Application with CU1521 and CU1521-0010

The CU1521, CU1521-0010 are intended for application with optical fiber cables with the following characteristics:

SC duplex connector.
CU1521: Duplex multimode 50/125 µm or 62.5/125 µm (inner/outer core diameter). The use of both diameters is possible. However, the use of 50/125 µm is recommended due to the lower attenuation.
CU1521-0010: Duplex single-mode 9/125 µm (inner/outer core diameter). A typically usable cable can be manufactured according to the specification ITU-T G.652.D (0.4.4dBm/km at 1310 nm).

	Recommended connectors The use of SC/PC connectors is recommended for connecting to the CU1521, CU1521-0010. The advantage of the "PC" (physical contact) version of this connector is the crowned end face, which allows the region of the fiber core that is relevant to transmission to be optimally joined when the connector is pushed together. Other versions include, for instance, the SC/UPC (ultra-polish PC), SC/HRL (high return loss) and the SC/APC plug (angled physical contact). An additional feature of these connectors is that light that is reflected by the connector's end face, which is at an angle of about 8° to the fiber axis, is refracted from the core by the cladding glass into the air. This avoids interference with the data transmission, optimizing the core size of the back-scatter.

	50/125 µm or 62.5/125 µm The use of both diameters is possible. However, the use of 50/125 µm is recommended due to the lower attenuation.

In optical fibers the wavelengths 850 nm and 1310 nm are usually used for data transfer. Commercially available optical fiber cables are usually optimized for application in one of these ranges, since signal attenuation is frequency-dependent (like in copper cable), so that large ranges of several km can be achieved for the respective wavelength. In general, optical fiber cables exhibit a lower attenuation at a wavelength of 1310 nm than at 850 nm.

In the CU1521, CU1521-0010 a transceiver with the wavelength of 1310 nm is used.

	Range and bandwidth product Optical fiber cables are available in different qualities from reputable manufacturers. One of the relevant parameters for the user is the frequency-dependent bandwidth product of a cable, specified in [MHzkm]. The greater the bandwidth product, the lower the attenuation, and therefore the larger the range that can be achieved with this cable (see ITU-T G-651). To maximize the range with the CU1521, CU1521-0010 optical fiber cables with a maximum high bandwidth product at 1310 nm should therefore be used. We recommend optical fiber cables from the OM2 class (EN50173:2002). Standard optical fiber cables have a minimum bandwidth product of 500 MHzkm at 1310 nm, higher-quality cables are suitable for distances > 500 m over > 1000 MHz*km. For maximum distances the remote counterpart of the CU1521, CU1521-0010 should also support such ranges.

	Installation notes The following parameters must be taken into account in the installation of optical fiber cables permitted bending radius permitted tensile strength sensitivity of the exposed contact ends

Further information can be found in the following documents:

ITU recommendation ITU-T G.651 - G.655
EN 50173:2002
EN 60793-2