JPH0610323Y2 - Optical coupler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an optical coupler for optical communication, and in particular, it includes an optical functional element such as an interference film filter, an optical fiber and a lens for optically coupling them. The structure of the optical coupler.

[Conventional technology]

An example of a conventional optical coupler is shown in FIG. An optical coupler 1 shown in FIG. 3 includes an optical functional element 2 such as an interference film filter and a plurality of lenses 3 arranged on both sides of the optical functional element 2 and a rectangular pipe 4.
It is housed inside and fixed by an adhesive 5, and further, the square pipe 4 is mechanically held in a cylindrical holder 6 and fixed by an adhesive. After adjusting the respective fibers 8, 9 and 11 so that the light beam emitted from the incident fiber 8 is efficiently coupled to the emission fibers 9 and 11,
The fibers 8, 9 and 11 are fixed to the holder 6 by adhesives via the supports 12 and 13.

[Problems to be solved by the invention]

In the structure of the conventional optical coupler, since the optical function element 2 such as the interference film filter is square, it is necessary to process the hole of the square pipe 4 for accommodating it into a square hole. When the material of the square pipe 4 is metal, it is difficult to sufficiently improve the processing accuracy of the square pipe 4, and the square pipe 4 and the lens 3
The adhesive layer with and becomes non-uniform, and in the environmental test such as heat cycle, the optical axis of the lens 3 of the optical coupler changes,
The characteristics became unstable over time.

Therefore, in the conventional optical coupler, the optical functional element 2 such as an interference film filter and the lens 3 are connected to the ceramic rectangular pipe 4.
In this case, the adhesive layer was reduced by storing the holder 6 in the holder, and the holder 6 was drilled with high precision so that the square pipe 4 was inscribed. Therefore, it is difficult to reduce the cost of the optical coupler due to the complexity of the structure of the optical coupler, and the stability of the optical axis is insufficient when a single mode fiber is used due to the large number of adhesive layers. There was a flaw.

An object of the present invention is to provide a low-priced and highly reliable optical coupler that solves the above drawbacks.

[Means for solving problems]

The optical coupler of the present invention functions by setting the shape and dimensions of the optical function element such as the interference film filter so that the outer circumference of the cylindrical lens is equal to or smaller than the rectangular shape inscribed in the hole of the holder to be fitted. The device and the lens are housed in a holder. In the configuration in which the optical functional element of the optical coupler is housed in the holder so as to be inscribed on the outer circumference of the lens, the structure is simple and the adhesive layer can be made uniform. As a result, the rectangular pipe is unnecessary, and the number of parts and the assembly time can be reduced as compared with the conventional optical coupler.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show one embodiment of the optical coupler of the present invention, and those having the same functions as those shown in FIG. 3 are designated by the same reference numerals and their explanations are omitted.

In FIG. 1 and FIG. 2, the optical function element 21 such as an interference film filter and the cylindrical lens 3 are fixed in the holder 22 by the adhesive 5, and the cylindrical lens 3 causes the optical function element 21 and the optical fiber 8 to be fixed. , 9, 11 are optically coupled.

The shape and dimensions of the optical functional element 21 are set so that the rectangular optical functional element 21 can be inscribed in the hole of the holder 22 in which the outer periphery of the cylindrical lens 3 is inscribed. The element 21 is fixed by the adhesive 5.
The positions of the optical fibers 8, 9 and 11 are adjusted so that the light beam emitted from the incidence fiber 8 is efficiently coupled to the emission optical fibers 9 and 11 via the optical functional element 21 by the cylindrical lens 3. After this adjustment, the incident fibers 8, 9, 11 are fixed to the holder 22 via the supports 12, 13 with an adhesive or the like.

In this embodiment, the rectangular optical function element 21 is used as the holder 2
Although the example in which the optical function element 21 is inscribed in the second hole is shown, the size of the optical function element 21 does not necessarily have to be inscribed in the hole of the holder 22. In addition to the interference film filter, an optical thin film having absorption characteristics and reflection characteristics can be used as the optical function element 21.

[Effect of device]

As described above, according to the present invention, the shape and dimensions of the optical function element such as the interference film filter are set so that the outer circumference of the cylindrical lens is equal to or smaller than the rectangular shape inscribed in the hole of the holder to be fitted. By accommodating and fixing the lens and the optical function element in the holder, the adhesive layer between the holder and the lens can be made uniform, so that a stable optical system can be obtained. As a result, there is no need for a ceramic rectangular pipe, and there is an effect that a highly reliable optical coupler can be implemented at a lower cost than before.

[Brief description of drawings]

1 is a vertical sectional side view of an optical coupler showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a vertical sectional side view showing an example of a conventional optical coupler. Fig. 4 and Fig. 3
It is the BB sectional drawing in the figure. 3 ... Lens, 5 ... Adhesive, 8 ... Incident fiber, 9, 11 ... Emitting optical fiber, 21 ... Optical functional element, 22 ... Holder.

Claims (1)

[Scope of utility model registration request] 1. At least one prismatic optical functional element, at least one optical fiber, a plurality of cylindrical lenses for optically coupling them, and the optical functional element and the cylindrical lens are housed. In the optical coupler composed of the holder, the shape and size of the optical functional element are set so that the outer circumference of the cylindrical lens is equal to or smaller than the rectangular shape inscribed in the circular hole of the holder to be fitted. Optical coupler characterized by being set.