+44 (0)24 7671 8970
More publications     •     Advertise with us     •     Contact us
 
Technical Insight

Quantum-well intermixing leads to Intense products (Fiber-optic Components)

Several recently formed start-up companies are addressing the monolithic integration of multifunctional devices and waveguides on indium phosphide. One of these is Intense Photonics, based at the West of Scotland Science Park in Glasgow, Scotland. The company has licensed a technology, quantum-well intermixing, which was developed at the University of Glasgow over a period of some 12 years by the optoelectronics group led by John Marsh. Quantum-well intermixing (QWI) uses rapid thermal annealing to alter the shape of a quantum well from its regular square profile. Elements inside the quantum well diffuse out while elements in the barrier layers diffuse in, creating a more Gaussian shape. "The effect is to increase the quantum-well bandgap, forming a transparent waveguide," explains Craig Hamilton, Intense Photonics technical director. "The QW-intermixed regions do not absorb light created in the regions where intermixing has not been applied." QWI is applied to selected regions of an epitaxial wafer, after which devices are defined by more conventional processing techniques such as dry etching. One application of the QWI process is the incorporation of non-absorbing mirror structures onto the device facets of 980 nm pump lasers. Since QWI is a wafer-scale process, it offers manufacturing advantages over other techniques that use regrowth onto cleaved facets of individual devices (see ). There are other benefits too, explains Hamilton. "As well as generating low-loss regions we can manipulate the light, for example by incorporating spatial mode filters to maintain a singlemode output," he says. "We can also incorporate mode stabilizers to prevent the beam from moving around as the output power is increased." Intense Photonics has already demonstrated 980 nm pump lasers in the laboratory that provide output powers of up to 500 mW. Commercial products are expected to be available towards the end of the year. Monolithic integration A key focus now for Intense Photonics is to apply QWI technology to monolithic integration on InP. The research team which generated the IP behind the QWI approach have fabricated laboratory demonstrators such as all-optical packet switches and crosspoint switches that have nanosecond switching speeds. The latter example integrates active devices such as amplifiers and modulators with waveguides and multimode interference couplers for splitting and combining. In the short term Intense Photonics is developing discrete components such as 980 nm pump lasers, using QWI to add functionality to these devices. "We re also engaging with companies doing hybrid integration, with a view to providing them with components that make integration easier," says Hamilton. "In the longer term we will move towards true monolithic integration." Intense Photonics began life as the first company to use the services of Compound Semiconductor Technology (CST), an independent foundry and technology-transfer company. Intense Photonics was initially housed with CST, but now occupies its own facilities on the same campus. The company uses CST s foundry processing services, although the critical QWI procedure is performed at Intense Photonics laboratories. The company has not yet committed to a plan to build its own manufacturing facilities, given the uncertain state of the market. Intense Photonics was incorporated in May 2000 with seed capital from 3i and ACT Venture Capital; the University of Glasgow also took an equity stake in return for an exclusive license to its QWI patent portfolio and technology. Its first round of funding should close soon.
×
Search the news archive

To close this popup you can press escape or click the close icon.
×
  • 1st January 1970
  • 1st January 1970
  • 1st January 1970
  • 1st January 1970
  • View all news 22645 more articles
Logo
×
Register - Step 1

You may choose to subscribe to the Compound Semiconductor Magazine, the Compound Semiconductor Newsletter, or both. You may also request additional information if required, before submitting your application.


Please subscribe me to:

 

You chose the industry type of "Other"

Please enter the industry that you work in:
Please enter the industry that you work in: