MPO jumper Test parameters
Currently, 40G/100G in the data center mainly uses OM3/OM4 optical fiber, and the interface is mainly MPO, and the polarized MPO jumper is used to access the equipment. Some 40G devices are connected with LC-LC jumpers, and the loss is relatively large. Therefore, for typical data center optical cable test objects, the characteristics are “MPO-MPO” link, “MPO + MPO/LC branch jumper” link, “MPO -MPO” direct connection jumpers, etc., can be regarded as ordinary “links under test”. The biggest difference from the original wiring system test is the need to use EF light sources to reduce the fluctuation of test results and handle the interfaces at both ends. and jumper/polarity for correct corresponding access. The test model mainly includes:
(1) MPO-MPO link: MPO adapters are used on both ends of the frame, and the MPO-MPO jumper or MPO-LC jumper is used to connect to the device.
(2) MPO-MPO jumper direct connection: directly use MPO-MPO jumper to connect devices, generally used for short links.
(3) MPO/12LC-MPO/12LC link: Use MPO-12LC transition boxes at both ends, and use LC-LC jumpers to connect devices.
Among them, (3) is generally shown in the pre-termination system, and the link loss will be high due to the inclusion of the MPO/LC transfer module.
- Test parameters
Fiber loss test is the basic test (Tier 1 test or T1 test), length is optional. The T1 test cannot guarantee that the bit error rate of the 40G/100G link meets the requirements. The high-speed optical fiber system should choose to add an extended test (secondary test or T2 test). The T2 test is to add an OTDR test to the T1 test and judge the event (connection , welding points, etc.) are qualified.
Table 1 T2 = T1 + OTDR + event judgment
parameter name
Parameter requirements
Parameter source
Remark
Insertion loss
(T1 test)
Indefinite value standard: TIA568C or ISO11801;
Value standard: IEEE802.3
TIA568C,
ISO11801,
IEEE802.3
Optical Fiber Level 1 Test (Basic Test, T1)
length
(T1 test)
Indefinite value standard: TIA568C or ISO11801;
Value standard: IEEE802.3
TIA568C,
ISO11801,
IEEE802.3
Optical Fiber Level 1 Test (Basic Test, T1)
connection point loss
(T2 test)
0.75/0.5dB,
0.3/0.3MM,
0.5/0.3SM
TIA568C,
ISO11801
ISO11801
Optical Fiber Class 1 Test (Basic Test, T1) Bidirectional Test, Evaluation by Average
Splice loss
(T2 test)
0.3dB
TIA568C,
ISO11801
Optical fiber secondary test (extended test, T2), bi-directional test, evaluation by average
return loss
(T2 test)
-20dB,MM;
-35dB,SM;
advanced options:
-35dB, MM & SM
-40dB, MM & SM
-45dB, MM & SM
ISO11801:2010
Suggested limit values for conventional fiber end faces
Optical fiber secondary test (extended test, T2).
Bi-directional test, evaluating conventional fiber by average -35dB (PC polished)
-35 dB (PC grinding)
-40 dB (UPC grinding)
-55 dB (APC grinding)
End face quality assessment
See IEC61300-3-35
IEC61300-3-35
Limits the number and diameter of scratches, stains, damage, blemishes, etc. and gives pass/fail results
The above table lists the requirements of the relevant specifications and standards for the test values. In the actual test process, due to the requirements of the user, the particularity of the system link or other reasons, more stringent requirements are put forward for the test results and standards.
If the OTDR test link contains an MPO-LC transfer module, due to the existence of short optical fibers inside the module in the actual test, the test value of the return loss deviates or does not match the actual value. If the link will be used for 40G/100G For high-speed optical fiber systems, it is recommended to increase the test threshold of return loss from -20dB to -35dB.
