21 December 2017
FBH presenting diode lasers and UV LEDs at Photonics West
Berlin-based Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik (FBH) – which researches compound semiconductor-based electronic and optical components, modules and systems – is presenting developments and advances of its diode lasers and UV light-emitting diodes (LEDs) at Photonics West 2018 in San Francisco, CA, USA (30 January - 1 February). FBH is also represented at the accompanying conferences (27 January - 1 February) with more than 30 scientific contributions. At the German Pavilion (booth 4529-51), FBH is showcasing its full range of capabilities, offering the full value chain in-house: from design through chips to modules. The institute is increasingly advancing these devices up to operational systems. Exhibits include the following:
High-power pulse laser source for LiDAR systems
Lasers generating short optical pulses with widths of 200ps to 20ns are key components for a broad range of applications including light detection and ranging (LiDAR), 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 compact laser source. The module uses a tailored design for pulse generation from the FBH’s diode laser technology as well as a laser driver with a gallium nitride (GaN) transistor in the final stage, offering pulses up to 250A with controllable pulse amplitude and width. Integrated on these drivers is FBH’s latest generation of wavelength-stabilized laser diodes that emit 5ns pulses with 40W (single emitter) or up to 100W (three-emitter array) pulse power near 905nm with good beam quality and up to 85°C. This concept can be transferred to further wavelengths.
Compact laser module offering frequency stabilization for interferometry
FBH has developed a very compact laser module emitting at 633nm. Measuring just 76mm x 54mm x 15mm, the module uses a novel butterfly-type housing and aims to replace bulky helium-neon (HeNe) lasers. Offering a flexible platform for the integration of a wide range of photonic components, it simplifies adaptation for different applications, says FBH.
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 wavelength. The MOPA uses newly developed chips, achieving an optical output power of more than 30mW. A miniaturized optical isolator (purpose-built for 633nm wavelength) is interposed between the MO and PA, and features optical isolation of more than 30dB and a transmission loss of less than 3dB. The iodine gas cell is also miniaturized, offering a length of just 30mm and a clear aperture of 2mm. The module’s emission frequency can be stabilized by project partner Toptica to be absolute within a 10MHz band over a time period of 1 hour. This corresponds to a frequency stability of 2x10-8, which translates to an accuracy of about 2μm on a length scale of 100m. Such accuracy could previously only be reached by using large-sized HeNe lasers. The new laser modules should allow significantly greater miniaturization of interferometric measurement systems in the near future, it is reckoned.
Wavelength-stabilized high-brightness light sources
FBH develops customized wavelength-stabilized high-power diode lasers with laser emission in the 630-1180nm spectral range for spectroscopic applications and as pump sources for non-linear frequency conversion. Developments include monolithic dual-wavelength distributed Bragg reflector (DBR) diode lasers with optical output powers up to 200mW, 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, improving Raman spectroscopy in real-world applications. DBR tapered lasers and MOPA systems show diffraction-limited output powers up to 10W and are used for efficient second-harmonic generation of the emission into the visible spectral range and upconversion of mid-infrared radiation via sum frequency generation to the near-infrared range.