OmniCure Assembly Solutions Assembly of TOSA/ROSA Modules Challenge Low cost assembly of the TOSA/ROSA receptacle modules. Solution The OmniCure S2000 UV Spot Curing System with Closed-Loop Feedback technology and a three leg High Power Fiber Light Guide along with a light curable adhesive. Benefit A uniform, repeatable curing process which will increase reliability and reduce manufacturing costs. Application Note: OMNICURE TOSA008/09 April 1, 2009
Optical Modules are electronic components that simultaneously convert an electrical signal to an optical signal or an optical signal into an electrical signal. A transmitter is a device that includes a source (LED or laser diode) and driving electronics. It functions as an electrical-to-optical converter. A receiver is a terminal device that includes a detector (photodiode) and signal processing electronics. It functions as an optical-toelectrical converter. A transceiver is a device that performs, within one chassis, both transmitting and receiving functions. Optical Modules are divided into several industry types. One type is known as Receptacle Modules. This type is represented by TOSA (Transmitter Optical Sub- Assembly) and ROSA (Receiver Optical Sub-Assembly) Assemblies. Optical modules are the core devices for any optical communication system. They enable highspeed voice, video and data communications for networking, storage and wireless applications over Local Area Networks (LANs), Storage Area Networks (SANs), and Metropolitan Area Networks (MANs) using Ethernet, Fiber Channel, IP, SAS, SATA and SONET/SDH protocols. Application Note: OMNICURE TOSA008/09 April 1, 2009 Page 2
Figure 1 :: TOSA/ROSA Modules The main features of the TOSA (Transmitter Optical Sub Assembly) and ROSA (Receiver Optical Sub Assembly) receptacle modules are simplicity in assembly and low cost, compared to the conventional receptacle modules. This is the reason why they became key components of transceivers for optical data links. Figure 2 :: Optical Network Most OC vendors attributed revenue growth to carrier network expansion and project further growth as traffic from wide-scale demand for video is still to come. Equipment vendors in all segments are reporting strong revenue gains, another indicator that the market is continuing to expand. This application note will show how the OmniCure S2000 UV Spot Curing System and a three legged High Power Fiber Light Guide will help manufacturers of TOSA/ROSA receptacle modules to improve the reliability of their products while also reducing assembly costs. Optical Component Market The optical component market has shown steady growth since mid-2007 after recovering from an inventory correction that weakened the industry for much of 2007. The global optical components market reached $1241 million in Q3 of 2008, a 12% advance versus the same quarter in 2007 1. Total revenue through Q3 of 2008 is at 3.7 billion 2, well ahead of 2007 pace where revenue for the full year totaled just over $4 billion, which was up 4% compared to 2006 3. Market leader JDSU posted a 5% sequential growth led by ROADMs, tunable lasers, and transponders 4. Finisar, the second-largest optical component company, posted a gain of 9% driven by sales of LAN/SAN transceivers 5. Opnext, the fifth-largest optical component company, posted the strongest quarter-over-quarter growth among the top 10 suppliers at 9% 6. Growth came from 10- and 40-Gbit/sec transceivers and transponders. Bookham posted the strongest year over year growth at 39%, citing strong demand for tunable lasers and transponders 7. Assembly of TOSA/ROSA Modules The transmitter of a TOSA assembly contains a light source, most often an LED or laser diode. To ensure that an optimal signal is emitted from the optical component, the source is actively aligned and then bonded into position using a UV curable adhesive. It is important that the adhesive receives a uniform distribution of UV light, in a controlled manner, in order to preserve precision alignments. If the adhesive is not cured in a controlled manner, it will shrink at different rates and to different degrees. The resulting differential shrinkage shifts the component, causing misalignment, effectively rendering the device useless. Therefore, a uniform and repeatable curing process is required to maximize yields in the assembly of TOSA/ROSA modules. The OmniCure S2000 UV Spot Curing System along with specialized UV curable epoxies, formulated to minimize shrinkage, are ideal for this application. Once the component has been properly aligned, it is important to secure it in place quickly before it moves out of alignment. The 200W lamp found in the OmniCure S2000 System will cure most UV curable epoxies in seconds. The resulting bond will be strong and environmentally resistant to insure years of reliable service from the optical component. 1, 2. Article Market Share: 3Q08 global OC www.feedage.com, Dec 2008, source Ovum 3. Article Ovum RHK: Optical component sales top $1 billion for the second sequential quarter. www.lightwave.com March 2008, Source Ovum 4, 5, 6, 7. Article Ovum: Optical components market up 4% in 1Q08, lightwave.com, Sept 2008, Source Ovum Application Note: OMNICURE TOSA008/09 April 1, 2009 Page 3
A three-legged High Power Fiber Light Guide is recommended for this application to provide an even distribution of UV energy to the adhesive. Proprietary technology within the High Power Fiber Light Guide insures that an equal amount of UV energy is transmitted from each leg of the light guide, arranged radially symmetrical around the device. This provides even curing of the adhesive to preserve the optimum alignment. Following the alignment procedure, the entire component housing is sealed using a UV curable material, protecting the component from the environment and providing structural strength. At this point, the packaged source may be incorporated into the TOSA assembly. The receiver of a ROSA assembly contains a detector, most often a photodiode. To insure that an optimal signal is received from the transmitter, the detector can also be actively aligned and then bonded into position using a UV curable adhesive. This also requires a uniform distribution of UV light, in a controlled manner, in order to preserve alignments. Differential curing can shift the component, causing misalignment, effectively rendering the device useless. Figure 3 :: Closed-Loop Feedback The OmniCure S2000 provides adjustment of the UV irradiance in 1% increments allowing for the precise selection of the irradiance level required for curing the adhesive in a controlled manner. Once the optimum irradiance level is selected, the proprietary Closed-Loop Feedback control maintains that level for every cure, insuring a repeatable curing process. LUMEN DYNAMIC UV CURING TECHNOLOGY PRECISE AND REPEATABLE The OmniCure S2000 UV System cures UV epoxies in seconds forming a strong environmentally resistant bond. The Closed-Loop Feedback technology found in the OmniCure S2000 System insures constant irradiance levels, for a repeatable curing process. The three leg High Power Fiber Light Guide insures that the epoxy is cured evenly so that the optical component is maintained in proper alignment. Application Note: OMNICURE TOSA008/09 April 1, 2009 Page 4
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