JPH0248431A - Rare earth element-doped fiber - Google Patents

Abstract

PURPOSE:To enable efficient oscillation or amplification of light with a weave length longer than that of usual rare earth element-doped fibers by doping the core of an optical fiber having the core consisting of GeO2 glass as the main component with rare earth elements. CONSTITUTION:The subject fiber is formed by doping the core mentioned below with one or more rare earth elements in an optical fiber having the core consisting of GeO2 glass as the main component. The resultant rare earth element-doped fiber can efficiently oscillate or amplify light with a weave length of the order of 2-3mum.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a rare earth element-doped fiber whose core is doped with a rare earth element.

(Prior Art) A rare earth element-doped fiber in which a core mainly composed of S10° glass is doped with a rare earth element is well known. That is, the core of conventional rare earth element-doped fiber is mainly composed of S102 glass, and Ge
It contained at most about 20 to 30% by weight of 02 glass.

(Problems to be Solved by the Invention) Although the conventional configuration described above can oscillate or amplify light with a wavelength of about 1 to 2 μm, it cannot efficiently oscillate or amplify light with a wavelength of about 2 to 3 μm. could not.

(Means for Solving the Problems) In order to solve the above problems, the rare earth element-doped fiber of the present invention is an optical fiber having a core mainly composed of GeO2 glass, in which the core has at least 1 f! I
! It is doped with a class of rare earth elements.

(Function) The core whose main component is SiO2 glass has the smallest attenuation rate for light with a wavelength of about 1.8 μm;
The core whose main component is GeO2 glass has the smallest attenuation rate for light with a wavelength of about 2.5 μm. Therefore, by doping a core mainly composed of GeO2 glass with a rare earth element, it is possible to efficiently oscillate or amplify light with a wavelength of about 2 to 3 μm.

(Example) An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a cross-sectional view of a rare earth element-doped fiber in one embodiment of the present invention, where 1 is a core and 2 is a cladding. Core 1 contains 90% by weight or more of GeO2 glass,
Further, one type of rare earth element such as neodymium (Nd), erbium (Er), or holmium () is doped. Further, the core 1 has a graded shape in which the refractive index gradually decreases from the center to the outer periphery. The cladding 2 has, for example, 5102 glass as its main component.

Next, the effect will be explained. The core whose main component is SiO2 glass has the lowest attenuation rate for light with a wavelength of about 1.6 μm, but the core 1, whose main component is GeO2 glass, has the lowest attenuation rate for light with a wavelength of about 2.5 μm. In contrast, the attenuation rate is the smallest. Therefore, by doping the core 1 mainly composed of Geo 2 glass with a rare earth element, 2 to 3
Light with a wavelength on the order of μm can be efficiently oscillated or amplified. For example, when a conventional core whose main component is 8102 glass is doped with Er, the wavelength of light that is most efficiently oscillated or amplified is l, 55 μm. In this case, the wavelength of light most efficiently oscillated or amplified was 2.9 μm. Furthermore, when core 1 is doped with Nd, the wavelength of light that is most efficiently oscillated or amplified is 1.08 μm, and when core 1 is doped with Ho, the wavelength of light that is most efficiently oscillated or amplified is 2.1 μm. Met.

In this way, by using the rare earth element doped fiber consisting of the core 1 and the cladding 2 as a laser fiber or optical direct amplification fiber, it is possible to oscillate or emit light with a longer wavelength more efficiently than conventional rare earth element doped fibers. Since it can be amplified, it can be used for new purposes in all fields, such as medicine, communications, processing, etc.

(Another Example) In the above example, an example was explained in which the core 1 was doped with one type of rare earth element, but the core 1 may be doped with two or more types of rare earth elements. By doing so, it is possible to efficiently oscillate or amplify light of multiple wavelengths.

Further, in the above embodiment, an example was explained in which the refractive index of the core 1 changes in a graded type, but it goes without saying that it may also be changed in a step type.

(Effects of the Invention) As explained above, according to the present invention, GeO. In an optical fiber having a core mainly composed of glass, the core is doped with at least one kind of rare earth element, so that this rare earth element-doped fiber can be used as a laser fiber or a fiber for direct optical amplification, etc. Since it can efficiently oscillate or amplify light at a wavelength of about 2 to 3 μm, which is longer than conventional rare earth element-doped fibers, it has new applications in various fields such as medicine, communications, and processing.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a rare earth element-doped fiber in one embodiment of the present invention. 1... Core

Claims (1)

[Claims] 1. A rare earth element-doped optical fiber having a core mainly composed of GeO_2 glass, characterized in that the core is doped with at least one type of rare earth element.