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1-D modulator array
(128 modulators) |
Spatial light modulators for high-speed signal processing
Acreo has a 10-year experience in designing, assembling and evaluating optical signal processing systems based on liquid crystal spatial light modulators. More recently, Acreo has developed its own spatial light modulators (SLM) based on surface-normal electroabsorption modulators for higher signal processing performance. Prototypes of 1-D (up to 128 modulators) as well as 2-D arrays (128x128 modulators) are available, and custom devices can be made on demand.
Proven technology
Acreo’s spatial light modulators capitalise on mature III-V technologies developed for quantum well infrared photodetectors (QWIP), currently in volume production at Acreo, but require a simpler fabrication process. Process techniques that are continuously developed at Acreo for QWIP and other imaging devices to improve yield, uniformity and pixel count (currently 640x480) can therefore be directly transfered to SLM fabrication.
Electroabsorption SLM: the best of optics and of electronics in one device
Optics offer fast processing performance by massively parallel computing of data at the speed of light. Electronics offer programmability and flexibility in data processing. Electroabsorption SLMs are key components in efficient optical signal processing systems, and merge processing speed and flexibility into one device by hybrid integration of high-speed III-V semiconductor modulators with state-of-the-art drive electronics.
Unique performance
The surface-normal electroabsorption modulator technology provides the fastest modulator arrays currently available. Compared to other technologies such as liquid crystals and MEMS, it offers switching times that are several orders of magnitude smaller, and very low sensitivity to incident light polarisation. Recent progresses in the technology at Acreo have also led to the experimental demonstration of high contrast ratio performances (up to 300:1).
Custom design
Different structure and component designs are already available at operating wavelengths around 850nm and 1550nm. Custom devices can be fabricated on demand, and require short development periods at these operating wavelengths. Prototype devices operating at other wavelength ranges (UV and long IR) are currently under development. Other wavelength areas can also be investigated on demand.
Drive electronics
Different drive schemes have been developed, including flip-chip bonding of modulator arrays on CMOS ASIC drivers or on passive Si interconnect chips with external drive electronics.
Potential applications in signal processing
High-speed processing of wideband microwave radar signals, high-speed image processing, automatic target/object recognition, personal identification systems, aid for satellite navigation, on-the-fly optical signal processing in optical networks (ex: header recognition in optical packet switching).
Contact us to discuss performance and applications of SLM.
Recent publications
- Qin Wang, Stéphane Junique, Daniel Ågren, Susanne Almqvist and Bertrand Noharet, "Arrays of vertical-cavity electroabsorption modulators for parallel signal processing," Opt. Express 13, 3323-3330, 2005
- Stéphane Junique, Qin Wang, Susanne Almqvist, Juanhua Guo, Henk Martijn, Bertrand Noharet and Jan Y. Andersson, “GaAs-based multiple quantum well spatial light modulators fabricated by a wafer-scale process”, Applied Optics, Vol. 44, No. 9, pp. 1635-1641, 2005
- Bertrand Noharet and Stéphane Junique, “Multiple quantum well spatial light modulators for correlation-based processors”, Optoelectronic Information Processing: Optics for Information Systems, Critical Reviews Vol. CR81, SPIE Press, pp. 314-334, 2001