Nicholas Traynor

Millijoule-class Yb-doped pulsed fiber laser operating at 977 nm

We report what we believe to be the first millijoule-class ytterbium-doped fiber laser system operating on the zero-phonon line at 977 nm. An actively Q-switched master fiber oscillator delivers nanosecond pulses (FWHM 12-32 ns) at adjustable multiples of 10 kHz repetition rates that are further amplified in an ultralarge core photonic crystal fiber amplifier. At the highest available pumping level, a maximal average power of 78 W was obtained for 32 ns pulses at a repetition rate of 190 kHz, whereas the millijoule energy level was reached for 12 ns pulses at the lower repetition rate of 10 kHz.

High-energy femtosecond fiber laser at 976 nm

We report on a passively mode-locked fiber laser emitting around 976nm. The self-starting mode locking is achieved in an unidirectional ring cavity by means of nonlinear polarization evolution. Stable single-pulse operation is observed for 480mW of average output power. This all-normal dispersion laser generates naturally chirped pulses with 1ps duration. The repetition rate is 40.6MHz, resulting in 12nJ pulse energy. External compression using bulk grating shortens the pulse duration down to 286fs.

High-power and low-intensity noise laser at 1064 nm

We have developed a single-frequency, narrow-linewidth (Δν<50u2009u2009kHz) laser operating at 1064xa0nm with a high output power (50xa0W). The laser is based on an ytterbium-doped fiber master oscillator power amplifier architecture with an output beam at the diffraction limit. An output power of 50xa0W is obtained with two amplification stages using a 50xa0mW diode laser seeder. We have carefully studied the relative intensity noise at each amplification stage. The detrimental effect due to stimulated Brillouin scattering on residual amplitude noise has been observed on the high-power booster stage. After careful optimization, this laser exhibits low intensity noise with a RMS value equal to 0.012% (1xa0kHz/10xa0MHz) at 50xa0W.

High Average Power, High Energy Fiber Laser System: Operation at 977 nm and Frequency Doubling at 488 nm

A pulsed fiber laser operating at 977 nm generating >0.75 mJ, 12 ns pulses at adjustable multi-10kHz of repetition rate is reported. Generation of 16 W of blue light by frequency conversion is also demonstrated.

Yb-doped fiber laser system generating 12-ns 0.7-mJ pulses at 82 kHz at 977 nm

We demonstrate an Ytterbium-doped fiber laser system generating high energy pulses at the non-conventional wavelength of 977 nm. An actively Q-switched master fiber oscillator delivers 1.2 W of average power in 12 ns pulses at 82 kHz of repetition rate. This pulsed fiber source is then amplified in an ultra-large core photonic crystal fiber amplifier up to 71 W. Deducing the fraction of power contained in interpulse ASE, we obtained 0.7 mJ pulses at 977 nm, resulting in a pulse peak-power of >55 kW. To the best to our knowledge, this system delivers the highest performances ever demonstrated in this spectral window.

Watt-level single-frequency tunable neodymium MOPA fiber laser operating at 915-937 nm

We have developed a Watt-level single-frequency tunable fiber laser in the 915-937 nm spectral window. The laser is based on a neodymium-doped fiber master oscillator power amplifier architecture, with two amplification stages using a 20 mW extended cavity diode laser as seed. The system output power is higher than 2 W from 921 to 933 nm, with a stability better than 1.4% and a low relative intensity noise.

200-W single frequency laser based on short active double clad tapered fiber

High power single frequency lasers are very attractive for a wide range of applications such as nonlinear conversion, gravitational wave sensing or atom trapping. Power scaling in single frequency regime is a challenging domain of research. In fact, nonlinear effect as stimulated Brillouin scattering (SBS) is the primary power limitation in single frequency amplifiers. To mitigate SBS, different well-known techniques has been improved. These techniques allow generation of several hundred of watts [1]. Large mode area (LMA) fibers, transverse acoustically tailored fibers [2], coherent beam combining and also tapered fiber [3] seem to be serious candidates to continue the power scaling. We have demonstrated the generation of stable 200W output power with nearly diffraction limited output, and narrow linewidth (Δν<30kHz) by using a tapered Yb-doped fiber which allow an adiabatic transition from a small purely single mode input to a large core output.

Gain dynamics and intensity noise suppression of a clad-pumped Yb-fiber amplifier

Low intensity noise laser sources are a fundamental prerequisite for demanding fundamental research such as interferometric gravitational-wave detection (GWD) [1], precision spectroscopy, LIDAR, and ultra-cold atom/molecular optical lattices. Besides, high power lasers with low intensity noise also attract great interest in the industry applications. Direct pump current control is the simplest method to suppress the laser intensity noise. However, the modulation of high current multi-mode pump diodes is not straightforward and achieving wide feedback control bandwidth beyond 200 kHz is challenging. For the laser sources used in GWD, the intensity noise could be suppressed down to −140 dBc/Hz (1 kHz-10 kHz) for an output power of 160 W. However, this approach requires a quite complex setup and the feedback bandwidth is limited to ∼10 kHz [1].

Single frequency, ultra-low noise, CW, 4W 488nm fiber laser

We have recently developed an industrial laser platform emitting in the non-conventional range around 976 nm. This 15 W continuous wave spatially single mode linearly polarized fiber laser can be forced to work in narrow line width or single frequency configuration. Its frequency doubling at 488 nm can be used to replace argon gas laser technology in many applications. We have studied the second harmonic generation of our source to verify its suitability with several industrial application needs in terms of efficiency, temporal stability and noise level.

Femtosecond fiber oscillator at 976 nm

We report on a passively mode-locked fiber laser emitting around 976 nm. The laser emits chirped pulses with a duration of 1.02 ps and 12 nJ at 40,7 MHz. External compression leads to pulses as short as 286 fs.