Fiber-coupled Diode Laser Module Research Articles

1342 nm 2.8ns electro-optical cavity damping Nd: YVO<sub>4</sub> laser

1.3 μm Nd laser has significant practical applications in various fields, such as fiber communication, medical treatment, frequency conversion, and scientific research, etc. Many applications of a 1.3 μm laser, especially like frequency conversion, benefit much from a short pulse width with high peak power. In the paper, an electro-optical cavity dumping Nd:YVO<sub>4</sub> laser at 1342 nm wavelength has been studied theoretically and experimentally. The pulse width for an electro-optical cavity dumping laser is determined by the optical length of the cavity. A narrower pulse width can be obtained by reducing the length of the cavity and the round trip time of the laser in the cavity. However, when the round trip time in the cavity approaches to the falling edge time of the electro-optical switch, shortening the length of the cavity will not get a narrower pulse width, and the falling edge time of the electro-optical switch will influence the laser pulse width. The temporal characteristics of the laser pulse are simulated when the falling edge time of the electro-optical switch is close to the round trip time in the cavity. Influences of the falling edge time of the electro-optical switch on the laser pulse duration are analyzed theoretically. The modified rate equation is used to study the relationship between the falling edge time and the laser pulse width. We demonstrate an electro-optical cavity dumping Nd:YVO<sub>4</sub> laser. The 0.3 at.% Nd:YVO<sub>4</sub> placed in a short Plano-concave cavity is in-band pumped by an 880 nm quasi-continuous-wave diode. A fiber-coupled diode laser module (NA=0.22) with a power of 30 W was used. A LiNbO<sub>3</sub> electro-optical switch was employed for the cavity-dumping. The 1342 nm cavity-dumping laser operates at a repetition rate of 1kHz, and a single-pulse energy of 0.21 mJ is obtained with a pulse width of 2.8 ns. Near-diffraction-limited beam quality with an M<sup>2</sup> value of < l.2 is achieved. The setup provides efficient second harmonic generation at 671 nm using a MgO:PPLN crystal, and the pulse width is 1.8 ns. To the best of our knowledge, this is the shortest pulse duration obtained from 1.3μm actively Q-switched Nd-doped laser.

Cladding-pumped, Yb:YAG-core, fiber-like waveguide laser: modeling and experiment.

We developed a model describing the performance of the cladding-pumped, Yb:YAG-core, fiber-like waveguide laser with a large cladding-to-core area ratio. We analyzed how pump absorption and laser output efficiencies depend on the Yb-doping level as well as the waveguide parameters, such as clad-to-core area ratio and waveguide length. We also determined the conditions that maximize both pump and laser efficiency. We showed that, depending on the waveguide design, cavity parameters as well as the core temperature, this laser can operate either at 1030 or 1050 nm. We have also shown that the main factor limiting power scaling of such a waveguide laser is the core temperature. The model was validated by laser experiments with a 174 mm long, double-clad, Yb(20%):YAG-core waveguide, with the cladding-to-core area ratio of 43.4. An output power of 41.6 W and slope efficiency of 73% with respect to the absorbed pump power have been achieved with cladding pumping by a fiber-coupled laser diode module at 933 nm. Our experimental results were in a good agreement with the modeling predictions.

三波长合束单管激光器光纤耦合模块设计

三波长合束单管激光器光纤耦合模块设计

Tm-doped fiber laser resonantly diode-cladding-pumped at 1620 nm

We report the first demonstration of an efficient, high power, resonantly (in-band) diode-cladding-pumped Tm-doped fiber laser operating on the 3F4 ⇒ 3H6 transition of Tm3+ ion. The laser, pumped by a fiber coupled laser diode module at ~1620 nm, delivered ~15 W of power at 1930 nm with a slope efficiency of 67% versus the absorbed pump power. This presents, to the best of our knowledge, the highest slope efficiency and the highest output power reported so far for resonantly diode-cladding-pumped 2 µm fiber lasers based on double-clad Tm-doped silica fibers. These very preliminary results, obtained with commercial double-clad Tm-doped fibers, unoptimized for in-band pumping at the peak of resonant absorption, indicate a very high potential of resonantly diode-cladding-pumped Tm fiber lasers for major power scaling unaffected by photodarkening. Fiber optimization for resonant pumping at the maximum of the Tm3+ 3H6 ⇒ 3F4 absorption band in silica (1610–1710 nm) can lead to a new generation of Tm fiber lasers with power and wall-plug efficiency, competing with those of high power tandem-pumped Tm-doped fiber lasers, but potentially with a lighter weight and smaller dimensions.

Design of 20 W fiber-coupled green laser diode by Zemax**Project supported by the National Key R& D Program of China (No. 2016YFB0402105), the Key Deployment Program of the Chinese Academy of Sciences (No. KGZD-SW-T01-2), and the National Natural Science Foundation of China (No. 61404135).

We represent a design of a 20 W, fiber-coupled diode laser module based on 26 single emitters at 520 nm. The module can produce more than 20 W output power from a standard fiber with core diameter of 400 μm and numerical aperture (NA) of 0.22. To achieve a 20 W laser beam, the spatial beam combination and polarization beam combination by polarization beam splitter are used to combine output of 26 single emitters into a single beam, and then an aspheric lens is used to couple the combined beam into an optical fiber. The simulation shows that the total coupling efficiency is more than 95%.

110 W高功率高亮度915 nm 半导体激光器光纤耦合模块研究

110 W高功率高亮度915 nm 半导体激光器光纤耦合模块研究

High pulse repetition frequency fiber-coupled laser-diode module

A practical and simple approach of achieving a high pulse repetition frequency fiber-coupled laser-diode device is demonstrated both by experiment and TRACEPRO software simulation, which is obtained by beam collimating, spatial beam combining, and polarization beam combining based on multiple cycle-emitting pulsed laser-diode emitters. Using this method, fiber-coupled laser-diode module output pulse repetition frequency from the multimode fiber with 200-μm core diameter and 0.22 numerical aperture can reach 300 kHz, and the coupling efficiency is beyond 72%. This technique has superiors of great flexibility, low cost, and high reliability for wide applications.

High brightness laser-diode device emitting 500 W from a 200 μm/NA0.22 fiber

A practical method of achieving high brightness and high power fiber-coupled laser-diode device is demonstrated both by experiment and ZEMAX software simulation, which is obtained by technologies of precision beam collimation, free space beam combining and polarization beam combining based on mini-bar diode laser chip. Using this method, fiber-coupled laser-diode module output power from the multimode fiber with 200μm core diameter and 0.22 numerical aperture (NA) could reach 528W, equalizing brightness is 11.0MW/(cm2sr) and electro-optical efficiency (defined as fiber output power divided by voltage and current of the module) is 43.0%. By this method, much wider applications of fiber-coupled laser-diode are anticipated.

High brightness laser-diode device emitting 160 watts from a 100 μm/NA 0.22 fiber.

A practical method of achieving a high-brightness and high-power fiber-coupled laser-diode device is demonstrated both by experiment and ZEMAX software simulation, which is obtained by a beam transformation system, free-space beam combining, and polarization beam combining based on a mini-bar laser-diode chip. Using this method, fiber-coupled laser-diode module output power from the multimode fiber with 100 μm core diameter and 0.22 numerical aperture (NA) could reach 174 W, with equalizing brightness of 14.2 MW/(cm2·sr). By this method, much wider applications of fiber-coupled laser-diodes are anticipated.

Beam shaping design for compact and high-brightness fiber-coupled laser-diode system.

Fiber-coupled laser diodes have become essential sources for fiber laser pumping and direct energy applications. A compact and high-brightness fiber-coupled system has been designed based on a significant beam shaping method. The laser-diode stack consists of eight mini-bars and is effectively coupled into a standard 100μm core diameter and NA=0.22 fiber. The simulative result indicates that the module will have an output power over 440W. Using this technique, compactness and high-brightness production of a fiber-coupled laser-diode module is possible.

High power high efficiency fiber coupled diode laser module

The high coupling-efficiency fiber coupled diode laser module is obtained by beam shaping. The wavelength of the CW diode laser bar is 976 nm, and five bars are collimated by a fast axis collimation lens. Then the beams are transformed and collimated by slow axis collimation optics. Then all the beams are combined in space, and focused into a multimode fiber (400 m core diameter, the numerical aperture (NA) is 0.22). Experimental results show that the laser output from fiber could reach 327 W, and the coupling-efficiency is more than 93.6%. Experimental results demonstrate that this module lays a foundation for multi-wavelength, polarization beam combining and the high beam quality, high coupling efficiency diode laser module with CW thousands watts class output power can be developed.

High brightness beam shaping and fiber coupling of laser-diode bars.

The strong beam quality mismatch in the fast and slow axes of laser-diode bars requires a significant beam shaping method to reach the parameters needed for fiber coupling. An effective solution to this problem is proposed that is based on a right-angle prism array and a distributed cylinder-lens stack. Coupling 12 mini-bars into a standard 100μm core diameter and 0.15 numerical aperture fiber is achieved, and the output power can reach 400W. Using this technique, production of compact and high brightness fiber-coupled laser-diode modules is possible.

高功率高效率光纤耦合半导体激光模块研制

高功率高效率光纤耦合半导体激光模块研制

200W级高亮度半导体激光器光纤耦合模块

200W级高亮度半导体激光器光纤耦合模块

A continuous wave Yb:KGW laser with polarization-independent pump absorption

A polarization-independent pumping scheme for an end-pumped Yb:KGd(WO4)2 laser oscillator is proposed. It enables the use of compact, high power and high brightness fiber-coupled laser diode modules as pump sources and results in reduced thermal effects, good beam quality and improved output power stability. Based on this design, a continuous wave Yb:KGW laser with polarization-independent pump scheme is demonstrated. The laser delivered 2 W of average output power in TEM00 mode at 1040 nm. The induced thermal lens is reduced by a factor of 2 when compared to conventional diode pumping schemes, which clearly demonstrates the potential of the geometry of this crystal for power scaling.

High‐Brilliance, Fiber‐Coupled, Turn‐Key Diode Laser System

AbstractBased on an optimized chip design suitable for efficient fiber coupling, socalled tailored mini‐bars, DILAS has introduced a new platform of fiber‐coupled diode laser modules. In the following, we describe the basic ideas of the concept, together with the integration of such fiber‐coupled diode laser modules into a new series of turn‐key diode laser systems.

百瓦级高亮度光纤耦合半导体激光模块的研制

Three 976 nm diode laser short bars were used as submodule to manufacture high brightness fiber coupled module with CW hundred watts class output power.First,beam transform systems were employed to shape beams emitted from each submodlue;Second,the three beams were stacked in direction of lower beam parameter product by means of spatial multiplexing technology;Finally,the laser was focused into a multimode fiber with 200 μm core diameter and NA=0.22 by optimized lens.Experiment result showed that divergence angle of the focused laser beam was 24.8° and its beam waist diameter was 175.2 μm;laser output from fiber could reach to 107 W,equalizing brightness of 2.23 MW/(cm2·sr),which is a higher level in China.Furthermore,the wall plug efficiency is 43.1% when driving current is 52.5 A,which is far higher than that of solid state laser.Finally the thermal resistance was computed by means of measuring spectrum with different current and the result is 1.29 K/W which indicates favorable heat dissipation of the module.All of the result showed that the module can be used in the field of pumping fiber lasers,medical,material processing and so on.

Focus on lasers and imaging

Focus on lasers and imaging

880 nm半导体激光主动照明光纤耦合模块

880 nm半导体激光主动照明光纤耦合模块

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal. With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457 nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the output power is better than 1.2% for 8 h continuously working.