Branch waveguides are essential elements in modern technologies that demand precise manipulation of electrical and optical signals to realize compact, efficient, and high-performance systems. They underpin applications such as passive optical networks and quantum key distribution. Among these, Y-branch junctions (YBJs), where one input channel divides into multiple output branches, serve as fundamental building blocks for directing and controlling signal flow. The rapid development of two-dimensional materials has opened new avenues for creating planar electronic waveguides that emulate fiber-optic functionality while enabling miniaturized optoelectronic switching. This review traces the evolution of YBJs from classical semiconductor architectures to atomically thin platforms, with emphasis on graphene-based implementations. It provides a comparative assessment of representative device concepts, including splitters, interferometers, and logic gates, summarizes theoretical progress and experimental demonstrations, and concludes with a perspective on key challenges and opportunities for future research in nanoscale signal control.

Nanophotonics could sound like a contradictio in adjecto in view of the wavelength scales involved, on the order of microns. This is very different from e g electron wavelengths (around 1 nm at 10 5m/s as an example) studied in a possible novel class of electronics.

Poly-3-hexylthiophene (P3HT) nanofibers are semiconducting high-aspect ratio nanostructures with anisotropic absorption and birefringence properties found at different regions of the optical spectrum. In addition, P3HT nanofibers possess an ability to be aligned by an external electric field, while being dispersed in a liquid. In this manuscript we show that such collective ordering of nanofibers, similar to liquid crystal material, significantly changes the properties of transmitted light. With a specially fabricated opto-fluidic component, we monitored the phase and transmission modulation of light propagating through the solution of P3HT nanofibers, being placed in the electric field with strength up to 0.1 V/μm. This report describes a technique for light modulation, which can be implemented in optical fiber-based devices or on-chip integrated components.

This Letter reports the electro-optical (EO) effect of Poly(3-hexylthiophene-2,5-diyl) (P3HT) nanofibers colloid in a polymer micro-fluidic EO cell. P3HT nanofibers are high aspect ratio semiconducting nanostructures, and can be collectively aligned by an external alternating electric field. Optical transmission modulated by the electric field is a manifestation of the electro-optical effect due to high inner crystallinity of P3HT nanofibers. According to our results, the degree of alignment reaches a maximum at 0.6 V/μm of electric field strength, implying a big polarizability value due to geometry and electrical properties of P3HT nanofibers. We believe that one-dimensional crystalline organic nanostructures have a large potential in EO devices due to their significant anisotropy, wide variety of properties, low actuation voltages, and opportunity to be tailored via adjustment of the fabrication process.

A graphene-based silicon hybrid plasmonic waveguide modulator with 25GHz 3dB bandwidth is proposed in this work. Due to high optical power density at the graphene layers, modulation depth can reach as high value as 0.95dB/μm.

A Mach–Zehnder interferometer (MZI)-based liquid refractiveindex sensor, utilizing a hollow hybrid plasmonic (HP)waveguide as the sensing element, has been investigated,showing large sensitivity to the refractive index changesof the tested liquids, as well as lower propagation loss incomparison to typical plasmonic waveguide-based ones.The sensor is fabricated using conventional silicon-oninsulator(SOI) technology; therefore, it is compatible toother standard SOI devices. The waveguide sensitivity, Sw,is experimentally demonstrated to be 0.64, with a propagationloss less than 0.25 dB/μm. Using a 20 μm long hollowHP waveguide in the sensing arm, the sensitivity of the MZIsensor (device sensitivity, Sd ) is about 160 nm/RIU, with anextinction ratio larger than 40 dB.

The decades long development in shrinking footprint and improving performance of photonics integrated circuits has seemingly slowed down in recent years, posing problems in e g interconnects in data centers with their ever increasing power requirements. Thus, routes to a continued development towards smaller footprint, lower power, higher performance integrated nanophotonics will be presented and discussed. Comparison to some nanoelectronics devices will be made.

A MEMS tunable hybrid plasmonic-Si (HP) waveguide is investigated, showing verylarge changes of both effective refractive index and propagation loss when applying bias voltage.Preliminary experimental results show that: with 15μm MEMS structure in Si waveguideplatform, the extinction ratio can be over 20dB between “on” and “off” states.

This paper gives a review of the recent progresses in our research on nanophotonics and hybrid plasmonic geometries, structures and devices. In the first part we present SOI-nanowire-based integrated components. The concept and different configurations of hybrid plasmonic structures will be then discussed. Finally different fabricated devices for applications in optical interconnects and sensing will be presented and characterized.

Optical excitation transfer in nanostructured matter has been intensively studied in various material systems for versatile applications. Herein, we theoretically and numerically discuss the percolation of optical excitations in randomly organized nanostructures caused by optical near-field interactions governed by Yukawa potential in a two-dimensional stochastic model. The model results demonstrate the appearance of two phases of percolation of optical excitation as a function of the localization degree of near-field interaction. Moreover, it indicates sublinear scaling with percolation distances when the light localization is strong. Furthermore, such a character is maximized at a particular size of environments. The results provide fundamental insights into optical excitation transfer and will facilitate the design and analysis of nanoscale signal-transfer characteristics.