JPH07140338A - Parallel optical multi-branching device - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides an optical multi-branching device used in an optical network such as optical communication and optical information processing, and a device. The present invention realizes an optical multi-brancher capable of high-density mounting by planar coupling, and is a parallel optical multi-brancher in a planar type optical waveguide, in which a reflection surface on one side of an optical waveguide core is diffracted. It is a parallel optical multi-branching device in a planar type optical waveguide in which an element is provided, and guided light is reflected by the element and emitted outside the optical waveguide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical multi-branch element used in optical networks such as optical communication and optical information processing, and devices.

[0002]

2. Description of the Related Art Conventionally, as a means for branching this kind of guided light into a large number of light beams, a method of using a flat plate lens having a large number of lenses and a method of manufacturing a plurality of optical fibers by fusion splicing , There is a method of entering guided light into a multi-branching waveguide and branching it.

[0003]

However, in the prior art, the method of using a flat lens as shown in FIG. 4 requires a plurality of parts and a space for spatial separation. In the method of fusion-stretching a large number of optical fibers, it is necessary to provide a fusion-stretching portion, and both are not suitable for high-density mounting. In the method using the multi-branched optical waveguide, there is a limit to the number of branches due to the increase in loss due to the branching portion of the waveguide core. The following is a summary of the problems associated with the above technologies. (1) A plurality of lenses are used for multi-branching, or there is a fusion extending part, so that the space required becomes large. (2) It is not suitable for high-density mounting because it is difficult to make a planar multi-layer branch from the optical waveguide. (3) Requires adjustment of optical system and position of optical fiber,
It takes time to assemble.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve these problems of the prior art, and realizes an optical multi-brancher capable of high-density mounting by planar coupling. The present invention is a parallel optical multi-brancher in a planar optical waveguide, in which a diffractive element is provided on a reflecting surface on one side of an optical waveguide core, and the guided light is reflected by the diffractive element to be emitted outside the optical waveguide. A parallel optical multi-branching device in the planar optical waveguide, further comprising a plurality of diffractive elements for entering guided light from an optical fiber connected thereto and for outputting to the outside in the planar optical waveguide. In addition, the planar optical waveguide is a parallel optical multi-branching device in the planar optical waveguide in which a pinhole plate is installed to prevent scattered light on the emission side.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are schematic views of the configuration of an embodiment of the present invention, in which the same parts are designated by the same reference numerals. Figure 1
1 is a cross-sectional view of an embodiment of a multi-branching device according to the present invention, in which a diffractive element 3 is provided on one side of a flat optical waveguide 2 and the reflected light is diffracted to change its direction by 90 ° and emitted outside the optical waveguide. . The optical waveguide 2 is a planar type optical waveguide called a planar type, and is connected to the optical fiber 1 at the end face. Also,
A plate having a pinhole 4 is installed on the exit side of the optical waveguide to remove unnecessary scattered light such as high-order light mainly due to the diffraction element 3.

In this embodiment, a reflection type off-axis lens is used as the diffraction element 3. Optical waveguide core 2
Each time the guided light propagating in a is passed through the diffractive element 3, it undergoes wavefront conversion and is emitted as diffracted light outside the optical waveguide. The position of the diffractive element in the planar type optical waveguide is arranged by etching the buffer layer 2c on one side of the core in an appropriate shape. Alternatively, it may be separately manufactured and attached. The point is that it is sufficient if it can reflect the guided light. Further, the planar positions of the diffractive element in the embodiment are installed at equal intervals in a region where light is evenly distributed. Although the diffraction grating used is an off-axis type lens in the embodiment, a part of the light incident at an angle θ is reflected and guided as it is, and a part of the light is converted into a wavefront by diffraction, and the diffraction characteristics are collected. Light is emitted to the outside of the optical waveguide.

In FIG. 2, FIG. 2A shows emission of light by diffraction from optical waveguide propagation according to the present invention, and FIG. 2B shows a schematic shape of a relief grating. Light propagating in a single mode propagates at an angle θ that satisfies the condition. Therefore, as the relief grating, the angle θ and the required incident light,
The surface shape of the relief can be set based on the relationship with the convergence of the emitted light. The equation of the interference fringes obtained from the phase transfer functions of the incident light 5 and the outgoing light 6 in this case is shown in Equation 1. Figure 2
As shown in (b), a radial lattice is shown. Thus, the relief shape that can be arbitrarily set according to the necessary conditions can be easily duplicated by the photolithography process.

[0008]

[Equation 1]

By setting θ as in the above equation, the incident condition in the single mode can be satisfied and the light can be emitted to the outside by diffraction. Further, the function of the interference fringe can be set according to the application such as beam branching. When a diffractive element is used, high-order light above the second-order light is emitted in addition to the zero-order light and the first-order light used, but a pinhole plate is installed on the emission side surface to remove such unnecessary light. To do. As a result, the secondary light and higher-order light are blocked and removed on the pinhole plate.

FIG. 3 shows an embodiment in which the parallel optical multi-branching device according to the present invention is applied as a planar optical switching device, and the parallel optical multi-branching device is opened and closed by energization using, for example, a liquid crystal element. It is possible to switch to an arbitrary address by placing it on the type optical modulator and receiving light and photoelectrically converting it by the flat type light receiving element array in the lower stage. As described above, by using the parallel optical multi-branching device according to the present invention, it is possible to form an optical component in close contact with multiple layers.

[0011]

As described above, according to the structure and method of the present invention, the following excellent effects can be obtained. (1) The incident fiber can be directly connected to the optical waveguide core, a connecting lens is not required, and space is not required. (2) Due to the direct branching due to the deflection of the light from the flat plate element,
Stacking enables high-density mounting. (3) The number of parts is small and optical adjustment during mounting becomes easy.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an embodiment of a parallel optical multi-branching device according to the present invention.

FIG. 2 is a schematic diagram illustrating the operation of a diffractive element in an optical waveguide.

FIG. 3 is a schematic diagram of a configuration example of a conventional parallel multi-branching device.

FIG. 4 is a schematic diagram of an optical switching device using a parallel optical multi-branching device according to the present invention.

[Explanation of symbols]

1 Optical Fiber 1a Optical Fiber Core 1b Optical Fiber Clad 2 Optical Waveguide 2a Optical Waveguide Core 2b Optical Waveguide Substrate 2c Buffer Layer 3 Diffraction Element 4 Pinhole 5 Incident Light 6 Outgoing Light

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G02B 6/30 9317-2K 8106-2K G02B 6/28 D

Claims (3)

[Claims] 1. A parallel type optical multi-brancher in a planar type optical waveguide, wherein a diffractive element is provided on a reflecting surface on one side of an optical waveguide core, and the guided light is reflected by the diffractive element and emitted to the outside of the optical waveguide. Parallel optical multi-branching device in optical waveguide. 2. The planar type optical waveguide according to claim 1, wherein in the planar type optical waveguide, a plurality of diffractive elements are provided for allowing guided light to enter from a connected optical fiber and to emit to the outside. Parallel optical multi-branching device. 3. The parallel optical multi-branching device in a planar type optical waveguide according to claim 1, wherein a pinhole plate is installed in the planar type optical waveguide to prevent scattered light on the emission side.