AN117

The Photonics Pioneer

Measuring Insertion Loss and Return
Loss of Hybrid Cables in OPL-Max
Overview
Obtaining connector-level insertion loss (IL) and return loss (RL) for hybrid cables is complicated by the different connector types
on either end of the cable. Hybrid cables cannot simply be flipped to test the reverse direction when the reference and device
under test (DUT) connectors are no longer compatible. A test setup comprised of the OP940 IL and RL Meter with two detectors, theOP725 Benchtop Optical Switch, and OPL-Max Application Software solves the compatibility issue and allows for hybrid cable testingwith high speed, accuracy, and repeatability.
*Details on how to perform these measurments through the front panel of the OP940 can be foundin Application Note AN-111 Measuring Insertion Loss and Return Loss on Hybrid Cables.

Setup
A High Performance Reference Cable should be connectedfrom the source port of the OP940 to the input port of theAD-SC

OP725. In order to accommodate the different connectors ofAD-LC

the hybrid cable, reference cables for each connector typeare mated to the right-hand ports of the switch. The left-HPR
Cable

hand output port of the OP725 is not used in this test setup
and the unit functions as a 1x2 switch.

Figure 1: OP940 + OP725 test systemwith FC-APC to LC-PC and FC-APC toSC-PC reference cables.

OPL-Max Test Sequence

LC HPR
Cable

SC HPR Cable

The sequence file in OPL-Max for this test is as follows:

Figure 2: Sequence file for simplex hybrid cable testing.

1

OptoTest Corp.

SANTEC
4750
CalleCORPORATION
Quetzal5823
Ohkusa-Nenjozaka,
Komaki,
Camarillo,
CA 93012
Aichi 485-0802,
UnitedStates Japan+81-568-79-3536

Doc: AN-117 Rev. A 8/24/19

Advancing the World of Fiber Optics®
www.optotest.com
www.santec.com
The Photonics Pioneer

SANTEC USA CORPORATION
1.805.987.170 0
USA Toll Free+1-800-726-8321
sales@optotes
t.com
engineering@optotes t.com
SANTEC EUROPE LIMITED
Tel. +44-20-3176-1550

AN117

The Photonics Pioneer

Measuring Insertion Loss and Return
Loss of Hybrid Cables in OPL-Max
For this test, the OP725 will be treated as an external 1x2switch. It should be connected directly to the computer via
USB and assigned as the source switch in the Instruments
tab. (Figure 3) For light to emit from the top right port of theOP725, the source channel in column D (Figure 2) should beset 1. Likewise, the source channel should be set to 2 for thebottom right port.
In order to allow the operator to move the DUT from thefirst reference cable to the second, a pause step is added
between the test steps. A pause is not needed duringreferencing, so the measurement type in column J (Figure 2)
is set to 101 to create a test-only pause step.

Figure 3: From the Instruments tab of OPL-Max, selecting a switch
brings up the switch assignment dropdown.

Referencing Instructions
To reference IL, connect the reference cables to thedetectors of the OP940 using appropriate mating adapters.
In this example, the connectors are LC and SC. (Figure 5)
Since the connection to the detectors is non-contact, theFigure 4: Test controls along the bottom of the screen in OPL-Max.

cables can also be connected this way for the RL reference.
Alternatively, they can be disconnected, with the LC and SC
connectors open to air. OPL-Max can execute the referencesAD-SC

in either order. Clicking Ref (Figure 4) on the bottom bar ofAD-LC

the software begins the referencing process.
HPR
Cable

Figure 5: The reference cables are connected totheir corresponding detectors for referencing.

SC HPR
Cable

LC HPR Cable

2

OptoTest Corp.

SANTEC
4750
CalleCORPORATION
Quetzal5823
Ohkusa-Nenjozaka,
Komaki,
Camarillo,
CA 93012
Aichi 485-0802,
UnitedStates Japan+81-568-79-3536

Doc: AN-117 Rev. A 8/24/19

Advancing the World of Fiber Optics®
www.optotest.com
www.santec.com
The Photonics Pioneer

SANTEC USA CORPORATION
1.805.987.170 0USA Toll Free+1-800-726-8321
sales@optotes
t.com
engineering@optotes t.com
SANTEC EUROPE LIMITED
Tel. +44-20-3176-1550

AN117

The Photonics Pioneer

Measuring Insertion Loss and Return
Loss of Hybrid Cables in OPL-Max
Measurement Instructions
For testing, the DUT is first connected on one side to the SC reference cable on channel 1 of the OP725 and on the other side to
the first detector. (Figure 6) Note that to achieve this, the adapters on the detectors are swapped so that the correct sidecan be mated. This swap does not invalidate or otherwise affect the reference that was just done. The pause step that was built
into the sequence gives the operator time to move the DUT to channel 2. The software will also take care of switching channels
during both the reference and measurement.

AD-LC
AD-SC

HPR
Cable

DUT

LC HPR
Cable

SC HPR Cable
Figure 6: After swapping the adapters on the detectors, the DUT is connected to the SC reference cable and the top detector (left).
Then the DUT is moved to the LC reference cable and the bottom detector (right).

Test Report
The test report contains both IL and
RL results for each channel at eachwavelength tested, in this case 1310nm
and 1550nm. The report also contains
operator, work order, and other relevantbatch information for the DUT as enteredby the operator prior to testing.

Figure 7: Sample test report

3

OptoTest Corp.

SANTEC
4750
CalleCORPORATION
Quetzal5823
Ohkusa-Nenjozaka,
Komaki,
Camarillo,
CA 93012
Aichi 485-0802,
UnitedStates Japan+81-568-79-3536

Doc: AN-117 Rev. A 8/24/19

Advancing the World of Fiber Optics®
www.optotest.com
www.santec.com
The Photonics Pioneer

SANTEC USA CORPORATION
1.805.987.170 0
USA Toll Free+1-800-726-8321
sales@optotest.com
engineering@optotes t.com
SANTEC EUROPE LIMITED
Tel. +44-20-3176-1550