidths.
Silicon modulators are used to generate frequency agile electro-optical frequency combs. Applications are discussed for both fine resolution dual comb spectroscopy and data communications based on wavelength division multiplexing transmission.
We present an optical phased array parameter analysis for automotive and handheld device applications and preliminary results from a 1×16 silicon optical phased array using p-i-n phase shifters built on a 300-mm industrial platform to reach high-speed operation and low power consumption at a 1.55𝜇𝑚 wavelength. Using 2 𝜇𝑚-spaced grating antennas OPA with theoretical beam steering range of 48°, we demonstrate a beam steering range of ±4° while average power consumption after the beam-shape optimization is measured to be 12.6 mW. Experimental setup, beam forming and scanning are discussed and a final analysis on future large-scale OPA integration is made.
Silicon photonic modulators are a key component for electro-optic transmitters within data centers. Electro-refractive modulators relying on free carrier plasma dispersion in a Mach-Zehnder interferometer (MZI) have become the most popular solution. Among the different electrical configurations, PN silicon modulators show a high bandwidth but at the price of a low efficiency. Accumulation–based capacitive modulators are an alternative, allowing to reduce the modulator power consumption. Additionally, strained SiGe exhibits a stronger plasma dispersion effect than silicon for holes. In this work we study the behavior of capacitive modulators with a thin layer of strained SiGe. The modulator fabrication process is based on the standard process flow with only few add-ons. In the first demonstration we show that the thin SiGe layer improved the modulator efficiency by 25%. In addition, further improvement is possible by optimization of the SiGe deposition condition to maximize the SiGe layer stress.
The Si transparency (1.1 μm – 8 μm wavelength) contains the strongest absorption features of a wide range of chemical and biological substances. However, the use of SOI in the mid-IR is hampered by the large absorption of the buried oxide (BOX) for wavelengths above 4 μm. Silicon membranes have garnered great interest for their unique capability to overcome the BOX limitation while leveraging the advantages of Si photonics. On the other hand, silicon is uniquely poised for the implementation of wideband mid-IR sources based on nonlinear frequency generation.
Promising supercontinuum and frequency comb generation have already been demonstrated in Si. Still, current implementations have a limited flexibility in the engineering of phase-matching conditions and dispersion, which complicates the shaping of the nonlinear spectrum. Patterning Si with features smaller than half of the wavelength (well within the capabilities of standard large-volume fabrication processes) has proven to be a simple and powerful tool to implement metamaterials with optimally engineered properties.
Here, we present the design of nanostructured silicon membrane waveguides with ultra-wideband flat anomalous dispersion in a wavelength span exceeding 5 µm. Our three-dimensional finite difference time domain (FDTD) calculations predict flat anomalous dispersion near 50 ps/km⋅nm between 2.5 µm and 8 µm wavelength. These results illustrate the potential of subwavelength metamaterial engineering to control chromatic dispersion in Si membrane waveguides. This is a promising step towards the implementation of wideband nonlinear sources in the mid-IR for silicon photonics.
This paper highlights the optimization of Deep Rib High Speed Phase Modulators for 400G applications thanks to the optimal choice of structure and implants through a Design Of Experiment analysis, including the proposal of a new Deep Rib HSPM with Z-implants. Results show 1,6dB gain in OMA (Optical Modulation of Amplitude) at the same cutoff frequency (fc=[2Pi*RC]-1) compared to the previous generation [1] with optimized vertical implants, and up to 2,15dB gain vs [1] with the new Z-implant Deep Rib device.
MicroAnalytical Systems (µAS) adapted to Point-of-Care Testing are expected to provide simple chemical, molecular or cellular analysis to be used directly on the field. Different formats of µAS are already classically used, from pregnancy tests to glycemia for diabetic people. Increasing µAS analytical performances involves for instance improving limits of detection, reduce time of analysis, or increase the amount of information provided per test. These improvements may be reached by using more refined technology, involving integrated technologies such as biosample processing, enzymatic reactions, fluidic circuitry and/or biosensors. However being able to fabricate and produce cheap µAS relying on miniaturized components is still a challenging goal, particularly when dealing with low concentrated species. For example, on the one hand it may be interesting to use miniaturize nanotransducers in biosensors (e.g. photonic transducer enabling both SPR and SERS thanks to nanostructuration) ; but on the other hand the transducers size reduction may prevent the targets to reach the biosensor’s active zone in a short time, because of mass transfer phenomena. Futhermore, when the sensing area is small by comparison with the other µAS zones, it targets are likely to get adsorbed on undesired surfaces. These targets are therefore lost and cannot contribute to the final, useful signal of the µAS. In these conditions the effectivity of the µAS can be questionned.
Different ways are being explored to overcome such challenges, and may enable µAS for detection of low concentration targets. For instance, it is possible to perform selective chemical modifications of surfaces bearing different materials, in order to bind molecular probes only on the transducing zone, while repelling molecular targets from other material surfaces. We will show how it is possible to perform such orthogonal surfaces modifications with a submicronic spatial resolution, relying on self-assembly phenomena.
Point-of-care tests (POCT) are important for detecting illnesses and monitoring patients without the need of a medical laboratory. To be useful, POCT must be sensitive, specific, integrated, and affordable. Since the early 2000s, integrated photonics have offered a possible solution for this problem. In particular, silicon micro-ring resonators represent a compact and sensitive choice known in the industry. This paper details the design, fabrication, and characterization of two methods for improving the performance of ring resonators by engineering their cross section. More precisely, improving devices made out of silicon nitride in an industrial environment to work in the infrared (around 1.31 µm).
The first approach is to selectively excite the first order mode of the ring resonator’s waveguide. The first order mode, with its greater exposure to the sensing liquid than the fundamental mode, results in a higher device sensitivity. The second method consists in coupling a dielectric mode with a surface plasmon polariton (SPP) forming a hybrid plasmonic waveguide. Hybrid plasmonic waveguides combine the low losses of the dielectric mode with the high sensitivity of the SPP, which increases the sensitivity in comparison to conventional dielectric ring resonators. Furthermore, hybrid plasmonic micro-ring resonators make possible a stable and easy differential functionalization.
Through the optical characterization of the devices, this study shows an experimental sensitivity of first order ring resonators of over 200 nm/RIU* and of hybrid plasmonic devices of 300 nm/RIU*. This demonstrates improvement with respect to the reference silicon nitride dielectric ring (120 nm/RIU*). Characterizations were performed using a PolyDiMethylSiloxane (PDMS) fluidic system to prove the compatibility of the substrate to POCT applications.
This paper shows two alternative approaches to integrated nano-photonic sensing for point of care testing. The proposed structures, demonstrate not only a higher sensitivity, but consider selectivity and manufacturing issues, which are fundamental for POCT development.
*RIU = Refractive Index Unit
Harvesting human kinetic energy to produce electricity is an attractive alternative to batteries for applications in wearable electronic devices and smart textile. Dielectric elastomers generators (DEGs) represent one of the most promising technologies for these applications. Nevertheless, one of the main disadvantages of these structures is the need of an external polarization source to perform the energetic cycle. In the present work, a hybrid electret-dielectric elastomer generator in DEG mode is presented. In this configuration, the electret material is used as polarization source of a classical DEG, i.e. an electrostatic generator based on electrical capacitance variation. The electrical energy output in this mode (1.06mJ.g−1) could be higher than the one obtained using a classical electret mode (0.55mJ.g−1), i.e. charges recombination. In this paper, the operation principle of the hybrid generator will be fully described and the design rules for the realization of the prototype will be presented. The experimental data obtained from the prototype will be compared to the results of FEM simulations.
KEYWORDS: Transducers, Ferroelectric polymers, Solar energy, Thin films, Capacitance, Thin film devices, Energy harvesting, Energy efficiency, Electronic circuits, Energy conversion efficiency
The paper presents the examination of modern flexible piezoelectric thin films made of PVDF (polyvinylidene
difluoride) in terms of their application in electromechanical transducers, a brief overview of available piezoelectric
materials and energy harvesting devices based on piezoelectric. In order to assess the usefulness of these films from the
perspective of described devices, the energy efficiency coefficient determined under the pulse excitation conditions was
taken into account. Normalized volumetric efficiency ratio allows to evaluate the commercially available flexible
piezoelectric films.
This paper describes the idea of the energy harvester which converts thermal gradient present in environment into
electricity. Two kinds of such devices are proposed and their prototypes are shown and discussed. The main parts of
harvesters are bimetallic spring, piezoelectric transducer or electrostatic transducer with electret. The applied piezomembrane
was commercial available product but electrets was made by authors. In the paper a fabrication procedure of
electrets formed by the corona discharge process is described. Devices were compared in terms of generated power,
charging current, and the voltage across a storage capacitor.
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