has several possible variants. The information being conveyed in the
market regarding areas such as compatibility, splicing and cable construction
varies greatly. This variation in information creates confusion and introduces the
potential for a customer to use a specific type of cable that does not meet
their expectations or requirements. Let’s look closer at single mode fiber
and some of the common misconceptions in the industry.
OS1 and OS1 ZWP
OS1 single mode fiber is based on the
fiber glass specification ITU-T
G652.A or B (equivalent to using IEC 60793-2-50 Type B1.1 fibers). This
specification has standard attenuation of 1 dB/km maximum across both 1310 nm
and 1550 nm wavelengths. OS1 zero water peak single mode fiber is based on theglass fiber specification ITU-T G652.D. This specification has standard attenuation
of 1 dB/km max and a low water peak above and below the 1383 nm
wavelength and controlled polarization-mode dispersion.
The zero water peak is important because it allows forcoarse
wave division multiplexing (CWDM), thus substantially increasing the
bandwidth potential of the single mode fiber. Low water peak fiber is also
marketed as zero water peak. International standards will address this
potential confusion shortly by creating a new fiber type known potentially as OS1a.
OS1a will have standard attenuation of 1 dB/km, but measured in three
The OS2 specification has a much lower attenuation of0.4 dB/km maximum at three wavelengths (1310 nm, 1383 nm
and 1550 nm) and low water peak. There are two types
B1.3 of IEC 60793-2-50 (ITU-T G652D), specified out to 1550 nm
B6 a using IEC 60793-2-50 (ITU-T
G657A and G657B), specified out to 1625 nm
Type G657A/B is commonly referred to as bend insensitive fiber
or reduced bend radius fiber. It is capable
of a smaller minimum bend radius without degrading the attenuation of the fiber.
Bend insensitive fiber cables are compliant with
G652.D standards so they can be spliced and connected to G652.D fibers without
excessive loss. All core/cladding sizes are the same (9/125 microns); however,
some fusion splicing machines may suffer difficulty in determining the fiber
type of the bend insensitive cable when trying to splice to a more typical
G652D cable. This is largely because of the “trenches” that are used around the
nine-micron core of the fiber, enabling the fiber cable to bend much more. The
fusion splicer can be set to cladding alignment to alleviate this issue.
A common misunderstanding in the market is the ability
of tight buffered fiber cable construction to be used with OS2 fiber and
maintain full performance and compliance.
it is true that buffering cable with aramid yarn/Kevlar construction puts
higher stress on the glass compared to a loose tube gel fill cable or loose
buffer cable, CommScope spends much time developing and implementing innovative
ways of encasing the glass fibers within the yarn/ Kevlar weave to provide a
robust and protected environment.
Further strengthening the cable with central
strength members or outer protection materials in and around the cable sheath
helps assist with enabling a stronger cable with both torsional and tensional
strength. Combine this with decades of Research and Development across both
cable and connectivity, and cable performance is maintained with 100 percent
compliance with the aforementioned IEC and ITU-T Standards being achieved. Paying attention to all details of
the cable construction, not just the glass alone, ensures the customer’s
expectations are consistently met to the highest quality in the industry.
What else would you like to know about these fibers?