Abstract: An overview of the most recent developments and improvements to the low-loss TriPleX Si3N4 waveguide technology is presented in this paper The TriPleX platform provides a suite of waveguide geometries (box, double stripe, symmetric single stripe, and asymmetric double stripe) that can be combined to design complex functional circuits, but more important are manufactured in a single monolithic process flow to create a compact photonic integrated circuit All functionalities of the integrated circuit are constructed using standard basic building blocks, namely straight and bent waveguides, splitters/combiners and couplers, spot size converters, and phase tuning elements The basic functionalities that have been realized are: ring resonators and Mach–Zehnder interferometer filters, tunable delay elements, and waveguide switches Combination of these basic functionalities evolves into more complex functions such as higher order filters, beamforming networks, and fully programmable architectures Introduction of the active InP chip platform in a combination with the TriPleX will introduce light generation, modulation, and detection to the low-loss platform This hybrid integration strategy enables fabrication of tunable lasers, fully integrated filters, and optical beamforming networks

Abstract: An optoelectronic oscillator (OEO) is a hybrid microwave and photonic system incorporating an amplified positive feedback loop to enable microwave oscillation to generate a high-frequency and low-phase noise microwave signal. The low phase noise is ensured by the high Q factor of the feedback loop enabled by the use of a long and low-loss optical fiber. However, an OEO with a long fiber loop would have a small free spectral range, leading to a large number of closely spaced oscillation modes. To ensure single-mode oscillation, an ultranarrowband optical filter must be used, but such an optical filter is hard to implement and the stability is poor. Here, we use a novel concept to achieve single-mode oscillation without using an ultranarrowband optical filter. The single-mode operation is achieved based on parity-time (PT) symmetry by using two identical feedback loops, with one having a gain and the other having a loss of the same magnitude. The operation is analyzed theoretically and verified by an experiment. Stable single-mode oscillation at an ultralow phase noise is achieved without the use of an ultranarrowband optical filter. The use of PT symmetry in an OEO overcomes the long-existing mode-selection challenge that would greatly simplify the implementation of OEOs for ultralow-phase noise microwave generation.

Abstract: We present an extensive analysis of an optical Blass-matrix architecture as a beamforming network with potential for multibeam operation in wireless systems. Its design relies on the use of phase shifters and Mach–Zehnder Interferometers (MZIs) inside an $M\times N$ matrix, and enables the generation of M beams by N -element antenna arrays. We start our analysis from an optical signal with amplitude modulation by discrete microwave tones, and confirm the possibility to translate its optical phase shifts inside the matrix into equivalent phase shifts in the microwave domain. We show this is possible when the input is an optical single-side band signal and the optical carrier is reinserted before photodetection. We extend the conclusions to the case of an optical signal carrying a microwave with quadrature amplitude modulation (QAM) and the case of simultaneous inputs at the M input ports. Based on this analysis, we propose a Blass-matrix configuration algorithm taking into account the properties of the MZIs. Through simulations, we validate the potential for multibeam operation, and evaluate the beamforming performance at 28.5 GHz with respect to the QAM order, symbol rate, and pulse shaping parameters. In all cases with rate up to 3 Gbaud, the bit-error rate remains lower than 10–3, showing that the beam squinting effect, which is present in our design, can be tolerated. Finally, we study the frequency dependence of the beamforming performance due to inevitable asymmetries of the MZIs and length variations of the waveguides, and evaluate the impact of the imperfections in the couplers inside the MZIs and the phase shifters. We show that in all cases the performance degradation is negligible for realistic fabrication and operation conditions.

Abstract: Many optical systems require broadband filters with sharp roll-offs for efficiently splitting or combining light across wide spectra. While free space dichroic filters can provide broadband selectivity, on-chip integration of these high-performance filters is crucial for the scalability of photonic applications in multi-octave interferometry, spectroscopy, and wideband wavelength-division multiplexing. Here we present the theory, design, and experimental characterization of integrated, transmissive, 1 × 2 port dichroic filters using spectrally selective waveguides. Mode evolution through adiabatic transitions in the demonstrated filters allows for single cutoff and flat-top responses with low insertion losses and octave-wide simulated bandwidths. Filters with cutoffs around 1550 and 2100 nm are fabricated on a silicon-on-insulator platform with standard complementary metal-oxide-semiconductor processes. A filter roll-off of 2.82 dB nm−1 is achieved while maintaining ultra-broadband operation. This new class of nanophotonic dichroic filters can lead to new paradigms in on-chip communications, sensing, imaging, optical synthesis, and display applications. Optical filters are an integral part of many optical devices and circuits. Here, Magden et al. use a design based on mode evolution to demonstrate CMOS-compatible dichroic filters with more than an octave bandwidth, sharp roll-off and transmissive short- and long-wavelength outputs

Abstract: Many promising approaches for designing interactions of synthetic materials with light involve solid optical monocrystals and nanofabricated photonic crystal structures with spatially periodic variations of refractive index. Although their high costs limit current technological applications, remarkably, such photonic and optically anisotropic materials have also evolved throughout nature and enable narrow or broad-band spectral reflection of light. Here we use self-assembly of biomaterial cellulose nanocrystals to obtain three-layer films with helicoidal and nematic-like organization of the cellulose nanoparticles, which mimics naturally occurring polarization-insensitive reflectors found in the wings of Plusiotis resplendens beetles. These films were characterized with polarized optical microscopy and circular dichroism spectrometry, as well as scanning and transmission electron microscopies. These films exhibit high reflectivity tunable within the visible and near-infrared regions of the optical spectru...

Abstract: A silicon-based hybrid demultiplexer for wavelength-division multiplexing (WDM) and mode-division multiplexing (MDM) is proposed and demonstrated by integrating an M-channel-mode demultiplexer and N-channel WDM filters based on microring resonators (MRRs) with box-like responses. For the mode demultiplexer, the 2k-th output port is connected with the (2k+1)-th output port through the bus waveguide for the k-th MRR array, so that each MRR-based optical filter works bi-directionally and provides two drop ports. As an example, a 32-channel hybrid MDM-WDM demultiplexer is realized by integrating a 4-channel mode demultiplexer based on dual-core adiabatic tapers and two bi-directional MRR-based WDM filters with eight wavelength-channels. For the fabricated hybrid demultiplexer, the excess loss is 0.5–5 dB, the intermode cross talk is −16.5 to −23.5 dB, and the cross talks between the adjacent and nonadjacent wavelength channels are about −25 dB and −35 dB, respectively.

Abstract: A novel-integration-based technique employing a cascaded pair of microring resonators on silicon-on-insulator platform that can achieve a tunable single-passband microwave photonic filter with improved shape factor and extinction ratio is presented. It is based on an integrated optical double notch filter using a cascaded pair of nonidentical microring resonators, in conjunction with optical phase modulation. This results in minimal net phase being introduced by the overall filter at radio frequencies falling outside the region of the notch stopband, thus enabling nearly full antiphase cancellation of the modulation sidebands, which results in the achievement of an improved filter shape factor and extinction ratio. Additionally, it features a bandwidth that is directly determined by the difference between the bandwidths of the two optical notch filters, rather than by their absolute individual bandwidths. Experimental results have verified the concept, and have demonstrated a single-passband filter having tuning range of 6–17 GHz, a shape factor of 1.78, shape-invariant tuning, and a good out-of-band suppression ratio of approximately 20 dB throughout the entire tuning range.

Abstract: A novel hybrid multiplexer for wavelength-division- multiplexing (WDM) and polarization-division-multiplexing (PDM) is proposed and realized by integrating a polarization-splitter-rotator (PSR) and an optical-filter array based on novel microring resonators (MRRs). With the PSR, the launched TM-polarized light is rotated to be TE-polarized and outputs from the cross port while the launched TE-polarized light outputs from the through port directly. In the proposed novel configuration, the cross- and through-ports of the PSR are connected through the bus waveguide for all the MRR-based optical filters. In this way, each MRR-based optical filter works bidirectionally and has two drop ports, from which the same wavelength channel of TE- and TM-polarizations are dropped separately. As an example, a 16-channel hybrid WDM-PDM multiplexer is designed and realized with eight wavelength channels and dual polarizations by integrating a PSR and eight MRR-based optical filters with box-like responses. The fabricated PSR has an excess loss of ∼0.6 dB and an extinction ratio (ER) of ∼20 dB in the wavelength range from 1550 to 1580 nm. The optical filters are designed by using cascaded MRRs with bent directional couplers, which works for TE polarization only with very high ER (>35 dB) and, thus, reduces the polarization crosstalk greatly. For the MRR-based optical filters of the present hybrid (de)multiplexer, the channel spacing is 400 GHz (3.2 nm), the crosstalk between the adjacent channels is μ m × 300 μ m. The present hybrid (de)multiplexer can be extended for more channels by reducing the channel spacing as well as increasing the free-spectral range of the MRRs.

Abstract: We derive compact equations describing the modification of amplified spontaneous emission signal beat noise arising from optical and electrical filtering in optically preamplified direct detection receivers. In particular, we show that this modification typically results in a further decrease of the signal quality factor. This is particularly pronounced in the presence of electrical filters with steep transfer functions such as, e.g., occurring when feeding the signal through an antialiasing filter prior to analog-to-digital conversion or in a real-time oscilloscope, in the latter case leading to counter-intuitive dependencies of the measured signal quality on the characteristics of the test setup. Predictions are exemplified in concrete system models and verified with experiments. While the modeling assumptions and the accuracy of the predictions are in line with models previously reported in the literature, derived expressions allow straightforwardly tying the modification of the level dependent noise to signal levels, baud rate, signal spectrum, and filter transfer functions.

Abstract: Fiber optics channels provide flat channel response per wavelength in general, owing to the ultrawide available bandwidth of optical fibers and optical amplifiers. However, the recent transport capacity upgrade, which drives the signal baud-rate from 10 to >100 Gbaud, has given rise to severe power fading at high-frequency ranges, induced at levels of both optoelectronic transceivers and optical networks. Especially, the modern meshed optical networks rely on more and more reconfigurable optical add and drop multiplexers (ROADM) to enhance the network flexibility with low latency. These cascaded ROADMs bring about a well-known filter-narrowing effect that has become a severe issue in the deployed networks. This strongly limits the achievable channel bandwidth, and leads to an optical channel with colored signal-to-noise ratio (SNR). Within the linear transmission regime, the capacity-approaching strategy for an individual wavelength channel is to design a Gaussian source, which has been extensively studied recently. However, there is the lack of investigation on approaching the capacity of a channel with colored SNR. This paper addresses this issue with rigor. It reviews the optimum power allocation that determines the capacity of colored-SNR Gaussian channels, and proposes entropy loading based on multicarrier modulation that offers a theoretically optimum strategy to approach the capacity. The entropy loading advantage is verified by a 400-Gb/s coherent optical transmission through band-limited fiber channels with cascaded ROADMs. Entropy loading can be generalized to a variety of applications under colored-SNR Gaussian channels beyond the optical communication.

Abstract: A novel automatic bias control (ABC) method which could lock an optical IQ modulator at arbitrary bias points is proposed and experimentally demonstrated for the first time. In the proposed method, the sequences and parameters of the used dither signals and the switch of the applied bias voltages are specially designed to minimize the influence of the power coupling between three MZMs in optical IQ modulator and the nonideal extinction ratios. By this way, precise electro-optical characteristic parameters of these three MZMs can be obtained by calculating the relevancy of the produced dither signals and the optical output signal. Based on these obtained parameters, any-bias-locking operation could be achieved via a feedback control loop. The accuracy and stability of the proposed ABC scheme are experimentally verified by using 1 GHz sine signals and 6 Gbaud single-carrier QPSK signals, and the accuracy of the proposed ABC algorithm is about 0.4° due to the limit of DAC resolution. Moreover, thanks to this ABC scheme, a simple and stable 29.2 GHz millimeter wave generation with SNR of 30 dB by optical frequency quadrupling technique could be realized without any optical or electrical filter.

Abstract: For simplification of mobile base station architecture, we present remote beamforming of an array antenna integrated with photodiode based on photonics. Variable optical delay lines (VDLs) and variable optical attenuators (VOAs) are utilized for tailoring the RF phases and amplitudes and radio-over-fiber (RoF) technique is adopted for RF signal transmission. First, we show a simple demonstration of 60-GHz antenna beamforming using VDLs and VOAs with the aim of simplification of RoF signal generation at a control site. Next, we present experimental results on 60-GHz band digital signal transmission at 7 and 14 Gbit/s with beamforming function, in which eight compact antenna modules are arrayed in a row. Finally, we investigate RoF signal generation at 40 GHz utilizing the 1.3- μ m band electroabsorption modulator-integrated laser diode, where an optical filter and an optical amplifier are used to boost the modulation component and the successful formation of various beam patterns by tuning VDL and VOA is shown.

Abstract: In this paper, we present an overview of the current efforts toward integration on chip of fiber Bragg grating (FBG) sensor interrogators. Different photonic-integration platforms are discussed, including monolithic planar lightwave circuit technology, silicon on insulator (SOI), indium phosphide, and gallium arsenide material platforms. Furthermore, various possible techniques for wavelength metering and methods for FBG multiplexing are discussed and compared in terms of resolution, dynamic performance, multiplexing capabilities, and reliability. The use of linear filters, array waveguide gratings (AWG) as multiple linear filters, and AWG-based centroid signal processing techniques are presented as well as interrogation techniques based on tunable microring resonators and Mach–Zehnder interferometers for phase sensitive detection. FBG sensor interrogation based on SOI platform using active and passive phase sensitive detection is also described, demonstrating specifically the potential of passive phase demodulation for high-speed dynamic strain measurements. This paper finally presents the challenges and perspectives of photonic integration to address the increasing requirements of several industrial applications.

Abstract: Dielectric nanoresonantors may generate both electric and magnetic Mie resonances with low optical loss, thereby offering highly efficient paths for obtaining integrated optical devices. In this paper, we propose and design an optical filter with a high working efficiency in the mid-infrared (mid-IR) range, based on an all-dielectric metasurface composed of silicon (Si) nanodisk arrays. We numerically demonstrate that, by increasing the diameter of the Si nanodisk, the range of the proposed reflective optical filter could effectively cover a wide range of operation wavelengths, from 3.8 μm to 4.7 μm, with the reflection efficiencies reaching to almost 100%. The electromagnetic eigen-mode decomposition of the silicon nanodisk shows that the proposed optical filter is based on the excitation of the electric dipole resonance. In addition, we demonstrate that the proposed filter has other important advantages of polarization-independence and incident-angle independence, ranging from 0° to 20° at the resonance dip, which can be used in a broad range of applications, such as sensing, imaging, and energy harvesting.

Abstract: We propose and demonstrate an integrated polarization-independent optical filter with variable bandwidth and tunable central wavelength based on silicon-on-insulator waveguides. It consists of a polarization splitter-rotator (PSR), a polarization combiner-rotator (PCR) and two MRR filters. The PSR and PCR are based on a bi-level taper and an asymmetric directional coupler with the same structure. The MRR filter consists of two stages of second-order microring resonators with different radiuses. The two stages are serially cascaded, with each stage having a flat-top spectrum. The free spectral range (FSR) of the cascaded structure is expanded via the Vernier effect. The central wavelength of the proposed optical filter is tuned by synchronous tuning of the two stages. The 3 dB bandwidth is adjusted via intentional misalignment of the passbands of the two stages. We demonstrate a prototype of such an optical filter on the silicon-on-insulator platform. The FSR of the fabricated device is around 90 nm. We show the tuning of the central wavelength from 1460 nm to 1550 nm. We adjust the 3 dB bandwidth from 37.5 GHz to 100 GHz with a step of 12.5 GHz, with the insertion loss varying from -5.4 dB to -7.9 dB.

Abstract: In this paper, we propose an additional noise-free, independent center frequency and bandwidth tunable optical filter based on stimulated Brillouin scattering (SBS) losses. By suppressing the out-of-band signal with two broadened symmetric SBS losses, tunable pass bandwidths from 500 MHz to 9.5 GHz and the independent center frequency tunability are demonstrated. Considering the limited SBS interaction in the center frequency range, a flat-top response with minimum 0.3 dB ripple is achieved. Assisted by the extra suppression from polarization pulling, a maximum selectivity of 20 dB and an ultrahigh 250 dB/GHz roll-off are reached. A gain-based SBS filter adds noise to the filtered signal. However, for our proposed filter setup, no additional noise is detected due to the transparency in the passband. Considering the wide independent bandwidth and center frequency tunability, flat-top response, and low-noise characteristic, our proposed filter can be perfectly used as a supplement of most commercialized conventional tunable optical single bandpass filters, whose minimum bandwidth is limited by 10 GHz.

Abstract: We simulate a phoxonic crystal which shows complete phononic and TM-polarized photonic bandgaps. The constituent materials are tungsten and polymethyl methacrylate, and we obtained these bandgaps with a filling factor of only 28%, which is very compatible with the fabrication method. A cavity was then defined that selects narrow passbands of optical and elastic waves. In order to maximize the quality factor, a defect rod is added in the output waveguide. The final structure filters an optical wavelength of 840 nm (with corresponding frequency of 357 THz) and an elastic frequency of 3.6703 GHz. Simulations are done by using finite element, plane wave expansion, and finite difference time domain methods.

Abstract: An integrated optical delay line is presented and experimentally demonstrated with a true-time delay continuously tuned up to 125 ps. The proposed device is based on a Mach–Zehnder interferometer with tuneable couplers, can be ideally operated with a single control signal, and achieves a bandwidth-delay product consistently larger than ring-based delay lines. The device is successfully used in a transmission system to control the delay of a 10 Gbit/s data stream.

Abstract: A comprehensive study about the structural engineering of high quality nanoporous anodic alumina optical microcavities (NAA-μCVs) fabricated by rationally designed anodisation strategies to enhance the light-confining capabilities of these photonic crystal (PC) structures is presented. Two types of NAA-μCV architectures are produced: (i) GIF-NAA-μCVs composed of a cavity layer featuring straight nanopores that is sandwiched between two gradient-index filters (GIFs) with sinusoidally modulated porosity in depth, and (ii) DBR-NAA-μCVs formed by sandwiching a cavity layer with straight nanopores between two distributed Bragg reflectors (DBRs), in which the porosity is engineered in a stepwise fashion. The geometric features of GIF-NAA-μCVs and DBR-NAA-μCVs are engineered and optimised through a systematic modification of the anodisation parameters (i.e. cavity anodisation time, cavity anodisation current density, anodisation period and number of anodisation pulses, and pore widening time). This methodology enables fine-tuning of the optical properties of GIF-NAA-μCVs and DBR-NAA-μCVs, such as quality factor and position and width of resonance band, to generate NAA-μCVs with unprecedented quality factors (i.e. 170 ± 8 and 206 ± 10 for the first and second order resonance bands – threefold and fourfold quality enhancement as compared to previous studies). Our results demonstrate that an optimal design of the geometric features and the nanoporous architecture of NAA-μCVs can significantly enhance resonant recirculation of light within these PC structures, creating new opportunities to develop ultrasensitive optical platforms, highly selective optical filters, and other photonic devices.

Abstract: A photonic multiple microwave frequency measurement system is presented and demonstrated based on a swept frequency silicon microring resonator (MRR). The drop-port of a high-Q MRR is employed as a periodic narrowband scanning filter driven by a sawtooth voltage signal. The unknown frequency can be mapped to time interval between pulse appearances when scanning the modulated signal and the frequency-to-time mapping is established. In the experiments, we obtain a measurement range of 25 GHz with an error of ±510 MHz. Meanwhile, the measurement resolution for multi-frequency measurement is about 5 GHz. Our scheme offers a simple structure, low-cost solution, capability of multiple frequency measurement, and potential of chip-integration.

Abstract: Reconfigurable photonic filters are promising candidates to meet the requirements of future microwave communication systems. However, sensitivity to process and temperature variations necessitates an automatic calibration solution to enable robust operation. This paper demonstrates fully automatic tuning of silicon photonic all-pass filter (APF)-based pole/zero filters using a monitor-based tuning method that calibrates the initial response by controlling each pole and zero individually via microheaters. The proposed tuning approach calibrates severely degraded initial responses to the designed elliptic filter shapes and allows us for automatic bandwidth and center-frequency reconfiguration of these filters. This algorithm is demonstrated on second- and fourth-order filters fabricated in a standard silicon photonics foundry process. After the initial calibration, only 300 ms is required to reconfigure a filter to a different center frequency. Thermal crosstalk between the microheaters is investigated, with substrate thinning demonstrated to suppress this effect and reduce filter calibration to less than half of the original thick substrate times. This fully automatic tuning approach opens the possibility of employing silicon photonic filters in real communication systems.

Abstract: We observed parametrically down converted x-ray signal photons that correspond to idler photons at optical wavelengths. The results demonstrate a new method for probing valence-electron charges and microscopic optical responses of crystals at the atomic-scale resolution.

Abstract: We thoroughly explore the characteristics of an ultrafast all-optical NOR gate for 160 Gb/s return-to-zero Gaussian data signals using a single quantum-dot semiconductor optical amplifier (QD-SOA) and an optical filter (OF). In this proposed scheme, we employ an optical clock signal as a probe in addition to data signals as pumps between which the Boolean NOR function is executed. By conducting numerical simulations, we investigate and evaluate the effects of various critical factors on the extinction ratio and Q2-factor. This enables us to specify the margins of clock wavelength, peak power of data and clock signals, current density, electron relaxation time from the excited state to the ground state, linewidth enhancement factor, small signal gain of QD-SOA, OF bandwidth and order, the permissible extent of arrival time difference between data signals and clock, and the effect of amplified spontaneous emission. Moreover, we demonstrate that the proposed device can be applied to a multiple-input NOR gate. The results show that the proposed NOR gate can be achieved with both logical correctness and high quality when the specified conditions are satisfied.

Abstract: In this letter, different types of plasmonic ultra-wide band band-pass filters (UWB-BPFs) have been studied and numerically analyzed. The filters have been designed based on the angular ring resonators (ARRs) and square ring resonators (SRRs) connected with a coupled feed line. The UWB can be realized by suitably adjusting the coupling gaps both sides of the resonator. Based on the ideal characteristics of the proposed ARRs and SRRs, all miniaturized UWB-BPFs are operating at THz frequencies. Multiple transmission zeros are generated to improve the selectivity of the filter. All simulated results have been studied using CST Microwave studio suite. The transmission performance is explained by the resonance condition, which agrees well with the numerical simulation or theoretical calculation. This letter provides a promising application for plasmonic UWB-BPFs and plasmonic integrated optical circuits.

Abstract: An optical vector analyzer (OVA) based on symmetric optical double-sideband (ODSB) modulation using a phase modulator (PM) and an intensity modulator (IM) is proposed and demonstrated. In the symmetric-ODSB-based OVA, frequency response measurements are implemented by transmitting the phase-modulated and intensity-modulated ODSB signals through an optical device-under-test (DUT), respectively. Then, removing the responses of the two electro-optic modulators and processing the measured responses, accurate frequency responses of the DUT on both sides of the optical carrier are obtained. Comparing with the conventional OVA based on optical single-sideband (OSSB) modulation, the proposed ODSB-based OVA has the doubled measurement range and the simple wavelength-independent configuration. Moreover, the measurement system inherently has large dynamic range and high accuracy, which is difficult to achieve for the OSSB-based OVA due to the restriction of the limited sideband suppression ratio. An experiment for measuring the magnitude and the phase responses of a programmable optical filter is carried out. The responses in a range of 100 GHz are measured with a resolution of 10 MHz by using 50-GHz components.

Abstract: In this paper, we report on the performances of silicon photomultipliers (SiPMs) with commercial long-pass interferential and plastic filters integrated on the detector's package for environmental light rejection. Several applications, including functional near infrared (NIR) spectroscopy or light detection and ranging, would benefit from the use of highly sensitive detectors like SiPMs with optimized electro-optical characteristics in NIR wavelength range. To this purpose, it is fundamental to reduce the absorption of environmental spurious light leading in application to a decrease of the detector's sensitivity, especially for very weak photon fluxes. We will show how the use of both types of filters has a relevant impact on the electro-optical performances of the bare detectors, in terms of cross talk reduction at high overvoltage values, detection efficiency, spectral response and capability to shield effectively the devices from the absorption of stray light, at the different light wavelengths used for the measurements.

Abstract: Metal-dielectric micro/nano-composites have surface plasmon resonances in visible and near-infrared domains. Excitation of coupled metal-dielectric resonances is also important. These different resonances can allow enhancement of the electromagnetic field at a subwavelength scale. Hybrid plasmonic structures act as optical antennae by concentrating large electromagnetic energy in micro- and nano-scales. Plasmonic structures are proposed for various applications such as optical filters, investigation of quantum electrodynamics effects, solar energy concentration, magnetic recording, nanolasing, medical imaging and biodetection, surface-enhanced Raman scattering (SERS), and optical super-resolution microscopy. We present the review of recent achievements in experimental and theoretical studies of metal-dielectric micro and nano antennae that are important for fundamental and applied research. The main impact is application of metal-dielectric optical antennae for the efficient SERS sensing.