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.
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.
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.
In this paper we propose a design of an integrated wavelength-tunable vortex beam emitter based on the silicon photonics platform. The proposed device utilizes the free-plasma dispersion effect in order to change the effective index of the ring waveguide, which leads to displacement of the resonant wavelengths. This scheme allows to bypass the dependence of the emitter resonant characteristics from the fabrication errors. Our simulations also show that for the micro-ring resonators with a small free spectral range it becomes possible to switch the emitted vortex order keeping the same wavelength. Such capabilities make the proposed emitter useful in a wide applications range from communication systems to sensors.
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