AN-115
Referencing Return Loss
Using the MTP Reference Reflector
It is not uncommon for a tester to find themselves attempting to test return loss on an MTP connection, but findthemselves unable to reference to the correct location. Sometimes this is due to dust or oil contamination or physicaldamage on the endface of the fiber, which can be corrected and prevented through proper care and maintenance.

TO REMOVE

MTP

PULL

MTP

TO REMOVE

PULL

Sometimes, however, the cable will not properly reference because it is terminated with an angled polish. OptoTest
equipment requires a 14dB Fresnel reflection to properly reference return loss. For a detailed explanation of thereasons behind the need for a 14dB reference reflection, please read the upcoming Application Note “14dB: What’s
in a Reference Reflection?”.

Figure 1: Short APC to PC MTP cable.

Due to the increasing demand to test MTP connectors, OptoTest has begun manufacturing our own solution to allow
our customers to test MTP cables as easy as possible—MTP Reference Reflector Cables (RRCs). These six-inch
cables are terminated with an MTP-APC connector on one side and an MTP-UPC connector on the other side and canbe either male or female and with either singlemode or multimode fiber. They will produce a reliable 14dB reference
reflection at the correct position, allowing the tester to streamline their reference process without compromising thequality of their results.

1310nm

RL

77.8 F

dBdBm
Mode

1310
1660

OP930-SM-SWXX
IL/RL Test System

MTP

PULL

TO REMOVE

Figure 2: OP930 with MTP fanout reference cable.

1

SANTEC CORPORATION
OptoTestCorp.

5823 Calle
Ohkusa-Nenjozaka,
Komaki,
4750
QuetzalAichi
485-0802,
JapanCamarillo, CA 93012
Doc:AN-115 Rev. A 7/17/13+81-568-79-3536

www.santec.com

SANTEC USA CORPORATION
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

Referencing Return Loss
Using the MTP reference Reflector

AN-115

To properly use the Reference Reflector Cable, connect the angle-polished end of the RRC to the angle-polished endof the reference cable and perform a return loss reference cycle.
NE W

IL/RL Test SystemMTPPULLTO REMOVE

PULLMTPTO REMOVE

MTP

1310
1660

OP930-SM-SWXX

PULL

14.00dB

dBdBm
Mode

TO REMOVE

1310nmRL

Figure 3: The MTP reference reflector cable provides a large reflection for the OP930 to reference return loss.

Once the return loss reference is completed, disconnect the RRC and connect the device under test.

1310
1660

OP930-SM-SWXX
IL/RL Test System

OVE

MTP

TO REM

PULL

MTP

PULL

TO REMOVE

MTP

55.50dB

dBdBm
Mode

PULL

1310nmTO REMOVE

RL

Figure 4: After the RL reference has been completed, the MTP reference reflector can be removed.
If insertion loss measurements are to be performed, an IL reference can now be performed.

2SANTEC CORPORATION
OptoTest
Corp.

5823 Calle
Ohkusa-Nenjozaka,
Komaki,
4750
QuetzalAichi
485-0802,
Japan
Camarillo, CA 93012
Doc:
AN-115 Rev. A 7/17/13+81-568-79-3536

www.santec.com

SANTEC USA CORPORATION
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