IQE material helps push VCSEL performance beyond 10 Gbit/s

31 July 2008

IQE plc (AIM: IQE, “IQE” or the “Group”), the leading global supplier of advanced semiconductor wafer products and wafer services to the semiconductor industry, is pleased to announce that VCSEL optoelectronic materials produced at its Cardiff manufacturing facility have enabled researchers to produce potentially reliable devices capable of operating at speeds greatly in excess of 10 Gbit/s.

In an article published in this month’s Electronics Letters, Professor Anders Larsson of Sweden’s Chalmers University of Technology said:

“The vertical cavity surface emitting laser (VCSEL) emitting at 850 nm has become the laser of choice for short reach data communication links in local and storage area networks operating at single channel data rates up to 10 Gbit/s. While there is a future need for even higher data rates it has been commonly believed that VCSELs operating at rates much higher than 10 Gbit/s will have to be scaled down in size to achieve the modulation bandwidth needed, thus operating at current densities too high for reliable operation.”

Professor Larsson’s research group at the Photonics Laboratory at the Department of Microtechnology and Nanoscience, Chalmers University of Technology, in Göteborg, Sweden, has recently shown that this is not necessarily the case. By optimizing the VCSEL design with respect to differential gain, capacitance, electrical resistance and thermal impedance, it was demonstrated that 850 nm oxide confined VCSELs with an aperture as large as 9 µm can achieve low threshold current, high differential efficiency and a modulation bandwidth as large as 21 GHz (Figs. 1 and 2). At a bias current of 6.5 mA, clear and open eyes could be generated at bit rates up to 25 Gbit/s and an extinction ratio of 6 dB (Fig. 3). This current corresponds to a current density of 10 kA/cm2, which is at the level where the present 10 Gbit/s VCSEL technology operates. This clearly indicates the potential for reliable operation of directly modulated 850 nm VCSELs at very high data rates for future, high capacity data communication links.

Professor Larsson went on to say that the epitaxial material for the work was provided by IQE and the project was supported by the European project VISIT and the Swedish Foundation for Strategic Research.


IQE plc (+44 29 2083 9400)
Chris Meadows
Andrew Joel


About IQE

IQE is the leading global supplier of advanced semiconductor wafers with products that cover a diverse range of applications, supported by an innovative outsourced foundry services portfolio that allows the Group to provide a 'one stop shop' for the wafer needs of the world's leading semiconductor manufacturers.

IQE uses advanced crystal growth technology (epitaxy) to manufacture and supply bespoke semiconductor wafers ('epi-wafers') to the major chip manufacturing companies, who then use these wafers to make the chips which form the key components of virtually all high technology systems. IQE is unique in being able to supply wafers using all of the leading crystal growth technology platforms.

IQE's products are found in many leading-edge consumer, communication, computing and industrial applications, including a complete range of wafer products for the wireless industry, such as mobile handsets and wireless infrastructure, Wi-Fi, WiMAX, base stations, GPS, and satellite communications; optical communications, optical storage (CD, DVD), laser optical mouse, laser printers & photocopiers, thermal imagers, leading-edge medical products, barcode, high efficiency LEDs and a variety of advanced silicon based systems.

The manufacturers of these chips are increasingly seeking to outsource wafer production to specialist foundries such as IQE in order to reduce overall wafer costs and accelerate time to market.

IQE also provides bespoke R&D services to deliver customised materials for specific applications and offers specialist technical staff to manufacture to specification either at its own facilities or on the customer's own sites. The Group is also able to leverage its global purchasing volumes to reduce the cost of raw materials. In this way IQE's outsourced services, provide compelling benefits in terms of flexibility and predictability of cost, thereby significantly reducing operating risk.

IQE operates six manufacturing facilities located in Cardiff (two) and Milton Keynes in the UK; in Bethlehem, Pennsylvania and Somerset, New Jersey in the USA; and Singapore. The Group also has 11 sales offices located in major economic centres worldwide.

About Chalmers University of Technology

Chalmers is a university of technology in which research and teaching are conducted on a broad front within technology, natural science and architecture. Our inspiration lies in the joy of discovery and the desire to learn. Underlying everything we do is a wish to contribute to sustainable development both in Sweden and world-wide.
Our research work deals ultimately with improving people’s conditions, and we often cross traditional boundaries in order to solve the problems of the future. Chalmers has become strong within several areas of science, and some of our research leads its field internationally. We wish in particular to develop and strengthen our research in the fields of bioscience, information technology, environmental science and nanotechnology.

Chalmers is a pioneer in Europe in the field of start-up companies, and has built up an efficient system of innovation in order to find applications in research into the formation of companies.

Chalmers has great aspirations to develop continually by opening doors to the outside world and by thinking innovatively. We have a close and productive collaboration with business and society at large. In this way we reinforce our own development, at the same time as we contribute to the growth of society.
Chalmers was founded in 1829 as a result of a donation from the director of the Swedish East India Company, William Chalmers.