Optical fiber quality appraisal

optical fiber is based on the core principle of total reflection transmission of optical signals in high-purity quartz glass or plastic fibers. It is widely used in communication networks, sensor monitoring, national defense and security and other fields. In the field of communications, it carries ultra-high-speed data transmission of 5G base stations and submarine optical cables; in industrial monitoring, it realizes distributed sensing of oil pipeline leaks and bridge structural stress; in terms of national defense and security, it serves as an anti-interference transmission medium for missile guidance and radar systems.

Compared with traditional copper cables, optical fiber has the characteristics of low loss, anti-electromagnetic interference, high bandwidth, etc., and is the core carrier of the new generation of information technology infrastructure.

Zhongke Testing is a product quality appraisal service organization registered with the court. It can provide optical fiber quality appraisal services. It has a professional appraisal team and advanced instruments and equipment to provide fair and accurate appraisal results for optical fiber quality appraisal.

As optical fiber application scenarios become more complex, quality dispute cases are gradually increasing. The judicial dispute focuses on:

1. Disputes over performance indicators: whether the attenuation coefficient meets the standard and whether the bandwidth meets the design value;

2. Material and process defects: uneven core doping concentration and insufficient coating layer thickness;

3. Environmental adaptability issues: additional attenuation after high and low temperature cycles exceeds 0.1dB, anti-microbending performance is not up to standard;

4, contract performance issues: the delivered optical fiber does not comply with the technical agreement.

Optical fiber quality identification technical methods include:

1. Appearance inspection: Check whether there are scratches, bubbles, cracks and other defects on the surface of the optical fiber.

2. Geometric measurement: Measure parameters such as fiber diameter, cladding diameter and eccentricity to ensure compliance with standard requirements.

3. Optical testing: including light attenuation test, fiber bandwidth test, etc., to measure the transmission performance of optical fiber.

4. Connection test: Check the workmanship quality of the fiber optic connector to ensure the connection firmness and low optical loss.

A communication engineering company of the applicant signed a "Single-mode Optical Fiber Procurement Contract" with an optical fiber manufacturing enterprise of the respondent, agreeing to purchase 1,000 kilometers of G.652D optical fiber for the construction of 5G base stations. During the construction process, abnormal attenuation occurred in multiple sections of optical fiber, causing network transmission to be interrupted. The engineering company believed that the optical fiber had quality defects and demanded compensation for losses. The manufacturing company argued that the problem was caused by improper construction, and both parties went to court.

Identification and analysis results:

The quality analysis expert group discussed and comprehensively analyzed data related to "optical fibers", contract technical agreements, on-site investigation case materials and other data, and made the following quality analysis opinions:

The core GeO₂ content of the involved optical fiber is only 2.5% (contract requirement 3.0%), resulting in a refractive index distribution deviation exceeding 0.2%; the coating layer thickness is 110μm (standard 125±10μm), and the microbending resistance is reduced by 30%; the drawing speed fluctuates by more than 5%, and the fiber diameter deviation reaches ±3μm (standard ≤±1μm); hydrogen aging treatment is not carried out according to the standard, and the hydrogen loss value exceeds 0.05dB/km.

The manufacturing company failed to control the core doping concentration and coating layer thickness according to the contract, and the drawing process was unstable, which was the main reason for the equipment problems.

Optical fiber quality identification report should include the following content:

1. Test results such as appearance, geometric dimensions and optical performance of the optical fiber.

2. Comparative analysis with contract or standard requirements.

3. Fiber quality identification conclusion.