Ultra-low bending loss of 0.007 dB/loop for 10 mm of bending diameter at 1550 nm in the double trenched bend insensitive optical fiber

The increase in the usage of FTTH in the optical communication has drawn much attention among the fiber optics engineers to face the challenges of sharp bends that are unavoidable at city apartment corners. In the current communication, we report experimental demonstration of the ultra-low bending loss in the single mode optical fiber. The optical fiber was fabricated using the modified chemical vapour deposition (MCVD) process. The optical fiber´s core was surrounded by five cladding layers: innermost being the silica cladding followed by the first low-index trench, then the second silica cladding, the second low-index trench, and finally the third silica cladding. The double trenched bend insensitive optical fiber had the LP₁₁ cutoff wavelength at 1190 nm. Its mode field diameter was determined using the lateral splice loss measurement technique and it was found to be about 8.5-9.5 mum at 1550 nm.