11 October 2016

FBH introduces diode lasers & UV LED developments at micro photonics expo

In hall 7.2C, booth 207, at the micro photonics 2016 International Congress & Expo in Berlin, Germany (11-13 October), Berlin-based Ferdinand-Braun-Institut (FBH) is presenting novel developments of its diode lasers and UV light-emitting diodes (LEDs). Also, in the conference, Martin Maiwald is presenting the capability of mobile SERDS technology using FBH's compact handheld probe with implemented dual-wavelength laser.

FBH develops diode lasers and LEDs from the chip through to the final module, and increasingly advances these devices up to the operational system. Customers and partners can hence test their developments in the respective application. FBH's customized diode lasers open up a variety of applications, from material analytics, sensors, and display technology to materials processing. Similarly, UV LEDs (focusing on the UV-B and UV-C spectral range) can be adjusted flexibly to the requirements. Applications cover medical diagnostics and fluorescence spectroscopy as well as surface treatment and disinfection.

FBH's exhibits include the following:

Industrial diode laser modules with optical fiber connection

FBH offers compact diode laser modules that allow customers to use high-brilliance laser radiation in their applications. Due to an integrated single-mode fiber (SMF) port, the matchbox-sized modules can be installed into different systems. Efficient laser light sources are hence available for the near-infrared spectral range, delivering diffraction-limited radiation with narrow bandwidth where it is needed.

So far, three different module types have been demonstrated. For modules with both high output power (>2W) and high spectral radiance, FBH has expanded the available wavelengths to the spectral range 804-1064nm. This setup can be transferred to wavelengths up to 1180nm and is thus suitable for pumping solid-state lasers as well as for frequency doubling. Additionally, seed-laser modules emitting at 633nm and 1180nm have been demonstrated that deliver output power of >20mW ex fiber, featuring an optical micro-isolator and polarization-maintaining SMF (PM-SMF) at the output. A polarization extinction ratio of more than 20dB was shown for modules with PM-SMF output in the spectral range 633-1180nm. As a third design, an amplifier module emitting at 1180nm with PM-SMF input and free-space output yielding >1W output power has been developed. By coupling light from a seed-laser source into the PM-SMF, this radiation can be easily amplified, says FBH. The principle is also transferable to other wavelengths.

Tailored, flexible picosecond light impulse source

With PLS 1030, FBH offers an efficient pulsed laser source that utilizes in-house-developed optical and electronical semiconductor components. The laser system is currently being optimized so that all functionalities are integrated in just one compact device, instead of two separate components previously, offering improved capability. The all-in-one PLS 1030 delivers ultra-short light impulses at a wavelength of 1030nm within an adjustable time range of 5-15ps and provides freely selectable repetition frequencies, in a range of hertz to megahertz. Pulse peak performance is over 20W. Due to these properties, the laser source is suited to applications in materials processing, especially in connection to fiber amplifiers, for biomedical examinations based on fluorescence spectroscopy, and for mobile LIDAR systems. The device can be equipped with semiconductor components for 1030nm and 1064nm, but can be flexibly transferred to other wavelengths. It consists of a mode-locked laser with a repetition rate around 4GHz, a pulse picker element, and an optical amplifier. Electronic control has also been developed using FBH's gallium nitride (GaN) transistors. As a result, short impulses can be flexibly selected from single to multiple serial pulses (burst mode) and amplified. The PLS 1030 is computer-operated to enable it to be easily integrated into various laser systems, ensuring stable and user-friendly operation.

Higher brilliance and output power for diode lasers and bars

FBH develops high-brilliance diode lasers in a wide variety of designs and packages, covering wavelengths from 630nm to 1180nm. Single emitters with a stripe width of 90µm, for example, reach peak brilliance of 3.5W/mm-mrad. In addition, smaller stripe widths deliver up to >6W/mm-mrad (from 20…30µm apertures) – again a record value. For materials processing applications FBH has developed custom arrays for spectral beam combining, consisting of five brilliant DFB lasers with 30µm apertures, each yielding 5W output power with 50% efficiency. The emitter-to-emitter wavelength spacing is 2.5nm. Future activities aim to improve efficiency, reliability and output power. For example, record results have recently been achieved from novel QCW bars that demonstrate 60% efficiency when operated with 1kW output power at 15°C. This rises to 70% at the same output power when operated at a temperature of -70°C.

Module for water disinfection with UV-C LEDs

Using in-house-developed 262nm LEDs, FBH has designed a rod-shaped module for water disinfection that aims to replace conventional low-pressure mercury vapor lamps. UV LEDs have higher lifetimes and are maintenance-free and, since they do not require toxic chemicals like mercury, they are environmentally friendly (mercury lamps need to be disposed of safely after a few thousand hours of operation). Wavelength and emission characteristics can also be adjusted specifically to the desired application. FBH's demonstrator (shown for the first time at micro photonics) uses 40 LEDs, each delivering optical output power of 1.7mW; the average irradiation intensity at a distance of about 2cm is roughly 2.0W/m2. The geometry follows conventional flow-through water disinfection reactors, for example, for the treatment of drinking or process water. The FBH setup is modularly expandable and can thus be adapted to various reactor sizes. Two LEDs form an assembly group with a constant current supply (maximum 100mA per LED) and a temperature termination for security reasons. Heat is dissipated via a heat pipe with an attached fan.

Tags: Diode lasers UV LEDs

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Visit: www.fbh-berlin.com