Abstract: The invention relates to optical fiber communications. A multicore optical fiber comprises at least two light-guiding cores made of doped fused silica with refractive indices nc1, nc2, nck, each light-guiding core of the at least two light-guiding cores being surrounded by a respective arbitrarily shaped inner reflecting cladding made of fused silica or doped fused silica with refractive indices nc11, nc12, nclk, which are less than the refractive indices nc1, nc2, nck of respective light-guiding cores; a continuous or intermittent barrier region made of fused silica and having an arbitrary cross-sectional shape, the barrier region being formed in the space between the inner reflecting claddings and an outer cladding of fused silica with refractive index n0, the barrier region having refractive index nb, which is less than the refractive index of each of the inner reflecting claddings; and an external protective coating.

Abstract: The invention relates to optical fiber communications. A multicore optical fiber comprises at least two light-guiding cores made of doped fused silica with refractive indices nc1, nc2, nck, each light-guiding core of the at least two light-guiding cores being surrounded by a respective arbitrarily shaped inner reflecting cladding made of fused silica or doped fused silica with refractive indices nc11, nc12, nclk, which are less than the refractive indices nc1, nc2, nck of respective light-guiding cores; a continuous or intermittent barrier region made of fused silica and having an arbitrary cross-sectional shape, the barrier region being formed in the space between the inner reflecting claddings and an outer cladding of fused silica with refractive index n0, the barrier region having refractive index nb, which is less than the refractive index of each of the inner reflecting claddings; and an external protective coating.

Abstract: An amplifying optical fiber includes a core containing oxides of elements selected from the group consisting of silicon, germanium, phosphorus, bismuth, aluminum, gallium with a concentration of bismuth oxide of 10-4-5 mol %, a total concentration of silicon and germanium oxides of 70-99.8999 mol %, a total concentration of aluminum and gallium oxides of 0.1-20 mol % wherein both aluminum and gallium oxide are present and a ratio of aluminum oxide to gallium oxide is at least two, and a concentration of phosphorus oxide from 0 to 10 mol %, and provides a maximum optical gain at least 10 times greater than the nonresonant loss factor in the optical fiber. An outside oxide glass cladding comprises fused silica. The core has an absorption band in the 1000 nm region, pumping to which region provides an increased efficiency of power conversion of pump light into luminescence light in the 1000-1700 nm range.

Abstract: The invention relates to lasers and fiber optics. An amplifying optical fiber operating at a wavelength in the range of 1000-1700 nm comprises an oxide glass core to provide amplification and at least one oxide glass cladding. According to the invention the core contains oxides of elements selected from the group consisting of silicon, germanium, phosphorus, bismuth, aluminum, gallium at concentration of bismuth oxide of 10-4-5 mol %, concentration of silicon and germanium oxides, taken together or separately, of 70-99.8999 mol %, concentration of aluminum and gallium oxides, taken together or separately, of 0.1-20 mol % concentration of phosphorus oxide from 0 to 10 mol %, and provides a maximum optical gain at least 10 times greater than the nonresonant loss factor in the optical fiber. An outside oxide glass cladding comprises fused silica.

Abstract: The invention relates to the field of laser engineering and fiber optics and is industrially used to pump optical amplifiers used in wide band fiber-optical communication systems. The subject matter of the invention is a Raman fiber laser based on a phosphosilicate fiber, comprising a pumping radiation source 1, a length 2 of a phosphosilicate fiber, at least two pairs of Bragg gratings as reflectors 3 and 4, wherein each pair of Bragg gratings forms an optical resonator, wherein the transmission of energy between the resonators is effected due to stimulated Raman scattering, both at relatively high frequency intramolecular oscillations, related to the presence of phosphorus oxide in the fiber (the frequency difference of such resonators being selected from the range of 1305-1355 cm−1), and at relatively low frequency oscillations related to a silicate matrix of the fiber, the shift of frequencies between such resonators being selected from the range of 50-560 cm−1.

Abstract: The inventions relate to measurements of a hydrostatic and/or fast-changing pressure by optical means, and are suitable for aerodynamic investigations of aircraft and small spacecraft, in robotics, including small force micro-clamps, in remote pressure monitoring (in wells, vessels, cylinders), in medicine and medical and biological investigations, hydroacoustics, security systems. The object is to improve the sensitivity and enhance the temperature and vibration stability of a pressure sensor. The pressure sensor is a low Q-factor Fabry-Perot cavity/interferometer 6 at the end of a single-mode optical fiber 1 with the 4% Fresnel reflection from the silica glass/air interface. Another movable mirror of the cavity is formed by an end face 10 of a short (1-3 mm) optical fiber length 9 having a small inertial mass and inserted into the center of a flexible membrane 9 of 500-700 &mgr;m in diameter, tightly sealing a small air volume of about 1-3 mm3 inside a second capillary 3 with the external diameter of 0.

Abstract: The inventions relate to measurements of a hydrostatic and/or fast-changing pressure by optical means, and are suitable for aerodynamic investigations of aircraft and small spacecraft, in robotics, including small force micro-clamps, in remote pressure monitoring (in wells, vessels, cylinders), in medicine and medical and biological investigations, hydroacoustics, security systems. The object is to improve the sensitivity and enhance the temperature and vibration stability of a pressure sensor. The pressure sensor is a low Q-factor Fabry-Perot cavity/interferometer 6 at the end of a single-mode optical fiber 1 with the 4% Fresnel reflection from the silica glass/air interface. Another movable mirror of the cavity is formed by an end face 10 of a short (1-3 mm) optical fiber length 9 having a small inertial mass and inserted into the center of a flexible membrane 9 of 500-700 &mgr;m in diameter, tightly sealing a small air volume of about 1-3 mm3 inside a second capillary 3 with the external diameter of 0.

Abstract: The invention relates to the field of laser engineering and fiber optics and is industrially used to pump optical amplifiers used in wide band fiber-optical communication systems. The subject matter of the invention is a Raman fiber laser based on a phosphosilicate fiber, comprising a pumping radiation source 1, a length 2 of a phosphosilicate fiber, at least two pairs of Bragg gratings as reflectors 3 and 4, wherein each pair of Bragg gratings forms an optical resonator, wherein the transmission of energy between the resonators is effected due to stimulated Raman scattering, both at relatively high frequency intramolecular oscillations, related to the presence of phosphorus oxide in the fiber (the frequency difference of such resonators being selected from the range of 1305-1355 cm−1), and at relatively low frequency oscillations related to a silicate matrix of the fiber, the shift of frequencies between such resonators being selected from the range of 50-560 cm−1.

Abstract: The invention relates to fiber optics and can be employed in fiber radiation collimators, optical waveguide couplers, spectral filters, optical isolators, long-period gratings, dispersion compensators, cascade mode field diameter conversion fibers on simulated Raman effect, physical value sensors, radiation suppression units for predetermined wavelengths, and for smoothing the gain spectrum in erbium fiber amplifiers. The invention facilitates fabrication of optical waveguides and apparatuses based on them. To produce preforms for optical waveguides (1) by a plasma chemical vapor deposition method, molecular gaseous agents, fed to a substrate tube (24), are mixed so that less than five atoms of oxygen fall on every atom of silicon and more than one atom of nitrogen falls on every 1000 atoms of oxygen. The refractive index is locally changed by heating a length of an optical waveguide (1). This causes a local thermal diffusion of elements contained in a core (3) into a cladding (2), or vice versa.

Abstract: The inventions relate to the sphere of the laser technology, the fibre and integrated optics, and are industrially applicable in elements of the fibre and waveguide optics made of germanium silicate glass, particularly in fibre-optical Bragg gratings and long-spacing gratings, scattering compensators, integrated optical waveguides, etc. The objective of simplification of Raman fibre lasers emitting in the wavelengths of 1.24 mc and 1.48 mc and enhancement of the radiation conversion efficiency in Raman scattering is attained. A laser emitting in the wavelength of 1.24 mc comprises a pumping source (1), a fibre light guide (2) containing P205 in the amount from 1 to 30 mole %, portions of a fibre light guide that contain GeO2 in the amount from 11 to 39 mole % and are Bragg fibre-optical gratings (3) and (4), grating (3) forming a blank distributed reflector of an optical resonator for first Stokes component, and grating (4)--the output distributed reflector for the same resonator.