Polymer optical fiber tapering without the use of external heat source and its application to refractive index sensing

Abstract

We perform a pilot trial of the highly convenient taper fabrication of perfluorinated graded-index polymer optical fibers. Instead of conventional external heating, we utilize internal heating caused by high-power propagating light (500 mW in this experiment). An approximately 4-mm-long section of a polymer fiber is tapered, and the outer diameter of the >2-mm-long waist around its midpoint is approximately 200 µm, which is quite uniform with a standard deviation of 4.3 µm. The polymer fiber taper fabricated by this technique is shown to be capable of generating evanescent waves and thus measuring the refractive indices of liquids from 1.333 to 1.410.

Intensity-Modulated Polymer Optical Fiber-Based Refractive Index Sensor: A Review

“…The tapered POF can be fabricated by the heat-drawing method [ 72 , 73 , 74 ] or the chemical etching method [ 75 , 76 ]. Different heating sources including the furnace [ 72 ], the solder gun [ 52 ], and the flame [ 73 ] were used to heat the POF.…”

“…Different heating sources including the furnace [ 72 ], the solder gun [ 52 ], and the flame [ 73 ] were used to heat the POF. Ujihara et al [ 74 ] fabricated a tapered GI perfluorinated POF by a high-power light propagating inside the fiber, an approximately 4 mm long tapered region was obtained, and a RI sensitivity of 107 dB/RIU was achieved by using this fiber probe. In 2008, a tapered graded-index POF was fabricated and proposed for RI measurement by J. Arrue et al [ 77 ].…”

Polymer optical fiber tapering using hot water

“…25) To date, many kinds of tapering techniques have been demonstrated. [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] Among them, what we call a heat-andpull technique has been most widely used to taper optical fibers, including glass fibers, [26][27][28][29][30][31][32] PMMA-POFs, 33,34) and PFGI-POFs. 25,[35][36][37] Many kinds of heat sources have been used for heating fibers, including a flame, [25][26][27][28][29] a CO 2 laser, 30) a compact furnace, 31,[33][34][35][36] a fusion splicer, 32) and a solder gun, 37) but these are sometimes not easy to handle, prepare, or control.…”

Refractive index sensing using ultrasonically crushed polymer optical fibers

“…However, glass optical fiber tapers are fragile and need to be fabricated and handled with care. One promising way to address this concern is to exploit polymer optical fiber (POF) tapers, [14][15][16][17][18][19][20] which exhibit much greater flexibility.…”

“…A POF tapering technique for converting the propagating light energy into heat without using an external heat source has been developed. 19) However, the required high-power light injection may cause burning at the POF ends 21) and=or what is called the fuse effect. 22,23) RI sensing using V-shaped POFs has also been reported.…”