Eugeny M. Dianov

Mode-locked Bi-doped fiber laser

Mode locking is obtained for what we believe to be the first time in a Bi-doped fiber laser. Stable 50 ps laser pulses with a pulse repetition rate of 13 MHz are generated at a wavelength of 1161.6 nm with a 2 mW average power.

Single-mode microstructured optical fiber for the middle infrared

Microstructured crystalline optical fiber from silver halides is described. Both experimental and theoretical evidences are presented to establish that the fiber is effectively single mode at wavelength 10.6 micro m with numerical aperture NA=0.16 and optical losses of approximately 2 dB/m. Crystalline microstructured optical fibers offer key advantages over step-index optical fibers from silver halide crystals. The wide transmission range of wavelengths 2-20 micro m provides great potential for applications in spectroscopy and for the development of a range of new crystalline-based nonlinear optical fibers.

Broadband dispersion-compensating fiber for high-bit-rate transmission network use.

The optimum refractive-index profile and drawing temperature were investigated so as to maximize the figure of merit for multicladding broadband dispersion-compensating fibers. Based on the results of the investigation, the authors have fabricated a highly bend-resistant fiber with a 92.6-ps/(nm dB) figure of merit using the modified chemical-vapor deposition method for dispersion compensation in the 1.5-1.6-µm wavelength region. The manufactured dispersion compensator does not suffer bend loss at 1.55 µm for curvatures of radia of 6.3 and 3.3 cm, and it has a 1.1-dB/km bend loss at a curvature of radius of 1.6 cm. Codoping the germanium silicate core with fluorine diminishes the optical loss down to 0.70 dB/km at a 1.55-µm wavelength.

Refractive index spectral dependence, Raman spectra, and transmission spectra of high-purity Si28, Si29, Si30, and Sinat single crystals

Precise measurement of the refractive index of stable silicon isotopes Si, Si, Si single crystals with enrichments above 99.9 at.% and a silicon single crystal Si of natural isotopic composition is performed with the Fourier-transform interference refractometry method from 1.06 to more than 80 μm with 0.1 cm resolution and accuracy of 2 × 10 . . . 1 × 10. The oxygen and carbon concentrations in all crystals are within 5 × 10 cm and the content of metal impurities is 10 . . . 10 at.%. The peculiar changes of the refractive index in the phonon absorption region of all silicon single crystals are shown. The coefficients of generalized Cauchy dispersion function approximating the experimental refractive index values all over the measuring range are given. The transmission and Raman spectra are also studied.We performed precise measurement of the refractive index of stable silicon isotopes 28Si, 29Si, and 30Si single crystals with enrichments above 99.9 at.% and a silicon single-crystal natSi of natural isotopic composition with the Fourier-transform interference refractometry method from 1.06 to more than 80 μm with 0.1 cm(-1) resolution and accuracy of 2×10(-5)…1×10(-4). The oxygen and carbon concentrations in all crystals are within 5×10(15) cm(-3), and the content of the metal impurities is 10(-5)…10(-6) at.%. The peculiar changes of the refractive index in the phonon absorption region of all silicon single crystals are shown. The coefficients of the generalized Cauchy dispersion function approximating the experimental refractive index values all over the measuring range are given. The transmission and Raman spectra are also studied.

Calculation of soft atomic potentials caused by three-center bonds in silica glass

Abstract Properties of the SiOSi linkage stretched from 0.30 to 0.46 nm in vitreous silicon dioxide are studied with MNDO and PM3 quantum-chemical methods in an isolated cluster model. The soft atomic potential caused by the three-center bond is proved to arise in the stretched linkage. The calculated electronic structure of the three-center bond and vibrational properties of the linkage are discussed.

Optical and gain characteristics of high-concentration erbium-doped fibers on base of cesium-silicate glasses

In conclusion, using MCVD and solution-doping techniques, a high concentration (-1 wt %) Er-doped fibre (EDF) on base of cesium-silicate glasses was fabricated. A signal gain 25 dB at 1538 /spl mu/m in a 30-cm-long fiber was achieved without optimizing the pump wavelength. The study of amplification properties of EDF with higher concentrations is under way.

Raman gain properties of germania-based core silica fiber

Raman amplification in singlemode fiber with germania-based core and silica cladding was investigated for the first time. Very short efficient Raman lasers based on this fiber were developed in 1.1 and 1.6 mkm spectral bands.

Singlemode leakage channel fiber for the middle infrared

We fabricated leakage channel microstructured crystalline fiber (MCF) from solid solution AgClxBr1-x for middle IR with one ring of six rods and large mode field area 13 600 μm2 for the first time. Experiments proved that MCF is effectively single mode at 10.6 μm wavelength, which corresponds to numerical simulation. Measured optical losses are 8 dB/m.

Singlemode crystalline fibers for the middle infrared

Microstructured and step-index fibers from silver halides singlemode at 10.6 mum and 5.5 mum are demonstrated. Experimental and theoretical evidences are presented to establish that the step-index fibers are singlemode at 10.6 mum.

A Mode-locked Bi-doped Fiber Laser

Mode-locking is obtained for the first time in Bi-doped fiber laser. Stable 50-ps laser pulses with a pulse repetition rate of 13 MHz are generated at a wavelength of 1161.6 nm with 2 mW average power.