The paper presents a photonic integrated circuit (PIC) concept for dual-band swept-source optical coherence tomography (SS-OCT). We designed the PIC for work with two swept sources with operation bands 820-880 nm and 1260-1360 nm. The PIC contains reference and sample arms and k-clocks for both bands. In both cases, k-clocks are unbalanced MachZehnder interferometers with a free spectral range greater or equal to the light sources’ operation bands. The PIC is developed for a silicon nitride manufacturing platform with minimum losses.
Intelligent systems significantly reduce routine work for doctors and improve diagnostic accuracy in medical diagnostics. However, the algorithms' effectiveness may be hindered by the heterogeneity of medical data and intermediate phases of a patient's clinical presentation. Additionally, not all intelligent systems can provide sufficient interpretability to analyze the clinical correlation between the system's responses and the actual clinical picture, thereby limiting their implementation in real medical practice. This article presents a solution for developing an intelligent algorithm to stage age-related macular degeneration of the fundus, a socially significant disease, including the challenging-to-detect intermediate stage, and an approach to visualize the algorithm's work in predicting disease stages. The algorithm's performance, developed based on a multimodal approach, was compared with deep neural networks and other multimodal approaches with commonly used data fusion algorithms. The comparison results demonstrate the elimination of the class imbalance effect due to the difficulty of detecting the intermediate disease stage, resulting in a reduction in the dynamic range of specificity and sensitivity values for all classes to no more than 5% for the developed approach. Moreover, the accuracy for the intermediate stage increased by 20% compared to existing commonly accepted data fusion algorithms.
Vortex beams, characterized by a spiral phase distribution and bearing orbital angular momentum, have unique properties that make them valuable for the research and practical applications. Such beams are used in optical communications, optical manipulation, including tweezers, super-diffraction limit imaging, mode-division multiplexing, and quantum coding. This work investigates the dependence of the radiation flux density of an emitted optical vortex beam depending on the emitting structure geometry. A micro-ring resonator with etched holes is used as a vortex beam emitter. In our study, optimizing the width of the ring waveguide leads up to 30% for the resonant wavelength 1563 nm increase in the power flow density. In order to analyze how the whispering gallery modes are distributed in the cross-section of the ring waveguide, we enlarged the width of the ring waveguide from 400 nm to 500 nm. This approach can be applied to radiating micro-ring resonators in various applications.
Optoelectronic oscillator (OEO) output frequency stabilization in various use cases is urgent, especially for integrated photonics realizations. OEO environmental changes sensitivity limits the commercial use of this frequency generator type. In this article, we showed the application possibility of the tunable optical delay element for frequency stabilization. Also, we presented a mathematical model of the OEO with a tunable delay element for the output frequency control. We used Ansys Lumerical software for the mathematical model verification. The frequency tuning range is 2.6 GHz with a 50 MHz/ps frequency step.
This study presents a model of a fully connected neural network (NN) implemented on elements of integrated photonics, including the software implementation of this architecture. The main purpose was to compare the results of two NNs, for this reason the average correlation coefficient was calculated, which amounted to 0.9904. This indicates a high degree of similarity and accuracy between the model's performance on PC and photonics elements.
High-frequency signal generators are required in such applications as telecommunications, radar, medical equipment, remote control, probing, radio astronomy, and spectroscopy. One can use an optoelectronic oscillator on a photonic integrated circuit in these applications due to its ease of implementation and low phase noise level. This article considers an optoelectronic oscillator with a phase shifter as a phase modulator implemented in a photonic integrated circuit to simplify the photonic integrated circuit design. The simulation results show that this system can generate microwave signals with a high signal-to-noise ratio (at least 35.27 dB). The side mode suppression ratio was up to 5.94 dB lower than the Mach-Zehnder modulator scheme. This proposed scheme can be used for microwave signal generation in various telecommunication applications and in interrogation tasks.
This article analyzes the influence of the accuracy of manufacturing microring resonators on the characteristics of sensors based on silicon-on-insulator and silicon nitride platforms of integrated photonics. We estimated a deviation of 8 nm in increasing and decreasing the waveguide width. The results indicate that inaccuracies in the width of the waveguides lead to a resonant shift, but they do not affect the sensor’s sensitivity.
The up-to-the-date electrical systems for beamsteering of the phased antenna arrays are widely used; however, possessing significant drawbacks, including high losses, electromagnetic interference, and high power consumption. To overcome these challenges, microwave photonic systems, both discrete and integrated, have demonstrated outstanding potential. In this context, we discuss the two primary methods for beamsteering, i.e., true time delay (TTD) and phase shift (PS). This paper provides simulation results for a four-channel photonic integrated circuit (PIC) for beamsteering based on the TTD method. The PIC design could be implemented on any fabrication platform. The results demonstrate the approach’s feasibility and its potential to improve the performance of phased array antenna systems.
The paper proposes a photonic integrated circuit (PIC) design for multi-channel swept-source optical coherence tomography (SS-OCT) with a high-scale elements integration on the chip. The PIC contains a tunable reference arm, four spaced apart sample arms, a k-clock based on an unbalanced Mach-Zehnder interferometer, an OCT interferometer, and balanced photodiodes. The PIC is developed for a silicon nitride manufacturing platform, providing minimum losses. The simulation results demonstrate the possibility of simultaneous reception of OCT data from four different points of the studied tissue sample, which can significantly increase the scanning speed.
This paper analyzes the prospects for applying optical beams carrying orbital angular momentum (vortex beams) for sensing. We give short retrospectives on environmental properties one can measure with vortex beams, such as liquids turbulence, temperature, and movement. We also propose a new method based on photonic integrated circuits for determining liquids’ refractive index and turbulent properties using vortex beams. The essence of the method is to measure the refractive index and detect the vortex order simultaneously. The developing sensor consists of two microring resonators: a vortex emitter, which also acts as a refractive index-based temperature sensor, and a receiver. This method can potentially increase the measurements’ accuracy and measure the liquid’s turbulence.
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