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The importance of 3D indicators for fiber optic jumpers

Fiber optic connectors are widely used connection components in optical communications. The success of the connection of optical fiber lines depends on the quality of the physical connection of the optical fiber. In order to improve the efficiency of optical fiber connection and optical signal transmission, the geometry of the end face of the fiber optic connector must be strictly controlled to reduce insertion loss and return loss. If the geometry of the end face is not strictly controlled, Or if the geometric size cannot meet the requirements, there will be a huge risk of system connection failure, and there will be no long-term reliable connection of the network.


In addition, 3D inspection is not only a necessary step for the end-face inspection of high-standard optical fiber connectors, but also has important guiding significance and reference value for the design and manufacture of the device itself. The quality of the connector end face is inseparable from its design and manufacturing process. Therefore, , we can improve and perfect the process according to the 3D inspection results .



  1. Radius of curvature

The radius of curvature is the radius that describes the axis of the ferrule to the end face. It can also be described as: the radius of the ferrule end face curve, the connector achieves the tightness of the end face of the fiber through the pressure of the spring, and the radius of curvature controls the compression force to maintain the matching force of the fiber center.

An unqualified curvature radius will increase or decrease the pressure of the optical fiber, and under the effect of aging, it will eventually lead to the matching spacing of the optical fiber center, and even damage the end face of the optical fiber. Insertion Loss and Echo Variations will slowly vary the loss, and the horror is that this cannot be accurately simulated by any standard method that exists.

Curvature radius index PCΦ2.5 is 8~24mm, MuΦ1.25 is 11~24mm, LcΦ1.25 is 8~24mm, APC is 5.5~11.5mm.

Bad reasons:

  • The polishing pad is too hard (R is too large) or too soft (R is too small).
  • Grinding pressure is too large (R is too small) or too small (R is too large).
  • The abrasive paper is severely worn.

Improve methods:

  • According to the 3D inspection results, select the appropriate polishing pad.
  • According to the 3D detection results, adjust the pressure of the grinder to the appropriate level.
  • If it is confirmed that the grinding pad and pressure are correct, check whether the grinding paper is worn, and replace it in time if worn.
  1. Vertex Offset

The apex offset is the distance from the highest point of the ferrule end face curve to the axis of the fiber core. Apex offset will increase the effective coupling area of the fiber, thereby increasing insertion loss and return loss.

The general requirement is ≤50um.

Bad reasons:

  • Grinding disc offset.
  • Grinding pressure is too small.
  • The abrasive pad is hard.
  • If it is APC, there will be a positioning block offset.

Improve methods:

  • Test out which hole of the grinding disc is offset for trimming.
  • According to the 3D detection results, adjust the grinding pressure and grinding pad grinding.
  • After the grinding disc is manufactured, it is necessary to use a projector to measure whether the grinding disc is offset, and it needs to be used in the production line, and the 3D results should be recorded. If the interference ring deviates to the left during the 3D inspection, the angle of the grinding disc is too small. If it is biased to the right, the angle of the grinding disc is too large; if the interference ring is biased upward, the positioning block is biased upward, and if it is biased downward, the positioning block is biased downward.


  1. Fiber height

Fiber height is the distance from the end face of the fiber to the end face of the ferrule. Fiber height is an indicator used to measure fiber-to-fiber contact. When the material expands or shortens, fiber depressions form air gaps between fiber contacts, changing insertion and return losses. The height of the optical fiber will increase the pressure between the optical fibers, thereby damaging the optical fiber, or transmit the pressure to the epoxy resin fixing the optical fiber, thereby destroying the fixing of the optical fiber and affecting the stability of performance. High-quality optical fiber connectors must pass 3D testing, and very few optical fiber connectors currently on the market have passed interferometer testing.

The general requirement is -100-+50

Bad reasons:

Distilled water is not clean.

0.3um is dirty and defective.

Improve methods:

When distilled water is fed, take a part of each barrel for testing, and it can be used in the production line only if there is no problem.

For 0.3um feed, for each production batch, several sheets need to be taken out for grinding test. If there is no problem, they can be sent to the production line for use. Merchant.