High Power Yb Fiber Laser With Picosecond Bursts and the Quasi-Synchronously Pumping for Efficient Midinfrared Laser Generation in Optical Parametric Oscillator

Abstract

A fiber laser-pumped high-power burst-mode-operated picosecond midinfrared (IR) laser at 3.8 m is reported. A gain-switched distributed Bragg reflector laser diode with a pulse repetition rate (PRR) of 138 MHz and pulse duration around 200 ps was applied as the seed laser of a master oscillator power amplifier (MOPA)-structured Yb fiber laser. The PRR of the MOPA was increased to about 1.1 GHz through a pulse multiplier consisting of four cascaded 2 Â 2 fiber couplers. A fiberpigtailed acousto-optic modulator was used to carve the pulse train into pulse bursts so that the peak power of the final linearly polarized fiber laser output could be optimized by adjusting the duty cycle of the pulse bursts correspondingly. The output of the fiber laser was directed to pump a periodically poled magnesium-oxide-doped lithium niobate-based optical parametric oscillator through the quasi-synchronized pump scheme. Efficient parametric conversion was realized with a maximum average power output of 7.3 W at 3.8 m under pump power of 45 W at 1.064 m with pump-to-idler conversion efficiency exceeding 16%.Index Terms: Optical fiber lasers, optical parametric oscillators (OPOs), periodically poled magnesium-oxide-doped lithium niobate (PPMgLN), quasi-synchronously pumping.

Review of advanced progress of χ2-based all-optical devices on thin-film lithium niobate

“…Meanwhile, the parametric light becomes oscillated and highly constrained due to the introduction of the PPLN thin film-based resonant cavity. Hence, the equivalent intensity of oscillation in the cavity can be increased hundreds of times, which greatly reduces the threshold power (∼microwatt) as compared with crystal OPO (∼milliwatt and watt) [108][109][110][111][112] . In order to reduce the threshold in the resonators, the standard method is to improve the Q-factor when the optical loss and the optical gain are balanced.…”

Compact narrow bandwidth, linearly polarized burst-mode fiber amplifier with high burst energy of 1 mJ

“…Burst-mode operation is an interesting alternative, where the laser system produces a group of highrepetition-rate pulses at a much lower repetition rate. Benefiting from the special compound mode of the pulses, burst-mode ultrashort fiber lasers have been widely used in many applications, such as combustion diagnostics [4], flow measurements in aerodynamics [5], Thomson scattering experiments [6], photoacoustic microscopy [7], ablation-cooled material removal [8,9], mid-infrared optical parametric oscillators (OPOs) [10] and laser deposition [11].…”

“…Besides external active modulation and direct seed modulation, the burst-mode operation can also be achieved by using frequency multiplier component (cascaded 3 dB fiber output couplers (OCs)) [18]. Compared to the lower repetition rate of the intraburst pulses, higher repetition rate GHz-level burstmode fiber laser possesses many more advantages and is thus more suitable to be the laser source for an ablation-cooled laser material removal system [19][20][21] and the pump laser of a compact linear-cavity mid-infrared OPO [10]. In order to increase the intraburst pulse repetition rate to GHz-level, the frequency multiplier component could be used in burst-mode fiber laser systems [18].…”