Introduction: The single-mode fiber, in English called Single Mode Fiber. The center of the core glass is very fine, can realize the long distance, high quality signal transmission. How would the continuation of single-mode fiber?
Many methods of fiber connection among them, the most widely used, is also the most superior method is arc welding method. The principle of this method and high temperature arc generated by the optical fiber at high temperature and high pressure melting properties of the discharge, the optical fiber to weld. At present, the market of multi welding machine using image processing technology, can automatically set the end position, and, by switching the picture tube, optical fiber can be observed on the heart and the fusion situation from two aspects of vertical and horizontal. Also according to the core axis deviation and inclination degree of estimated splice loss and display.
Single mode fiber splice general have the following steps:
1, set in advance optical cable Connecting parts for reinforcing the steel wire with the heat shrinkable sleeve;
2, remove the coating, coating fiber and vertical clamp vise, stripping a coating of 20mm–30mm long and two coating, soaked with alcohol cotton ball or lens paper hard core fiber will wipe, wipe clean, to avoid cracks and scratches on the surface of fiber.
3, cutting the fiber, making the end. In the optical fiber connection, is the key process is the production of optical fiber end face. To improve the fiber end and determines the loss of fiber connection. The fiber end face not only need to face smooth, showing a smooth mirror area, no burr, no defect, and the vertical axis, also need to keep the face clean, avoid dust pollution.
The end made the following three methods: one is the indentation method. A mechanical cutting knife, with a diamond knife on the surface perpendicular to the fiber direction to delimit notch from the coating layer of 10 mm, slightly touched, natural fracture position on fiber notch. The two is the cutting clamp method, it is the use of a simple hand-held clamp self-made cutting operation. The three is the ultrasonic electric cutting method. These three methods as long as the equipment excellent, operating properly, the preparation of end effects are very good.
4, to take the two fiber into welding machine, welding machine by automatic welding.
5, using the OTDR instrument connection performance test and evaluation, with connection index, reinforcing protection and connecting parts, namely hot melt heat shrinkable tube with steel wire.
6, finally, in all the core connection after receiving income disc, using OTDR instrument retest, failed to be re housed or re connection, until they are qualified. Single mode optical fiber splice loss index is 0.08dB. In the construction, according to the provisions of the actual situation index, but generally not more than 0.08dB.
Optical fiber splice loss is due to the imperfect splice point and influence factors of imperfect connection point, summed up in two categories, namely the external and internal factors.
Refers to the internal fiber itself is not perfect, not by improving the connection process to reduce the loss, it includes the core diameter mismatch, refractive index mismatch, fiber concentricity, mode field diameter mismatch, so in the next test, splice loss values will appear is large and negative phenomenon. Through multiple connection only one-way value is small, the average value of zero, but can not avoid the phenomenon of positive and negative, positive and negative phenomena have certain effects on the optical fiber transmission loss. In engineering, fiber optic disc should be selected in the same batch of finished cable, A, B to end the one one corresponding to a certain extent, can reduce the splice loss.
External factors refer to the optical fiber itself is not perfect, but the connection process caused by the poor. External factors have strict requirements on subsequent personnel. The core position of horizontal and vertical deviation, fiber axial angle, fiber end face pollution phenomenon, is composed of a connecting process caused by welding machine maintenance is not timely, improper operation of human factors.
Finally note, heat shrinkable tube should also pay attention to clean, clean, clean, or hot melt, dust damage to the connection point, causing loss increases. Contained in a containing disc, try to avoid increasing crop circle, the loss caused by the small circle. In a disk to tape fiber to fixed, not bomb on the trend, to avoid future damage.
