Measuring method for loss of optical fiber

[Detailed Description of the Invention]

The present invention relates to the measuring method of an optical fiber loss of a laying fiber-optic cable. The measuring method of the conventional optical 7 iron-permanent-wave loss measures optical power P1 from the other end, after measuring optical power P of a standard light source, as shown in Drawing 1, and they are I and =P. -the error which was being searched for from P and (a) according [ take time, after obtaining, however measuring standard light source P- in this method before measuring Pl and ] to P, and the time jitter of optical power and fluctuation arises. A possibility of degrading accuracy also has the vibration accompanying movement of a power meter. There is the object of the present invention in providing the measuring method which measures an optical fiber loss in real time while saving time required for the above-mentioned power meter movement. Instead of measuring light P0 which enters into a former fiber, and light P1 to emit, without moving a power meter, it devised so that a total-internal-reflection mirror receptacle might be attached to an outgoing end and an optical fiber loss could be measured from the catoptric light. Hereinafter, Drawing 2 explains one example of the present invention. It is an optical directional coupler which the light from a light source takes out to a straw-man fiber for 1 to carry out a standard light source and for 2 make propagation mode of light uniform, takes out 6 in the direction of an axis through, and gives off catoptric light in the right-angled direction. 6 is a power meter. The light which came out of the light source comes out in the optical connector of 7 through 1->2->6. This light is reflected by the total-internal-reflection theory receptacle of 8, and Po is measured. ... Drawing 2 (a) Next, this 7 is reflected in the laying fiber-optic cable of 5 by the total-internal-reflection mirror receptacle of 8 by through and its exit end through the receptacle of 4, and reflective power P at that time is measured. ... at this time [ Drawing / 2 ], it can ask for section light fiber loss Ri by L = / (P, -P) 2 (dB). If a straw-man fiber is removed and an optical transmitting machine is used as a light source, the power and receiving power of the transmitting side can measure simultaneously.

[Brief Description of the Drawings]

The figure in which Drawing 1 shows the conventional fiber-optic cable loss measuring method, and Drawing 2 are figures showing the measuring method of the present invention. 1 ... standard light source 2 ... straw-man fiber 3 ... power meter h Optical fiber cable 6 ... output side optical connector plug 8 of optical directional coupler 7...6 ... 4 ... receptacle 5 ... laying -- total-internal-reflection mirror receptacle representative patent attorney Thin 1 profit Happiness and ? + 1 power +two lots