In hall B2, booth 350 at the Laser World of Photonics 2017 trade show in Munich, Germany (26–29 June), Berlin-based Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik (FBH) – which offers the full value chain in-house (from design through chips to modules), and increasingly develops these devices for use as operational systems – is presenting its latest developments in diode lasers and ultraviolet (UV) light-emitting diodes (LEDs).
Specifically, FBH is showcasing a unique, computer-controlled picosecond light source delivering high-precision pulses in the pico- and nanosecond ranges, a 6kW fiber-coupled pump module for solid-state laser systems, and a demonstrator module equipped with UV-C LEDs for water disinfection purposes. The LEDs have been developed within the Advanced UV for Life consortium managed by FBH.
Flexible all-in-one pulse light source
With its PLS series, FBH offers laser sources that deliver high-precision pulses in the pico- and nanosecond range with nanojoule energies. Pulse energy, width, and spacing as well as repetition frequencies can be flexibly adjusted. The laser system offers freely selectable repetition rates from the hertz to the megahertz range and peak pulse powers of up to 50W. It uses tailored diode lasers for impulse generation combined with optimized RF components as electronic drivers (both are core competencies of FBH).
The computer-controlled all-in-one system can be switched into different pulse modes and thus be integrated into various laser systems with little effort. The system is equipped with 1030nm diode lasers, but can easily be adapted to other wavelengths. It is therefore suitable for applications such as material processing, bio-medical examinations, and mobile LIDAR systems. The PLS 1030 was constructed jointly by laser and RF circuit experts with engineers from the in-house Prototype Engineering Lab, an FBH team that develops industry-ready and user-friendly prototypes. Companies hence get direct access to the latest research results.
Efficient diode lasers for applications with kilowatt-class output
FBH develops high-brilliance diode lasers in a large variety of designs in the wavelength range 630-1180nm. All activities aim to steadily increase efficiency, reliability and output power of diode lasers and bars. In recent work, laser bars with a 6mm-long resonator and 10mm aperture have reached output powers of 1kW while maintaining a conversion efficiency of 63%. Detailed results for these bars are being presented at the CLEO Europe conference in Munich, which takes place on 25-29 June (in parallel with Laser World of Photonics).
Bars with long cavities of this kind provide ultra-low thermal and electrical resistances. They are therefore expectted to be highly beneficial for kW-level continuous-wave (CW) operation and thus particularly attractive for industrial and scientific high-power applications. For example, such diode laser bars are used as pump sources for solid-state and fiber lasers or employed directly in material processing.
FBH says that innovations regarding chip design and technology along with mounting and module design have simultaneiuosly enabled advances in pumping of solid-state systems. Novel chips with a very broad aperture of 1.2mm were integrated into innovative side-cooled stacks that are particularly suitable for pulsed operation with a larger duty cycle of 20%. The high-intensity output of the single emitters in the stacks is optically combined into a beam and then coupled with low losses into a fiber. A pump laser system is hence available for the first time that simultaneously offers high power, good efficiency, and a long duty cycle. Novel high-energy-class solid-state lasers can therefore be efficiently pumped with these systems. In its booth, FBH is presenting an example pump laser module with 6kW peak power and an electro-optical efficiency of 50%.
High-brilliance tapered lasers with further increased output power
Tapered lasers deliver high optical output powers in a narrow spectral line with equally good beam quality. FBH recently further enhanced its output power in the spectral range 980-1120nm. The newly developed 1030nm tapered diode lasers yield up to 10.3W diffraction-limited output power, much increased on the previous record of 8W. This corresponds to 76% of the emitted light output. This improvement was due to further optimization of the lateral spatial mode filtering and the internal wavelength-selective gratings. The latter ensure laser emission within 22pm spectral width over the full operating range. The diode lasers are hence also suitable for challenging applications like non-linear frequency conversion.