JPH02242203A - Optical fiber collimator - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a gap between optical axes with the lapse of time or due to an environmental change of temp. or humidity and to obtain stable coupling efficiency by melting and connecting one end of a rod lens and one end of an optical fiber. CONSTITUTION:The flat end of a rod lens 1 obtd. by making one end of cylindrical quartz convex and one end of a single-mode optical fiber 2 having a quartz core and clad are melted and connected by a method similar to fiber splice after the optical axes are adjusted. Since the fiber 2 is directly fixed on the lens 1 without interposing an adhesive layer, a gap occurs hardly between the optical axes with the lapse of time. The optical axes are also stable to an environmental change of temp. or humidity because the fiber 2 and the lens 1 are made of the same material. Since the boundary face between the lens 1 and the fiber 2 is vanished, the lowering of coupling efficiency due to Fresnel reflection is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical fiber collimator that is mounted and used inside a semiconductor laser module or the like used in optical communication, optical information processing, etc.

[Conventional technology]

Conventionally, as an optical fiber collimator, as shown in FIG. 2, a ferrule 4 into which an optical fiber 2 is inserted and fixed is used.
There is one in which a lens 1 and a lens 1 are inserted into a precision sleeve 3 and fixed.

[Problem to be solved by the invention]

In the conventional optical fiber frimeter described above, the optical axes of the lens 1 and the optical fiber 2 are fixed with respect to the inner surface of the precision sleeve 3, and the optical axes of the lens 1 and the optical fiber 2 are fixed with respect to the inner surface of the precision sleeve 3, between the lens 1 and the precision sleeve 3, between the ferrule 4 and the precision sleeve 30, and between the ferrule 4 and the precision sleeve 30. An adhesive layer or a solder layer is interposed between the optical fiber 2 and the ferrule 4 to fix each of them. For this reason, adhesive or solder
The relative positions of the optical axes of the lens 1 and the optical fiber 2 tend to change due to expansion and contraction over time or due to environmental changes such as temperature and humidity. Therefore, when a semiconductor laser module or the like is constructed using this, there is a drawback that the light coupling efficiency tends to change over time or temperature fluctuations occur easily. It also has the disadvantage that the light coupling efficiency decreases due to Fresnel reflection at the end faces of the lens 1 and the optical fiber 2.

[Means to solve the problem]

The optical fiber frimeter of the present invention includes a lens and an optical fiber, and the lens end face and the optical fiber end face are fusion-spliced.

〔Example〕

Next, the optical fiber collimator of the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view showing one embodiment of the present invention. The lens 1 is a rod lens made of cylindrical quartz with one end surface processed into a spherical surface, and the optical fiber 2 is a single mode fiber having a quartz core and a cladding. The flat portion of the lens 1 and the optical fiber 2 are adjusted so that their respective optical axes coincide with each other, and then fusion spliced in the same manner as a fiber splice.

Therefore, since the optical fiber 2 and the lens l are directly fixed without intervening an adhesive layer or the like, it is difficult for their mutual optical axes to shift over time, and at the same time, the optical fiber 2 and the lens l are made of the same material. Therefore, it is stable against external environmental changes such as temperature and humidity. Further, since the interface between the lens 1 and the optical fiber 2 is eliminated by fusion, there is no reduction in coupling efficiency due to Fresnel reflection.

Furthermore, parts such as precision sleeves that have been used in the past are no longer necessary, allowing for miniaturization.

〔Effect of the invention〕

As explained above, in the present invention, by fusing the lens and the optical fiber, ■ Optical axis shift is less likely to occur over time or due to changes in the external environment such as temperature and humidity, and stable coupling efficiency can be obtained. .

■ Since there is no boundary between the lens and the optical fiber, there is no reduction in coupling efficiency due to Fresnel reflection.

■ The number of parts is small, making it possible to downsize.

There is an effect.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the optical fiber collimator of the present invention, and FIG. 2 is a sectional view showing the structure of a conventional optical fiber collimator. 1...Lens, 2...Optical fiber, 3
...Precision sleeve, 4. River ferrule. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] An optical fiber collimator comprising a lens and an optical fiber, wherein the lens and the end face of the optical fiber are fusion-spliced.