Page 358 - Optical Communications Essentials

Manufacturing Issues

348 Chapter Twenty

Significant cost reductions and enhanced performance are two key factors for
component design related to the growing use of dense WDM systems. These are
great challenges, since performance improvement often leads to more expensive
devices. This is being addressed through developments in areas such as planar
lightwave circuits (PLCs) and inexpensive passive athermal designs for thermal
wavelength stability. Since PLC technology increases the density and function-
ality of photonic devices per square centimeter, it leads to optical transmission
equipment designs that are simpler, cost less, and are not as expensive to oper-
ate since they consume less electric power.
Sometimes what appears to be the simplest step in a fabrication process can
take a long time if individual pieces are processed manually. Among these are
connector attachment, preparation of optical fiber pigtails for use in devices,
and polishing of optical components. Several companies are offering integrated-
automation machines for such functions.
Packaging of devices for optical fiber communications must take into account
issues such as optical power coupling, thermal management, mechanical sup-
port, and hermetic sealing for environmental protection. Hermetic packaging
designs have the challenge of creating a hermetic seal at the point where the
optical fiber passes through the package wall. This can be achieved by stripping
the fiber down to the cladding and then bonding a thin metal layer to the glass.
This creates a strong metal coating that allows the fiber to be soldered to the
package at the point where it passes through the enclosure wall, thereby pro-
viding a hermetic sealing.

Further Reading

1. J. G. Bornstein, “Semiconductor techniques enhance production of planar lightwave circuits,”
Optical Manufacturing, vol. 1, no. 1, pp. 25–29, March 2002.
2. R. Cisneros and G. Shechter, “Integrated automation promises improved planar lightwave cir-
cuits,” Optical Manufacturing, vol. 1, no. 1, pp. 31–34, March 2002.
3. J. Sepulveda and L. Valenzuela, “Integrated subassemblies improve optoelectronic package per-
formance,” Optical Manufacturing, vol. 1, no. 2, pp. 27–29, May 2002.
4. B. Benton, “Automating optical and IC module assembly and thermal management,” Optical
Manufacturing, vol. 1, no. 2, pp. 23–25, May 2002.
5. G. Ogura, “Hermetic packaging,” Lightwave, vol. 18, pp. 28–30, October 15, 2001 (www.light-
wave.com).
6. S. J. Horowitz and D. I. Amey, “Ceramics meet next-generation fiber optic packaging require-
ments,” Photonics Spectra, pp. 123–126, November 2001 (www.photonics.com).

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