JPS6041327B2 - Optical signal coupling lens - Google Patents

Description

Detailed Description of the Invention {1} Technical Field of the Invention The present invention relates to a lens for optical signal coupling, particularly for coupling optical signals between semiconductor lasers and optical fibers arranged in a large number of arrays,
The present invention relates to an optical signal coupling lens suitable for coupling optical signals such as coupling between a large number of photodetectors and an optical waveguide.

'21 Background of the Technology The application fields of optical fiber communication and optical information processing are rapidly expanding, and there is a demand for the provision of a variety of optical circuit elements.

For example, an optical signal coupling lens is indispensable for optical communication processing. Optical signal coupling lenses include east-focusing rod lenses and ball lenses, which are used, for example, to increase coupling efficiency when connecting semiconductor lasers and optical fibers, and to reduce insertion loss in various optical passive components. It is also used to reduce
Ball lenses include, for example, those made of sapphire and those made of plastic, but those made of plastic generally suffer from deterioration over time.

Conventionally, there has been no sapphire spherical optical signal coupling lens in which a large number of lenses are fixed at desired intervals and arranged on the same plane.

[3] Object and structure of the invention The present invention provides a lens in which spherical lenses made of sapphire are arranged in a matrix at desired intervals, so that, for example, a large number of laser diodes and optical fibers can be reliably connected to each other. The purpose of the present invention is to provide an optical signal coupling lens that can be used for a wide range of applications, such as

Therefore, the optical signal coupling lens of the present invention is characterized by being formed by embedding a plurality of spherical sapphires arranged in a matrix in a disk-shaped green sheet whose main component is aluminum oxide, and then solidifying the green sheet. Embodiments will be described below with reference to the drawings. ■ Embodiments of the Invention Fig. 1 shows an embodiment of the present invention, Fig. 2 is an explanatory diagram of a method for manufacturing an optical signal coupling lens according to the present invention, and Figs.
The figure shows an explanatory diagram of an applied example of the present invention, and FIG. 5 shows an explanatory diagram of another embodiment of the present invention.

The optical signal coupling lens of the present invention, for example, as shown in FIG. It has a structure in which a spherical lens 2 made of sapphire is embedded.

Needless to say, alumina ceramic has a polycrystalline structure, while sapphire has a single crystalline structure.
However, they are of the same quality in that the main component is aluminum oxide (AI203), and by firing, the alumina ceramics 1 and the sapphire spherical lens 2 are fused on the surface,
Tightly bond. The arrangement of each spherical lens 2 can be arbitrarily determined when a hole for embedding the spherical lens 2 is made in advance in the green sea before firing. They may be simply arranged in a line at desired intervals, or they may be arranged at the vertices of a planar continuous pattern such as a regular triangle or a regular hexagon. Note that the alumina ceramic base has a thickness of, for example, 0.5 willow. The optical signal coupling lens of the present invention can be manufactured, for example, as shown in FIG.

First, as shown in FIG. 2A, holes are punched at desired intervals in a disc-shaped green sheet 3 of an appropriate thickness using, for example, an NC processing machine 4. The size of the hole is approximately the same as the diameter of the sapphire spherical lens 2 to be embedded. A spherical lens 2 made of sapphire is inserted into this hole. The opening in FIG. 2 shows a cross-sectional view of the spherical lens 2 inserted in iron. When this is fired in the process shown in Figure 2 C, as shown in Figure 2 2,
Green sheet 3 changes to alumina ceramics,
By shrinking and fusing, the spherical lens 2 is firmly held as if it were integrated. Note that a suitable impurity may be mixed into the green sheet 3 to color the alumina ceramic. The optical signal coupling lens manufactured in this manner can be used in packages for various array devices.

FIG. 3 shows an example used for connecting a semiconductor laser and an optical fiber. Recently, semiconductor lasers have come into the spotlight in the field of optical communications. For example, as shown in FIG.
Alumina ceramic and sapphire spherical lens 2
Connection can be made using the optical signal coupling lens of the present invention consisting of the following. Compared to the case where the devices are simply connected separately, it is possible to downsize the entire device, and it is also possible to construct a stable device with little change over time. Also,
As shown in FIG. 4, it can also be used as a component of an optical sensor.

By associating the optical signal coupling lens according to the present invention with an array device 7 consisting of a large number of photodetectors 8 arranged in a matrix to receive light, high quality light can be detected. In particular, by passing the light beam through the spherical lens 2, it becomes possible not only to simply detect the light beam, but also to detect the direction in which the light beam moves when it moves. By making the spherical lens 2 according to the present invention have the following structure, a particularly short focus lens can be constructed.

However, short focal length lenses require a complicated and long manufacturing process and are extremely expensive.

Therefore, it has not been used in actual products as a normal optical circuit component other than for special purposes. However, if it were inexpensive, it would greatly contribute to the miniaturization of devices, for example, and would have a wide range of applications as optical circuit components. Conventionally, short focus lenses have been expensive. The reason is that the same performance is efficiently achieved,
In some cases, it was difficult to reproduce and manufacture products of high quality. For example, as shown in FIG. 5A, a green sheet or a small piece 10 of alumina or the like is attached onto a sapphire spherical lens 2 inserted into a green sheet 3.

This small piece 10 may be a fine powder of sapphire material. Then, as explained in FIG. 2, it is fired together with the base of the green sheet 3. Then, the small piece 10
As shown in the figure, is firmly fused to the spherical lens 2 to form a convex portion 11 on the spherical lens 2. This convex portion 11 is made of alumina ceramics, and exhibits almost the same properties to light as sapphire. A certain amount of surface tension acts on the tip of the convex portion 11, and the tip naturally becomes hemispherical. A small piece 10 such as a green sheet is first attached to the spherical lens 2, and then a fifth
By stacking them in a potbell shape as shown in Figure B,
It is also possible to form the cone-shaped convex portion 12 on the spherical lens 2 by firing it.

It is also easily possible to make the tip of the cone-shaped convex portion 12 into a spherical shape, for example, about 5 mm, and to form the cone-shaped portion to have a length of 204 mm or less. Furthermore, although not shown, the convex portions 11 or 12 may be formed on both sides of the upper and lower surfaces of the spherical lens 2. The spherical lens 2 having the convex portion 11 or 12 has a double lens structure and has short focus lens characteristics.

As shown in FIG. 5C, by using this spherical lens 2 to couple the laser diode 5 and the optical fiber 6, the east focusing effect of the laser beam can be enhanced. For example, the characteristic beam spot size of the laser light emitted by the laser diode 5 is WLD, and the characteristic beam spot size of the optical fiber 6 is WLD.
Suppose the spot size is WF. In addition, the convex portion 12
Assuming that the lens characteristic of is the focal length n, and the lens characteristic of the main body portion of the spherical lens 2 is n2, the following relationship is satisfied. WLD・Na, WF−−Na2 In this way, the optical signal coupling lens according to the present invention can be easily made to have a short focus.

Note that the cone-shaped convex portion 12 and the like are fused to the original spherical lens 2 and will not come off. (2) Effects of the Invention As explained above, according to the present invention, it is possible to provide an optical signal coupling lens for an array device that is stable and stable over time.

It has a wide range of applications as an optical circuit component.

[Brief explanation of the drawing]

Fig. 1 shows the configuration of an embodiment of the present invention, Fig. 2 is an explanatory diagram of a manufacturing method of an optical signal coupling lens according to the present invention, Figs. 3 and 4 are explanatory diagrams of an application example of the present invention, and Fig. 5 shows an explanatory diagram of another embodiment of the present invention. In the figure, 1 is alumina ceramics, 2 is a spherical lens, and 3
5 represents a green sheet, 5 represents a laser diode, and 6 represents an optical fiber. O diagram O 2 diagram 3 diagram 4 diagram Pig 5 diagram

Claims (1)

[Claims] 1. An optical signal coupling lens characterized in that a plurality of spherical sapphires are arranged and embedded in a matrix in a disc-shaped green sheet mainly composed of aluminum oxide, and then sintered.