Christian Hambeck

A 2.4µW Wake-up Receiver for wireless sensor nodes with −71dBm sensitivity

This paper presents a complete ultra-low power receiver with direct down conversion architecture. It is designed as Wake-up Receiver for wireless sensor nodes. The 130nm CMOS chip includes envelope detector, low noise baseband amplifier, PGA, mixed-signal correlation unit and auxiliaries for stand-alone operation. At 868MHz, a receiver sensitivity of −71dBm is achieved with total power consumption of 2.4µW at 1.0V supply by means of baseband correlation over 7ms with 64 bit pattern, 99% detection probability and a false wake-up rate of 10−3/s.

Integrated RGB laser light module for autostereoscopic outdoor displays

We have developed highly compact RGB laser light modules to be used as light sources in multi-view autostereoscopic outdoor displays and projection devices. Each light module consists of an AlGaInP red laser diode, a GaInN blue laser diode, a GaInN green laser diode, as well as a common cylindrical microlens. The plano-convex microlens is a so-called “fast axis collimator”, which is widely used for collimating light beams emitted from high-power laser diode bars, and has been optimized for polychromatic RGB laser diodes. The three light beams emitted from the red, green, and blue laser diodes are collimated in only one transverse direction, the so-called “fast axis”, and in the orthogonal direction, the so-called “slow axis”, the beams pass the microlens uncollimated. In the far field of the integrated RGB light module this produces Gaussian beams with a large ellipticity which are required, e.g., for the application in autostereoscopic outdoor displays. For this application only very low optical output powers of a few milliwatts per laser diode are required and therefore we have developed tailored low-power laser diode chips with short cavity lengths of 250 μm for red and 300 μm for blue. Our RGB laser light module including the three laser diode chips, associated monitor photodiodes, the common microlens, as well as the hermetically sealed package has a total volume of only 0.45 cm³, which to our knowledge is the smallest RGB laser light source to date.

Design and evaluation of a large-scale autostereoscopic multi-view laser display for outdoor applications

State-of-the-art autostereoscopic displays often do not comply with mandatory requirements for outdoor use, because of their limitations in size, luminance, number of 3D viewing zones, and maximum 3D viewing distances. In this paper we propose a concept for a modular autostereoscopic multi-view laser display with sunlight readable luminance, theoretically up to several thousand 3D viewing zones, and maximum 3D viewing distances of up to 70 meters. Each picture element contains three laser diodes, a cylindrical microlens, as well as a MEMS mirror, which deflects the collimated light beams to the left and right eyes of multiple viewers in a time-multiplexed manner. To demonstrate the principle, we have developed a prototype display with 5 x 3 picture elements.

Software Beam Combiner for Ultra-compact RGB Laser Light Modules with MEMS Mirrors

We have developed an ultra-compact RGB laser light module with an external MEMS mirror. The red, green, and blue laser beams are combined by adapting the laser diode driving signals in the time domain. Article not available.

Calibration method for synchronizing the viewing zones of a large-scale autostereoscopic multi-view laser display

We have developed a calibration method for synchronizing the autostereoscopic viewing zones displayed by an array of “trixels”, i.e., laser modules with integrated MEMS mirrors. Calibration patterns are projected onto a calibration screen and recorded by a camera. The distortion functions, which map the laser diode driving signals from the time domain to the intensity distributions in the spatial domain, are extracted from the recorded calibration patterns. Unlike conventional autostereoscopic displays, e.g., with lenticular lenses or parallax barriers, the optimal 3D viewing distance of the display can be adapted on-the-fly by transforming the distortion functions using linear operations.

4×1O-Gb/s CWDM Transmission using VCSELs from 1531nm to 1591nm

We demonstrate 4×10-Gb/s coarse wavelength-division multiplexed (CWDM) transmission using commercial vertical cavity surface emitting lasers (VCSELs) over ≫ 45 km of standard single-mode fiber without any dispersion compensation. The 10.7-Gb/s bit rate allows for enhanced forward error correction.