Novel diodes and UV-LEDs presented at Berlin expo

13 Oct 2016

FB Institute among exhibitors showcasing latest developments at Micro Photonics 2016.

Berlin’s Ferdinand-Braun-Institut (FBH) has this week presented novel developments and advances of its diode lasers and UV LEDs at the city’s Micro Photonics congress and expo that closes today.

At the corresponding conference, FBH’s Dr Martin Maiwald presented the capabilities of mobile SERDS technology using FBH’s compact handheld probe with implemented dual-wavelength laser.

Maiwald explained that FBH’s customized diode lasers enable a variety of applications, from material analysis, sensing, and displays to materials processing. “Our UV LEDs with a focus on the UV-B and UV-C spectral range can be adjusted flexibly to suit various requirements," he said.

Typical applications are in medical diagnostics and fluorescence spectroscopy as well as surface treatment and disinfection.”

Diode laser modules

Three different compact diode laser modules were demonstrated. For modules with output powers above 2W and high spectral radiance, FBH has expanded the available wavelengths from 804nm to 1064nm. This setup can also be transferred to wavelengths up to 1180nm, which is suitable for pumping of solid-state lasers and for frequency doubling.

Seed-laser modules emitting at 633nm and 1180nm that deliver >20 mW were also on show, with an optical micro-isolator and polarization-maintaining fiber at the output. A third design featured an amplifier module emitting at 1180 nm with PM-SMF input and free-space output yielding >1W output.

Materials processing

FBH also showed some of its high-brilliance diode lasers, which cover the wavelength range from 630nm to 1180nm. Single emitters with a stripe width of 90μm achieve peak brilliance results with 3.5 W/mm-mrad; smaller stripe widths deliver up to >6 W/mm-mrad from 20 to 30μm apertures.

For materials processing applications, FBH presented custom arrays for spectral beam combining, comprising five brilliant DFB lasers with 30μm apertures, each yielding 5W with 50% efficiency. The emitter-to-emitter wavelength spacing is 2.5nm. Recently, the institute has achieved “record results” from novel QCW bars that demonstrate 60% efficiency when operated with 1 kW output power at 15°C.

Water disinfection

FBH has developed a rod-shaped module for water disinfection using its in-house 262 nm LEDs. This module could replace conventional systems based on low-pressure mercury vapor lamps. Besides environmental advantages, UV LEDs offer higher lifetimes and maintenance-free working. Wavelength and emission characteristics can also be set to the desired application.

The demonstrator, which was shown for the first time at Micro Photonics, uses 40 LEDs, each delivering an 1.7mW; the medium irradiation intensity at a distance of around 2 cm is at approximately 2.0 W/m².

The FBH water disinfection system geometry is modularly expandable and can be adapted to various reactor sizes. Two LEDs form an assembly group with a constant current supply (max. 100 mA per LED) and a tem- perature termination for security reasons. Heat is dissipated via a heat pipe with attached fan.

Advanced UV for Life

The FBH developments shown at Micro Photonics are part of the Advanced UV for Life consortium, which comprises academic institutions and industrial companies working with UV LEDs.

Activities of the consortium cover the value chain: from materials through UV LEDs and photodiodes, modules and systems with tailored properties to the final application. Cooperation between component developers and end users of UV are expected to open up new markets. Advanced UV for Life is founded by the German Federal Ministry of Education and Research within the program "Twenty20 - Partnership for Innovation".