Stanislav O. Leonov

Ultra-short pulse generation in the hybridly mode-locked erbium-doped all-fiber ring laser with a distributed polarizer

We report for the first time to the best of our knowledge on the ultra-short pulse (USP) generation in the dispersion-managed erbium-doped all-fiber ring laser hybridly mode-locked with boron nitride-doped single-walled carbon nanotubes in the co-action with a nonlinear polarization evolution in the ring cavity with a distributed polarizer. Stable 92.6 fs dechirped pulses were obtained via precise polarization state adjustment at a central wavelength of 1560 nm with 11.2 mW average output power, corresponding to the 2.9 kW maximum peak power. We have also observed the laser switching from a USP generation regime to a chirped pulse one with a corresponding pulse-width of 7.1 ps at the same intracavity dispersion.

High-energy, sub-100 fs, all-fiber stretched-pulse mode-locked Er-doped ring laser with a highly-nonlinear resonator.

We report on ultra-short stretched pulse generation in an all-fiber erbium-doped ring laser with a highly-nonlinear germanosilicate fiber inside the resonator with a slightly positive net-cavity group velocity dispersion (GVD). Stable 84 fs pulses were obtained with a 12 MHz repetition rate at a central wavelength of 1560 nm with a 48.1 nm spectral pulse width (full width at half maximum, FWHM) and 30 mW average output power; this corresponds to the 29.7 kW maximum peak power and 2.5 nJ pulse energy obtained immediately from the oscillator.

Visible supercontinuum generation in large-core photonic crystal fiber with high air-filling fraction

We demonstrate new experimental results for visible supercontinuum generation in large-core photonic crystal fiber with high air-filling fraction. Supercontinuum is generated by picosecond pulses from a passively mode-locked Yb:KGW laser. A smooth supercontinuum generation near 800 nm is achieved using 4.5 m long large-core photonic crystal fiber even with 6 mW average coupled power. These results are of interest in high power white light sources and have potential applications in precise frequency metrology and spectroscopy. The data obtained could be used also in theoretical studies of nonlinear interaction in large-core photonics crystal fibers with high air-filling fraction.

Stable Similariton Generation in an All-Fiber Hybrid Mode-Locked Ring Laser for Frequency Metrology

Ultrashort pulse lasers constitute an important tool in the emerging field of optical frequency metrology and are enabling unprecedented measurement capabilities and new applications in a wide range of fields, including precision spectroscopy, atomic clocks, ultracold gases, and molecular fingerprinting. We demonstrate the generation of stable 127-fs self-similar pulses at a central wavelength of 1560 nm with 7.14-mW average output power. Similariton lasers have a low repetition rate deviation in the averaging time interval 1-1·103 s, a low relative intensity noise -120 dBc/Hz (30 Hz to 10 kHz), a narrow single comb line width of 32 kHz, and high reliability. Thus, such lasers are highly promising for further development of the stabilized combs and open up a robust and substantially simplified route to synthesizing low-noise microwaves.

Generation of ultrashort pulses with minimum duration of 90 fs in a hybrid mode-locked erbium-doped all-fibre ring laser

Regimes of ultrashort pulse generation in an erbium-doped all-fibre ring laser with hybrid mode locking based on single-wall carbon – boron nitride nanotubes and the nonlinear Kerr effect in fibre waveguides are studied. Stable dechirped ultrashort pulses are obtained with a duration of , a repetition rate of , and an average output power of , which corresponds to a pulse energy of and a peak laser power of .

Stable similariton generation in hybrid mode-locked erbium-doped all-fiber ring laser for application in optical frequency standard

Recently similariton (or self-similar pulse) fiber lasers have attracted great attention due to their capabilities of highenergy pulse generation that could find different applications in science and industry. Moreover it is very important to reach stable pulse generation for the application as a frequency divider in optical frequency standard. Hybrid modelocking mechanism was used for obtaining stable similariton generation at 38 MHz pulse repetition frequency. It involves two types of mode-locking mechanisms in the cavity - saturation of carbon nanostructures absorber (recovery time Trt ~ 500 fs) and nonlinear polarization evolution based on the nonlinear Kerr-effect (Trt ~ 10 fs). It was shown that total intracavity dispersion should be slightly positive for generating stable similaritons with duration of less than 90 fs and spectral bandwidth of more than 50 nm at 11.2 mW output average power that could be further applied in an all-fiber MOPA setup.

Observation of cladding modes spatio-spectral distribution in large mode area photonic crystal fiber

We report the observation of spatio-spectral distribution in cladding modes of a single-mode large mode area photonic crystal fiber. The cladding modes excitation was achieved without any external fiber exposure. The optical field patterns of the cladding modes within different pump wavelength are investigated. To the best of knowledge the spatio- spectral distribution in cladding modes of large mode photonic crystal fiber is demonstrated for the first time. The results are of immediate interest in applications demanding devices based on core and cladding mode coupling in photonic crystal fibers.

Comb characterization of Erbium All-fiber Hybrid Mode-locked ultra-short pulse Ring laser for Frequency Metrology

Stable 92.6 fs dechirped self-similar pulses were obtained at 1560 nm with 11.2 mW average output power. Similariton laser has low repetition rate deviation at 1 - 103 s, a single comb linewidth of 110 kHz and high reliability, which makes it promising for further development of the stabilized comb.

Terahertz frequency standard

An idea of highly stable terahertz pulse train designing by transforming stabilized optical femtosecond pulses using photoconducting antenna is offered. Experimental data obtained with THz pulsed spectrometer were used for creating a numerical mathematical model of THz comb.

1 Watt, 59 % slope efficiency, 2.65 pm Cr 2+ :CdSe laser with tenability of 560 nm

We report the highest slope efficiency from a Cr²⁺:CdSe laser. The sample was multilayered dielectric coated with TaO<inf>2</inf> and SiO<inf>2</inf> to achieve this performance. The output beam was a diffraction limited TEM<inf>00</inf> gaussian mode.