JPS5922021A - Photocoupler - Google Patents

Abstract

PURPOSE:To obtain a photocoupler which reduces the reflection and scattering of light, by arranging plural polarizing plates and attachable and detachable lambda/2 plates on the optical path of plural input/output terminals. CONSTITUTION:There are semiconductor laser light sources I1-I4; and the light outputs of the I1 and I3 have polarized components parallel to this paper surface, and those of the I2 and I4 have polarized component perpendicular to the paper surface. Polarizing filters (PF) 41-43 fixed among glass substrates 71- 73 reflect the vertical polarized components while allowing the parallel polarized components to pass. The lambda/2 plates 81 and 82 are freely attachable and detachable along thin slits made in the glass substrates 72 and 73. When the lambda/2 plates 81 and 82 are detached, the light from the light source I1 enters a light guide 3 through a parallel lens 51, the PFs 41 and 42, and a condenser lens 6. When the lambda/2 plate 81 is inserted, the light from the light source I2 is reflected by the PF41 to enter the light guide 3 through the lambda/2 plate 81 and PF42. Thus, the photocoupler which reduces the reflection and scattering of light is obtained.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention relates to an optical coupler that handles single polarized light such as output light of a semiconductor laser, and particularly relates to an optical coupler that handles a single polarized light such as output light of a semiconductor laser, and particularly relates to an optical coupler that handles a single polarized light such as output light of a semiconductor laser. This relates to an optical coupler that can switch a 1'/IIJ element to one of a plurality of optical inputs 0 (11 elements). Suitable for optical repeaters, etc.

[Description of prior art]

Conventionally, this type of optical coupler guides output light from a plurality of semiconductor lasers 11, 12...ln to sub-waveguides 21, 22, . These sub-waveguides 21, 22, . . . 2n are configured to be coupled to one main waveguide 3. In such a configuration, the sub waveguides 21, 22...2 are connected at the branch part.
Mode conversion may occur between the waveguide light in n and the waveguide light in the main waveguide 3, or due to imperfections in the mechanical integration of the branch part, the waveguides 2+, 22...2n may The guided wave light that has been propagating is reflected or disturbed at the branching part and coupled.

It has the disadvantage of causing

As an optical coupler that eliminates this drawback, there is also known an optical coupler as shown in FIG.
are arranged at right angle positions, and the polarized light from one light source 11 is transmitted through the polarizing filter 4 from the collimating lens 51. The light is totally reflected from the optical lens 52 by the polarizing filter 4 and guided to the leading waveguide 3, thereby coupling the two into one optical waveguide 3. In such a configuration, the only light sources that can be used are 2 (fli+), and there is a drawback that it cannot be applied to the combination of 2 light sources on 3 and 4 sides.

[Object 1 of the Invention] The present invention has been made to eliminate the above-mentioned drawbacks, and its purpose is to provide a plurality of predecessor output ζrlRI elements in line with one optical input/output terminal. An optical coupler that can selectively couple either of the The object of the present invention is to provide a configuration that can reduce reflection and scattering.

[Key points of the invention]

The present invention has a plurality of 11 & I, preferably 3 x 4 side first optical output terminals and 111 & I second optical terminal output terminals, and these first optical terminal output terminals and second optical input/output terminals are connected to each other. &f! A polarizing filter of 2111i1 or more is arranged between the I elements, and one or more optical means such as a wave plate (for example, a two-wavelength plate) that changes the polarization direction of the incident light by approximately 90 degrees is placed between the polarizing filters. The optical means are arranged to be freely insertable and removable, and the optical path is changed by changing the optical means (+11 or removed), and the first output terminal, which is optically coupled to the second optical input/output terminal, is inserted into the optical means. The present invention is characterized in that it is configured to be different when it is removed and when it is removed.

[Explanation based on examples]

Hereinafter, an optical coupler according to an embodiment of the present invention will be explained with reference to the drawings.

FIG. 3 is a block diagram of an apparatus according to an embodiment of the present invention.

In the figure, 11, 12, 13, and 14 are semiconductor lasers that act as light sources, and the semiconductor lasers 11 and 13 output light with polarized components parallel to the NIL plane (components indicated by ↓ marks in the figure). Place the semiconductor laser 12
．． 14 is arranged so that its output light has a polarization component perpendicular to the N-plane (component indicated by a symbol ■ in the figure). The output light from each semiconductor laser 11, 12, 13, 14 is input to an optical circuit surrounded by a glass substrate 71, 72, 73 via a parallel lens 5t, 52, 53, 54, respectively.

In this optical circuit, polarizing filter 41. ．． 42.43 is the glass substrate 71, ? It is fixed between 2.73 and 2.73.

These polarizing filters 41, 42, and 43 have a characteristic of transmitting a polarized light component parallel to the plane of the paper (↓ mark in the figure) and totally reflecting a perpendicular polarized light component (■ mark in the figure). Each polarizing filter 41.42.43 is a parallel lens 51.52.53
．． Semiconductor ray II which became a parallel beam by 54
, 12, 13, and 14 are arranged at an angle of 45° with respect to the emitted light, and by reflecting or transmitting these emitted lights depending on the difference in polarization direction, the focusing lens 1ζ optical waveguide through 6! It is designed to lead to 233.

Semiconductor laser 11, 12, 13, 14 output 1 (on the optical path of the light, 'A wavelength plate 81.82, glass substrate 72.7
The wavelength plates 81 and 82 are inserted along the thin slits provided in the optical path by moving the wavelength plates 81 and 82 along the slits using an insertion/removal mechanism using electromagnets. It can be inserted and removed freely. This 2
The wave plates 81 and 82 have an optical path length that is an odd number multiple of the two wavelengths of the incident light, and convert the polarization direction of the transmitted light by approximately 90 degrees. It is manufactured so that the optical path length becomes an appropriate length.

Next, the operation of the apparatus configured as described in item 1 will be explained.

First, when guiding the emitted light from the semiconductor laser 'J' L
Remove 2. The fourth figure 1 is a diagram showing the trace of the light ray 11i1 inside the device when the %6JL long plates 8+ and 82 are removed. Emitted from semiconductor laser 11! 4J 1. , the polarized light component parallel to the desk surface becomes a parallel beam by the parallel lens 51, and passes through the glass substrate 71, the polarizing filter 41, the glass substrate 72, the polarizing filter 42, and the glass plate 73 in this order, and then passes through the focusing lens 6. is guided to the optical waveguide 3 by. Similarly, the polarized light component perpendicular to the normal plane emitted from the semiconductor laser I3 becomes a parallel beam by the collimating lens 53, is guided to the glass; guided to the optical waveguide 3.

Next, when guiding the emitted light from the semiconductor laser 12 or 11 to the optical waveguide 3, an 'A wavelength plate 81 or 82 is inserted. FIG. 5 is a diagram showing the trajectory of light rays within the device when the Noiwa Jru Handling 01.82 is inserted. Semiconductor laser 12
The polarized light component perpendicular to the paper surface emitted from the parallel lens 5
2, the beam is made into a parallel beam, transmitted through the glass substrate 72, totally reflected by the polarizing filter 41, bent at a right angle, and transmitted through the % wavelength plate 81. converted. Thereafter, this parallel beam passes through the polarizing filter 42 and the glass substrate 73 and is guided to the optical waveguide 3 by the focusing lens 6. Similarly, the polarized light component parallel to the paper surface emitted from the semiconductor laser 14 is
Parallel lens 54, glass substrate 71, polarizing filter 43
1. After passing through the glass substrate 73, it passes through the % wavelength plate 82, and is converted into a polarized component perpendicular to the plane of the paper by the % wavelength plate 82. After that, it is totally reflected by the polarizing filter 42, and then sent to the optical waveguide by the focusing lens 6. Guided by 3.

Although the embodiment device described above is a configuration example in which there are four light sources, it is possible to combine even more light sources by adding a polarizing filter and a V2 wavelength plate. FIG. 7 shows the apparatus of this embodiment.

The embodiment shown in FIG. 6 has a large number of blocks arranged in tandem, each consisting of a semiconductor laser 12, a collimating lens 52, a glass substrate 72, a polarizing filter 42, and a z-wave plate 81. The plates 81 to 80 are configured to be freely inserted and removed, and by this insertion and removal, the optical path is changed and the coupling state of a large number of light sources can be switched. The embodiment shown in FIG. 7 is obtained by arranging two of the embodiments shown in FIG. 6 so as to be perpendicular to each other. Further, each reference numeral in the figure indicates the same component as in the apparatus of the above-described embodiment.

Note that in this example device, a two-wavelength plate was used as a means for converting the polarization direction of light by approximately 90'; however, the present invention is not limited to this, and it is possible to change the polarization direction of transmitted light. Other possible optical means may also be used. In addition, the angle of the polarization direction of the wave plate, the arrangement angle of the polarizing filter, etc. are not limited to the values shown in the 10 examples of this practical ability, and can be processed! It goes without saying that there may be slight variations in the design made by IVJ, but various design changes are possible depending on the design, and wave 1
Various methods can be applied to the means for inserting and removing the number plate.

Furthermore, there is reversibility between the optical input (Illil) and the optical output 111:1 of the device of this embodiment, and the optical input terminal of the device of this embodiment is the optical output terminal, and the optical output 61:1 is the optical input. 11b, an optical coupler having one child can also be realized, and this is also included in the present invention.

〔Effect of the invention〕

As explained above, according to the optical coupler of the present invention, it is possible to switch the optical outputs of a plurality of semiconductor lasers by inserting and removing a wavelength plate and to couple them into a single leading wave 17&, and furthermore, this coupling is Last time b1F! This can be done with low fjl loss because there is little reflection and scattering of light that occurs.

Moreover, this optical coupler is small and easy to manufacture. Furthermore, there is no limit in principle to the number of light sources to be switched, and a large number of light sources can be combined.

Therefore, this type of optical coupler is suitable for submarine optical transmission systems.
) Suitable for use as an optical coupler for switching light sources when configuring redundant light sources in submarine repeaters. In other words, since semiconductor lasers have lower optical characteristics than other elements, it is necessary to install multiplexes of semiconductor lasers in submarine repeaters and guide their output light to a single leading wavepath. In this case, the optical coupler of the present invention, which has low loss and is compact, is optimal.

[Brief explanation of the drawing]

1 and 2 are configuration diagrams of a conventional optical coupler. FIG. 3 is a block diagram of an optical coupler according to an embodiment of the present invention. FIG. 4 and S5 are ray trajectory diagrams for explaining the operation of the embodiment optical coupler of FIG. 3. FIGS. 6 and 7 are configuration diagrams of optical couplers according to other embodiments of the present invention.

Claims (1)

[Claims] (11'4M number of 1111 first optical input/output terminals, one second optical input/output terminal, the plurality of first optical outputs and output terminals, and the second optical output terminals) A plurality of light input terminals are arranged between the terminals, and each of the above-mentioned 1. A polarizing filter that optically couples between the optical input/output terminal and the second optical input/output terminal; an optical means that is removably placed at one or more locations on the optical path of the manually inputted light to change the polarization direction of the passing light; By changing the optical path, the first light input 11 power αj1.1 which is optically coupled to the second light output i'11 is "-1"
An optical coupler configured differently depending on whether a recording optical means is inserted or removed. (2) The first optical input/output terminal is used as a first input noj':11:1 child, and the second optical input/output terminal is used as an optical output ☆1111 child (claim 11) Optical coupler. (3) Claim (1) or ti+, wherein the optical means for changing the polarization direction is a wavelength plate having a thickness that is an odd multiple of the V2 wavelength, and changes the polarization direction by approximately 90 degrees. No. (
The optical coupler described in section 2).