What is a qualified patchcord?
 Many manufacturers over-emphasize the performance of back reflection and insertion loss figures but ignore the importance of topography measurement of the polished ferrule. The three main important measurements that characterize the shape of the polished connector endface are radius of curvature, vertex offset and undercut.
Radius of Curvature
This is defined as the radius of curvature of the portion of the endface that is domed by polishing for physical contact.
Vertex offset
 Vertex offset indicates how well the sphere forming the connector endface is centered on the fiber.
It is measured by determining the position of the highest point of the endface and measuring the distance
between this point and the centre of the fiber
Undercut
Undercut is the difference in height between the surface of the ferrule and the surface of the fiber. Undercut is usually measured by finding two points which lie on the centerline of the fiber. One point lies where the sphere forming the surface of the ferrule intersects the centerline of the fiber. The second point lies where the surface of the fiber intersects the centerline of the ferrule. The distance between these two points is the undercut. Serious undercut can be seen at above picture.
Go4Fiber Standard of topography measurement of polished ferrule
| Measurement Parameter |
Pass/ Fail Limits (Min) |
Pass/Fail Limits (Max) |
| Radius of Curvature |
10.0 mm |
25.0 mm |
| Fiber Height (Spherical Fit) |
-50.0 nm |
50.0nm |
| Fiber Height (Planar Fit) |
-10.0 um |
150.0 nm |
| Apex Offset |
-0.00 um |
50.0 um |
| Angle |
-0.3 degree |
0.3 degree |
| Fiber Roughness (Rq) |
0 nm |
50 nm |
| Fiber Roughness (Ra) |
0 nm |
50 nm |
| Ferrule Roughness (Rq) |
0 nm |
50 nm |
| Ferrule Roughness (Rq) |
0 nm |
50 nm |
| Diameter |
125.0 um |
135.0 um |
Guaranteed Performance by Go4Fiber
| |
APC
|
UPC
|
|
Insertion Loss (dB)
|
<0.3
|
<0.3
|
|
Return Loss (dB)
|
>65
|
>50
|
Topography measurement Parameter and Pass/Fail Limits
Testing System
In order to assure a satisfactory performance, a rigid testing procedure is applied to every patchcord assembled by Go4Fiber. The aim of this testing procedure is to make sure every Go4Fiber patchcords are in best condition before delivery.
Insertion Loss Test - For singlemode fiber optic cable
When tested in accordance with the GR-326-CORE, the maximum insertion loss shall not exceed 0.3dB against master connector.
Go4Fiber typical value is 0.1dB.
For multimode fiber optic cable:
In accordance with FOTP-34 (interconnection device insertion loss test) and FOTP-171 (attenuation by substitution measurement),
all tests are performed by advanced testing equipment. The maximum insertion loss shall not exceed 0.3dB against master connector.
Again, typical value is 0.1dB.
Return Loss Test-For singlemode fiber optic cable only:
Strictly following FOTP-107, JDS-Uniphase RX and RM series Power and Back Reflection Meter is used as testing instrument.
Ferrule Surface Inspection
Every connector is inspected by 200X microscope to ensure there is no visible scratch on the fiber.
Topography measurement of the ferrule
 DORC interferometer can display an accurate measurement of radius of curvature, fiber height, apex offset, fiber roughness and ferrule roughness. Sample checked by our QC manager could make sure all the critical parameters are within specifications defined by international organizations. One interferometric quality control report would be provided free of charge per 400 terminations. Please contact us for special request of quality control report or higher sampling ratio.
Download above details in PDF format
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