Single mode optical fiber with low bend loss at small and large bend diameters
AssigneeCorning Incorporated
InventorsMing-Jun Li, Snigdharaj Kumar Mishra, Pushkar Tandon
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Abstract
The single mode optical fiber disclosed herein has a core, an inner cladding, a trench and an outer cladding, along with a non-glass protective coating. The refractive index profile of the optical fiber is such that the optical fiber has relatively low bend loss at both small and large bend diameters. The relative refractive indices of the inner cladding, trench and outer cladding are such that a tunneling point that arises during bending is pushed out beyond the trench and thus sufficiently far away from the core so that bending losses for both small and large radius bends are relatively small.
Claims21
An optical fiber, comprising:
- a) a glass core having a radius r1 and a relative refractive index Δi;
- b) a glass cladding immediately surrounding the core, the cladding comprising:
- 1. an inner cladding immediately surrounding the core and having a radius r2 and a relative refractive index Δ2;
- 2. a trench immediately surrounding the inner cladding and having a radius r3, relative refractive index Δ3 and a trench volume V3 with a magnitude |V3|;
- and
- 3. an outer cladding immediately surrounding the trench and having a radius r4, and a relative refractive index Δ4 and defining a fiber diameter DF=2r4;
- and
- c) wherein:
- i) Δ1>Δ2>Δ4>Δ3;
- ii) 0.005%≤Δ2−Δ4≤0.05%;
- iii) 15 μm≤r2≤25 μm;
- iv) 30 Δ%·μm2≤|V3|≤80Δ%·μm2;
- vi) a mode field diameter (MFD) at a wavelength of 1310 nm in the range 9.0 μm≤MFD≤9.5 μm;
- and
- vii) at a wavelength of 1550 nm:
- a bend loss BL15≤0.5 dB/turn for a 15 mm bend diameter, a bend loss BL20≤0.2 dB/turn for a 20 mm bend diameter, and a bend loss BL30≤0.005 dB/turn for a 30 mm bend diameter;
- and
- d) wherein:
- the relative refractive index Δ2 has a minimum value Δ2MIN greater than Δ4.
Dependencies are inferred from the claim text.