JPS61256311A - Multiterminal laser diode module - Google Patents

Abstract

PURPOSE:To facilitate assembly by providing the light emission surface of a laser diode in contact with one end surface of a slab type converging optical transmitter which decreases in refractive index gradually in one direction and is uniform in refractive index in the other direction, and providing respective end surfaces of optical fibers in contact with the other end surface of the transmitter. CONSTITUTION:The light emission surface of the laser diode 2 is provided in contact with one end surface of the converging optical transmitter 1 and the end surface of an optical fiber arrays of plural optical fibers is provided in contact with the other end surface. The converging optical transmitter 1 decreases in refractive index gradually from the center to the periphery in one of orthogonal (x) and (y) directions in a plane parallel to both end surfaces, e.g. (y) direction in a plane parallel to both end surfaces and is uniform in refractive index in the (x) direction and in such a slab shape that the distance between both end surfaces is a multiple of 1/2 pitch. The converging optical transmitter 1 uses a unidirectionally distributed index slab lens constituted by stacking a couple of glass plates which are decreased in refractive index only at right angles to the surfaces by diffusion and injecting high refraction ions from the surfaces so that the glass surfaces contact each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a multi-terminal laser diode module that evenly distributes output light from one laser diode to a plurality of optical fiber terminals.

[Prior Art] In recent years, optical communication is reaching the stage of practical application as the performance of optical fibers and laser diodes has improved. One of the optical beam control technologies used in such optical communication systems is the use of a light source, the Ray IJ'-diode (LD).
>, light emitting diode (l[r)) output light, optical fiber terminal, etc. Optical coupling technology is essential for optical communication! It is not an important technology. Particularly useful is a multi-terminal laser diode module that can extract a plurality of homogeneous lights from one light source and that integrates the laser diode of the light source with a plurality of optical fiber terminals on the output side.

In a conventional multi-terminal laser diode module of this type, for example, as shown in FIG. There is a device in which the planar waveguide 11 is used as a mixer to evenly distribute the light to the optical fiber array 13 formed by arranging a plurality of optical fibers. It has a cylindrical light focusing property [l Rad lens is also used.

[Problems to be solved by the invention] However, this J, the conventional one, has a ball lens 1.
Since it is necessary to insert light into the input end of the planar waveguide 11 using a cylindrical rod lens 5 or a cylindrical rod lens, complicated position adjustment is essential, and there are problems such as complicated and troublesome assembly. there were.

It is an object of the present invention to solve the problems of the above-mentioned conventional devices and to provide a multi-terminal laser diode module that does not require complicated position adjustment and can be easily assembled.

[Means for Solving the Problems] In order to achieve the above object, the present invention gradually decreases the refractive index from the center to the periphery only in one direction that is perpendicular to each other in a plane parallel to both end faces, The light-emitting surface of the laser diode is brought into contact with one end face of a slab-shaped convergent optical transmitter whose refractive index is uniform in the other direction and whose distance between both end faces is approximately a multiple of 1/2 pitch. Further, each end surface of a plurality of optical fibers arranged along the other direction is provided in contact with the other end surface of the focusing optical transmission body.

[Function 1] By employing the above-mentioned means, the present invention installs a laser diode and an optical fiber array in which a plurality of optical fibers are arranged in contact with each end face of a convergent optical transmission body. With the simple configuration of [), the output light from the laser diode passes through the convergent light transmission body and is evenly distributed to each optical fiber.

[Example] Embodiments of the invention shown in the drawings will be described below.

FIG. 1 shows an embodiment of the present invention, in which a convergent optical transmission body 1
The light emitting surface of the Rayleigh diode 2 is provided in contact with one end surface of the optical fiber array 3, and the end surface of an optical fiber array 3, which is formed by arranging a plurality of optical fibers, is provided in contact with the other end surface. The convergent light transmitting body 1 has a refractive index that gradually changes from the center to the periphery only in the X direction among the X directions and the X directions that are perpendicular to each other in a plane parallel to both end surfaces, as shown in FIG. The refractive index is uniform in the X direction as shown in Figure 2 (a), and the distance between both end faces is 1/2.
The pitch (or a multiple of 1/2 pitch may be used) is shaped like a slab. Such a convergent light transmitter 1
As for the patent application filed earlier by the applicant of this invention in 1982,
As disclosed in Japanese Pat. A unidirectional refractive index gradient type slab lens configured by stacking them in contact with each other can be used. The refractive index of such a slab lens, that is, the focusing optical transmitter 1, in the refractive index distribution direction, that is, the X direction, is expressed by the following formula (%). is approximately NA = 0.7, which can sufficiently cover the maximum beam divergence angle of the laser diode.
The above numerical values can be obtained.

Laser diode 2 has its maximum beam divergence angle -〇
The beams are oriented so that the direction of - coincides with the X direction of the convergent light transmitter 1, and therefore the direction of the minimum beam divergence coincides with the X direction of the convergent light transmitter 1. Further, the optical fiber array 3 is arranged along the X direction of the convergent light transmission body 1 so as to fill a width approximately equal to the width in the X direction.

In the multi-terminal laser diode module described above, the laser beam in the X direction emitted from the laser diode 2 at the maximum beam divergence angle is refracted within the convergent light transmission body 1 and focused on the optical fiber array 3, as shown in FIG. The laser beam in the X direction, which is emitted from the laser diode 2 at the minimum beam divergence angle, is repeatedly reflected on the side surface of the convergent light transmission body 1 or goes straight, as shown in FIG. 3, so that the output light from the laser diode 2 passes through the convergent light transmission body 1 and is equally distributed to all the optical fibers of the optical fiber array 3. Note that, as shown in FIG.
It can prevent the loss of light in the direction.

[Effects of the Invention] Since the present invention is configured as described above, it is only necessary to provide an optical fiber array in which a laser diode and a plurality of optical fibers are arranged in contact with both end surfaces of the convergent optical transmission body. It can be easily assembled without the need for complicated positioning, and has excellent effects such as the ability to distribute the output light from the laser diode evenly to each optical fiber through the convergent light transmitter. be.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG.
)(b) is a graph showing the refractive index distribution of the convergent light transmitting body in Fig. 1, Fig. 3 is an explanatory diagram showing how the light travels in the X direction of Fig. 1, and Fig. 4 is the graph shown in Fig. 1. FIG. 5 is an explanatory diagram showing another embodiment of the present invention, and FIG. 6 is a perspective view showing an example of a conventional device. DESCRIPTION OF SYMBOLS 1... Focusing light transmission body, 2.12... Laser diode, 3.13... Optical fiber array, 4... Reflection film, 15... Ball lens. Applicant Hoya Co., Ltd. Agent Masayuki Asakura Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. In a plane parallel to both end faces, the refractive index gradually decreases from the center to the periphery only in one direction orthogonal to each other, and the refractive index is uniform in the other direction, and both end faces A light emitting surface of a laser diode is provided in contact with one end face of a slab-shaped convergent light transmitting body whose distance between the two is a multiple of approximately 1/2 pitch, and a light emitting surface of a laser diode is provided in contact with the other end face of the convergent light transmitting body. , a multi-terminal laser diode module characterized in that each end face of a plurality of optical fibers arranged along the other direction is provided in contact with each other. 2. The multi-terminal laser diode module according to claim 1, wherein the laser diode is oriented such that the direction of its maximum beam divergence coincides with the one direction of the focusing light transmission body. 3. The focusing light transmission body is provided with a pair of glass plates whose refractive index is gradually reduced only in a direction perpendicular to the surface by diffusing and importing high refractive ions from the surface, and the surfaces of both glass plates are in contact with each other. A multi-terminal laser diode module according to claim 1, which is constructed by stacking the multi-terminal laser diode module in such a manner. 4. The multi-terminal laser diode module according to claim 1, wherein the convergent light transmitting body is adapted to reflect light on both sides in the other direction. 5. The multi-terminal laser diode module according to claim 1, wherein the optical fibers are arranged so as to fill a width substantially equal to the width of the focusing optical transmission body in the other direction.