Fiber optics is one of today's hottest industries. But, manufacturers can't supply enough optical components to keep up with demand. One of the biggest challenges facing the industry is finding a way to automate the assembly process.

If the popular movie, "The Graduate," was remade today, the title character would probably be advised to seek his fame and fortune in "fiber optics" rather than the infamous "plastics." Optical technology is expected to be as important to the 21st century as electricity was to the 20th century.

With a 30 percent annual growth rate, fiber optics is one of today's hottest industries. And there appears to be no end in sight. Construction crews are working feverishly to install thousands of miles of optical fiber cable under oceans, city streets and farm fields and alongside highways, railroad tracks and pipelines.

Last year, long-distance telecommunication carriers deployed 11 million kilometers of fiber in North America, according to KMI Corp. (Newport, RI). The market research company predicts $2.6 billion will be invested in worldwide fiber optic capacity expansion between 2000 and 2002. Even more money--$3.7 billion--will be invested in 2003 and 2004.

Installing long-distance optical fiber cable is one thing. Getting it to work is another. That depends on a wide variety of components that form the building blocks behind optical telecommunication networks.

Unfortunately, there's a severe shortage of these key devices today. And, the market is expected to grow dramatically during the next 4 years. In fact, observers predict the fiber optic component field will mushroom from $6 billion today to $24 billion by 2003 and more than $50 billion by 2005.

To satisfy that huge demand, manufacturers are scrambling to build fiber optic components, such as amplifiers, attenuators, connectors, lasers, filters and switches, as fast as they can. Right now, most assembly work is done by hand. But, with demand continuing to soar, the race is on to automate the process.

Many different issues pose a challenge to automating fiber optic component assembly, however. Issues such as a lack of standardized assembly and test techniques have hindered the development of process automation equipment.

Fiber optic components require many manual, labor-intensive customizations and precise adjustments throughout the assembly process, adding to the overall cost. In addition, a lack of standardized package designs have crippled the ability of manufacturers to move from small scale to high volume production.

High Stakes Race

The stakes are extremely high in the fiber optics field. According to RHK Inc. (South San Francisco, CA), a market research and consulting firm, the entire market will be worth $52.3 billion by 2005 as more telecommunication carriers try to accommodate the rapidly increasing flow of data traffic over their networks, all driven by the Internet.

Not surprisingly, that explosive growth is coupled with fast-paced change. The fiber optics market is under a constant barrage of new technology, tongue-twisting acronyms and obscene stock prices. The business is attracting scores of entrepreneurs and every few months, a startup company claims a "breakthrough technology."

According to one industry observer, it's not uncommon for companies to develop products that are obsolete before they get out the door. At the same time, there has been rampant merger and acquisition activity: approximately $50 billion in stock and cash has changed hands within the last two years as companies jockey for strategic position.

Companies such as JDS Uniphase Corp. (San Jose, CA) have been the darlings of Wall Street in recent months. Between October 1998 and January 2000, the company's stock shot up an unbelievable 2,680 percent. JDS Uniphase has grown into the largest fiber optic component manufacturer in the world by gobbling up other companies. For instance, last summer it acquired rival SDL Inc. for a whopping $41 billion.

Despite such rapid growth and huge demand, JDS Uniphase and other component manufacturers have been plagued by slow assembly processes. "Manufacturing capacity and optical component availability remain low relative to demand," says Andrew McCormick, a senior analyst at the Aberdeen Group Inc. (Boston). "Equipment suppliers, both old and established, are struggling to meet demand from carriers, while the financial community is investing billions of dollars in anticipation of double- and triple-digit returns."

A Cottage Industry

The term "cottage industry" has been widely used to describe the fiber optic component industry. That's because most devices are still built in fairly low volumes.

Randy Heyler, vice president of photonics packaging and advanced automation systems at Newport Corp. (Irvine, CA), says the way most fiber optic components are currently manufactured resembles a watch factory in the days before automated assembly. The majority of components are assembled manually, with tremendous variances from operator to operator.

Heyler and other observers claim there are many parallels between the development of the semiconductor industry 25 years ago and the fiber optic component market today. "During its infancy, a significant portion of semiconductor equipment was made in-house," says Kyle Eales, general industrial market manager at Loctite Corp. (Rocky Hill, CT). "The automation of that industry was spurred by innovators who designed, developed and implemented tools and techniques to improve productivity, cut costs and raise quality."

According to John Lively, a senior analyst at RHK Inc., the fiber optics industry is capacity constrained and labor intensive. He claims the industry is not very scalable, with "predominantly piece-part assembly."

Assembly processes are notoriously slow. For instance, thin-film filter production requires a technician to manually glue separate pieces together. The process can take up to 45 minutes per device. After the device is assembled, it has to be tested. "If you go into any component plant, you see rows and rows of people," says Elizabeth Bruce, an optical components analyst at the Aberdeen Group.

In fact, the majority of employees at JDS Uniphase are involved in production tasks, according to Bruce and other analysts who have toured the company's facilities. Demand continues to be so strong that JDS Uniphase has not been able to improve on lead times. The company says its growth is limited by how fast it can increase capacity.

"JDS Uniphase is committed to increasing capacity by a factor of four over the next 18 months," says Kevin Slocum, head of telecom research at Wit SoundView Corp. (New York), an investment banking firm that specializes in the high tech industry. To ramp up production volume, JDS Uniphase is relying on an ambitious combination of plant and employment expansion, huge investments in automation and increased use of outsourcing.

Other companies are facing the same hurdle when it comes to scaling up volume. They are desperately searching for new assembly techniques and automated solutions. "If we continue on our current path, we will need 45,000 employees and 8 million square feet of manufacturing capacity to meet our customers' expected demand over the next 3 years," laments an executive at a leading component manufacturer.

Optical Components

Fiber optic communication requires more than just hair-thin strands of glass. A wide variety of optoelectronic components and photonic devices are necessary to generate, modulate, guide, amplify, switch and detect light.

Optical components are tiny, complex devices that form the backbone behind telecommunication networks. Devices are assembled into a package or module that couples the light into or out of fiber optic cable.

Two classes of fiber optic components exist: active and passive. Active components consist of the semiconductor laser technology that is necessary to provide the light in a fiber optic network. These devices are generally easier to assemble. They require the integration of electronics and wiring into the package using traditional assembly technologies, such as soldering and die- and wire-bonding techniques. Receivers, transmitters, modulators, amplifiers and switches are examples of active components.

Passive components operate on the light passing through the fiber and do not require power or electronics. Their function is to filter, divide or combine the light signals traveling through the optical fiber. These components are much more labor intensive and costly to manufacture. Passive devices include couplers, isolators, and wavelength division multiplexers and demultiplexers.

Optical components are made of many different types of materials, such as gallium arsenide, indium phosphate, lithium niobate, silicon and zirconia. Last year, researchers at the University of Washington developed an electro-optic polymer for making optical components.

Up until now, the big problem with using polymers for optical applications has been high light losses and poor thermal and photochemical stability. However, the university scientists claim their material offers improved signal quality and lower optical losses, which enable faster switching speeds.

Right now, many components are expensive because technologies are new and manufacturing processes aren't well developed. In addition, demand is outstripping supply, keeping prices high.

Certain key components remain inefficient, hindering the expansion of fiber optic networks. One of these devices is called an optical splitter. It splits the light traveling along a single transmission line into several new lines so that the signal can be distributed to customers.

Splitting the light results in a large loss of light intensity and signal quality. A typical splitter divides the light from a single optical fiber into 16 new lines, losing 94 percent of the light intensity in the process. To counteract this loss, fiber optic networks must use expensive optical-power boosting amplifiers.

"Next-generation optical networking is the hottest segment in the industry today," says Aberdeen Group's Bruce. When fully implemented, all-optical networks are expected to deliver vast amounts of information unimpeded by the bottlenecks of conventional transport systems. With an all-optical network, information can be carried via light particles from PC to PC without ever having to be converted to electrical signals.

The fastest growth is coming from components used to make dense wavelength division multiplexing (DWDM) gear, which increases the number of wavelengths on a single beam of light. With DWDM technology, 6.4 terabits of data per second can be transmitted over a single fiber, which is a 3,000-fold increase over what was possible in the past.

Analysts at RHK Inc. predict the market for DWDM systems will skyrocket from $5 billion in 2000 to $24 billion by 2004. During the next 12 months alone, the DWDM optical component market will grow 90 percent.

Component manufacturers are under tremendous pressure to introduce higher and higher capacity DWDM systems. Rapidly growing demand for DWDM-based bandwidth has created a corresponding increase in demand for high-performance components, such as optical amplifiers, pump lasers and vertical-cavity surface-emitting lasers.

One of the key elements of the all-optical network is the all-optical switch. This device uses microscopic mirrors--more than 250 mirrors fit on a 1-square-inch chip--and lasers that can be tuned to pump out different colors of light. Many of today's switches must first convert optical signals into electrical signals, read them, process them and then convert them back to optical signals before sending them on their way. That conversion causes bottlenecks that slow down the routing process.

Lucent Technologies Inc. (Murray Hill, NJ) recently unveiled the world's first high-capacity, all-optical switch. The WaveStar LambdaRouter is capable of routing more than 10 trillion bits of information per second. That's the equivalent of nearly 2,000 CD-ROMs or 2 billion one-page e-mails. Early this year, Lucent plans to unveil an even faster router that contains 1,024 mirrors.

Joining Methods

Optical components are typically joined with adhesives, laser welding or solder. "The most common way to join optical fibers and components is to use adhesives," says Kevin Ely, manager of microjoining and plastics at the Edison Welding Institute (EWI, Columbus, OH). "Most are acrylic blends that match the optical quality of the fiber."

Adhesives tend to be popular with assemblers because they are versatile, fill gaps on uneven surfaces, join dissimilar substrates and offer flexible adjustment time to position parts accurately. "The adhesives are matched to the index of refraction of the fiber so energy is not lost in the connection interface," explains Ely.

"Light-curing adhesives are the preferred products, although they are just beginning to catch on in this industry, as throughput and higher yields become high priorities," says Loctite's Eales. "Both light-curing free-radical and cationic epoxies are used, with the later typically requiring a thermal bump to complete the cure."

According to Eales, the primary advantage of light-cure processing is speed of cure. "Depending on the product and system, cures can be achieved within seconds," claims Eales. "Free-radical curing products are extremely versatile and offer the fastest cures, but are not ideal for every application.

"Cationic systems are not subject to oxygen inhibition like free-radical systems, and they provide excellent surface cures, along with high thermal resistance and low outgassing. Unlike free-radical systems, some cure continues after the light source is removed." Loctite is unveiling a new line of epoxies and anaerobic acrylics for fiber optic applications early this year.

In very high-volume assemblies, laser welding provides the fastest and most cost efficient joining process. It puts considerable limitations on package design, however.

Laser welding ranks as the "most automatable" of the attachment approaches, says Newport's Heyler, because it lends itself to high volumes. But, laser welding requires that all components be housed in metal ferrules to protect optical fibers from the heat. "Appropriate attention to the design of the joint and the execution of the weld must be taken to achieve a successful implementation," Heyler points out.

Newport has developed a machine that uses two pulsed Nd:YAG laser beams--one on each side of the ferrule--to weld components into place. The machine performs postweld shift compensation and correction with a combination of laser hammering and automated mechanical adjustment. According to Heyler, this results in a repeatable, epoxy-free process that can be used to assemble high-volume quantities of laser diode modules, such as the pump laser diode used in fiber optic amplifiers.

Soldering is less expensive than welding, while offering some of the benefits of laser welding. Soldering is used to a lesser extent, mainly because it has not been proven in optical applications. Concerns exist over control of shrinkage and its inability to be controlled effectively.

Solder is used to join optical fibers parallel to substrates with surface-mounted electronics, such as lasers or sensors. In this process, the thin optical fiber is pulled out of alignment first by capillary forces during wetting of the solder on the fiber, and then by solder shrinkage during solidification and cooling. Engineers face the challenge of predicting the extent of fiber shift due to these two mechanisms and developing reduced or more reproducible fiber shift.

Gould Fiber Optics (Millersville, MD) has developed a glass solder process for making a glass-to-glass bond between optical fibers and a silica substrate. The company claims that its GlasSolder process can eliminate epoxy as the primary bonding mechanism and is not susceptible to degradation from humidity.

Assembly Challenges

Optical component assemblers face numerous challenges, such as developing standardized align and attach processes, improving the bonding process to reduce bond shifts, developing devices that are easier to access and manipulate, and designing next-generation devices with automated manufacturing in mind.

Most of these problems stem from the fact that the fiber optics industry is still quite young. As a result, no standards exist for many products and there is a wide variation in package designs and configurations. "Every product is built differently, because packaging standards are very fragmented," says Newport's Heyler. "It's absolutely incredible. There is no industry association driving standardization."

Each time a technological advancement is made, the ability to produce components in volume gets more difficult. Each successive performance hurdle requires both higher performance components and more of them.

Many optical fiber components are so new that the manufacturing processes for making them are still slow and inefficient. In many cases, new ways of automating the process haven't been invented yet. "The people who have designed many of the packages are scientists," Heyler points out. "As a result, the designs don't match volume manufacturing requirements."

"Most methodologies were developed in the lab, with a process similar to pilot production," adds Joe Campbell, vice president of marketing at Adept Technology Inc. (San Jose, CA). "The industry is in a transition phase."

Compounding the problem is the fact that many assemblers are new to the industry. "The average tenure at most companies is less than a year," claims Heyler. Optical component manufacturers are eagerly searching for veterans of the semiconductor, disk-drive and cell-phone industries.

And, on top of all that, optical fiber is very difficult to work with. It is vulnerable to excessive bending, kinking and crushing. Assembling optical components requires extremely high precision, with placement accuracy of the optics typically at less than 1 micrometer. This tolerance is critical to ensure the reliability of the device. Most assembly is done in clean room environments.

"Actual device fabrication is similar to semiconductor industry manufacturing, particularly on laser diodes and photodetectors," says Loctite's Eales. "The process requires several specialized, intricate processes, particularly when aligning and attaching fibers and optical components. This step often must be customized or adjusted to each component design." A single component can cost several thousand dollars and require up to 30 minutes to assemble.

"The bonding process itself can introduce large amounts of heat into the package, so minimizing any shift or movement during bonding and curing becomes an important aspect in the assembly," adds Eales. "Even with highly skilled operators, working with high magnification vision systems and extremely precise motion control systems, bond-shift problems occur and must be dealt with."

Automated Solutions

The need to inexpensively supply increasing quantities of components, while maintaining high reliability and yield, is pushing manufacturers toward automated assembly and test operations. They're scrambling to develop machine-assisted alignment and attachment processes to assemble products efficiently in large volumes.

To increase product yields, the National Institute of Standards and Technology (Gaithersburg, MD) estimates that capital costs for fabrication lines need to be reduced by 75 percent while module testing times are reduced by 90 percent. Packaging, which includes methods for aligning optical elements and integrating electronic components, currently accounts for 60 to 80 percent of manufacturing expenses.

Fiber optic component manufacturers are struggling to achieve increased performance and lower cost. Automation allows component manufacturers to significantly reduce their time-to-market and quickly increase capacity, while reducing their dependence on highly skilled assemblers.

Nortel Networks Corp. (Brampton, Ontario) has invested more than $660 million during the last 12 months to triple production capacities for its components business. The company plans to invest more than $1 billion to boost its production by 30 percent next year.

Another large component manufacturer that has invested heavily in automation is Corning Inc. (Corning, NY). The 150-year-old company recently opened a state-of-the-art thin-film assembly line in Marlborough, MA. The new facility cuts down assembly time from hours to minutes, resulting in a ten-fold increase in throughput.

One of the processes that Corning has automated involves soldering. "The soldering machines use optical power peaking measurements to align parts perfectly before they are attached," explains Windsor Thomas, business manager of micro-optics components at Corning. "In the new packaging line, the soldering process takes just 45 seconds per device. The older soldering method required 45 minutes per device and needed a highly skilled technician to precisely align and solder the package manually. Manufacturing yields from the old process were in the 60 to 70 percent range. The new process has resulted in a 25 percent improvement in manufacturing yield."

Corning also recently formed a joint-venture with Samsung Electronics to mass produce optical networking products. The new company is assembling DWDM components using robotics and other automation technology developed by Samsung.

"We have taken the manufacturing process from a highly manual, labor-intensive, low yield, high cycle time situation where many highly specialized technicians sit at rows and rows of benches, and have turned it into a streamlined, automated environment resulting in high yields, low cycle times and high-quality DWDM components," says Thomas. "This radically improves the quality and uniformity, of the devices that we are selling to the market today."

Not to be outdone by its rivals, Lucent Technologies unveiled a state-of-the-art optoelectronics center in Breinigsville, PA, last year. Thanks to automated manufacturing technology, Lucent can currently produce as many components in a week as it used to in a year.

Until recently, Lucent and other component manufacturers were forced to design and develop their own automation systems. But, assembly automation companies, such as Adept Technology and Newport, are beginning to see the light. Eager to capture a slice of the lucrative fiber optics pie, those two companies have been aggressively acquiring specialist firms.

For instance, during the last 9 months, Adept Technology has bought several motion control and machine vision companies to shore up its fiber optics expertise. Recent acquisitions include HexaVision Technologies (Sainte Foy, Quebec), NanoMotion Inc. (Santa Barbara, CA) and Pensar Tuscon Inc. (Tucson, AZ).

Newport is using a similar strategy to develop new technology for high-speed fiber optic component assembly. In September, it acquired Unique Equipment Co. (Chandler, AZ), a systems integrator specializing in robotics.

Precise Alignment

Alignment is extremely critical to fiber optic component assembly. "It's a very precise assembly process," says Heyler. "Precision is measured in nanometers." Tolerances often are in the submicrometer range.

"The major issue in joining fibers is getting the face of each fiber aligned and square to each other," explains EWI's Ely. "Any misalignment means reflected energy, which equates to loss."

To understand the precision required in fiber optic assembly, consider the following scenario: take a human hair and sharpen the end to 1/10th of its width. Then attempt to align the tip to the end of a laser diode of similar size at a distance 1/20th of its width. Then bond it in place with an accuracy of 1/1,000th of the width. Too much movement and the laser diode is either destroyed or the device will not have enough power. In either case, a $2,000 device gets thrown out.

According to Heyler, this is the most critical step in a multifaceted process to create one 980-nonometer pump laser diode, a key enabling component for optical amplifiers and DWDM applications. Market estimates call for more than 2.2 million of these devices to be manufactured in 2004, compared to just 100,000 in 1998.

Holding and handling optical components is one of the most critical aspects of automated assembly. "With fiber, you have a piece that's not very rigid," says Adept's Campbell. "The biggest challenge is hanging on to a piece of fiber. But, the better you can put it together, there's more value added because of better light transmission."

The process of attaching an optical fiber to a component is commonly referred to as pigtailing. A small length of optical fiber is grabbed and its tip is encapsulated in a ferrule, which provides a metallic housing necessary for rigidity and bonding purposes. Once optimum coupling efficiency is achieved, with the help of lasers, machine vision systems, linear motors and piezo stages, the component is attached.

Adept Technology is developing flexible automation platforms for fiber optic component assembly applications. The platforms include four- to six-axis material handling robots, vision systems and precision stages for final fiber alignment. A high-speed positioning tool includes both motorized and piezo stages that enable assemblers to test, align and assemble fiber optic components with greater speed than has been possible in the past. "With assembly requirements ranging from the 10-micron range down to submicron levels, the tight integration of machine vision represents a critical factor for achieving accurate and consistent assembly results," says Campbell.

A variety of chucks, grippers and fixtures are used to automatically manipulate optical fibers and ferrules. According to Heyler, parts handling must work in concert with the component design, alignment process and attachment method. In some applications, pneumatically actuated tweezers are used for gripping and positioning. Special vacuum chuck fixtures also are used to secure packages.

When the attachment and alignment steps are completed, a rigorous inspection process begins. Component assembly requires a significant amount of testing to ensure that the fiber and component are coupled correctly. Accurate coupling is critical for minimizing dispersion losses and maximizing achievable distances and bandwidths.

Evolving Trends

Traditionally, fiber optic devices have been assembled using various discrete components. Some observers believe integrated optical components and wafer scale manufacturing provide an answer to the assembly woes that have been plaguing the industry.

Companies such as Bookham Technology (Abingdon, Oxfordshire, UK), Digital Optics Corp. (Charlotte, NC), Lightwave Microsystems Corp. (San Jose, CA) and Nanovation Technologies Inc. (Miami) have developed processes to manufacture components based on silicon chips. By using this technology, the companies take advantage of standard, high-volume semiconductor assembly processes that offer much higher yields.

"While traditional fiber optic component manufacturers combine discrete elements, such as lasers, lenses and filters, in manually assembled devices, we can achieve the same functionality in a single integrated silicon chip," says Andy Cornish, vice president of manufacturing at Bookham Technology. Cornish boasts that this process significantly reduces the cost, time and complexity of manufacturing fiber optic components.

Scalable, high-volume production permits a wide variety of optical components to be manufactured using established process steps developed by the semiconductor industry. "Conventional optical devices require considerable skill and manual manipulation to attach and align optical fibers," Cornish points out. "Our technology allows for a much simpler fiber attachment, resulting in easier and quicker device packaging and interfacing."

Sidebar: Why Fiber Optics?

Fiber frenzy is being driven by an insatiable demand for fast Internet access. Existing communication networks are straining to handle Web traffic, which is doubling every four months. Meanwhile, users are clamoring for as much bandwidth as possible so they can download data faster both at work and at home.

To satisfy that demand, telecommunication companies are expected to spend $1 trillion updating their networks during the next 20 years. Carriers such as AT&T Broadband, MCI WorldCom and Sprint are investing heavily in optical networks and optical equipment to lower operating costs in the face of intense competition.

"During the next 10 years, network traffic will grow 1,000 times, while revenues will increase 10 times," says Mark Storm, fiber optics analyst at Frost & Sullivan Inc. (Palo Alto, CA). "Equipment and operation cost must reduce the unit cost of bandwidth 100 times to make this possible. Optical technology that reduces component and subsystem cost is important."

Super thin strands of glass fiber provide the key to high-speed data communication. Fiber optics is much faster than traditional copper wire because light waves encounter much less resistance in glass than electricity does in wire.

One optical fiber can carry 130,000 simultaneous phone calls. Several hundred fibers are typically bundled into a single cable. The result is Internet access speeds that are 60 times faster than today's fastest copper wire connection.

Optical networks promise to open the door to a new class of real-time multimedia services and applications, such as crystal clear videoconferencing, interactive television and full-length movies that can be downloaded in seconds rather than hours.

"There is an ongoing shift in network traffic from voice to data," says Storm. "Data will grow from less than 20 percent of carrier revenues today to 50 percent of revenues by 2005.

"As bandwidth cost comes down, demand will continue to grow astronomically," Storm predicts. "We're just at the beginning of a large secular trend toward an optically connected world."