HP 83487A, User Manual, Page: 83 / 98

5-15
Reference
Cleaning Connections for Accurate Measurements
• Is repeatability tolerance for reflection and loss important? Do your specifica-
tions take repeatability uncertainty into account?
• Will a connector degrade the return loss too much, or will a fusion splice be re-
quired? For example, many DFB lasers cannot operate with reflections from
connectors. Often as much as 90 dB isolation is needed.
Figure 5-1. Basic components of a connector.
Over the last few years, the FC/PC style connector has emerged as the most
popular connector for fiber-optic applications. While not the highest perform-
ing connector, it represents a good compromise between performance, reli-
ability, and cost. If properly maintained and cleaned, this connector can
withstand many repeated connections.
However, many instrument specifications require tighter tolerances than most
connectors, including the FC/PC style, can deliver. These instruments cannot
tolerate connectors with the large non-concentricities of the fiber common
with ceramic style ferrules. When tighter alignment is required,
HP instruments typically use a connector such as the Diamond HMS-10, which
has concentric tolerances within a few tenths of a micron. HP then uses a spe-
cial universal adapter, which allows other cable types to mate with this preci-
sion connector. See
Figure 5-2 on page 5-16 .