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Lasers & Laser Systems
Yu. A. Adamenkov, M. A. Gorbunov, A. A. Kalacheva, V. A. Shaidulina, A. V. Yuriev, B. A. Vyskubenko
Generation of a Four-Level Laser with Optical Pumping on Metastable Argon Atoms DOI: 10.22184/1993-7296.FRos.2026.20.1.8.15
This paper describes laser generation obtained using a four-level scheme at a wavelength of 965 nm of an optically pumped rare gas laser (OPRGL) on the metastable argon atoms, and compares it with generation at the principal argon atomic line (912 nm). The experimental data were obtained in relation to the dependence of lasing power at a wavelength of 965 nm on the gas mixture flow rate and the discharge pulse repetition rate, as well as in relation to the dependence of lasing intensity on the time between two discharge pulses.
Generation of a Four-Level Laser with Optical Pumping on Metastable Argon Atoms DOI: 10.22184/1993-7296.FRos.2026.20.1.8.15
This paper describes laser generation obtained using a four-level scheme at a wavelength of 965 nm of an optically pumped rare gas laser (OPRGL) on the metastable argon atoms, and compares it with generation at the principal argon atomic line (912 nm). The experimental data were obtained in relation to the dependence of lasing power at a wavelength of 965 nm on the gas mixture flow rate and the discharge pulse repetition rate, as well as in relation to the dependence of lasing intensity on the time between two discharge pulses.
L. V. Gavrilenko, P. A. Bushuikin, D. I. Kuritsyn, E. E. Orlova, V. I. Gavrilenko, M. A. Fadeev, R. A. Khabibullin, A. A. Yantser, S. V. Morozov
Measurement of the Spatial Emission Pattern of a Wire THz Quantum Cascade Laser Using Longitudinal Movement of the Receiving Aperture DOI: 10.22184/1993-7296.FRos.2026.20.1.16.28
The spatial emission pattern of a quantum cascade laser (QCL) with a double metal waveguide with the subwavelength cross-sectional dimensions and a length significantly greater than the wavelength (wire laser) was examined using a hemispherical lens and a spacer (a plate separating the laser and the lens) in the laser’s near field and without them. The integrated emission power collected by an oversized waveguide with a circular aperture in a plane perpendicular to the longitudinal laser axis was measured as a function of the distance between the QCL and the receiver. A stepwise decrease in the received QCL emission power with increasing distance to the receiver was observed, specifying the radiance beam structure as the interference rings that extend beyond the receiving aperture’s field of view as it is moved away. When using the lens, a smooth longitudinal dependence of the received power was observed, demonstrating spatial separation of the interfering radiation contributions. The observed dependencies are in good agreement with the emission calculation of a wire laser in the model of two-point sources at its ends.
Measurement of the Spatial Emission Pattern of a Wire THz Quantum Cascade Laser Using Longitudinal Movement of the Receiving Aperture DOI: 10.22184/1993-7296.FRos.2026.20.1.16.28
The spatial emission pattern of a quantum cascade laser (QCL) with a double metal waveguide with the subwavelength cross-sectional dimensions and a length significantly greater than the wavelength (wire laser) was examined using a hemispherical lens and a spacer (a plate separating the laser and the lens) in the laser’s near field and without them. The integrated emission power collected by an oversized waveguide with a circular aperture in a plane perpendicular to the longitudinal laser axis was measured as a function of the distance between the QCL and the receiver. A stepwise decrease in the received QCL emission power with increasing distance to the receiver was observed, specifying the radiance beam structure as the interference rings that extend beyond the receiving aperture’s field of view as it is moved away. When using the lens, a smooth longitudinal dependence of the received power was observed, demonstrating spatial separation of the interfering radiation contributions. The observed dependencies are in good agreement with the emission calculation of a wire laser in the model of two-point sources at its ends.
Optical Devices & Systems
A. S. Voitov, M. P. Egorenko, V. S. Efremov
Liquid Doublet Design with an “Antigravity” Membrane DOI: 10.22184/1993-7296.FRos.2026.20.1.54.60
A design of a liquid doublet for optical systems has been developed that has the ability to compensate for gravitational distortions. During the development process, the liquid doublet designs were examined, and the physicochemical properties of the liquids used were investigated to minimize the gravity influence on the elastic membrane shape of the liquid doublets. When selecting the liquid combinations, special attention is paid to the parameters such as refractive index, dispersion coefficient, density, viscosity, and the dependencies between them. The results obtained in the form of line targets and angular resolution, demonstrate the feasibility of using a liquid doublet with an elastic membrane separating the liquids, although it is not final and require further research to minimize any spherical aberration in the optical system.
Liquid Doublet Design with an “Antigravity” Membrane DOI: 10.22184/1993-7296.FRos.2026.20.1.54.60
A design of a liquid doublet for optical systems has been developed that has the ability to compensate for gravitational distortions. During the development process, the liquid doublet designs were examined, and the physicochemical properties of the liquids used were investigated to minimize the gravity influence on the elastic membrane shape of the liquid doublets. When selecting the liquid combinations, special attention is paid to the parameters such as refractive index, dispersion coefficient, density, viscosity, and the dependencies between them. The results obtained in the form of line targets and angular resolution, demonstrate the feasibility of using a liquid doublet with an elastic membrane separating the liquids, although it is not final and require further research to minimize any spherical aberration in the optical system.
Microwave Photonics
A. A. Kokolov, A. S. Koryakovtsev, D. V. Khodzhikov
An Optical Receiver with a DC 2.1 GHz Band Based on the Domestic CMOS Transimpedance Amplifier DOI: 10.22184/1993-7296.FRos.2026.20.1.44.52
The paper provides the results of development and experimental study of a transimpedance amplifier (TIA) integrated circuit based on 180 nm CMOS technology, as well as the frequency-response characteristics of a hybrid optical receiver that adops the developed TIA and domestic InGaAs p-i-n photodiode with a bandwidth of up to 7 GHz. According to the data obtained, the operating frequency band of the hybrid optical receiver at a wavelength of 1 550 nm is 2.1 GHz that is sufficient for a data transfer rate of 2.5 Gbit/s.
An Optical Receiver with a DC 2.1 GHz Band Based on the Domestic CMOS Transimpedance Amplifier DOI: 10.22184/1993-7296.FRos.2026.20.1.44.52
The paper provides the results of development and experimental study of a transimpedance amplifier (TIA) integrated circuit based on 180 nm CMOS technology, as well as the frequency-response characteristics of a hybrid optical receiver that adops the developed TIA and domestic InGaAs p-i-n photodiode with a bandwidth of up to 7 GHz. According to the data obtained, the operating frequency band of the hybrid optical receiver at a wavelength of 1 550 nm is 2.1 GHz that is sufficient for a data transfer rate of 2.5 Gbit/s.
Fiber Optic Devices & Technoligies
S. S. Kogan, V. A. Konyshev, O. E. Nanii, I. I. Petrenko, V. N. Treshchikov, R. R. Ubaydullaev
New Modulation Formats for Coherent Fiber-optic Communication Networks. Part 1. Traditional and Hybrid Quadrature Modulation Formats DOI: 10.22184/1993-7296.FRos.2026.20.1.30.42
DP-nQAM modulation formats used in modern coherent fiber-optic transmission systems with digital signal processing are considered. In such formats, data is transmitted independently in two polarizations and using nQAM quadrature modulation in each of them, where n = 2k. The symbol efficiency of such modulation formats is equal to SmE = 2k. The disadvantage of traditional formats is the inability to implement intermediate values of symbol efficiency between two consecutive values. As a result, it is possible that the quality of the signal in the communication line, determined by the optical (electrical) signal-to-noise ratio, significantly exceeds the requirements for the format with SmE = 2k, but not enough to work with the SmE = 2 (k + 1) format. This article (Parts 1 and 2) discusses new modulation formats in which, for each polarization, 2k symbol values are used, as in traditional DP-nQAM formats, but the probabilities of different symbols appearing are different. When using such modulation formats, smooth adjustment of the SmE can be achieved, which allows for maximum bandwidth of the communication line at an arbitrary communication range.
New Modulation Formats for Coherent Fiber-optic Communication Networks. Part 1. Traditional and Hybrid Quadrature Modulation Formats DOI: 10.22184/1993-7296.FRos.2026.20.1.30.42
DP-nQAM modulation formats used in modern coherent fiber-optic transmission systems with digital signal processing are considered. In such formats, data is transmitted independently in two polarizations and using nQAM quadrature modulation in each of them, where n = 2k. The symbol efficiency of such modulation formats is equal to SmE = 2k. The disadvantage of traditional formats is the inability to implement intermediate values of symbol efficiency between two consecutive values. As a result, it is possible that the quality of the signal in the communication line, determined by the optical (electrical) signal-to-noise ratio, significantly exceeds the requirements for the format with SmE = 2k, but not enough to work with the SmE = 2 (k + 1) format. This article (Parts 1 and 2) discusses new modulation formats in which, for each polarization, 2k symbol values are used, as in traditional DP-nQAM formats, but the probabilities of different symbols appearing are different. When using such modulation formats, smooth adjustment of the SmE can be achieved, which allows for maximum bandwidth of the communication line at an arbitrary communication range.
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