J-fiber Gmbh

Christian Genz

Lothar Brehm

Wolfgang Hämmerle

Falk Wirth

Robert Hanf

Wolfgang Haemmerle

Harald Hein

A method for a defined deposition of a glass layer on an inner wall of a preform for an optical fiber and/or for setting a refractive index profile of the preform for a multi-mode fiber. The method includes providing the preform having a cavity and an inner wall which defines an inner diameter of the preform, and spreading a deposition gas at a flow speed (v) in the cavity of the preform so as to provide the defined deposition of the glass layer. The defined deposition is performed at a reduced change in the flow speed a*&#x394;v, where a&#x3c;1. Based on the defined deposition, a change in the flow speed (&#x394;v): forms at a volume flow (Q), a first diameter (d), and a second diameter (d).

Method for the defined separation of a glass layer on an inner wall of a preform and preform and communication system

Methods for making a preform for a graded-index multimode fiber by using an inside deposition process are disclosed. The methods are characterized by an iterative refractive index profile correction with the following steps: determining a target refractive index profile for the preform to be produced, carrying out an inside deposition process with fixed volume flows for the reacting gases inside a tube and a given burner speed for all deposited layers, collapsing the tube and measuring the actual refractive index profile, comparing the target profile with the actual profile and calculating a correction value of index differences, converting this correction value in corrected burner speeds as varying process parameter, carrying out a inside deposition process with fixed gas flows and corrected burner speeds for all layers to be deposited.

Methods for making a graded-index multimode preform and fiber

The invention relates to a bend insensitive gradient index multi-mode light conducting fiber comprising a leakage mode dependent optical core diameter that is uniform over its length and a numerical aperture that is uniform over its length, wherein for a light wavelength of 850 nm and an overfilled launch (OFL), the optical core diameter for a fiber length in a range between 2 m and 100 m decreases by less than 5% and the numerical aperture decreases by less than 2.5% and the curvature related attenuation increase for two turns and a curvature radius of 7.5 mm is less than 0.2 db.

Bend insensitive gradient index multi-mode light conducting fiber

The invention relates to a bend insensitive gradient index multimode light conducting fiber comprising a leakage mode dependent optical core diameter that is uniform over its length and numerical aperture that is uniform over its length, a core (), an inner cladding (), a refraction index trench () and an outer cladding (), wherein the core () includes a core radius R, an alpha-refraction index profile and a core refraction index difference dnwith respect to the outer cladding (), wherein the refraction index trench () includes a refraction index trench radius Rand a trench refraction index difference dnwith respect to the outer cladding (), wherein the outer cladding () includes an outer cladding radius Rand a refraction index between 1.40 and 1.55, wherein for a light wavelength of 850 nm and an overfilled launch (OFL), the optical core diameter for a fiber length in a range between 2 m and 300 m decreases by less than 5% and the numerical aperture decreases by less than 2.5% and the curvature related attenuation increase for two turns and a curvature radius of 7.5 mm is less than 0.2 db.

Growing community of inventors

Jena, Germany

Christian Genz