Mr. Haro Fritsche Profile

Mr. Haro Fritsche

Product Line Manager at DirectPhotonics Industries GmbH

SPIE Involvement:

Author

Websites:

Company Website

Publications (17)

PROCEEDINGS ARTICLE | February 22, 2017

Diode lasers for direct application by utilizing a trepanning optic for remote oscillation welding of aluminum and copper

Proc. SPIE. 10097, High-Power Laser Materials Processing: Applications, Diagnostics, and Systems VI

KEYWORDS: Continuous wave operation, Copper, Materials processing, Free space, Semiconductor lasers, Collimation, Aluminum, Free space optics, Fiber coupled lasers, Laser systems engineering

Read Abstract

We report the first direct diode laser module integrated with a trepanning optic for remote oscillation welding. The trepanning optic is assembled with a collimated DirectProcess 900 laser engine. This modular laser is based on single emitters and beam combiners to achieve fiber coupled modules with a beam parameter product or BPP < 8 mm mrad at all power levels up to 1 kW, as well as free space collimated outputs with even lower BPP. The initial design consists in vertically stacking several diodes in the fast axis which leads to a rectangular output of about 100 W with BPP of <3.5 mm*mrad in the fast axis and <5 mm*mrad in the slow axis. Next, further power scaling is accomplished by polarization combining and wavelength multiplexing yielding high optical efficiencies of more than 80% and resulting in a building block module with over 500 W launched into a 100 μm fiber with 0.15 NA. The beam profile of the free space module remains rectangular, with a nearly flat top and conserves the beam parameter product of the original vertical stack without the power loss of fiber coupling. The 500 W building blocks feature a highly flexible emitting wavelength bandwidth. New wavelengths can be configured by simply exchanging parts and without modifying the production process. This design principle provides the option to adapt the wavelength configuration to match a broad set of applications, from the UV to the visible and to the far IR depending on the commercial availability of laser diodes. This opens numerous additional applications like laser pumping, scientific and medical applications, as well as materials processing applications such as cutting and welding of copper aluminum or steel. Furthermore, the module’s short lead lengths enable very short pulses. Integrated with electronics, the module’s pulse width can be adjusted from micro-seconds to cw mode operation by simple software commands. An optical setup can be directly attached instead of a fiber to the laser module thanks to its modular design. This paper’s experimental results are based on a trepanning optic attached to the laser module. Alltogether the setup approximately fits in a shoe box and weighs less than 20 kg which allows for direct mounting onto a 3D-gantry system. The oscillating weld performance of the 500 W direct diode laser utilizing a novel trepanning optic is discussed for its application to aluminum/aluminum and aluminum/copper joints.

PROCEEDINGS ARTICLE | January 13, 2017

High power diode and solid state lasers

Proc. SPIE. 10254, XXI International Symposium on High Power Laser Systems and Applications 2016

KEYWORDS: Laser vision correction, High power lasers, Laser processing, Laser development, Solid state lasers, Fiber lasers, Semiconductor lasers, Gas lasers, Diodes, Diode pumped solid state lasers

Read Abstract

PROCEEDINGS ARTICLE | March 16, 2016

Comparative study of broadband, narrowband and multi-wavelength resonant pumping of Er:YAG lasers

Proc. SPIE. 9726, Solid State Lasers XXV: Technology and Devices

KEYWORDS: Methane, Crystals, Solid state lasers, Multiplexing, Semiconductor lasers, Diodes, Er:YAG lasers, Laser crystals, Laser systems engineering, Absorption

Read Abstract

PROCEEDINGS ARTICLE | March 4, 2016

Building block diode laser concept for high brightness laser output in the kW range and its applications

Proc. SPIE. 9733, High-Power Diode Laser Technology and Applications XIV

KEYWORDS: Optical filters, Electronics, Polarization, Lenses, High power lasers, Laser applications, Laser development, Multiplexing, Control systems, Fiber lasers, Semiconductor lasers, Buildings, Collimation, Diodes, Laser cutting, Laser systems engineering

Read Abstract

The modular concept of DirectPhotonics laser systems is a big advantage regarding its manufacturability, serviceability as well as reproducibility. By sticking to identical base components an economic production allows to serve as many applications as possible while keeping the product variations minimal. The modular laser design is based on single emitters and various combining technics.

In a first step we accept a reduction of the very high brightness of the single emitters by vertical stacking several diodes in fast axis. This can be theoretically done until the combined fast axis beam quality is on a comparable level as the individual diodes slow axis beam quality without loosing overall beam performance after fiber coupling. Those stacked individual emitters can be wavelength stabilized by an external resonator, providing the very same feedback to each of those laser diodes which leads to an output power of about 100 W with BPP of <3.5 mm*mrad (FA) and <5 mm*mrad (SA). In the next steps, further power scaling is accomplished by polarization and wavelength multiplexing yielding high optical efficiencies of more than 80% and resulting in a building block module with about 500 W launched into a 100 μm fiber with 0.15 NA. Higher power levels can be achieved by stacking those building blocks using the very same dense spectral combing technique up to multi kW Systems without further reduction of the BPP.

The 500 W building blocks are consequently designed in a way that they feature a high flexibility with regard to their emitting wavelength bandwidth. Therefore, new wavelengths can be implemented by only exchanging parts and without any additional change of the production process. This design principal theoretically offers the option to adapt the wavelength of those blocks to any applications, from UV, visible into the far IR as long as there are any diodes commercially available. This opens numerous additional applications like laser pumping, scientific applications, materials processing such as cutting and welding of copper aluminum or steel and also medical application.

Typical operating at wavelengths in the 9XX nm range, these systems are designed for and mainly used in cutting and welding applications, but adapted wavelength ranges such as 793 nm and 1530 nm are also offered. Around 15XX nm the diodes are already successfully used for resonant pumping of Erbium lasers [1].

Furthermore, the fully integrated electronic concept allows addressing further applications, as due to short lead lengths it is capable of generating very short μs pulses up to cw mode operation by simple software commands.

PROCEEDINGS ARTICLE | April 1, 2015

Highly modular high-brightness diode laser system design for a wide application range

Proc. SPIE. 9348, High-Power Diode Laser Technology and Applications XIII

KEYWORDS: Resonators, Polarization, Materials processing, Laser development, Semiconductor lasers, Collimation, Diodes, Laser cutting, Fiber couplers, Laser systems engineering

Read Abstract

PROCEEDINGS ARTICLE | April 1, 2015

Beam combining techniques for high-power high-brightness diode lasers

Proc. SPIE. 9346, Components and Packaging for Laser Systems

KEYWORDS: Optical filters, Polarization, Fiber Bragg gratings, High power lasers, Reliability, Multiplexing, Semiconductor lasers, Collimation, Diodes, Laser systems engineering

Read Abstract

PROCEEDINGS ARTICLE | March 26, 2015

Multi-wavelength resonant pumping of Er:YAG lasers for energy efficient trace gas detection systems

Proc. SPIE. 9342, Solid State Lasers XXIV: Technology and Devices

KEYWORDS: Methane, LIDAR, Laser applications, Semiconductor lasers, Laser resonators, Diodes, Laser damage threshold, Er:YAG lasers, Laser systems engineering, Absorption

Read Abstract

PROCEEDINGS ARTICLE | March 9, 2015

Direct diode lasers and their advantages for materials processing and other applications

Proc. SPIE. 9356, High-Power Laser Materials Processing: Lasers, Beam Delivery, Diagnostics, and Applications IV

KEYWORDS: Modulation, Materials processing, Laser applications, Solid state lasers, Fiber lasers, Semiconductor lasers, Diodes, Laser cutting, Laser systems engineering, Absorption

Read Abstract

The brightness of diode lasers is improving continuously and has recently started to approach the level of some solid state lasers. The main technology drivers over the last decade were improvements of the diode laser output power and divergence, enhanced optical stacking techniques and system design, and most recently dense spectral combining. Power densities at the work piece exceed 1 MW/cm² with commercially available industrial focus optics. These power densities are sufficient for cutting and welding as well as ablation. Single emitter based diode laser systems further offer the advantage of fast current modulation due their lower drive current compared to diode bars. Direct diode lasers may not be able to compete with other technologies as fiber or CO₂-lasers in terms of maximum power or beam quality. But diode lasers offer a range of features that are not possible to implement in a classical laser. We present an overview of those features that will make the direct diode laser a very valuable addition in the near future, especially for the materials processing market. As the brightness of diode lasers is constantly improving, BPP of less than 5mm*mrad have been reported with multikW output power. Especially single emitter-based diode lasers further offer the advantage of very fast current modulation due to their low drive current and therefore low drive voltage. State of the art diode drivers are already demonstrated with pulse durations of <10μs and repetition rates can be adjusted continuously from several kHz up to cw mode while addressing power levels from 0-100%. By combining trigger signals with analog modulations nearly any kind of pulse form can be realized. Diode lasers also offer a wide, adaptable range of wavelengths, and wavelength stabilization. We report a line width of less than 0.1nm while the wavelength stability is in the range of MHz which is comparable to solid state lasers. In terms of applications, especially our (broad) wavelength combining technology for power scaling opens the window to new processes of cutting or welding and process control. Fast power modulation through direct current control allows pulses of several microseconds with hundreds of watts average power. Spot sizes of less than 100 μm are obtained at the work piece. Such a diode system allows materials processing with a pulse parameter range that is hardly addressed by any other laser system. High productivity material ablation with cost effective lasers is enabled. The wide variety of wavelengths, high brightness, fast power modulation and high efficiency of diode lasers results in a strong pull of existing markets, but also spurs the development of a wide variety of new applications.

PROCEEDINGS ARTICLE | May 2, 2014

Generating a high brightness multi-kilowatt laser by dense spectral combination of VBG stabilized single emitter laser diodes

Proc. SPIE. 9134, Semiconductor Lasers and Laser Dynamics VI

KEYWORDS: Resonators, Polarization, Fiber Bragg gratings, High power lasers, Reflectivity, Semiconductor lasers, Collimation, Laser stabilization, Diodes, Fiber couplers

Read Abstract

PROCEEDINGS ARTICLE | March 12, 2014

High brightness direct diode laser with kW output power

Proc. SPIE. 8965, High-Power Diode Laser Technology and Applications XII

KEYWORDS: Optical filters, Resonators, Reflectivity, Fiber lasers, Semiconductor lasers, Collimation, Diodes, Laser cutting, Fiber couplers, Laser systems engineering

Read Abstract

High power, high brightness diode lasers are beginning to challenge solid state lasers, i.e. disk and fiber lasers. The core technologies for brightness scaling of diode lasers are optical stacking and dense spectral combining (DSC), as well as improvements of the diode material. Diode lasers will have the lowest cost of ownership, highest efficiency and most compact design among all lasers. In our modular product design tens of single emitters are combined in a compact package and launched into a 200 μm fiber with 0.08 NA. Dense spectral combining enables power scaling from 80 W to kilowatts. Volume Bragg Gratings and dichroic filters yield high optical efficiencies of more than 80% at low cost. Each module emits up to 500 W with a beam quality of 5.5 mm*mrad and less than 20 nm linewidth. High speed switching power supplies are integrated into the module and rise times as short as 6 μs have been demonstrated. Fast control algorithms based on FPGA and embedded microcontroller ensure high wall plug efficiency with a unique control loop time of only 30 μs. Individual modules are spectrally combined to result in direct diode laser systems with kilowatts of output power at identical beam quality. For low loss fiber coupling a 200 μm fiber is used and the NA is limited to 0.08 corresponding to a beam quality of 7.5 mm*mrad. The controller architecture is fully scalable without sacrificing loop time. We leverage automated manufacturing for cost effective, high yield production. A precision robotic system handles and aligns the individual fast axis lenses and tracks all quality relevant data. Similar technologies are also deployed for dense spectral combining aligning the VBG and dichroic filters. Operating at wavelengths between 900 nm and 1100 nm, these systems are mainly used in cutting and welding, but the technology can also be adapted to other wavelength ranges, such as 793 nm and 1530 nm. Around 1.5 μm the diodes are already successfully used for resonant pumping of Erbium lasers.[1] Optimized spectral combining enables further improvements in spectral brightness and power.

PROCEEDINGS ARTICLE | February 28, 2014

Increased efficiency of Er:YAG lasers at 1645 nm using narrow bandwidth diode lasers and dual-wavelength resonant pumping

Proc. SPIE. 8959, Solid State Lasers XXIII: Technology and Devices

KEYWORDS: Mirrors, Methane, Resonators, LIDAR, Crystals, Semiconductor lasers, Laser resonators, Diodes, Er:YAG lasers, Absorption

Read Abstract

PROCEEDINGS ARTICLE | October 22, 2013

Dual-wavelength resonant pumping of compact Er:YAG lasers providing high power output at 1645.55 nm for methane detection

Proc. SPIE. 8894, Lidar Technologies, Techniques, and Measurements for Atmospheric Remote Sensing IX

KEYWORDS: Mirrors, Fabry–Perot interferometers, Methane, Resonators, High power lasers, Crystals, Laser development, Semiconductor lasers, Er:YAG lasers, Absorption

Read Abstract

PROCEEDINGS ARTICLE | March 6, 2013

Efficient Er:YAG lasers at 1645.55 nm, resonantly pumped with narrow bandwidth diode laser modules at 1532 nm, for methane detection

Proc. SPIE. 8599, Solid State Lasers XXII: Technology and Devices

KEYWORDS: Fabry–Perot interferometers, Methane, Continuous wave operation, Resonators, Q switching, Crystals, Laser development, Semiconductor lasers, Er:YAG lasers, Absorption

Read Abstract

PROCEEDINGS ARTICLE | February 26, 2013

Compact high brightness diode laser emitting 500W from a 100μm fiber

Proc. SPIE. 8605, High-Power Diode Laser Technology and Applications XI

KEYWORDS: Optical filters, Electronics, Resonators, Polarization, Reflectivity, Multiplexing, Semiconductor lasers, Collimation, Diodes, Laser cutting

Read Abstract

PROCEEDINGS ARTICLE | February 22, 2013

Pulse compression and beam quality improvement of a single-frequency Nd:YAG MOPA system

Proc. SPIE. 8600, Laser Resonators, Microresonators, and Beam Control XV

KEYWORDS: Phase conjugation, Optical amplifiers, Oscillators, Birefringence, Scattering, Nd:YAG lasers, Laser scattering, Amplifiers, Picosecond phenomena, Liquids

Read Abstract

PROCEEDINGS ARTICLE | January 30, 2013

Ultrahigh brightness laser diode modules with narrow linewidth for resonant pumping Er:YAG lasers operating at 1.6 um

Proc. SPIE. 8677, XIX International Symposium on High-Power Laser Systems and Applications 2012

KEYWORDS: Optical fibers, Mirrors, Eye, Fabry–Perot interferometers, Methane, Q switching, Crystals, Semiconductor lasers, Er:YAG lasers, Absorption

Read Abstract

PROCEEDINGS ARTICLE | January 30, 2013

Barium nitrate Raman laser at 1.599 µm for CO2 detection

Proc. SPIE. 8677, XIX International Symposium on High-Power Laser Systems and Applications 2012

KEYWORDS: Oscillators, Carbon dioxide, Resonators, Nd:YAG lasers, Carbon dioxide lasers, Semiconductor lasers, Raman spectroscopy, Laser resonators, Barium, Absorption

Read Abstract

Showing 5 of 17 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years