معدل الشدة للبقعة الليزرية لليف البصري الاحادي النمط للمسافة الطويلة عن النصدر الليزري

I study the bending effect of the single-mode fiber optic on the mean intensity of spot laser at long distance (247)cm from laser source. I use Single-mode fiber optics have been used , such fiber was made from silica and turn over cylinders with variable diameters (3 , 5 and 10 )cm to obtain different bending diameter of optical fiber . Also i use Diode laser of wavelength (630- 680)nm and (5)mW maximum power have been used . The mean intensity of spot laser was calculated from algorithm program for each spot image which captured by digital camera connected to computer. There is three color bands (red, green, and blue) were clear in present study work .The mean intensity of red color was dominant independent of diameter of fiber. Increasing the bending diameter of fiber optic led to increase the mean intensity of three colors and decreasing with increasing the number of turns of fiber optic. I obtain region of high coherence for red color because of nearly constant of mean intensity, so that the fiber with diameter (10 cm) is the best.