Alexander A. Krylov

Thulium-doped mode-locked all-fiber laser based on NALM and carbon nanotube saturable absorber.

We report on a thulium-doped fiber laser mode-locked with a carboxymetylcellulose high-optical quality film with dispersed single-walled carbon nanotubes. Laser system based on the nonlinear amplifying loop mirror generates 450 fs pulses with 18 mW maximum average power.

Nonlinear Amplifying Loop-Mirror-Based Mode-Locked Thulium-Doped Fiber Laser

We present an SESAM mode-locked thulium-doped fiber laser incorporating nonlinear amplifying loop mirror with intracavity and external group velocity dispersion control, which generates sub-300-fs near-transform-limited pulses at 1920-nm wavelength, with 106-mW maximum average output power. The dispersion control was realized by implementing a low-loss highly doped germanium silica fiber.

SESAM and SWCNT Mode-Locked All-Fiber Thulium-Doped Lasers Based on the Nonlinear Amplifying Loop Mirror

We report on thulium-doped all-fiber lasers based on the nonlinear amplifying loop mirror and mode-locked with a semiconductor saturable absorber (SESAM) or single-walled carbon nanotubes (SWCNTs). An intracavity and external dispersion management was realized with the aid of a passive germanium-silicate fiber. The SESAM mode-locked laser generates as short as 230-fs pulses with a maximum average output power of 106 mW, corresponding to a 3.7 kW peak power and almost 2 nJ pulse energy. In contrast to the SESAM-based laser, the SWCNT mode-locked laser generates 450-fs pulses of mW-level average output power.

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.

Higher-Order Soliton Generation in Hybrid Mode-Locked Thulium-Doped Fiber Ring Laser

A thulium-doped all-fiber laser passively mode-locked by the co-action of nonlinear polarization evolution and single-walled carbon nanotubes operating at 1860-1980 nm wavelength band is demonstrated. Pumped with the single-mode laser diode at 1.55 μm laser generates near 500-fs soliton pulses at repetition rate ranging from 6.3 to 72.5 MHz in single-pulse operation regime. Having 3-m long cavity average output power reached 300 mW, giving the peak power of 4.88 kW and the pulse energy of 2.93 nJ with slope efficiency higher than 30%. At a 21.6-m long ring cavity average output power of 117 mW is obtained, corresponding to the pulse energy up to 10.87 nJ and a pulse peak power of 21.7 kW, leading to the higher-order soliton generation.

Transform-limited pulse generation in normal cavity dispersion erbium doped single-walled carbon nanotubes mode-locked fiber ring laser

We demonstrate an erbium doped fiber ring laser mode-locked with a carboxymetylcellulose high-optical quality film with dispersed single-walled carbon nanotubes (SWCNT). The laser with large normal net cavity dispersion generates near bandwidth-limited picosecond inverse modified soliton pulses at 1.56 µm.

Performance peculiarities of carbon-nanotube-based thin-film saturable absorbers for erbium fiber laser mode-locking

We have studied the saturation behavior of single-walled carbon-nanotube-based saturable absorbers (SWCNT-SAs) at different temperatures and SWCNT concentrations in the polymer matrix and tried to relate it to the mode-locked erbium-doped fiber laser performance. It has been observed that a modulation depth of SWCNT-SA transmission which we relate to the ground state recovery time monotonically decreases upon temperature growth. Comparing laser performance with different SWCNT-SAs, we suppose that the defects in the CNT lattice promote recovery acceleration resulting in shorter pulse generation as obtained for boron-nitride-doped SWCNTs. Moreover, for the first time, to the best of our knowledge, we have observed and studied the long-term relaxation of SWCNT-SA saturated transmission exhibiting temperature-dependent behavior.

Hybrid mode-locked erbium-doped all-fiber soliton laser with a distributed polarizer

A soliton-type erbium-doped all-fiber ring laser hybrid mode-locked with a co-action of arc-discharge single-walled carbon nanotubes (SWCNTs) and nonlinear polarization evolution (NPE) is demonstrated. For the first time, to the best of our knowledge, boron nitride-doped SWCNTs were used as a saturable absorber for passive mode-locking initiation. Moreover, the NPE was introduced through the implementation of the short-segment polarizing fiber. Owing to the NPE action in the laser cavity, significant pulse length shortening as well as pulse stability improvement were observed as compared with a SWCNTs-only mode-locked laser. The shortest achieved pulse width of near transform-limited solitons was 222 fs at the output average power of 9.1 mW and 45.5 MHz repetition frequency, corresponding to the 0.17 nJ pulse energy.

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.

Hybrid mode-locked ultrashort-pulse erbium-doped fiber laser

One of the implementations of fs-laser with CNT-film for mode-locking is considered. Scheme of single-pulse, self-starting, stable mode-locked laser generation by appropriate polarization controllers adjustment is suggested. The mechanism of cavity length stabilization for a femtosecond fiber laser based on the pump source modulation is considered. Bandwidth of the feedback frequency stabilization system based on pump source modulation method is defined.