Laser 2005
By John Latta, WAVE
0527 7/8/05
Cannes, France
June 13 - 15, 2005
This is one of the largest trade events devoted to laser technology. It is being held with two other conferences:
World of Photonics Congress 2005
Fibercomm 2005
The Congress is research focused having many sessions and paper presentations while the LASER event is a trade show which fills 3 halls at the Munich ICM.
One of the exhibitors stated that the Germans are strong in electro-optics and this is very evident here. The technology and applications are very diverse with a strong emphasis on automotive and medical uses.
The WAVE Report set out to understand some of the market dynamics in VCSEL technology.
VCSEL Technology Reemerges
VCSEL, or Vertical Cavity Surface Emitting Laser, is semiconductor microlaser diode that emits light in a cylindrical beam vertically from the surface of a fabricated wafer, and offers significant advantages when compared to the edge-emitting lasers currently used in the majority of fiber optic communications devices.
The first VCSEL was commercially sold in 1996. The market experienced a very rapid growth to 25m units in 2000 but then fell on hard times. As of Q1 2005 a total of 35m units have been sold. The reason for the decline in sales rate is the primary application in fiber optics telecommunications. Now the industry is actively engaged in increasing the number of applications, including tracking. Products have been shipped at the following wave lengths (nm):
665
850
980
1310
1300
1550
The target is 1550nm for fiber optics communication which most closely matches the performance of the fiber.
Major suppliers of VCSELS are:
Advanced Optical Components
Optek
Agilent
OSRAM
Fuji Xerox
ULM Photonics (Schott AG)
Infineon
Picolight
Avalon Photonics
Advanced Optical Components was known as Honeywell before being acquired by Finisar. This division which made VCSEL Optical Products, resulted in cash proceeds of $74 million that created a pretax gain of $32 million (after-tax $14 million) in Q1 2004. It is estimated that Advanced Optical Components has 70%+ market share.
http://www.advancedopticalcomponents.com/
This company is located in Texas as are some of the others. The location of this technology with the telecommunications sector is to be expected. But as the applications increase, it is expected that the supply base will also change – this is also reflected in the list of suppliers.
Looking for VCSELs
Both Panasonic and Sony have booths with laser diode products.
When asked, Sony stated they are working on VCSEL for communications but this is not yet a product. Currently the Sony products include laser diodes, edge emitters, for DVD playback, DVD recording, Blu-ray disc, laser printers and digital copiers and a high power laser diode.
Panasonic has none in production. Its laser diodes are listed mostly for pumping uses. Panasonic has reported on the development of a VCSEL which supports 12.5Gb/s communications rate using a 850nm device
China Optics
We are seeing a greater presence of Chinese companies in optics than we ever have before. We picked up a publication called “Coverage of Laser Technology & Applied Optics.” There are two survey articles on VCSEL – both done in part by authors at the Changehun University of Science and Technology. Also shown in the publication are VCSELs being produced by Jilin Provincial Engineering Center for Semiconductor Laser Technology. This is cited as based on the Changehun Institute of Optics. The VCSELs cited include:
980 – 990 nm
CW 50 to 500mw
The WAVE went looking for Chinese companies making VCSELs. We were initially told there are two of which one of the largest producers of lased diodes is Hi-Tech Optoelectronics. This company is a joint venture between the China Energy Conservation Investment Corp. and the Institute of Semiconductors of the Chinese Academy of Science in 1999 on the base of the National Engineering Research Center Optoelectronic Devices. It not only increases its production but engages in R&D of optoelectronics devices. The primary products are Epi wafers, Laser Diode and Photodetector chips, Laser diode arrays, photodetectors, modules and testing systems. Its catalog has a broad offering and professionally done. In conversations it was disclosed they have no VCSELs and the other company given to us also does not have VCSELs. In spite of the hints that VCSELs are available in China as products, we can only conclude that the activity is confined to university research facilities.
This is consistent with what we found at Electronica in Shanghai, China. Semiconductor optics technology is limited and only emerging in China. The center of expertise is the university. Given the difficulty in fabrication and early state of process control this would also limit the state of the technology in China, also based on what we saw at Electronica.
OSRAM – VCSELs need Volume
Buried in the OSRAM booth were samples of its 650nm VCSEL. When the WAVE spoke with Wolfgang Huber, the manager of the VCSEL product at OSRAM, he provided considerable insights into VCSEL market dynamics. VCSEL growth has stalled with the downturn of fiber optics communications and the industry is seeking new markets. The catch word is “sensors” but few know just what this means, except Agilent. The Agilent mouse laser is a sensor application which has high volume potential – just what is required to turn the market around.
According to Wolfgang:
The product operates at 650 or 850nm and can be made in single or multimode. OSRAM sells in bare chip, SmartLED or TO-Can. Fabrication can be done on 3” or 4” wafers.
OSRAM is focused on the sensor applications of VCSELs.
VCSELs only make sense in high volume applications. Yes, they could be used in a gas chromatograph but conventional side emitters work well here and the engineering cost of integrating VCSELs into the application is just not worth the effort. This is an application were the volume is not present to justify the change.
We have watched the laser mouse, first with the announcement with Logitech and Agilent, and this could be a sensor application that could drive the use of VCSELs.
We can make a VCSEL for this application but the volume has to justify it.
As we have examined VCSELs and those making them it is clear that most do not understand the needs of the sensor market. It takes a different mind set.
Our plastic SmartLED package is geared to surface mount conditions. However, it is very delicate. The VCSEL is quite sensitive to pressure. The package is only 1mm across and was shown in the booth under a magnifying glass.
Agilent Avoids VCSELs in its Booth
Agilent has a booth in the Fibercomm 2005 exhibition area. Given that they have 2 VCSELs listed on their web site for communications, we looked forward to speaking with them about the technology. The booth only had test instruments in it. We only presume a statement about the role that photonics and semiconductors plays given the intended divesture of this division.
One Sample of VCSEL Struggles
Finding VCSEL technology is not easy, in spite of the many laser products being shown. When we found one in the Laser Components booth it was time to ask more questions.
On display was a 665nm laser. This is being made by FireComms in Ireland, a fabless semiconductor company.
One of the problems is low yield, approximately 10%. The price is 60 € for samples and even in quantities of 1,000 the price is much too high. According to Laser Components the price should be about $3 - $4, but given the current fabrication issues such pricing is out of the question, at the current time.
Given that the cavity structure is based on the control of the fabrication process Laser Components felt that we are very early in the product development cycle. This VCSEL was fabricated on 4” wafers.
When asked about demand the response was simple – there is not much demand for VCSEL. It was stated that one application is for proximity sensing but given the low demand, from Laser Components perspective, the application cited may not be representative.
The low yields are likely to related to the early product status of the 665nm laser. The 850nm is a more established product.
Epiworks
Epiworks is a spin-off of the University of Illinois which specializes in the epitaxial wafers to create both edge and surface laser emitters. Epiworks states it mission as:
Using advanced technology to develop and manufacture high performance epitaxial wafers.
The WAVE discussed the potential for silicon integration of VCSELs and this is not in the near term.
This is accomplished with expertise in materials, devices and state-of-the-art growth systems. Our EpiLaser product has as the base material either GaAs or InP. The material capability on this wafer can include: AlGaAs, InGaP/GaAs, InGaAsP, InAlAs or InAlGaAs. We can work with 100mm or 150mm wafer diameters.
We prepare the wafers with the optical material growths required and the customer takes the wafer to fab for the final device preparation using mask based process technology associated with the semiconductor materials.
Most of the III - V compound semiconductor work is done on 2” or 3” wafers while those which use electronics in conjunction with photonics are on 3” or 4” wafters. One has to keep in mind that the optics technology is crude compared to silicon, i.e., CMOS technology.
In general, there is not the integration of circuit elements on the wafers we create. One exception is in GaAs where in cell phones for example, the power amplifiers are in this material. Thus, it is possible to integrate a circuit on the same die as a photonic element. We see 6” wafers in the GaAs materials but this is the largest size wafer required for the work that we do.
It would be possible to do the III - V material growth on Si and this is an area we have worked. Thus, it would be possible to have a photonic element on a Si wafer. The challenge is in making this happen so that quality components are possible in both the epitaxial regions and Si area. One has to keep in mind that the there are two different worlds in the process technology of 3-5 and Si. When asked if the polishing process in Si fabrication would destroy the epitaxial growths, it was countered that this can be included in the process design, the bigger issue is getting the epitaxial growth on Si in the first place.
Overall the desires of integrating photonic elements on Si can be seen but much remains to be done to make this practical.
VCSEL Fog Clears
Having struggled through multiple conferences to unlock the dynamics behind VCSEL technology and market. Consider the following:
The advantages of VCSELs are well known
High efficiency
Can be battery powered
Optical emission is suited for many applications
Well formed directional beam with Gaussian like shape
High Reliability
Single and MultiMode Lasers are possible
The first commercial VCSEL was sold in 1996 and a total of 1m were sold by 1998. During the telecom boom a total of 20m VCSELs were sold by 2001. By Q1 2005 a total of 35m were sold, from 1996. It is estimated that 50m VCSELs have been shipped and of that Advanced Optical Components, which was known as Honeywell, shipped 35m.
With the down turn of telecoms Honeywell sold its VCSEL division for a mere $74 million in cash. It is now a subsidiary of Finisar and called Advanced Optical Components. This division is actively seeking new applications for VCSELs, of which sensors, is one.
Most of the VCSEL research effort has been devoted to improving the communications bandwidth and matching the wavelength of emission to the best pass band of optical fiber. There is one problem – who cares about upgrading the bandwidth of all the dark fiber which is in the ground? It can be said that PON would be another telecom growth market but this has yet to materialize in high volumes.
VCSELs have not appeared in consumer electronics in that there has no demand for the attributes it brings. We find it telling that Sony is only developing VCSELs for the communications sector. Yes, there may be other applications but most of the high volume ones cited for its existing product line are the obvious uses – DVD and even Blu-Ray.
VCSELs are the product of sophisticated process technology, especially the epitaxial growth to achieve the cavity properties. From LASER it was clear that this is not in the grasp of the Chinese optical industry. We expect it will be years before we see production of high quality VCSELs from China.
Innovation in Optics and Design
The WAVE also went looking for innovative optics technology. We found a number of impressive examples.
viaoptic
Every time the WAVE walked past this small stand it was packed. viaoptic is a German company, listed as an affiliate of Leica, making optical components in Germany. Their advantage is the ability to make injected molded optics with the precision of glass. Here are examples of the components:
Laser scanner polygon – 8 plane faces – 3X8mm face flatness to 1 fringe
Lens – 2mm in diameter – flatness to 1 fringe
Lens – 20mm – both aspherical and spherical – 10microns
Lens array – 8 X 16mm – 3 fringes
Fraunhofer-Institute
The Institute Siliziumtechnologie is specializing in 3D structuring of optical elements using Grey Tone Lithography. This is a capability to make arbitrary shaped height profiles in photo resists, silicon or siliconoxide on silicon wafers. These surfaces can then be transferred to metal by electroplating or embossed into polycarbonate. Some of the parameters include:
Maximum substrate size = 6”
Structure height = 0 to 23 microns
Greytone levels > 280
Greytone pixel size < 1 micron
Lithography steps = 1
The surfaces can be specified mathematically. An example shown was a spherical micro lens array where the lenses were 150 microns X 150 microns. The curvature of the lenses is 440 microns.
IAOPE
The Institute for Applied Optics and Precision Engineering was showing its capabilities in optics for microdisplays. These are cited as particularly demanding systems due to the need for high efficiency and low levels of reflected light. Examples of designs include:
Color splitting and unifying systems
Polarization optics
Microoptics on-display
Coatings on display
False light analysis
IMOS Gubela
IMOS described its capabilities in creating micro-optics and microstructures. They work with PPMA, polycarbonate and optical glass. Their glass structures include:
Traffic reflector
Retroreflector
Diffuser
Complier
Collector
Half Wheel
Wheel
Fresnel
Ladder
Triangle
The structures can be as large as 100mm with grid pitches from .05mm to 6mm.
Digital Optics
This North Carolina company specializes in wafer based micro-optics. They do high efficiency diffractive optics, refractive optics and optical sub assemblies of these parts. One of the products is the ICE CUBE optical engine. This is a platform for the integration of passive and active optical elements. Through the use of wafer based integration and high speed die bonding they claim many benefits beyond the TO can.
Leister Microsystems
With headquarters in Switzerland, this company designs and fabricates micro-optics that include refractive microlens arrays and diffractive structures. The materials they can work with include:
Fused silica
Silicon
Plastics
Polymer on glass/silicon/GaAs
The capability of the company includes: design, fabrication form samples to large volume production and systems. They also cite the ability to do MOEMS.
One example of the designs they have done is microlens arrays in front of CCD sensors for digital cameras.
Center for Advanced European Studies and Research
They described work on digital holographic facial topometry. Using pulsed holography it is possible to construct very accurate 3D, i.e., sub-mm accuracy, profile with no motion blur (35ns pulse). It is also possible to construct a facial view that extends 270 degrees. Although not described as a biometric such a technique would certainly erase any issues on the accuracy of the recorded facial characteristics.
LightTrans
This small company in Jena, Germany has a state of the art optical engineering tool. They call it the photon management toolbox. The current version is 2.0 and coming is 3.0 at the end of 2005. The software has the ability to:
Represent light as harmonic fields
Generalized propagation of light
Detectors
Accomplish optical design also using tradition methods
The software input is similar to a spreadsheet. This can define the light sources, media, optical interfaces, propagation operators and light detectors.
The professional version of the software is $6k.
The company also provides consulting services in advanced optical concepts and design.
JCMWave
The tag line is “True Solutions in Optics.” The software is a rigorous solution of Maxwell’s equations using a finite element method. The company has as its background a mathematical institute in Germany and they pride themselves with accuracy and performance. This software can even run on notebook computers. The solutions provide a complete vector description of the propagation of waves thus it is possible to support smooth and abrupt changes in refractive index, multiscale structures in 1D, 2D and 3D, photonic crystals and polarization effects. We discussed the ability to model VCSELs and the software is well adapted to this problem. Further it is possible to output wavefronts what can be input to more traditional optical design programs.
The cost is $30k to $40k.