Mode-locked ytterbium-doped linear-cavity fiber laser operated at low repetition rate

Zhang, Ming; Chen, L.L.; Zhou, Chun; Cai, Yi; Ren, Lu; Zhang, Z.G.

doi:10.1002/lapl.200910047

Cited by 77 publications

(54 citation statements)

References 16 publications

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“…Schematic of extra-long mode-locked fibre laser: F2 -All-wave fibre, length of 2,6 km. New results obtained in the experiments (Kobtsev et al, 2008c) with relatively high energy of pulses directly in a passively mode-locked laser stimulated further investigations in this area Zhang et al, 2009;Lin et al, 2011;Song et al, 2011;Ai et al, 2011;Kobtsev et al, 2009;Senoo et al, 2010;Kelleher et al, 2009;L. Chen et al, 2009;Nyushkov et al, 2010;Kobtsev et al, 2010a;Ivanenko et al, 2010).…”

Section: Review Of Recent Progress In Mode-locked Fibre Lasers With Hmentioning

confidence: 98%

Mode-Locked Fibre Lasers with High-Energy Pulses

Smirnov¹,

Kobtsev²,

Kukarin³

et al. 2011

Laser Systems for Applications

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Section: Review Of Recent Progress In Mode-locked Fibre Lasers With Hmentioning

confidence: 98%

Mode-Locked Fibre Lasers with High-Energy Pulses

Smirnov¹,

Kobtsev²,

Kukarin³

et al. 2011

Laser Systems for Applications

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“…The next level was achieved in the breakthrough works [5,6] in mode-lock fibre lasers with a several km cavities. Other examples of passive mode locking in fibre lasers with > 1 km resonators have been demonstrated in the subsequent works [7][8][9][10][11][12]. Such a dramatic elongation of the laser resonator led to more than two orders of magnitude increase in the output pulse energy at the same pump power.…”

mentioning

confidence: 86%

Mode-locking in 25-km fibre laser

Ivanenko

Turitsyn

Kobsev

et al. 2010

36th European Conference and Exhibition on Optical Communication

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We demonstrate passive mode-locking and single pulse generation in a fibre laser with a record-setting cavity length of 25 km. Substantial increase in the pulse round trip duration leads to ultra-low repetition rate of 8.097 kHz and the pulse energy of 3.7 µJ.PACS numbers: 42.55. Wd, 42.60.Fc, 42.60.Da, 42.60.By Nowadays, lasers have become ubiquitous devices equally important in fundamental science, engineering technologies and in a range of practical applications. In the last decade there has been a revolutionary progress in laser science fuelled by advances in high-power systems, ultra-short pulse lasers and oscillators with high pulse energy. The progress was driven by a variety of new important applications that these advanced laser systems can open-up. This expansion has been facilitated by continuous advances in material science, achievements in technology and by the improvement in our understanding of the fundamental laser principles and physical effects underlying the operation and performance of new types of lasers. In particular, laser designs based on new physical concepts offer opportunities for creating systems with non-incremental changes of performance characteristics leading to disruptive progress. In this work we outline a new direction in development of pulsed lasers, by demonstrating a dramatic increase of the cavity length for modelocking fibre lasers to a record 25 km which corresponds to the cavity optical length of 37.05 km. Our result provides insight in design possibilities which may allow for non-incremental progress in laser technology by pulse energy up-scaling using very long cavities.The length of the resonator is, indeed, an important design parameter in mode-locked laser being responsible for repetition rate of generated pulses and their per-pulse energy. Higher per-pulse energy p E of the output in mode-locked lasers (at the same average power ave P of radiation) may be achieved by direct extension of the laser cavity, since(c is the speed of light, n-refractive index) -pulse energy is directly proportional to cavity length L and round trip time R T , while the repetition rate is inversely proportional to the resonator length. For a range of laser applications in material processing a high pulse energy or respectively high peak intensity is required. Different techniques such as Q-switching, cavity dumping and optical amplification are currently used to generate high energy pulses. One of the important physical and technical challenges in laser science is to achieve high pulse energy in mode-locked lasers to provide tools for a variety of applications ranging from material processing to advanced bio-medical imaging. Compared to Q-switching and cavity dumping techniques, mode-locked lasers allow a post-compression of output pulses, making possible generation of ultrashort optical pulses with high energy.Drastic increase of the laser cavity can be implemented using a fibre waveguide. In the case of CW fibre lasers, it has been recently demonstrated that resolvable reso...

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“…The ring cavity configuration is similar to [12][13][14] and the linear cavity is similar to [15,16], except that the end mirror was replaced by a narrow band fiber Bragg grating, for setting up the wavelength at 1064.4 nm. Figure 6 shows both pulse spectra at mode locking in the two fiber lasers.…”

Section: Laser Experimentsmentioning

confidence: 99%

Broadband SESAM for mode locked Yb:fiber lasers

Zhang

Wang

et al. 2011

Chin. Sci. Bull.

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We report a semiconductor saturable absorber mirror (SESAM) with phase shift compensation. The SESAM shows a uniform low-intensity reflectivity and a modulation depth up to 12% for the wavelength from 1000 to 1100 nm. A linear cavity all-normal dispersion Yb-doped fiber laser has proved its mode locking performance for the wavelength of both 1030 nm and 1064 nm. As the demand for highly reliable passively mode-locked fiber lasers is increasing, highly reliable SESAMs become important. Unlike in solid-state lasers, mode locking in fiber lasers requires a high modulation depth. A simple solution to the high modulation depth is to increase the absorption layer thickness. However, there are two issues in the SESAMs in doing such way: the large variation in the reflectivity and the possible optical damage on the SESAMs. A thick absorption layer introduces a large phase shift that results in a modulation over the reflection band of the Bragg mirror [4,5], due to the imaginary part of the refractive index of the absorption material. The high absorption may also cause a high saturation fluence, which is the origin of the optical damage. YbTo avoid the optical damage on the SESAM, Grange et al. [6] realized that a low the saturation fluence is the key solution for the damage since the low saturation fluence *Corresponding author (email: zhgzhang@pku.edu.cn) ensures the laser mode locking at relatively lower fluence, so that it never exceeds the damage threshold. They demonstrated that a thin layer can also show a relatively high modulation depth but with a saturation fluence as low as 1.1 μJ/cm 2 [7]. The key point is to locate the absorption layer in the maximum electric field, as well as to apply an anti-reflection coating to enhance the field.However, there has not been a solution reported for the thick absorption layer. The commercially available SESAMs with high modulation depth basically have a non-uniform low-intensity reflectivity with respect to wavelength, and a high saturation fluence (>50 μJ/cm 2 ). In this paper, we propose a phase shift compensated high modulation depth design of SESAM and demonstrate the uniform low intensity reflectivity and low saturation fluence. This SESAM has been verified in mode locking of a linear cavity all-normal dispersion Yb-doped fiber laser both in 1030 nm and 1064 nm, respectively [8,9].

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Mode-locked ytterbium-doped linear-cavity fiber laser operated at low repetition rate

Cited by 77 publications

References 16 publications

Mode-Locked Fibre Lasers with High-Energy Pulses

Mode-Locked Fibre Lasers with High-Energy Pulses

Mode-locking in 25-km fibre laser

Broadband SESAM for mode locked Yb:fiber lasers

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