Photonic Hybrid Research Articles

Analysis of ridges and grooves shape in grating coupler for optimization of integrated optics sensor structures.

The paper presents a theoretical analysis of a sensor structure based on a planar waveguide and grating coupler designed to determine selected physical properties of blood – hemoglobin concentration and oxidation level. In particular analysis were focused on optimization of selected geometrical properties of grating coupler (shape of ridges and grooves) to obtain maximum efficiency of uncoupling of light from the sensor structure. The analysis were carried out for three type of ridges and grooves shape in grating coupler: rectangular, triangular and sinusoidal. Full Text: PDF ReferencesI. . Singh, A.Weston, A. Kundur, G. Dobie, Haematology Case Studies with Blood Cell Morphology and Pathophysiology; Elsevier: Amsterdam, The Netherlands, (2017). DirectLink P. Jarolim, M. Lahav, SC. Liu, J. Palek, "Effect of hemoglobin oxidation products on the stability of red cell membrane skeletons and the associations of skeletal proteins: correlation with a release of hemin", Blood 76, 10 (1990). CrossRef E. Beutler, J. Waalen, "The definition of anemia: what is the lower limit of normal of the blood hemoglobin concentration?", Blood 107, 5 (2006). CrossRef M. Kiroriwal, P. Singal M. Sharma, A. Singal, "Hemoglobin sensor based on external gold-coated photonic crystal fiber", Optics & Laser Technology 149, 107817 (2022). CrossRef A. A. Boiarski, J. R. Busch, B. S. Bhullar, R. W. Ridgway, V. E. Wood, "Integrated optic sensor with macro-flow cell", Proc. SPIE Integrated Optics and Microstructures 1793 (1993). CrossRef L. Cheng, S. Mao, Z. Li, Y. Han and H. Y. Fu, "Grating Couplers on Silicon Photonics: Design Principles, Emerging Trends and Practical Issues", Micromachines 11, 666 (2020). CrossRef P. Struk, "Design of an Integrated Optics Sensor Structure Based on Diamond Waveguide for Hemoglobin Property Detection", Materials 12, 175 (2019). CrossRef P. Struk, "Numerical analysis of integrated photonics structures for hemoglobin sensor application", Phot. Lett. Poland 12, 2 (2020). CrossRef P.V. Lambeck, "Integrated optical sensors for the chemical domain", Meas. Sci. Technol. 17, (2006). CrossRef W. Lukosz, "Integrated optical chemical and direct biochemical sensors", Sens. Actuators B Chem 29 (1995). CrossRef P. Struk, T. Pustelny, K. Gołaszewska,E. Kaminska, M.A. Borysiewicz, M. Ekielski, A. Piotrowska, "Hybrid photonics structures with grating and prism couplers based on ZnO waveguides", Opto-Electron. Rev. 21, (2013). CrossRef P. Struk, "Design of an integrated optics sensor structure for hemoglobin property detection", Proc. SPIE 11204, (2019). CrossRef OptiFDTD Technical Background and Tutorials - Finite Difference Time Domain Photonics Simulation Software, Optiwave Systems Inc. (2008). DirectLink K. Yee, "Cutoff Frequencies of Eccentric Waveguides", IEEE Transactions 14, 3 (1966). CrossRef

Spectral purification of single-frequency Stokes pulses in doubly resonant integrated diamond resonators

Pulsed spectrally pure light is required for applications in high-resolution spectroscopy, optical coherent communications, and quantum technologies. In this work, we report on the efficient generation of high peak power, single-frequency, and tunable nanosecond pulses utilizing stimulated scattering, with an increased spectral brightness by exploiting double resonances in an integrated diamond Raman resonator. The device is based on a miniature monolithic Fabry–Perot design pumped by a milliwatt-class average power Q-switched single-frequency pulsed laser at 532 nm. Our device was capable of enhancing the peak spectral brightness by greater than three times compared with conventional singly resonant diamond Raman lasers by tuning the effective resonator length at pump and Stokes wavelengths simultaneously. Our results facilitate the integration of pulsed and power scalable single frequency sources into hybrid photonic integrated platforms with a broad range of applications.

Modeling and Performance Analysis of a Fault-Tolerant 3D Photonic Network-on-Chip Based on Hybrid Photonics-Plasmonics.

The performance of electro-optic modulators and optical routers and their routing algorithms are the key factors affecting the performance of networks on optical chips. This paper improves the mesh 3-dimensional photonic network-on-chip (3D-PNoC) topology. An SPP hybrid silicon-based electro-optic modulator and an improved fault-tolerant SPP router are used to improve the performance of the network on an optical chip. SPP switching and SPP MRR are combined to form a fault-tolerant SPP router. On this basis, an improved genetic optimization routing algorithm is implemented on the improved mesh 3D PNoC topology, which completes the data exchange of the IP core of the network on the optical chip. Compared with the case of traditional optoelectronic devices, the performance of on-chip optical networks can be improved effectively. The simulation results show that upon the application of the improved genetic optimization routing algorithm to the improved mesh 3D PNoC topology, the average end-to-end delay is reduced by 32.9%, the throughput rate is increased by 28.5%, and the system power consumption is reduced by 27.6%. On the other hand, the average insertion loss and noise of optical routers are increased by 2.94 dB and 2.95 dB, respectively.

Low-noise frequency-agile photonic integrated lasers for coherent ranging

Frequency modulated continuous wave laser ranging (FMCW LiDAR) enables distance mapping with simultaneous position and velocity information, is immune to stray light, can achieve long range, operate in the eye-safe region of 1550 nm and achieve high sensitivity. Despite its advantages, it is compounded by the simultaneous requirement of both narrow linewidth low noise lasers that can be precisely chirped. While integrated silicon-based lasers, compatible with wafer scale manufacturing in large volumes at low cost, have experienced major advances and are now employed on a commercial scale in data centers, and impressive progress has led to integrated lasers with (ultra) narrow sub-100 Hz-level intrinsic linewidth based on optical feedback from photonic circuits, these lasers presently lack fast nonthermal tuning, i.e. frequency agility as required for coherent ranging. Here, we demonstrate a hybrid photonic integrated laser that exhibits very narrow intrinsic linewidth of 25 Hz while offering linear, hysteresis-free, and mode-hop-free-tuning beyond 1 GHz with up to megahertz actuation bandwidth constituting 1.6 × 1015 Hz/s tuning speed. Our approach uses foundry-based technologies - ultralow-loss (1 dB/m) Si3N4 photonic microresonators, combined with aluminium nitride (AlN) or lead zirconium titanate (PZT) microelectromechanical systems (MEMS) based stress-optic actuation. Electrically driven low-phase-noise lasing is attained by self-injection locking of an Indium Phosphide (InP) laser chip and only limited by fundamental thermo-refractive noise at mid-range offsets. By utilizing difference-drive and apodization of the photonic chip to suppress mechanical vibrations of the chip, a flat actuation response up to 10 MHz is achieved. We leverage this capability to demonstrate a compact coherent LiDAR engine that can generate up to 800 kHz FMCW triangular optical chirp signals, requiring neither any active linearization nor predistortion compensation, and perform a 10 m optical ranging experiment, with a resolution of 12.5 cm. Our results constitute a photonic integrated laser system for scenarios where high compactness, fast frequency actuation, and high spectral purity are required.

異種材料接合技術を利用したハイブリッド光集積回路

異種材料接合技術を利用したハイブリッド光集積回路

Integrated Hybrid VO2–Silicon Optical Memory

Vanadium dioxide (VO2) is an interesting material for hybrid photonic integrated devices due to its insulator–metal phase transition. Utilizing the hysteresis of the phase transition in voltage-biased VO2, we demonstrate a compact hybrid VO2–silicon optical memory element integrated into a silicon waveguide. An optical pulse writes the VO2 memory, leading to an optical attenuation that can be read out by the optical transmission in a silicon waveguide. Our on-chip memory cell can be optically written with energy as low as 23.5 pJ per pulse and with a 10–90% rise time of ∼100 ns. This approach is promising for optical data storage in silicon photonic integrated circuits.

Multideck light-induced reset in a transparent bilayer synaptic device

The research of photoelectric memristors has been gaining momentum in recent years. Although resistive memory synaptic devices are usually electrically controlled, an opto-electronic one would certainly be advantageous. A light-responsive structure can extend the functionality of such devices and allow for coupling of light and electrical signals in the implementation of neuromorphic systems. This paper presents a detailed analysis of a transparent, bilayer synaptic device, capable of hybrid photonic and electronic response with multideck, erase functionality. Such steplike operation may allow for more degrees of freedom in the implementation of artificial vision systems based on these incremental conductance changes. Multilevel operation is demonstrated under different illumination intensities and functional methodologies (i.e., irradiation schemes). Statistical data are also presented to give a better foundation for this suggested functionality. Finally, the underlying physical mechanisms are discussed, supported by ultrahigh-vacuum conductive atomic force microscope measurements over a dedicated lateral test structure.

Study of the Effects of Cavity Mode Spacing on Mode-Hopping in III–V/Si Hybrid Photonic Crystal Lasers

We present a design methodology for hybrid lasers to realise mode-hop free operation by controlling the cavity mode spacing. In this study, a compact hybrid photonic crystal laser (H-PhCL) was employed which allowed a reduction of the Fabry–Perot length of the laser cavity and eliminated the need for an active mode stabilisation mechanism in order to realise mode-hop free operation. The H-PhCL was formed by butt-coupling a reflective semiconductor optical amplifier (RSOA) with a two-dimensional silicon (Si) photonic crystal (PhC) cavity. Continuous stable single frequency operation with >40 dB side-mode suppression ratio (SMSR) of the laser was achieved for gain currents of up to 100 mA, i.e., up to four times the threshold current. The shorter length of the laser cavity enabled single frequency operation due to the selection of a single longitudinal mode by the PhC narrowband reflector. Various longitudinal mode spacing regimes were studied to explain the mode-hop free characteristics of the H-PhCL. The proposed hybrid laser design methodologies can be adapted to eliminate mode-hopping in laser wavelength.

A Method for Improving Reflection Tolerance of Laser Source in Hybrid Photonic Packaged Micro-System

In multi-chip integrated photonic micro-systems, it is important to protect the laser source from reflection because the semiconductor laser is sensitive to the back reflection induced by the roughness of the waveguide sidewall or other on-chip optical structures. In order to maintain the stable operation of the light source, an additional micro-ring resonator coupled with the laser source is design before the optical circuit which enables the laser diode to enter a self-injection locking state and improves the reflection tolerance. It is experimentally demonstrated in the hybrid system that by tuning the phase shifter and the micro-ring resonate wavelength, the distributed feedback (DFB) laser enters a self-injection locking state, resulting significant improvement of the critical reflection ratio from −18.69 dB to −4.31 dB. The method can isolate the external reflection of laser diode without using heterogeneous integration, which provides a new idea for on-chip source isolation. The parameters design of the micro-ring and the coupling method with the laser are also introduced in the letter.

Ultrafast Photo‐Thermal Switching of Terahertz Spin Currents

AbstractDissipationless and scattering‐free spin‐based terahertz electronics is the futuristic technology for energy‐efficient information processing. Femtosecond light pulse provides an ideal pathway for exciting the ferromagnet (FM) out‐of‐equilibrium, causing ultrafast demagnetization and superdiffusive spin transport at sub‐picosecond timescale, giving rise to transient terahertz radiation. Concomitantly, light pulses also deposit thermal energy at short timescales, suggesting the possibility of abrupt change in magnetic anisotropy of the FM that could cause ultrafast photo‐thermal switching (PTS) of terahertz spin currents. Here, a single light pulse induced PTS of the terahertz spin current manifested through the phase reversal of the emitted terahertz photons is demonstrated. The switching of the transient spin current is due to the reversal of the magnetization state across the energy barrier of the FM layer. This demonstration opens a new paradigm for on‐chip spintronic devices enabling ultralow‐power hybrid electronics and photonics fueled by the interplay of charge, spin, thermal, and optical signals.

All-Optical Hybrid VO$_{2}$/Si Waveguide Absorption Switch at Telecommunication Wavelengths

Vanadium dioxide (VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) is one of the most promising materials for developing hybrid photonic integrated circuits (PICs). At telecommunication wavelengths, VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> exhibits a large change on the refractive index (Δn ~ 1 and Δκ ~ 2.5) between its insulating and metallic state. Such insulating-to-metal transition (IMT) can be triggered by light, which could enable all-optical hybrid VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -waveguide devices. Here, we experimentally demonstrate an all-optical absorption switch using a hybrid VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Si waveguide fully compatible with the silicon photonics platform. All-optical characterization was carried out for TE polarization and at telecommunication wavelengths using an in-plane approach. The temporal dynamics were retrieved by means of pump-probe measurements. Our results show an extinction ratio of 0.7 dB/μm with a maximum switchable length of 15 μm, a switching speed as low as 318 ns, and an energy per switch of 15.8 nJ. The inherit large optical bandwith of a non-resonant waveguide poses this device as a promising candidate for developing all-optical and broadband silicon PICs.

A silicon‐organic hybrid platform for quantum microwave-to-optical transduction

Low-loss fiber optic links have the potential to connect superconducting quantum processors together over long distances to form large scale quantum networks. A key component of these future networks is a quantum transducer that coherently and bidirectionally converts photons from microwave frequencies to optical frequencies. We present a platform for electro-optic photon conversion based on silicon‐organic hybrid photonics. Our device combines high quality factor microwave and optical resonators with an electro-optic polymer cladding to perform microwave-to-optical photon conversion from 6.7 GHz to 193 THz (1558 nm). The device achieves an electro-optic coupling rate of 590 Hz in a millikelvin dilution refrigerator environment. We use an optical heterodyne measurement technique to demonstrate the single-sideband nature of the conversion with a selectivity of approximately 10 dB. We analyze the effects of stray light in our device and suggest ways in which this can be mitigated. Finally, we present initial results on high-impedance spiral resonators designed to increase the electro-optic coupling.

Hybrid photonics beyond silicon

In the past years, significant progress has been made on the realization of high performance building blocks in photonic circuits, such as ultra-low loss waveguides, monolithic lasers, high-speed modulators, and high efficiency photodetectors. However, toward large scale integration with complete functions and breakthrough performance, there are still many challenging problems to solve. While silicon has proved to be an asset material for integrated optics, the combination of other materials with complementary properties has turned out to be critical for the realization of specific advanced photonic devices. Yet, the major challenge has been the materials’ differences that cause difficulties in hybrid integration. APL Photonics’ keen interest in the field leads us to offer this editorial, which will present a broad overview of the recent progress, current challenges, and future opportunities of hybrid photonics integration.

Strain-Driven In-plane Ordering in Vertically Aligned ZnO-Au Nanocomposites with Highly Correlated Metamaterial Properties.

Hyperbolic metamaterials demonstrate exotic optical properties that are poised to find applications in subdiffraction imaging and hyperlenses. Key challenges remain for practical applications, such as high energy losses and lack of hyperbolic properties in shorter wavelengths. In this work, a new oxide–metal (ZnO–Au) hybrid-material system in the vertically aligned nanocomposite thin-film form has been demonstrated with very promising in-plane two-phase ordering using a one-step growth method. Au nanopillars grow epitaxially in the ZnO matrix, and the pillar morphology, orientation, and quasi-hexagonal in-plane ordering are found to be effectively tuned by the growth parameters. Strong surface plasmon resonance has been observed in the hybrid system in the UV–vis range, and highly anisotropic dielectric properties have resulted with much broader and tunable hyperbolic wavelength regimes. The observed strain-driven two-phase in-plane ordering and its novel tunable hyperbolic metamaterial properties all demonstrate strong potential for future oxide–metal hybrid-material design toward future integrated hybrid photonics.

III-V-on-Silicon Integration: From Hybrid Devices to Heterogeneous Photonic Integrated Circuits

Heterogeneous integration of III-V materials onto silicon photonics has experienced enormous progress in the last few years, setting the groundwork for the implementation of complex on-chip optical systems that go beyond single device performance. Recent advances on the field are expected to impact the next generation of optical communications to attain low power, high efficiency and portable solutions. To accomplish this aim, intense research on hybrid lasers, modulators and photodetectors is being done to implement optical modules and photonic integrated networks with specifications that match the market demands. Similarly, important advances on packaging and thermal management of hybrid photonic integrated circuits (PICs) are currently in progress. In this paper, we report our latest results on hybrid III-V on Si transmitters, receivers and packaged optical modules for high-speed optical communications. In addition, a review of recent advances in this field will be provided for benchmarking purposes.

Silicon-Organic Hybrid Photonic Devices in a Photonic Integrated Circuit Technology

In this work, we present recent results on the hybrid integration of electro-optical organic materials in a photonic integrated circuit (PIC) technology. We review some of the identified challenges regarding process compatibility and present experimental results on the integration of organic materials in a PIC technology using a 0.25 μm SiGe BiCMOS pilotline. Here, we are focusing on electro-optical applications toward high-speed modulators with ultra-low energy consumption.

Optical properties of molecular nanocrystals consisting of J-aggregates of anionic and cationic cyanine dyes.

We report results of experimental studies of the photoabsorption, photoluminescent and photoelectric properties of a new type of multilayer molecular nanocrystals, consisting of highly ordered J-aggregates of one anionic and two cationic J-aggregates of cyanine dyes. In contrast to conventional J-aggregated dyes the multichromic nanocrystals synthesized in this work, are capable of efficient light absorption in three excitonic bands of the visible and near-IR spectral ranges. The spectral peak positions in the absorption bands can be controlled by appropriately selecting a set of dyes a molecular crystal is made of. Our investigations of the photoelectric properties of multichromic crystals have shown that each of them can potentially be used as a photosensitive layer of a photocell with photoconductivity in three peaks of excitonic absorption. The synthesized nanocrystals are attractive for the creation of thin-film organic photodetectors with a large photosensitive area and varied photoabsorption spectra, excitonic waveguides and for some other applications in organic and hybrid photonics and optoelectronics.

On-Chip Hybrid Photonic-Plasmonic Waveguides with Ultrathin Titanium Nitride Films

A solid-state hybrid photonic–plasmonic (HPP) waveguide geometry has been experimentally demonstrated with plasmonic titanium nitride. The configuration is made with robust fabrication techniques, ...

Optical and photoelectric properties of multichromic cyanine dye J-aggregates

We report the results of investigation of spectra and kinetics of photoluminescence as well as of photoabsorption and photoelectric properties for multichromic molecular crystals consisting of J-aggregates of three cyanine dyes with various structures. An original ‘self-assembly’ method is used for fabricating such prolate ordered structures with a thickness of 5 – 100 nm, width of 0.1 – 5 μm, and length of 50 – 300 μm. The method is based on the formation of the anionic platform in a water solution, which absorbs light in the blue spectrum range and comprises J-aggregates of magnesium complexes of anionic cyanine dye. Then the ‘matrix synthesis’ is used for coating its surface with J-aggregates of the two cationic dyes that have the absorption maxima in the green and red spectral ranges. It is shown that each of the multichromic organic crystals produced in this way is a multilayer photoelement, which possesses photoconductivity in three excitonic absorption maxima (in the blue, green, and red spectral ranges) with the external quantum efficiency varying from 2.7 % to 6.1 %. The results obtained provide a basis for technological development of highly-ordered molecular structures, which are promising for using in organic and hybrid photonics and optoelectronics including thin-film photo-converters operating in wide spectral ranges.

Vertical mode transition in hybrid lithium niobate and silicon nitride-based photonic integrated circuit structures.

This Letter presents an optical mode transition structure for use in Si3N4/LiNbO3-based hybrid photonics. A gradual modal transition from a Si3N4 waveguide to a hybrid Si3N4/LiNbO3 waveguide is achieved by etching a terrace structure into the sub-micrometer thick LiNbO3 film. The etched film is then bonded to predefined low pressure chemical vapor deposition Si3N4 waveguides. Herein we analyze hybrid optical devices both with and without the aforementioned mode transition terrace structure. Experimental and simulated results indicate that inclusion of the terrace significantly improves mode transition compared to an abrupt transition, i.e., a 1.78 dB lower mode transition loss compared to the abrupt transition. The proposed transition structure is also applied to the design of hybrid Si3N4-LiNbO3 micro-ring resonators. A high-quality factor (Q) resonator is demonstrated with the terrace transition which mitigates undesired resonances.