Graded Index Preforms

j-fiber offers a portfolio of graded index Multimode preforms. Our preforms are being manufactured by our j-fiber MCVD process with our own FiberCore Machinery equipment to provide for guaranteed fiber performance specifications.

Portfolio of our j-fiber graded index Multimode-preforms

Geometrical Characteristics	Multimode Preform 50/125	Multimode Preform 62.5/125	Multimode Preform 100/140	Unit
Core Composition	SiO2-GeO2	SiO2-GeO2	SiO2-GeO2
Refractive Index Profile	Nearly parabolic	Nearly parabolic	Nearly parabolic
Refractive Index Delta	13.7 x 10-3	25.9 x 10-3	28.8 x 10-3
Tolerance of Delta within a Rod	2.0 x 10-3	3.0 x 10-3	4.0 x 10-3
Numerical Aperture	0.200 +/- 0.015	0.275 +/- 0.015 0.290 +/- 0.020
Preform Diameter (O.D.)	39.0	26.0	19.0	mm
Tolerance of O.D. from Rod to Rod	+/- 2.0	+/- 2.0	+/- 2.0	mm
Tolerance of O.D. within a Rod	+/- 0.5	+/- 0.5	+/- 0.5	mm
Preform Length	600-1200	600-1200	600-1200	mm
Preform Bow	≤ 0.7	≤ 0.7	≤ 0.7	mm/m
Preform Non-Circularity	≤ 1.0	≤ 1.0	≤ 2.0	%
Clad Concentricity Error of O.D.	≤ 1.2	≤ 1.2	≤ 2.1	%

 

Target fiber specifications for MMF

Target Fiber Specifications Multimode Faser	Multimode Preform 50/125	Multimode Preform 62.5/125	Multimode Preform 100/140	Unit
Core Diameter	50 +/- 2.5	62.5 +/- 2.5	100 +/- 4.0	µm
Core Non-Circularity	≤ 5.0	≤ 5.0	≤ 6.0	%
Core/Clad Concentricity Error	≤ 1.5	≤ 1.5	≤ 3.0	µm
Cladding Diameter	125 +/- 2.0	125 +/- 2.0	140 +/- 3.0	µm
Cladding Non-Circularity	≤ 1.0	≤ 1.0	≤ 2.0	%
Attenuation 850 nm 1300 nm 1383 nm	≤ 2.4 ≤ 0.6 ≤ 2.0	≤ 2.9 ≤ 0.6 ≤ 2.0	≤ 4.0 ≤ 1.5 ≤ 8.0	dB/km
Bandwidth 850 nm 1300 nm	≥ 500* ≥ 600*	≥ 160** ≥ 500**	≥ 100** ≥ 100**	MHz.km

 

*A minimum of 70% of the fiber output is expected to meet the target fiber specifications
**j-fiber guarantees the bandwidth for 85% of the output



Our graded index preforms are being delivered upon request with a handle end, a rod or tube, to allow clamping of the preform for drawing.

The drop end (Taper) is formed as a cone and the "handle end" is a tube or rod with the same diameter as the preform.

O.D. handle = O.D. preform