Product in focus
Advances in MMIC for terahertz signal generation
Signal generation at frequencies above 100 GHz represents a technical challenge, which is addressed by FBH due to the strong demand for such signal sources. FBH has established two novel technologies: a transferred-substrate (TS) InP-DHBT process and SciFab, a heterointegrated InP-on-BiCMOS process. Both are available to external customers. FBH has advanced the state-of-the-art using both processes and demonstrated a number of interesting microwave monolithic integrated circuit (MMIC) signal sources, exhibiting record bandwidth and/or signal power levels. In particular, FBH has realized a broadband doubler in TS InP-DHBT technology covering the full G-band between 140 – 220 GHz with an output power of > 5 dBm across the band. Power amplifiers have also been improved in terms of output power > 20 dBm, thermal limitation, and power-added efficiency of > 20 %. Moreover, FBH has realized a 180 GHz frequency doubler with > 10 dBm output power and more than 20 GHz bandwidth.
Using the SciFab process, FBH has increased the output power of a signal source based on a VCO in BiCMOS and a doubler in InP technology to reach 7 dBm signal power at 164 GHz with tuning range limited only by the VCO. It has also realized a signal source at 330 GHz using the same VCO and a quadrupler with -12 dBm output power and 30 dB harmonic rejection.
Contact to SciFab foundry service at IHP.
High-power laser drivers for nanosecond pulses
Lasers generating short optical pulses with high peak power and pulse widths in the range from 10 ps to 100 ns are key components for a broad range of applications. These include LiDAR imaging as well as fluorescence spectroscopy and micromachining systems. In addition to the power and pulse width specs, high repetition rates, good beam quality, and high energy efficiency are required.
Gain switching of the laser diode, i.e., switching on and off the injected current, offers a simple, cost-effective, and power-efficient possibility to generate optical pulses with widths down to at least 0.5 ns. However, to reach optical powers in the high watt range, electrical pulses with current amplitudes beyond 10 A must be handled. The main challenges in realizing such drivers are twofold: (i) to have fast-switching transistors with the appropriate current capabilities and (ii) to drive the short current pulses through the board and laser parasitics into the internal diode.
FBH’s combined expertise in both laser diodes and high-speed power electronics forms the ideal setting for developing short-pulse laser components. Its modules with integrated GaN-based drivers offer unprecedented performance in terms of current and pulse width, from 430 A at 25 ns to 30 A at 0.4 ns.
- T. Hoffmann, A. Klehr, A. Liero, G. Erbert and W. Heinrich Compact high-current diode laser nanosecond-pulse source with high efficiency and 13 µJ output energy in Electronics Letters , vol. 51, no. 1, pp. 83-85, 1 8 2015 doi: 10.1049/el.2014.3204
- A. Liero, A. Klehr, S. Schwertfeger, T. Hoffmann, W. Heinrich Laser Driver Switching 20 A with 2 ns Pulse Width Using GaN IEEE MTT-S Int. Microw. Symp. Dig., Anaheim, CA, May 25-27, pp. 1110-1113 (2010).
Out now – overview on III-nitride ultraviolet emitters
This newly published book, which is edited by two FBH colleagues, gives a comprehensive in-depth look into the state-of-the-art of semiconductor UV emitters, about their technology and applications. ISBN 978-3-319-24100-5