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An Improved Optical Parameter Optimisation Approach Using Taguchi and Genetic algorithm for High Transmission Optical Filter Design
摘要： High transmission optical filters require specific filter characteristics and set of optimisation methods since precision in output performance plays a vital role in such applications. In this paper, an improved genetic algorithm approach to optimise high transmission optical filter is described. High transmission of around 99% in the wavelength region of 525-575 nm without any dips in between is the main performance requirement desired. The optimisation parameters are layer thickness, refractive index and number of layers and design wavelength is 550 nm in visible region. The method integrates the Taguchi method and genetic algorithm. First, Taguchi method is used to reduce the number of design experiments and find the minimum possible number of optimised set of values that represents the quality performance of the system. Then, genetic algorithm is applied to search the optimal design parameters. The performance is determined in terms of transmittance. Three levels for each optimisation parameter were considered. The total number of design experiments to be performed (in worst case) using genetic algorithm only with three optimisation variables and three levels is approximately 33=27 for obtaining the best design that matches the desired performance whereas Taguchi integrated genetic method helped in finding the best matching design with 9 design experiments. The best transmission performance was obtained for 24 layers, with thickness range 10-123.75 nm and high and low refractive index of 2.1 and 1.38. This method is a very robust approach that can be used for design parameter optimisation of optical filters for high transmission applications.
关键词： Optical filters,Genetic algorithm,Taguchi,Optimisation
更新于2025-09-23 15:23:52
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Flexible Filtering Element on SOI with Wide Bandwidth tunability and Full FSR tuning
摘要： We demonstrate a Silicon-on-Insulator flexible filtering element, relying on two serially coupled micro ring resonators equipped with three thermo-optically tuned Mach-Zehnder interferometers, acting as variable optical couplers. A single electrode configuration is adopted, enabling the low-complexity thermo-optical control of the filtering element for bandwidth and wavelength tuneability. The module's performance has been studied in detail via simulation analysis and the obtained results were verified through experimental evaluation. Wide bandwidth tunability from 9 GHz to 103 GHz is achieved with a power efficiency of 0.284 mW/GHz, while full Free Spectral Range wavelength tuning is achieved with an efficiency of 0.297 mW/GHz. Module's insertion loss lays below 3 dB.
关键词： Silicon photonics,Optical switches,Microring resonators,Bandwidth flexibility,Thermo-optic control,Wavelength division multiplexing,Optical filters
更新于2025-09-23 15:22:29
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[IEEE 2018 International conference on Computing, Electronic and Electrical Engineering (ICE Cube) - Quetta, Pakistan (2018.11.12-2018.11.13)] 2018 International Conference on Computing, Electronic and Electrical Engineering (ICE Cube) - Mathematical Modeling of Photonic Crystal based Optical Filters using Machine Learning
摘要： In this paper, we present a new approach to design photonic crystal based optical filters using machine learning based mathematical model. The presented optical filter device finds its application in near infrared spectral range. The design and spectral response of the filter can be predicted using the proposed mathematical model which can considerably reduce simulation time and efforts. The numerical simulation of the optical filter device along with its spectral results and mathematical modeling are described.
关键词： machine learning in optics,machine learning,optical filters,guided-mode resonance,Dielectric photonic crystals,low-index contrast,FDTD
更新于2025-09-23 15:22:29
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Towards an on-chip optical microsystem for spectroscopic detection of gastrointestinal dysplasia
摘要： This paper presents a CMOS optical microsystem with a 4×4 photodiodes array and their readout electronics, based on 16 light-to-frequency converters, and 16 high selective optical filters, for spectrophotometric measurement of diffuse reflectance and fluorescence signals, applied to the detection of gastrointestinal dysplasia. The photodiodes array is based on n+/p-epilayer junction silicon photodiodes. Their readout electronics outputs a digital signal, with a frequency proportional to the photodiode current, featuring a sensitivity of 26 Hz/nA at 550 nm, a spectral resolution of 9 MHz and a power consumption of 1 mW. The optical filters are based on 16 thin-film narrow-band Fabry-Perot resonators, in which dielectric mirrors are used. They feature high transmittances and low full-width-half-maximum. Experimental measurements, using phantoms representative of the main absorbing, scattering and fluorescence properties of gastrointestinal tissues, proved the viability of the CMOS optical microsystem with the optical filters to extract those signals, when comparing the obtained results with commercial equipment. The implemented apparatus is ready to be used as a portable system on a surgery room to verify the total removing of gastrointestinal cancer tissue. Moreover, the developed approach is a step forward in the implementation of a gastrointestinal dysplasia detection miniaturized tool.
关键词： Fluorescence,CMOS optical microsystem,Optical filters,Gastrointestinal dysplasia,Diffuse reflectance
更新于2025-09-23 15:21:01
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Narrowing of filters and laser mirror in tilt-modulated chiral sculptured thin films
摘要： Helicoidal multi-layered nanostructures obsess intriguing optical properties to develop various optical and photonic devices. The optical properties of such spiral materials are adjacent with helical rotation. Tilt-modulated chiral sculptured thin film (STF) can totally reflect or transmit light in the Bragg regime for varying amplitudes of oscillation angles. Particularly, twist defect chiral STFs of same handedness creating spectral hole for circularly polarized light at different oscillation amplitudes. A narrow bandstop or wide bandpass filters and Bragg reflectors are created in defect modulated chiral STF. While, increasing the number of oscillations in a structural half period of chiral STF, the filters are flattering and narrower having blue shift. For large number of oscillation, the modulated chiral STF behave as laser mirror and creating Bragg fringes in the Bragg regime. Similarly, for different angles of incidence light the spectral holes and optical filters are become narrowing and shifted to lower wavelength regime, eventually die out in the Bragg regime, with maximum reflection for large angle of incident light. Therefore, it is suggested that such chiral STF are very useful in optical devices which operating in different wavelength regime.
关键词： Electromagnetic waves,Laser mirror,Optical properties,Bragg reflector,Optical filters
更新于2025-09-23 15:19:57
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Fabrication of a CMOS-based Imaging Chip with Monolithically Integrated RGB and NIR Filters
摘要： Recent developments in multispectral cameras have demonstrated how compact and low-cost spectral sensors can be made by monolithically integrating filters on top of commercially available image sensors. In this paper, the fabrication of a RGB + NIR variation to such a single-chip imaging system is described, including the integration of a metallic shield to minimize crosstalk, and two interference filters: a NIR blocking filter, and a NIR bandpass filter. This is then combined with standard polymer based RGB colour filters. Fabrication of this chip is done in imec's 200 mm cleanroom using standard CMOS technology, except for the addition of RGB colour filters and microlenses, which is outsourced.
关键词： multispectral imaging,RGB,NIR,CMOS image sensor,monolithic integration,optical filters
更新于2025-09-19 17:15:36
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Self-Assembled Extended ??-Systems for Sensing and Security Applications
摘要： Molecules and materials derived from self-assembled extended π-systems have strong and reversible optical properties, which can be modulated with external stimuli such as temperature, mechanical stress, ions, the polarity of the medium, and so on. In many cases, absorption and emission responses of self-assembled supramolecular π-systems are manifested several times higher when compared with the individual molecular building blocks. These properties of molecular assemblies encourage scientists to have a deeper understanding of their design to explore them for suitable optoelectronic applications. Therefore, it is important to bring in highly responsive optical features in π-systems, for which it is necessary to modify their structures by varying the conjugation length and by introducing donor?acceptor functional groups. Using noncovalent forces, π-systems can be put together to form assemblies of different shapes and sizes with varied optical band gaps through controlling intermolecular electronic interactions. In addition, using directional forces, it is possible to bring anisotropy to the self-assembled nanostructures, facilitating efficient exciton migration, resulting in the modulation of optical and electron-transport properties. In this Account, we mainly summarize our findings with optically tunable self-assemblies of extended π-systems such as p-phenylenevinylenes (PVs), p-phenyleneethynylenes (PEs), and diketopyrrolopyrroles (DPPs) as different stimuli-responsive platforms to develop sensors and security materials. We start with how PV self-assemblies and their coassemblies with appropriate electron-deficient systems can be used for the sensing of analytes in contact mode or in the vapor phase. For example, whereas the PV having electron-deficient terminal groups has high sensitivity toward trinitrotoluene (TNT) in contact mode, the supercoiled fibers formed by the coassembly of self-sorted stacks of C3-symmetrical PV and C3-symmetrical electron-deficient perylene bisimide are capable of sensing vapors of nitrobenzene and o-toluidine. The power of different functional groups in combination with PVs has been further illustrated by attaching CO2-sensitive tertiary amine moieties to a cyano-substituted PV, which allowed the bimodal detection of CO2 using fluorescence and Raman spectroscopy. Interestingly, the functionalization of PVs with terminal amide groups and chiral alkoxy side chains provided a mechanochromic system that allows self-erasable imaging. Whereas PVs exhibit quenching of fluorescence in most cases during self-assembly, PE derivatives exhibit aggregation-induced emission. This property of PEs has been exploited for the development of stimuli-responsive security materials, especially for currency and documents. For instance, the blue fluorescence of a PE attached to hydrophilic oxyethylene side chains coated on a filter paper upon contact with water changes to cyan emission due to the change in the molecular packing. Interestingly, the molecular packing of a Bodipy-attached PE-based gelator allowed a stress-induced change in the emission behavior, resulting in strong near-infrared (NIR) emission upon the application of mechanical stress or gelation. Finally, the use of DPP-based π-systems for the development of NIR transparent optical filters that block UV?vis light and their security- and forensic-related applications are described. These selected examples of the π-system self-assemblies provide an idea of the current status and future opportunities for scientists interested in this field of self-assembly and soft materials research.
关键词： self-assembly,sensors,π-systems,NIR transparent optical filters,stimuli-responsive,mechanochromism,fluorescence,security materials,aggregation-induced emission
更新于2025-09-19 17:13:59
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Optimal LED Filtering for Fluorescence Microscopy
摘要： LED illumination systems for fluorescence microscopy offer a wealth of benefits in comparison to traditional mercury and metal halide lamps, including ease of use, improved stability, and enhanced control. To fully realize these benefits, it is important to ensure that optical filters are configured correctly, which often can be confusing. However, without the correct filter configuration, experimental conditions can be suboptimal, and results may therefore be inaccurate. This article looks at optical filter setup in more depth, explaining the purpose and benefits of optimal LED filtering.
关键词： fluorophores,LED light source,optical filters,illumination systems,fluorescence
更新于2025-09-19 17:13:59
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[IEEE 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Sarajevo, Bosnia and Herzegovina (2019.9.2-2019.9.4)] 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Integrated Photonic Filters for Flexible Analog-based Mobile Fronthauling
摘要： A Wavelength Division Multiplexing (WDM)-enabled analog mobile fronthaul architecture is presented supporting enhanced flexibility by exploiting the fine filtering properties of a fully reconfigurable, silicon photonics-based filtering element. The use of Photonic Integrated Circuit (PIC)-based elastic optical circuitries to support wavelength selectivity, reconfigurability and advanced signal processing at the optical edge is thoroughly discussed. Numerical studies are presented emphasizing on flexibility, low-energy consumption and the compatibility of our proposed PIC-based implementations with the analog Radio over Fiber (RoF)-based mobile transport schemes. Proof-of-concept analog photonic processing of 1 Gbaud Quadrature Phase Shift Keying (QPSK)- modulated radio through Intermediate Frequency over Fiber (IFoF) transmission experiments is successfully demonstrated.
关键词： analog optical signal processing,optical filters,silicon photonics,Analog radio-over-fiber,mobile fronthaul,wavelength division multiplexing,M-QAM
更新于2025-09-16 10:30:52
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Control and calibration recipes for photonic integrated circuits
摘要： This paper presents the key ingredients and the best practices for implementing simple, effective and robust control and calibration procedures for arbitrary photonic integrated circuit (PIC) architectures. Three main features are presented and discussed: a technique to cancel out the effects of mutual crosstalk among thermal tuners, the exploitation of labelling to identify different optical signals, the use of input modulated signal to automatically reshape the frequency response of the device. Examples of application are then illustrated to show the validity and generality of the approach, namely a cross-bar interconnect matrix router, a variable bandwidth filter and third order coupled microring filter. Further, the automatic and dynamic generation of the lookup table of add/drop hitless filters operating on a dense wavelength division multiplexing grid is demonstrated. The lookup table achieved with the proposed approach can dynamically update itself to new conditions of the chip or new requirements of operation, such as variations in channel modulation format or perturbation induced by neighboring devices due to a change in their working point.
关键词： control,optical filters,microring resonators,pilot tones,integrated photonics,calibration,look up tables,thermal cross talk,tuning,locking
更新于2025-09-16 10:30:52