Q-switching an all-fiber laser using acousto-optic null coupler

Berg, Yuval; Goldring, Sharone; Pearl, Shaul; Arie, Ady

doi:10.1007/s00340-013-5351-3

Cited by 1 publication

(5 citation statements)

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“…The transmission characteristics of the null coupler with and without the activation of the PZT was measured and found similar to the ones reported by Berg et al [11]. 15 % transmission under the PZT activation was measured, while ~40 dB isolation was measured between the output ports without activating the PZT.…”

Section: Oscillator Experimental Setupmentioning

confidence: 92%

“…Operating the null coupler at 1 µm as compared to the previous work at 1.5 µm [11] imposes some changes upon the null coupler design. The coupler should be constructed from single mode fibers at ~1 µm.…”

Section: Theory: Principles Of Null Coupler Switchmentioning

confidence: 97%

“…The coupler should be adiabatically tapered with respect to 1 µm. In addition, if the coupler's waist is to be approximately with the same diameter as in the one designed for 1.5 µm (~20 µm) [11], the acoustic frequency should matched to the mode propagation constants associated with 1 µm.…”

Section: Theory: Principles Of Null Coupler Switchmentioning

confidence: 99%

“…In order to induce acoustic waves on the null coupler, a PZT was attached to the null coupler out of the coupling zone, at the large-diameter fiber's section, as described in a previous work of Ref. [11]. The overall cavity length, including the active fiber and peripheral components, is 7.5 m. The PZT was driven by an Agilent 33522A function generator at various pulse repletion rates (PRR), ranging from 10 to 35 kHz.…”

Section: Oscillator Experimental Setupmentioning

confidence: 99%

“…In Berg et al's work [11], the null coupler was used as an active Q-switching element for the 1.55-µm ring laser. A piezoelectric transducer (PZT) was attached to the fused fibers of the null coupler.…”

Section: Introductionmentioning

confidence: 99%

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A robust all-fiber active Q-switched 1-µm Yb3+ fiber laser

et al. 2015

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traditional bulk lasers in their compactness, lightweight, high efficiency, beam stability and low price.However, most of the Q-switched fiber lasers are based on a master oscillator power amplifier (MOPA), which is composed of a Q-switched oscillator and a subsequent fiber amplifier; both are mainly based on Yb 3+ -doped fibers.One of the main obstacles in increasing the robustness and reducing the price of pulsed fiber lasers is the Q-switch element, embedded in the fiber laser oscillator. This element is usually a free space-based acousto-optic or electro-optic modulator. In case of an acousto-optic modulator (AOM) [1], the device requires high-power radio frequency (RF) sources and an optical bench for holding the free space optical elements in front of the oscillator's fiber tips, in order to allow efficient optical coupling between the fiber oscillator and the free space AO deflector. In case of an electro-optic modulator (EOM) [2], the same holding and optical coupling requirements apply, as in the AOM case. In addition, high voltage in the order of several kilovolts is required for operating the EOM, which poses additional isolation and safety requirements.During the last two decades, all-fiber Q-switched fiber lasers were demonstrated using an acoustically modulated long-period fiber grating attenuator [3,4], Bragg mirrors modulation [5, 6], stress-induced polarization modulation [7-9] and passive all-fiber saturable absorber [10]. However, presently available 1-µm Q-switched fiber lasers do not benefit from these technologies due to various reasons, among which are the stability of the components over time, their robustness and suitability to the 1-µm wavelength range.Another technique for Q-switching of 1.55-µm fiber lasers has been presented by Berg et al. [11]. This technique makes use of a null coupler incorporated into a ring Yb:Er fiber laser. The idea of incorporating null coupler for inducing an acoustic long-period grating (LPG) inside a ring Abstract An all-fiber active Q-switched Yb 3+ -doped fiber laser at 1 µm is presented. The laser is composed of a ring resonator with an embedded all-fiber Q-switch element, based on a null coupler with an attached piezoelectric transducer (PZT). The PZT is used as an acoustic actuator, for inducing longitudinal acoustic disturbance along the null coupler and causing light coupling between the null coupler's ports. A stable operation is achieved with an overall average output power of up to 275 mW at various pulse repetition rates (PRR), ranging from 10 to 35 kHz and typical pulse energy of 15 μJ. In addition, a self-monitoring method is implemented by an embedded microcontroller, in order to maintain stable Q-switch performance, in changing environmental conditions. An average power of 8.5 W and pulse energy of 420 μJ at a PRR of 20 kHz are demonstrated in a master oscillator power amplifier containing the Q-switched laser, followed by a power amplifier.

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Section: Oscillator Experimental Setupmentioning

confidence: 92%

Section: Theory: Principles Of Null Coupler Switchmentioning

confidence: 97%

Section: Theory: Principles Of Null Coupler Switchmentioning

confidence: 99%

Section: Oscillator Experimental Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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