Full Value Chain -- Tailored Diode Lasers and UV LEDs

The Ferdinand-Braun-Institut (FBH) presents novel developments and advancements of its diode lasers and UV light-emitting diodes (LEDs) at Photonics West 2018. The event is hosted in San Francisco (USA) from 30 January - 1 February 2018. FBH is also extensively represented at the accompanying conferences (27 January - 1 February 2018) with more than 30 scientific contributions. At the German Pavilion, FBH showcases its full range of capabilities, offering the full value chain in-house: from design through chips to modules. The institute increasingly advances these devices up to the operational system. Exhibits include:

High-power pulse laser source for LiDAR systems

Lasers generating short optical pulses with widths in the range from 200 ps to 20 ns are key components for a broad range of applications including LiDAR (Light Detection and Ranging), e.g., for autonomous driving, 3D object detection, laser scanning (airborne, satellite, and terrestrial) as well as fluorescence spectroscopy and micro-machining systems. FBH has developed a suitable, very compact laser source. The laser module uses a tailored design for pulse generation from the institute's diode laser technology as well as a laser driver with GaN transistor in the final stage offering pulses up to 250 A with controllable pulse amplitude and width. Integrated on these drivers is FBH's latest generation of wavelength-stabilized laser diodes that emit 5 ns pulses with 40 W (single emitter) or up to 100 W (3-emitter array) pulse power near 905 nm with good beam quality and up to 85°C. This concept can, of course, be transferred to further wavelengths.

Compact laser module offering outstanding frequency stabilization for interferometry

FBH has developed a very compact laser module with emission at 633 nm. The semiconductor laser module, sized only 76x54x15 mm³, uses a novel butterflytype housing and aims at replacing bulky HeNe lasers. It offers a flexible platform for the integration of a wide range of photonic components, thus simplifying adaptation for different application scenarios. The particular module presented features an all-semiconductor master-oscillator power-amplifier (MOPA) combined with an iodine gas cell to stabilize output power as well as emission wave-length. The MOPA uses newly developed chips, achieving an optical output power of more than 30 mW. A miniaturized optical isolator, purpose-built for the wavelength of 633 nm, is interposed between MO and PA. It features optical isolation of more than 30 dB and a transmission loss of less than 3 dB. The iodine gas cell is also miniaturized, offering a length of only 30 mm and a clear aperture of 2 mm. The frequency of the module's emission could be stabilized by the project partner Toptica to be absolute within a 10 MHz band over a time period of one hour. This corresponds to a frequency stability of 2·10 -8, which translates to an accuracy of about 2 microns on a length scale of 100 m. Such accuracy could previously only be reached by large-sized HeNe lasers. The new laser modules will allow a significantly higher degree of miniaturization of interferometric measurement systems in the near future.

Wavelength-stabilized high-brightness light sources

The Ferdinand-Braun-Institut develops customized wavelength-stabilized high-power diode lasers with laser emission in the spectral range between 630 nm and 1180 nm for spectro-scopic applications and as pump sources for non-linear frequency conversion. Developments include monolithic dual-wavelength DBR diode lasers with optical output powers up to 200 mW providing two emission lines with a small spectral linewidth for Shifted Excitation Raman Difference Spectroscopy (SERDS). With SERDS, Raman signals can be extracted efficiently and rapidly from disturbing backgrounds such as fluorescence and ambient light, thus improving Raman spectroscopy in real-world applications. DBR tapered lasers and MOPA systems show diffraction limited output powers up to 10 W and are used for efficient second harmonic generation of the emission into the visible spectral range and up-conversion of mid-infrared radiation via sum frequency generation to the near-infrared range.

EurekAlert!, the online, global news service operated by AAAS, the science society: https://www.eurekalert.org/pub_releases/2018-01/fb-fvc011118.php