A K Senatorov

Quasi-single-mode hybrid fibre with anomalous dispersion in the 1 μm range

We have proposed and demonstrated an approach for ensuring quasi-single-mode operation of a cylindrically symmetric hybrid fibre having anomalous dispersion at wavelengths around 1 μm. Basic to this approach are distinctions between spatial fibre mode distributions and the use of a high-loss ring layer in the region of a minimum in the electric field of the operating hybrid mode.

Fabrication of microstructured optical fibres by drawing preforms sealed at their top end

This paper presents results of a theoretical analysis and a series of experiments dealing with microstructured optical fibre (MOF) drawing from preforms sealed at their top end. We demonstrate that maintaining a constant temperature in the top part of the preform is of key importance for the ability to produce long MOFs with stable parameters. We have proposed and implemented a technique for additional, controlled heating of the top part of preforms, which allows one to fabricate long MOFs with both constant and varying parameters. Evidence is provided that MOFs with holes differing in size can be produced rather easily by this method.

1.56 μm Sub-microjoule femtosecond pulse delivery through low-loss microstructured revolver hollow-core fiber

Being capable of light localization in the large air-filled core, microstructured hollow-core fibers (HCF) are highly promising for a long-distance high-power ultra-short pulse (USP) delivery due to extremely low fiber nonlinearity. Among them negative-curvature revolver hollow-core fiber (RHCF) having a cladding formed with a single layer of non-touched cylindrical silica glass capillaries [1] is the most beneficial for high power USP delivery owing to its cost-effective fabrication technology (due to much more simple fiber design) in comparison with hypocycloid Kagome [2] or hexagonal-cladding [3] hollow-core photonic crystal fibers; very low group velocity dispersion (GVD) [4] and outstanding localization of the fundamental mode (more than 99.993%) [1], which means only ∼10−4 part of total optical power travelling inside silica glass elements of the fiber. In this work we develop and optimize high-power all-fiber USP MOPA source emitting femtosecond pulses with ∼1 MW peak power in the telecom spectral band near 1.56 μm and demonstrate long-distance high power pulse delivery through 11.7 m-long air-filled RHCF with attenuation of less than 30 dB/km and acceptable output beam quality (M2∼1.4).

Impact of dispersion on the output characteristics of an all-fiber Er-doped nanosecond mode-locked figure-eight laser with passive nonlinear optical loop mirror

A mode-locked all-fiber Er-doped laser based on a figure-eight scheme with a passive nonlinear optical loop mirror and pulse duration of few nanoseconds has been realized for the first time. It has been revealed that the main problem of utilization of standard fibers with anomalous dispersion is the propagation of low-energy optical solitons accompanied by nanosecond pulse break up. Herein, the solution to this problem is discussed and stable laser schemes (i.e. all-polarization maintaining) are realized. A strong influence of the total laser dispersion on the nanosecond laser spectral bandwidth has been found.

Rotation Sensors On Base Of Monomode Fibers With Low Birefrdigence

The polarization properties of the monomode fibers with low and high birefringence were investigated using the radiation sources of various spectrum widths. The gyroscopes on the base of fibers with low birefringence were investigated.