AN140

The Photonics Pioneer

RL Testing for APC Terminated Cables using
the OP940 Front Panel
Over view
The OP940 was designed as an upgrade to the existing OP930 product line. One of the many additional features isthe ability to reference to an angle polished connector through the front panel of the unit. The new feature works bysearching for small reflections that the unit would normally bypass. If, after following the instructions below, the unit isunable to reference to the APC connector on the reference cable, it is advised to employ the methods detailed in AN-114RL Testing for APC Terminated Cables.

Referencing Return Loss
The OP940 has an option to reference return loss directly to an open
angle-polished connector. In the RL Ref screen, navigate to thesecond set of options and select the APC Ref feature.

Once this option is selected, simply press the Start RL Ref button.

With the APC Reference option selected, the OP940 will scan for reflections much smaller than it would normally consider
to be relevant for RL referencing purposes. As a result of the criteria being much broader, the unit is more likely to pick up
unintended reflections.
To ensure that the unit references to the proper distance, minimize all reflections between the front panel of the unit andthe intended reference location, such as UPC-UPC connections and dirty or damaged interfaces. One way of reducing
reflections is to introduce index matching gel. If the unit is unable to reference past a certain reflection, use the Scan Offset
feature in the Settings screen to force the unit to begin referencing at a location after that reflection.

1SANTEC CORPORATION
5823 Ohkusa-Nenjozaka, Komaki,
4750 Calle Quetzal
Aichi 485-0802,
Camarillo,
CA Japan
93012

OptoTest Corp.

Rev. A 1/13 /15+81-568-79-3536

Doc: AN-140

www.santec.com
The Photonics Pioneer

SANTEC USA CORPORATION
1.8 05.987.170 0
USA Toll Free+1-800-726-8321
sales@ optotest.com
engineering @ optotest.com
SANTEC EUROPE LIMITED
Tel. +44-20-3176-1550

AN140RL Testing for APC Terminated Cables using the OP940 Front Panel The Photonics
Pioneer

Additionally, it is possible that the reflection from some APC cables is small enough that the unit will have a hard time
detecting it. In this case, it is suggested to place a dust cap on the end of the fiber to increase the light reflected backat that location, or one can place the open end into the OPM, which will increase the light reflected as well.

Input

If the APC Reference option still does not allow the unit to reference to the APC connector, please consult AN-114 for additional
methods of referencing return loss when the reference cable needs to have an angle polish such as using a short APC-to-PC
stub cable.

Input

Input

Note: If the unit is referencing to a UPC connector, the APC Reference option should not be utilized.

2

SANTEC CORPORATION
OptoTest
Corp.

5823 Ohkusa-Nenjozaka, Komaki,
4750 Calle Quetzal
Aichi 485-0802,
Camarillo,
CA Japan
93012
Doc: AN-140 Rev. A 1/13 /15+81-568-79-3536

www.santec.com
The Photonics Pioneer

SANTEC USA CORPORATION
1.8 05.987.170 0
USA Toll Free+1-800-726-8321
sales@ optotest.com
engineering @ optotest.com
SANTEC EUROPE LIMITED
Tel. +44-20-3176-1550