Fiber Optic Cable Detection Methods

Daily maintenance and testing of fiber

1. Daily maintenance of the fiber is very important, it is to ensure the safety of the fiber, stable and reliable operation of the fundamental guarantee;

2. Six months or a year to deal with the technical data of each optical fiber is given measured again and compared to the original data. Found that the issues discussed as soon as possible and troubleshooting to avoid unexpected accidents;

3. Inspections are carried out regularly on the cable line, cable sheath, cable connectors, line sag and other issues to make detailed records to facilitable early detection and treatment of problem on the tour, this is a very important aspect in the maintenance;

4. Regularly test export of RF receiver entrance optical power level, and found that large difference with the original records, failure should be analyzed from cable or optical receiver, is from live splice site or reasons caused by the optical transmitter itself.

Fiber Optic Cable Testing

Fiber optic cable connectors and test equipment is dedicated cable connector with ordinary tools and testing equipment is completely different. Cable connector with automatic fusing machine and the measured distance, loss Optical Time Domain Reflectometer expensive, but the quality of the joint good loss, the detection distance error, accurate and fast. A handheld optical power, the light level is very lightweight tester. In addition, there are several special instruments. The following describes the run out of time-domain reflectometer tests optical fiber cable.

In the construction of the fiber, the fiber length, the transmission loss is the main outcome measure, run out of time domain reflectometry measurement of these indicators is easy to operate, accurate measurement data, the TFS3031 micro-optical time domain reflectometer is a rugged, easy-to-use micro optical domain reflectometer (OTDR), well adapted to the field site for construction, while also providing accurate measurement of single mode or multi mode fiber optic systems.

Cable at the location of each connection, reflection loss extemely fast and clearly displayed on a 7-inch screen. Tekranger is the only micro-optical time donmain reflectometer, just press the speed, it will tell you in 5 m-100km away connector. Optical Time Domain Reflectometer (Mini-OTDR) can automatically adjust the capture parameters to provide the best possible resolution, while maintaining the dynamic range necessary for accurate measurement. Using a variety of different pulse widths, which will obtain extremely precise waveform capture. Readout on the display is very easy to curve, and simultaneously display one event table indicates that all of the relevant junction.

1. Fiber length of the test

The instrument to be tested to determine, fixed line obstacles. Before the test to determine impairment, the instrument cursor should be located at the end of the line curve crack breakpoint Fresnel reflection peak rising edge of the starting point. Test accuracy with optional fiber core refractive index n and the pulse width of the test optical. Due to test the length of the derivation of the formula D=ct/2n (where in C is the vacuum speed of light, C=3x10m/s, t is a light pulse from the transmitter to the end of the via line Fresnel reflection OTDR receiver to the light pulse time) n value, the more accurate the measurement results more real, so the test must be set to plant a given value of n, For example: construction melon seeds floor РMajiawan, fiber optical cable, all four joint construction after run out of time domain reflectometry check the technical specifications of each fiber, a fiber core shorten the distance half to prove that this fiber interrupted, and upon inspection of the raw data, is the second joint 4.2KM cable connector in a fiber break. Position to
judge accurately, open the connector box, and found to be construction, the fiber in the connector box, the joint financial contacts small bending radius, a larger force, so disconnect the re-connector, the indicators are normal.

2. Loss of the optical fiber line testing

The optical cable construction is completed, if run out of time domain reflectometry measured by an optical fiber splice loss is particularly large, determine the distance, be sure to open the connector box, re-connector this situation is generally the construction of the problems left behind.

Running fiber optic cable problems, as measured by the few fiber attenuation curve step, distance measurement, based on the original data to find the point of failure, the result is powder gun shot and wounded due to optical fiber but not completely disconnected.

3. Optical fiber splice loss test

One of the methods of measuring the splice loss, FSM-30S fusion splicing machines of the two optical fibers are connected together, the joint is completed, to display just joint Claim attenuation loss values on the display, the operator may be determined according to the data displayed on the head is qualified, if the loss is too large to disconnect re-fused.

The second metod is the OTDR measuring splice loss, generally using a five-point average method, set the cursor on the fiber contacts, The cursor to the left of the two points, respectively, in the near the test client that the curve of the optical fiber is smooth, so that two points into lines and curves overlap, as far as possible under the cursor on the right side of the two points on the curve of a single fiber is smooth, also let two straight lines and curves overlap as far as possible. So through the cursor on either side of the linear form of “steps” to show the size of the loss of fiber splice.

In order to accurately determine the point of failure, and maintenance and technical personnel should be familiar with the inherent error of the OTDR instrument, grasp the random variation of the refractive index of the instrument and the speed of light take the approximation of the deviation, but also pay attention to the improper operation of the instrument of the deviation, but also pay attention to the improper operation of the instrument error. OTDR measurement line, must be adjusted scale according to the actual situation, select the appropriate pulse width (pw), setting the refractive index of the fiber core values of n, in the two wavelengths (1310 nm, 1550nm) laser options, depending on the line future transmission wavelength of light used to select the appropriate wavelength value. Line optical characteristics test only after the above setting several parameters.

The above three error will affect the accuracy of the measurement line fault. The error of the instrument itself is reflected in the distance resolution, it is determined by the sampling frequency and the sampling pulse width, the smaller the errer is smaller, conversely, the greater the error and vice versa. The method of operation of the refractive index of the randomness and maintenance personal directly affect the distance error is the main reason for the different types of fiber have different refractive indices, the optical fiber measurement should be the first to know the refractive index of the fiber under test, so that the test errors to a minimum.