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To: Johnny Canuck who wrote (34402)	9/22/2001 4:06:24 PM
From: Johnny Canuck	Read Replies (2) \| Respond to of 67862

According to EMKR, the system integrator can reduce the cost of that part of the system to 20 percent of alternatives using VCSEL's. Manufacturers are EMKR and KOPN. [Note KOPN is not a pure play. They also make GaAs HBT for wireless with CNXT, TQNT, and ANAD as customers. CNXT is a greater that 50 percent customer in the past. They also make cyber displays for Camcorders and hopefully 3G handsets. They have a dominant share in camcorders and sell to everyone except Sony who makes their own viewers and dispalys. ] ************************ The VCSEL Evolution Revolution Bob Mayer -- Electronic News, 8/13/01 The increasing use of networks and the Internet by corporate America mandates that service providers and network administrators continually increase the bandwidth of their networks. In the network core, an increase in bandwidth means faster optical solutions for traditional intersystem interconnects and high-speed optical pipes for intrasystem applications. Further out into the network, in the metropolitan and access portions of the telecommunications network, optical interconnects are replacing copper-based interconnects. Optical interconnects are also driving the need for very dense optical interface solutions. The combined result is a growing demand for higher-speed optical interconnects that are lower cost, smaller and more power-efficient than optical interconnect solutions available today. Vertical cavity surface emitting laser (VCSEL) technology supports the evolution of current optical subsystems toward improved performance and cost for existing network infrastructures. It simultaneously aids the revolution in next-generation optical interconnects required for scalable, distributed system and network architectures. VCSEL's inherent differences in device structure and manufacturing methods allow it to overcome many of the limitations imposed by the edge-emitter laser structure on optical subsystems. The laser is the key component that generates the light in an optical subsystem, and VCSELs provide many benefits over edge-emitters. The laser's structure dictates the optical and laser-driver design as well as determining the capabilities the subsystem can support. Until recently, edge-emitting lasers were the only option capable of meeting the rigorous telecommunications standards' requirements that govern many of these optical interconnects. VCSELs are now capable of meeting these requirements and bringing several added benefits. The basic components of a semiconductor laser are the active region and mirrors. The active region creates light when current is applied and amplifies light that passes through it. Mirrors in the laser structure reflect the generated light back into the active region, thereby allowing it to amplify itself. This design makes lasers efficient at converting electrical power into optical power. Edge-emitters are designed to emit light from the edge of the device. They are fabricated by depositing materials onto a semiconductor wafer to create the active region. The wafer is subsequently cleaved to form the mirrors. The cleaving is carefully controlled to produce facets on the edge of each laser die. These facets act as mirrors, based on the change in refractive indices between the semiconductor and the air. Thin films are then applied to these facets to control reflectivity and prevent contaminants from entering the active region, which would affect the reliability of the device. This exacting manufacturing process makes the laser a challenge to produce, and the device structure makes it difficult to integrate into optical subsystems: both result in increased costs. The mirror facets of edge-emitters are also not very reflective. To compensate, edge-emitters are designed with longer active region cavities to provide more gain. This longer cavity makes the device more difficult to directly modulate at high data rates, increases the amount of current the device needs to operate and results in less efficient use of the wafer area. These factors limit the edge-emitter's speed, power efficiency and cost-effectiveness. Another limiting factor of edge-emitting technology is the broad spectral emission caused by the large cavity. This broad frequency spectrum causes chromatic dispersion that significantly reduces fiber optic-link distances. To minimize chromatic dispersion, some edge-emitter designs integrate a grating that damps all but one wavelength. These lasers are called distributed feedback lasers (DFBs); those without gratings are called Fabry-Perots. At 10Gbits/sec., 1,310nm Fabry-Perot-based interconnects can support up to 2 kilometers (km) over single-mode fiber while similar 1,310nm DFB-based interconnects can extend this reach up to 15km. The DFBs' narrow optical spectrum allows the optical link to reach greater distances but sacrifices efficiencies in power conversion and manufacturing cost. VCSELs are able to achieve lower manufacturing costs by eliminating the need for tight control over the cleaving process and by using on-wafer testing. The cleaving process for edge-emitters is time consuming and low yielding. For VCSELs, yield loss may instead be taken at the wafer level, without incurring the additional processing and packaging costs associated with edge-emitting lasers. Since the mirrors of the VCSEL are highly reflective, only a small cavity containing the active region is needed. This results in higher power efficiency than the edge-emitters. The resulting small size of the VCSEL die allows it to be directly modulated at higher frequencies and makes more efficient use of the wafer area. Typically, more than 20,000 individual VCSELs can be made on a single 3-inch wafer with each VCSEL supporting direct modulation well in excess of 10Gbits/sec. VCSELs now operate in each of the key wavelength windows for fiber optic communication: 850nm, 1310nm and 1550nm. With this, VCSELs now allow existing optical interconnect solutions to evolve into faster, smaller and more power-efficient and lower-cost generations. The capability of multi-VCSEL arrays, particularly two-dimensional arrays, boosts the revolution of optical subsystems that are significantly higher speed and more dense than can practically be developed with edge-emitting technology. -------------------------------------------------------------------------------- Author Information Bob Mayer is vice president of marketing at Cielo Communications Inc., Broomfield, Colo.

To: Johnny Canuck who wrote (34402)	9/22/2001 4:36:04 PM
From: Return to Sender	Read Replies (1) \| Respond to of 67862

Harry TSM is a Chip Foundry company. They make Integrated Circuits, among other things, built to the specifications of the companies that design products but do not have their own dedicated foundries. Have you got a link for that article? I cannot find it at Yahoo: biz.yahoo.com Thank you, RtS