Ytterbium-doped Fiber Amplifier Research Articles

20 THz-bandwidth continuous-wave fiber optical parametric amplifier operating at 1 µm using a dispersion-stabilized photonic crystal fiber

We report the experimental demonstration of a continuous-wave all-fiber optical parametric amplifier in the 1 µm band with a record bandwidth of more than 20 THz and a peak gain of almost 40 dB. This is achieved by using a photonic crystal fiber with a high figure of merit and strongly reduced longitudinal dispersion fluctuations. Due to their unique bandwidth and gain characteristics, fiber parametric amplifiers at 1 µm provide an interesting alternative to solid-state or ytterbium-doped fiber amplifiers for ultrafast optical pulse and signal processing.

High-power output of ytterbium-doped oxyorthosilicate lasers at 1018 nm

A high-power laser system at 1018 nm was realized with an ytterbium-doped oxyorthosilicate solid-state master oscillator and ytterbium-doped double-clad fiber amplifier. In the Yb:LSO (Yb:Lu2SiO5) and Yb:LYSO (Yb:LuYSiO5) master laser oscillator, we attained the broadest tunable wavelength range from 994.50 to 1094.22 nm. In the power amplifier, we achieved an output power up to 4.14 W at 1018 nm by amplifying the Yb:LSO laser under a pump power of 15.8 W.

All-Fiber Counter-Propagation Pumped Single Frequency Amplifier Stage With 300-W Output Power

We present a single frequency ytterbium-doped fiber amplifier, counter-propagation pumped with an all-fiber pump and signal combiner. The fiber combiner is capable of handling 440 W of pump power as well as the maximum achieved output power of 301 W. The threshold of stimulated Brillouin scattering of the high-power fiber amplifier was shifted from 175 to 280 W by external thermal management in combination with the pump-induced intrinsic temperature gradient.

20 W High-Power Picosecond Single-Walled Carbon Nanotube Based MOPA Laser System

Compact, high average output power with picosecond pulses laser was achieved through a carbon nanotube based master oscillator power amplifier, MOPA, configuration. The master oscillator was a single-walled carbon nanotube based passively mode-locked Nd:YVO4 laser. Then the ultrashort laser pulses from the master oscillator were amplified by a diode laser pumped ytterbium-doped fiber amplifier. The maximum average output power measured has been successfully achieved to be 20 W with a repetition rate of 82 MHz, and a pulse width of 15.7 ps. The pulse energy and peak power of the output laser were 244 nJ and 15.5 kW, respectively. The amplified spontaneous emission and stimulated Raman scattering were not observed.

Combined numerical model of laser rate equation and Ginzburg–Landau equation for ytterbium-doped fiber amplifier

We propose a combined model of the laser rate equation and the Ginzburg–Landau equation for simulation of the amplification of the ultrashort pulse in an ytterbium-doped fiber amplifier. An iterative procedure is designed for the repetition rate pulse sequence. The combined numerical model is compared with the pure dynamic rate equation for the amplification of a nanosecond single frequency pulse where both models are applicable. Good agreement is achieved. The combined model is then applied for the amplification of high repetition rate chirped pulse amplification in ytterbium-doped single-mode fiber. The slope efficiency, the wavelength shift, and the output spectrum width at different repetition rates are numerically investigated.

High power supercontinuum generation in a nonlinear ytterbium-doped fiber amplifier

High power supercontinuum generation with 70 W average output power in a nonlinear ytterbium-doped fiber amplifier is demonstrated using all-normal dispersion, all-fiber master oscillator power amplifier configuration. The supercontinuum covers from 1064 nm to beyond 1700 nm with spectral flatness better than 12 dB and 67.3% optical to optical conversion efficiency. The almost uniform spectral power density across the whole continuum is more than 70 mW/nm and the nanosecond bursts output have an effective peak power of 82.7 kW.

Hybrid Ytterbium-doped large-mode-area photonic crystal fiber amplifier for long wavelengths

A large-mode-area Ytterbium-doped photonic crystal fiber amplifier with build-in gain shaping is presented. The fiber cladding consists of a hexagonal lattice of air holes, where three rows are replaced with circular high-index inclusions. Seven missing air holes define the large-mode-area core. Light confinement is achieved by combined index and bandgap guiding, which allows for single-mode operation and gain shaping through distributed spectral filtering of amplified spontaneous emission. The fiber properties are ideal for amplification in the long wavelength regime of the Ytterbium gain spectrum above 1100 nm, and red shifting of the maximum gain to 1130 nm is demonstrated.

Polarization-maintaining amplification of phase modulated pulse employing ytterbium-doped single-mode fiber amplifier

Polarization-maintaining fiber amplifier using ytterbium-doped single-mode fiber (SMF) is proposed. A 45° Faraday rotator mirror (FRM) and a polarization independent fiber loop circulator (FLC) with polarization-maintaining fiber (PMF) pigtails are used to realize double-pass amplification and birefringence self-compensation. Arbitrary state of polarization (SOP) such as the linear polarization and elliptical polarization can be maintained. Polarization-maintaining amplification of phase modulated pulse with this amplifier is experimentally demonstrated while introducing little intensity modulation itself.

Maintaining the Polarization, Temperature and Amplification Characteristics of a Ytterbium-doped Rod-type Photonic Crystal Fiber (PCF) Amplifier

Maintaining the Polarization, Temperature and Amplification Characteristics of a Ytterbium-doped Rod-type Photonic Crystal Fiber (PCF) Amplifier

Thermo-optical effects in high-power Ytterbium-doped fiber amplifiers

We investigate the effect of temperature gradients in high-power Yb-doped fiber amplifiers by a numerical beam propagation model, which takes thermal effects into account in a self-consistent way. The thermally induced change in the refractive index of the fiber leads to a thermal lensing effect, which decreases the effective mode area. Furthermore, it is demonstrated that the thermal lensing effect may lead to effective multi-mode behavior, even in single-mode designs, which could possibly lead to degradation of the output beam quality.

Suppression of ASE by Using Pulsed-Pumped Technique in Fiber Amplifier

Implementation of pulsed-pump technique in fiber amplifier is highly useful in the situation of low repetition rate and high energy pulses operation. In this paper, the ASE (Amplified Spontaneous Emission) dynamics simulation in a pulsed-pumped ytterbium-doped double-clad fiber amplifier is presented for the first time, which provides important guidance about optimizing the pulsed-pump mode. The simulations of ASE dynamics are carried out by solving the rate equations and light power propagation equations in fiber using the finite elements analysis method, including variations of ASE output power at two terminals of the fiber in the time span from 0 ~ 740μs after pump light injection. Furthermore, a way of optimizing signal injection time is discussed.

All-fiber phase actuator based on an erbium-doped fiber amplifier for coherent beam combining at 1064 nm

Active phase control in fiber amplifiers is of considerable interest for low-noise single-frequency amplifiers and for coherent beam combining. We demonstrate phase control at 1064 nm by use of an erbium-doped fiber. We investigated the phase shift by guiding the beam through an erbium-doped fiber amplifier in a Mach-Zehnder configuration and applied the results to stabilize the relative phase of two ytterbium-doped fiber amplifiers. To the best of our knowledge, this is the first demonstration of an all-fiber coherent beam combining at 1064 nm employing an erbium-doped fiber as a phase actuator.

Megahertz OCT for ultrawide-field retinal imaging with a 1050nm Fourier domain mode-locked laser

We demonstrate ultrahigh speed swept source retinal OCT imaging using a Fourier domain mode locked (FDML) laser. The laser uses a combination of a semiconductor optical amplifier and an ytterbium doped fiber amplifier to provide more than 50 mW output power. The 1050 nm FDML laser uses standard telecom fiber for the km long delay line instead of two orders of magnitude more expensive real single mode fiber. We investigate the influence of this "oligo-mode" fiber on the FDML laser performance. Two design configurations with 684,400 and 1,368,700 axial scans per second are investigated, 25x and 50x faster than current commercial instruments and more than 4x faster than previous single spot ophthalmic results. These high speeds enable the acquisition of densely sampled ultrawide-field data sets of the retina within a few seconds. Ultrawide-field data consisting of 1900 x 1900 A-scans with ~70° angle of view are acquired within only 3 and 6 seconds using the different setups. Such OCT data sets, more than double as large as previously reported, are collapsed to a 4 megapixel high definition fundus image. We achieve good penetration into the choroid by hardware spectral shaping of the laser output. The axial resolution in tissue is 12 µm (684 kHz) and 19 µm (1.37 MHz). A series of new data processing and imaging extraction protocols, enabled by the ultrawide-field isotropic data sets, are presented. Dense isotropic sampling enables both, cross-sectional images along arbitrary coordinates and depth-resolved en-face fundus images. Additionally, we investigate how isotropic averaging compares to the averaging of cross-sections along the slow axis.

Experimental and theoretical studies on ytterbium sensitized erbium-doped fiber amplifier

The performance of a high power erbium–ytterbium doped fiber amplifier (EYDFA) is investigated experimentally and theoretically. The EYDFA provides a flat gain with an output power higher than 23 dBm in the wavelength region from 1541 to 1565 nm using a multimode pumping at 927 nm. In the theoretical analysis, the rate and power propagation equations are solved to examine the effect of fiber length on the bandwidth of the gain spectra. In the C-band region, the small signal gain of the EYDFA varies from 30 to 34 dB with 10 m long erbium–ytterbium doped fiber (EYDF) while the 927 nm pump power is fixed at 3.5 W. It is shown that the calculated output power is in good agreement with the experimental results, verifying the feasibility of our theoretical model. However, the experimental result shows a relatively lower gain compared to the theoretical result due to the spurious reflection in the cavity and the insertion loss of the EYDF which were neglected in our theoretical model.

Model of Temperature Dependence Shape of Ytterbium -doped Fiber Amplifier Operating at 915 nm Pumping Configuration

We numerically analyze the temperature dependence of an ytterbium-doped fiber amplifier (YDFA) operating at 915 nm, investigating its gain and Noise Figure properties variation with temperature. The temperature-dependent gain and noise figure variation with YDFA length are numerically obtained for the temperature range of +20 0C to +70 0C. The results show that good intrinsic output stability against temperature change can be achieved in ytterbium doped fiber amplifiers even when operating at high gain regime with small signal input. This result demonstrates the great potential for stable high power laser communication systems based on ytterbium system.

高功率单频线偏振掺镱全光纤放大器

We report an all-fiber high power, single frequency large-mode area (LMA) linearly polarized ytterbiumdoped fiber amplifiers (YDFA) module, which is based on the master oscillator multi-stage power amplifiers (MOPA). The maximum output power is 43.8 W at a wavelength of 1064 nm when 60-W launched pump light is coupled, with high slope efficiency of 88%, polarization extinction rate (PER) >17.2 dB and nearly diffraction-limited beam quality (M2<1.1).

脉冲泵浦的掺镱光纤放大器中放大自发辐射动态变化模拟

Implementation of pulsed-pump technique to fiber amplifier is significantly useful in the situation of low repetition rate and high energy pulses operating.The Amplified Spontaneous Emision(ASE) dynamics simulation in a pulsed-pumped ytterbium-doped double-clad fiber amplifier was presented,which provides important references about optimizing the pulsed-pump mode.By solving the rate equations and light power propagation equations in fiber using the finite elements analysis method,the simulations of ASE dynamics were carried out,including evolution of forward,backward ASE power distribution in the fiber and variations of ASE output power at two ends of the fiber in the time span from 0~740 μs after injection of pump light.Through the analysis of simulation results,the difference between forward and backward ASE powers increasing speeds and characteristics of the two kinds of ASE powers distributions dynamic in fiber were indicated.

高功率单频线偏振掺镱全光纤放大器

高功率单频线偏振掺镱全光纤放大器

All-fiber, high power single-frequency linearly polarized ytterbium-doped fiber amplifier

All-fiber, high power single-frequency linearly polarized ytterbium-doped fiber amplifier

单频保偏掺Yb光纤放大器中的受激布里渊散射实验研究

单频保偏掺Yb光纤放大器中的受激布里渊散射实验研究