AN111

The Photonics Pioneer

Measuring Insertion Loss / Return Losson Hybrid Cables
Overview
Testing simplex cables with unmatched connector types poses difficulties because the cable cannot simply be turned around to test

the reverse direction. While hybrid bulkheads (SC-FC, ST-FC, etc.) are one option that can solve the problem with only minor issues,in some circumstances hybrid bulkheads will not provide sufficiently accurate measurements. SC-LC cables are one such example.

SC-LC bulkheads have high loss and poor repeatability and, as a result, they should not be used in the testing process. Using anOP940 with two detector ports coupled with an OP725 will allow the operator to accurately test hybrid cables of all configurations withthe highest accuracy possible.

Setup
The operator should have a high performance grade cablewith APC connectors between the source output of theOP940 and the upper left S port of the OP725. A reference

cable for each of the connector types should be connectedto the two output ports of the OP725, 1 and 2 . In thisSAVerCable

method avoids adding uncertainty as a result of goldenS1O

2

configuration, the O port of the OP725 is not utilized. This

cable references, OPM offset tables, and hybrid bulkheads.
This setup requires the use of our OPL-MAX software.

For assistance configuring the software to do this, pleasecontact OptoTest.

Figure 1: The system with both reference
cables open to air for return loss reference.

LC HPR
Cable
SC HPR
Cable

Referencing
Prior to any referencing or testing, attach an AD-25 or
AD-SC OPM adapter to detector 1 and an AD-125 or
AD-LC OPM adapter to detector 2 . Once the adapters areon as above, connect the SC reference cable (FC/APC-SC/
PC) to channel 1 and connect the LC reference cable (FC/Insertion Loss on both reference cables by switching

2Figure 2: The system with both reference cables
connected to their respective detectors for
insertion loss reference.

OptoTest Corp.

Rev.B
11/21/16+81-568-79-3536

2AD-LC

1channels on the OP725.

Doc: AN-111

AD-SC

SAVer
Cable

APC-LC/PC) to channel 2 . Reference Return Loss andSANTEC CORPORATION
5823 Ohkusa-Nenjozaka, Komaki,
4750 Calle QuetzalAichi 485-0802,
Camarillo,
CA Japan
93012

1

www.santec.com
The Photonics Pioneer

SC HPRCableLC HPRCable

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

AN111The Photonics Pioneer

Measuring Insertion Loss / Return Losson Hybrid Cables
Testing the DUT
Switch the adapters on detector ports 1
and 2 . Connect the SC end of the DUT

to the reference cable on channel 1 andput the LC side of the DUT into detector
port 1 to make measurements.

1AD-LC

2AD-SC

SAVer
Cable

12DUT
Figure 3: Measuring the SC
side of the DUT.

LC HPRCable

SC HPR Cable

To test the LC side of the DUT, connect
the LC end to the reference cable onchannel 2 and connect the SC end of

the DUT into detector port 2 . Make sure
to switch to the proper channel on the1AD-LC

2AD-SCOP725.

SAVer
Cable

12Figure 4: Measuring the LC
side of the DUT.

SANTEC CORPORATION
5823 Ohkusa-Nenjozaka, Komaki,
4750 Calle Quetzal
Aichi 485-0802,Camarillo,
CA Japan93012
Rev.B
11/21/16+81-568-79-3536

Doc: AN-111

LC HPR
Cable

SC HPR Cable

OptoTest Corp.

www.santec.com
The Photonics Pioneer

DUT

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