Why is high-quality end-face processing of figure-8 optical cables so important for optical signal coupling?

As the transmission medium of optical signals, the quality of the end-face of optical fiber directly affects the coupling efficiency of optical signals. Coupling efficiency refers to the energy ratio that can be maintained when an optical signal is transmitted from one optical fiber to another. If the end-face of the optical fiber is not flat or contaminated, it will cause scattering and absorption of the optical signal during the coupling process, thereby reducing the coupling efficiency and increasing the loss.

For figure-8 optical cables, since their design requires self-crossing layout in a limited space, the processing of the optical fiber end-face is particularly important. If the end-face is not properly processed, it will not only affect the transmission quality of the optical signal, but also may cause damage to the optical cable due to friction and collision between the end-faces. Therefore, high-quality end-face processing technology is of great significance to ensure the stability and reliability of the figure-8 optical cable.

The high-quality end-face processing technology of the figure-8 optical cable mainly includes the following steps:
Precision cutting: High-precision cutting equipment is required to cut the optical fiber. This process requires strict control of the cutting speed and cutting angle to ensure the flatness and verticality of the optical fiber end face. The fiber end face after cutting should present a smooth, defect-free mirror effect.
Cleaning: After cutting, the fiber end face needs to be cleaned. The purpose of this step is to remove dust, oil and other contaminants on the end face to ensure that the optical signal will not be affected by contamination during the coupling process. Cleaning is usually carried out using methods such as ultrasonic cleaning or alcohol wiping.
Polishing: In order to further improve the finish and flatness of the fiber end face, polishing is also required. Polishing can be carried out using a polishing sheet or polishing liquid, and tiny flaws and scratches on the end face can be removed through slight friction to achieve a higher mirror effect.
Quality inspection: The processed fiber end face needs to be quality inspected. This step is usually carried out using high-precision inspection equipment such as microscopes or interferometers to ensure that the flatness and finish of the fiber end face meet the design requirements.
High-quality end face processing technology has a significant impact on improving the coupling efficiency of optical signals. Specifically, it can improve the coupling efficiency in the following aspects:
Reduce scattering: A flat and smooth fiber end face can reduce the scattering of optical signals during the coupling process. Scattering is a phenomenon that occurs when an optical signal encounters an irregular surface during transmission, which causes the optical signal to diffuse in all directions, thereby reducing the coupling efficiency. High-quality end-face processing can effectively reduce the occurrence of scattering and improve the coupling efficiency of optical signals.
Reduce loss: High-quality end-face processing can also reduce the loss of optical signals during the coupling process. Loss refers to the phenomenon that the optical signal gradually weakens during the transmission process due to various factors (such as absorption, scattering, reflection, etc.). A flat and smooth optical fiber end face can reduce the absorption and reflection of the optical signal during the coupling process, thereby reducing the loss and improving the transmission quality of the optical signal.
Improve stability: High-quality end-face processing can also improve the stability of the 8-shaped optical cable. Since the 8-shaped optical cable needs to realize self-crossing layout in a limited space, friction and collision between the optical fiber end faces are inevitable. If the end face is not properly processed, it may cause damage to the optical cable or performance degradation. High-quality end face processing can increase the wear resistance and collision resistance of the optical fiber end face, thereby improving the stability and reliability of the optical cable.