JPS62226103A - Polarizer - Google Patents

Abstract

PURPOSE:To make incident light and projection light parallel as to a P- and an S-polarized component and to facilitate to couple with an optical fiber and other various optical parts by bonding the slanting surface of a triangular prism and a glass plate optically and embedding a dielectric multilayered film only in the center part of the adhesion surface between the both. CONSTITUTION:The slanting surface of the triangular prism 12 whose main cut surface is a right-angled triangle and the glass plate 14 are allowed to adhere optically and the dielectric multilayered film 16 is embedded only in the center part of the adhesion surface between the both. Assuming that incident light is incident from the 1st surface of the triangular prism and reaches the dielectric multilayered film, the S-polarized component of the incident light is reflected by the dielectric multilayered film and projected from the 2nd surface. The P-polarized component, on the other hand, is transmitted through the dielectric multilayered film, reflected totally by the surface of the glass plate, and projected similarly from the 2nd surface. The P- and S-polarized components which are separated as mentioned above are projected as invariably parallel light beams.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polarizer using a dielectric multilayer film, and more specifically, a polarizer in which a dielectric multilayer film is sandwiched between a triangular prism and a glass plate and separated. This invention relates to a polarizer that is capable of emitting polarized P-polarized light components and S-polarized light components in parallel.

[Prior Art] As optical elements having a polarizing effect, there are prisms using birefringent materials as well as prisms using dielectric multilayer films, and these are applied to various optical devices.

Typical prisms using dielectric multilayer films are:
It has a structure in which two triangular prisms each having a dielectric multilayer film formed on their slopes are combined and optically bonded so that their slopes face each other.

Of the light incident almost perpendicularly on the first surface of the first prism, the P-polarized component passes straight through the dielectric multilayer film and the second prism and travels straight. On the other hand, the S-polarized light component is reflected by the adhesive surface and exits from the second surface of the first prism at a substantially right angle. In this way, the P polarized light component and the S polarized light component can be separated.

[Problems to be solved by the invention] In the conventional dielectric multilayer prism as described above, the P-polarized light component and the S-polarized light component of the emitted light are separated in directions that differ by approximately 90 degrees. There is a drawback that the size increases when an optical device is constructed by combining it with various other optical elements.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology, simplify the structure and reduce costs, facilitate manufacturing, and convert the P-polarized component and S-polarized component of the emitted light into parallel light. Therefore, it is an object of the present invention to provide a polarizer that makes it possible to reduce the size and weight of various optical components.

[Means for Solving the Problems] The present invention, which can achieve the above-mentioned objects, is such that the inclined surface of a triangular prism and a glass plate are optically bonded, and a dielectric multilayer film is applied only to the center of the bonding surface between the two. This is a polarizer that has a structure in which it is embedded.

[Operation] Assume that incident light enters the first surface of the triangular prism and reaches the dielectric multilayer film. The S-polarized component of the incident light is reflected by the dielectric multilayer film and exits from the second surface. Further, the P-polarized light component passes through the dielectric multilayer film, is totally reflected on the surface of the glass plate, and similarly exits from the second surface. The P-polarized light component and the S-polarized light component separated in this way are always emitted as substantially parallel light.

[Example code] FIGS. 1A to 1D are explanatory diagrams showing one embodiment of the present invention.

A polarizer 1o according to the present invention has a structure in which the slope of a triangular prism 12 whose main cut surface is a right triangle is optically bonded to a glass plate 14, and a dielectric multilayer film 16 is embedded only in the center of the bonded surface between the two. It is.

First, as shown in FIG. 1A, it is assumed that light is incident at right angles through approximately the center of the first surface 12a of the triangular prism 12 from the inside of the boat. The P-polarized component of the incident light is transmitted through the dielectric multilayer film 1.
6, the light travels straight, is totally reflected on the surface of the glass plate 14, and is emitted from the second surface 12b to the port (2). On the other hand, S
The polarized light component is reflected by the dielectric multilayer film 16, passes through the second surface 12b, and is emitted to the boat (2).

Figure B shows a case where light enters from port 2, which is slightly off the center of the first surface 12a.

The incident light passes through the triangular prism 12, is totally reflected on the surface of the glass plate 14, and heads toward the dielectric multilayer film 16. The P-polarized light component passes through as it is and is emitted from the second surface 12b to the boat (2). On the other hand, the S-polarized light component is reflected by the dielectric multilayer film 16 and further totally reflected by the surface of the glass plate 14, and is emitted from the second surface 12b to the port (2).

In the same figure, C is the boat on the second surface 12b side of the triangular prism 12.
The case where light is incident from is shown.

The S-polarized component is emitted to the boat ■, and the P-polarized component is output to the port ■
emitted to. Similarly, as shown in the figure, the P-polarized light component of the light incident from the port (2) is outputted to the boat (2), and the S-polarized light component is outputted to the port (2).

In this way, the incident light is polarized by the polarizer lO according to the present invention.
The light is separated into a polarized light component and an S-polarized light component, and in either case, they are emitted as parallel light.

FIGS. 2A and 2B are explanatory diagrams showing an example of an optical circulator constructed using a polarizer according to the present invention. Since the polarizer is the same as that shown in FIG. 1, corresponding parts are given the same reference numerals and explanations thereof will be omitted.

In this optical circulator, two polarizers 10 are arranged such that the slopes of the triangular prisms 12 are almost parallel to each other and the apex angles are close to each other. This configuration includes a 45-degree rotator 20 and a half-wave plate 22 made of a magneto-optical material.

As shown in Figure A, the light incident from boat ■ is polarized by polarizer 1.
0, the S-polarized light component and the P-polarized light component are separated into parallel light, and the 45-degree rotator 2o and the 172-wave plate 22 convert the S
The polarized light is converted into P-polarized light and the P-polarized light is converted into S-polarized light, and the P-polarized light component and the S-polarized light component are combined in the second polarizer 10 and emitted to the boat (2).

Furthermore, as shown in FIG. 2B, light incident from port (2) exits to port (2) in the same manner. Furthermore, although illustration is omitted, the light incident from the boat (2) is emitted to the boat (2), and the light that is incident from the port (2) is emitted to the port (2). In this way, the optical circulator is constructed.

[Effect of the invention] As described above, the present invention is a polarizer in which a dielectric multilayer film is embedded only in the central beam between the slope of the triangular prism and the glass plate. Light and emitted light can be made into parallel light, making it easier to couple with optical fibers and other various optical components.

Furthermore, since the present invention is a combination of a glass plate and a triangular prism, it is smaller and lighter than the conventional technology which requires two triangular prisms, and has the advantage of being easier and cheaper to manufacture.

[Brief explanation of drawings]

1A to 1D are explanatory diagrams of the operation of the polarizer according to the present invention;
Figures A and B are explanatory diagrams showing an example of an optical circulator constructed using a polarizer according to the present invention. 10...Polarizer, 12...Triangular prism, 14...
・Glass plate, 16...Dielectric multilayer film, 20...45
degree rotator, 22...1/2 wavelength plate. Patent applicant Fuji Electrochemical Co., Ltd. Agent Shigeru Hitoshi Estimate Figure 1

Claims (1)

[Claims] 1. The slope of the triangular prism and the glass plate are optically bonded,
A polarizer with a dielectric multilayer film embedded only in the center of the bonding surfaces.