Inkjet printing of high‐refractive‐index optical waveguides designed for single‐mode operation is presented. A waveguide core is printed with titanium dioxide nanoparticles that form a straight strip with a high refractive index. The quartz glass without preliminary processing is used as a substrate. The optimal waveguide thickness to provide single‐mode operation in the near‐IR range is calculated. The number of printed layers necessary to obtain the required thickness and the refractive index is established. The printing parameters to provide suitable morphology for waveguide application are thoroughly studied. Measurements confirm light propagation through the printed waveguides at 1.55 µm wavelength, and the mean power loss is estimated as 3.52 dB cm−1. The branched structure is printed, and its ability to transmit and split light is demonstrated. The received data have a directly applied value for application in the future development of integrated optical circuits and printing technologies.

We present a new approach for obtaining magnetic nanospheres with tunable size and high magnetization. The method is implemented via controllable destabilization of a stable magnetite hydrosol with glycerol, leading to the formation of aggregates followed by their stabilization with the citrate shell. This inexpensive, simple and easily scalable approach required no special equipment. The obtained samples were characterized by high stability and magnetization over 80 emu/g. Effects of synthetic conditions on physicochemical properties of nanospheres were monitored by hydrodynamic size, zeta potential, and polydispersity of magnetite aggregates. The size of the resulting aggregates varied between 650 nm and 40 nm, and the zeta potential from +30 mV to −43 mV by changing the ratio of the reagents. Under optimal conditions the clusters with a diameter of 80 nm were produced with a narrow size distribution ±3 nm. These characteristics allowed for optical response to the external magnetic field, thereby producing a magnetic photon liquid. Due to biocompatibility of the reagents used in the synthesis the nanospheres evoked a negligible cytotoxicity for human non-malignant and tumor cell lines. These results make new materials valuable in photonics and biomedicine.

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A method for calculation of the propagation constant of guided modes in the optical waveguides with trapezoidal cross-sections is proposed. The method enables to calculate a propagation constant correction factor that arises due to perturbations of the cross-section of a reference rectangular waveguide. The correction factor is analytically calculated within the framework of the coupled-mode theory. A refined form of the coupling coefficient is obtained owing to the application of a concept of effective excitation sources and accurate account of boundary conditions. An impact of the waveguide cross-section shape on its dispersion properties is analysed. The necessity to take into account the proposed form of the coupling coefficient is demonstrated by comparison of the simulation results with other methods of dispersion calculation.

Formation of losses in the dielectric optical micro-waveguides of rectangular cross section is analytically studied. It is shown that the two processes are involved in the formation of the frequency characteristic of the attenuation constant: the redistribution of energy in the waveguide-environment system and the group velocity dispersion. The group velocity dispersion determined by the geometry of the waveguiding structure leads to the formation of a local maximum of the attenuation constant in the frequency response.