Page 352 - Optical Communications Essentials

Manufacturing Issues

342 Chapter Twenty

to a platform consisting of a material which has the opposite thermal expansion
property from that of the FBG. With this method a wavelength stability of bet-
ter than 0.5pm/°C can be achieved together with a temperature-dependent loss
below 0.01dB/°C over an operating range of 0 to 70°C.
Likewise, bulk-grating-based optical products may be designed to be passively
athermal, so that no active temperature control is required. In contrast to com-
ponents that require active temperature control, for devices with passive ather-
mal compensation there is no need for electric power, alarms, and monitoring
circuitry.

20.3. Integrated Automation

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. This section examines integrated-automation
machines from two different vendors for these functions.
First consider the connector preparation system from Sagitta, which is shown
in Fig. 20.7. This system has the integrated capabilities of batch polishing,

Figure 20.7. Example of an automated connector preparation sys-
tem. (Photo courtesy of Sagitta; www.sagitta.com.)

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