GR-326 Standard

What is the Telcordia GR-326 Standard？

Regarded as the most complete and rigorous standard for single mode fiber optic connectors. The Telcordia GR-326 standard document sets forth the Telcordia view of the technical generic requirements for, and characteristics required of, connectors used for joining single mode optical fibers, and for the jumper assemblies made using such connectors. Specifically for single mode field-terminated connectors and jumper assemblies.

What Aspects Does it Cover？

The Telcordia GR-326 standard outlines specific parameters and test procedures to evaluate connector performance. Some key aspects covered by the standard include:

Connector Geometry: The standard defines the physical dimensions and tolerances of connector components, such as ferrules, mating adapters, housings, and guiding mechanisms. It ensures that connectors from different manufacturers are mechanically compatible and can be mated reliably.

Optical Performance: The standard specifies performance requirements related to insertion loss, return loss, and back reflection. It sets limits on the amount of signal loss allowed during transmission and establishes criteria for minimizing reflected light and maintaining signal integrity.

Mechanical Durability: The standard addresses the mechanical durability and reliability of connectors. It specifies the number of mating cycles a connector should withstand without significant degradation in performance. It also includes guidelines for connector handling, such as recommendations for cleaning procedures and precautions against damage.

Environmental Considerations: The Telcordia GR-326 standard covers the environmental conditions in which connectors should operate effectively. It includes requirements related to temperature cycling, humidity, vibration, and other factors that may impact connector performance.

Test Procedures: The standard provides detailed test methods and procedures to evaluate connector performance. These tests cover parameters like insertion loss, return loss, and mechanical durability. The standard outlines the equipment and measurement techniques to be used during testing.

Compliance with the Telcordia GR-326 standard ensures that fiber optic connectors meet industry-recognized criteria for performance and reliability. Manufacturers and suppliers often reference this standard when designing, manufacturing, and testing fiber optic connectors. Adhering to the standard helps ensure the interoperability, compatibility, and robust performance of connectors in telecommunications networks.

What Categories of Standard Telcordia GR-326 Connector Tests Include？

Service Life Test: The Environmental Tests are adopted to ensure the jumper assemblies will withstand exposure to 85°C or temperature fluctuations of up to 125°C and accelerate the effects of aging on jumper assemblies, which include six parts.

Thermal Age Test: Content: simulate and accelerate the processes that may occur during shipping and storage of the product.Requirements: Connectors are subjected to a temperature of 85℃ with uncontrolled humidity for a duration of 7 days.

Thermal Cycle Test: Content: make the temperature fluctuate over an expansive range—extreme heat and cold, and apply heavy stress and strains to the sample to check whether it's qualified.Requirements: Hanging the ambient temperature of the connector by 115℃ (75℃ to -40℃ ) over the course of three hours.

Humidity Aging Test: Content: Introduce moisture into the connector and determine the effect that the moisture has on the samples.Requirements: Setting the elevated temperature of 75℃ for 168 hours (7 days) while the connectors are exposed to 95% RH (relative humidity).

Humidity/Condensation Cycling Test: Content: To examine the effect that water has on the connector when a rapid transition in moisture occurs. If water molecules freeze or evaporate within the connector assemblies, then the issue of "gaps" in the physical contact between connectors within an adapter may be exposed. Requirements: Temperature cycle from -10°C to + 65°C with 90%-100% RH for 168 hours (7 days) of 14 cycles.

Dry-out Step Test: Content: Prior to the last phase of the Environmental Tests. To remove any moisture that may remain from the previously performed Humidity/Condensation Cycling test.Requirements: A drying step at 75℃ for 24 hours (1 day) before the Post-Condensation Thermal Cycle is performed.

Post Condensation Thermal Cycle Test: Content: Similar to the Thermal Cycle that was previously performed. The changes that may occur in the connector during Humidity/Condensation cycling are often revealed once the condensation is removed, and these changes can potentially affect the loss and/or reflectance of the connector. Requirements: Conduct after the Dry-out step. The mechanical tests will be required to be performed once the aging is complete.

Vibration Test: Content: The connector assemblies are mounted in the "shaker," singly or in batches, in order to examine whether high frequencies of vibration will influence the performance of the samples.Requirements: Conducted on three axes for two hours, and each axis is at an amplitude of 1.52mm with the frequency sweeping continuously from 10 to 55 Hz at a rate of 45 Hz per minute.

Flex Test: Content: Intended to simulate stresses on the terminated cable and the mated connector.Requirements: Apply 0.9 kgf load, (may be reduced to 0.6 kgf load for Small Form Factor Connectors), then rotate the angle of the test fixture arm through the following cycle: 0°, 90°, 0°, -90°, 0°, and repeat for 100 cycles. Compare with the before and after numerical values of the loss and reflectance.

Twist Test: Content: A rotational strain will be put on the fiber, and the strength that is coupled with the connector will be tested. Like the flex test, the twist test will help to identify weaknesses in the termination process—the adequacy of the crimp. Requirements: After mounting the test samples, apply the load according to the instructions. Then rotate the capstan X revolutions about the axis of the fiber and reverse direction and rotate Y revolutions. Reverse direction again and rotate Y revolutions. After repeating the load-applying procedure, nine times, the measure of loss and reflectance will be.

Proof Test: Content: Ensures the strength of the latching mechanism of the connector, as well as the crimp during the termination process. Requirements: Conducted through straight pull and 90° side pull tests to get the loss and reflectance measurement results.

Impact Test: Content: Conducted to verify that the connectors are not damaged when they are dropped.Requirements: A cinderblock is mounted to the bottom of the fixture, and the connector will be dropped from approximately 1.5 m from the horizontal planet. The connector contacts the cinderblock, and the process is repeated 8 times.

Durability Test: Content: Performed to simulate the repeated use of a connector to reveal the problems with the design or material flaws in the connector, such as any part of the latching mechanism that may be heavily strained or flawed by frequent use. Requirements: Inserting the connector into an adapter repetitively (200 times) at different heights (in the sequence of 6ft., 4.5ft., 3ft., 3 ft., 4.5 ft., and 6ft.) so as to simulate what a user in the field might encounter when standing in front of a telecom rack.

Extended Service Life Test: The testing is non-sequential, so there is no cumulative effect. The Exposure Tests cover the following testing items: The dust has a great impact on optical performance. Particles that contaminate the end-face will block optical signals and induce loss. This test involves intense exposure to dust of specified size particles in order to examine if there is a risk of any particle finding its way to the ferrule end-faces.

Salt Fog Test: The Salt Fog test is designed to guarantee the performance of the jumper assembly in free-breathing enclosures near the ocean, which involves exposing the connector to a high concentration of Sodium Chloride (NaCl) over an extended period. Optical testing is performed and followed by visual inspection to confirm that there is no evidence of corrosion on the materials.

Airborne Contaminants Test: The Airborne Contaminants test is designed to guarantee the performance and material stability of connectors in outdoor applications with high concentrations of pollution. The mated and unmated connectors will be exposed to various gases repeatedly to examine both optically and visually. An assortment of volatile gases is used in a small chamber for 20 days to simulate prolonged exposure to these elements.

Immersion/Corrosion Test: No optical requirements but involves a prolonged submersion in uncontaminated water instead. Mated connectors are checked for ferrule deformation by measuring the Radius of Curvature before and after the test, and comparing the values, while unmated connectors are checked for Fiber Dissolution, which involves checking to see if the fiber core has not recessed too far into the fiber cladding.

Groundwater Immersion Test: This is intended to verify the ability of the product to withstand underground applications. During the test, the connector is exposed to a variety of chemicals found in sewage treatment and agricultural fertilization, among other applications, as well as biological mediums. These chemicals include ammonia, detergent, chlorine, and fuel.