JPH0357458B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to improvements in polarizing elements used in optical switches and the like.

(2) Background technology Optical switches using polarizing elements are known and improvements are being made, but currently known optical switches using polarizing elements have a The reality is that the optical system coupled to the optical switch has to be disposed in a bulky manner around the optical switch, and there is a need for the development of technical means that can make it more compact.

(3) Prior art and problems When optical switch a is constructed by arranging two polarizing elements and a Faraday rotator such as YIG as shown in Fig. 1, which has already been proposed by the applicant as prior art, In order to input and output the polarizing elements b and c, an optical system must be arranged as shown by the dotted line, which has the disadvantage that the space occupied by them must become large. Note that d is Faraday rotator, e ₁ , e ₂
is a transparent flat plate, f ₁ and f ₂ are polarization separation films, g ₁ and g ₂ are reflective films, h ₁ and h ₂ are first right-angle prisms, and i ₁ and i ₂ are second prisms.
It is a right angle prism.

(4) Purpose of the Invention The present invention was devised in view of the drawbacks of the prior art as described above, and its purpose is to provide a polarizing element that is useful for compactly configuring optical switches, etc. 5) Structure of the Invention The object of the invention is to provide a first polarizing element that separates incident light into a vertically polarized component and a horizontally polarized component that are parallel and close to each other and outputs the same; a second polarizing element that emits as emitted light;
and a second polarizing element so that both components pass through the Faraday rotator and a wavelength plate, the first polarizing element having a first polarizing element and a second right-angled polarizing element. an equilateral prism, and the second
The slope facing the right angle of the right-angled isosceles prism and the first
A transparent flat plate having a parallel plane sandwiched between opposing sides of one of the right-angled isosceles prisms, and between the slope of the second isosceles right prism and one plane of the transparent flat plate. a polarization separating film sandwiched between a partial region of the two components and reflecting one component of the two components and transmitting the other component; The second polarizing element includes a light reflecting film that is sandwiched between the polarized light separating film and the other component that has passed through the polarized light separating film and the transparent flat plate. 2 right-angled isosceles prisms, and the first
a transparent flat plate having a parallel plane sandwiched between opposing surfaces of one of the side surfaces of the right-angled isosceles prism that intersects at a right angle and a slope facing the right angle of the second right-angled isosceles prism; a polarization separation film that is sandwiched in a partial area between the slope of the slope of the isosceles prism and one plane of the transparent flat plate, and that reflects one component of the two components and transmits the other component; The polarized light separation film is sandwiched between one side of the prism and the other plane of the transparent flat plate in a partially misaligned area, and makes one component that has passed through the second isosceles right prism and the transparent flat plate transparent again. the wavelength plate has one of the sides of the second right-angled isosceles prism that intersects at right angles as an incident surface on which the two components are incident; The first polarizing element and the second polarizing element are provided between the incident surface and the Faraday rotator, and each of the first polarizing element and the second polarizing element has a transparent flat plate tilted in the same direction with respect to both components and arranged in a parallel state. , the one component from the polarization separation film of the first polarization element enters the light reflection film of the second polarization element via the Faraday rotator and the wavelength plate, and the light reflection film of the first polarization element enters the light reflection film of the first polarization element. are arranged to face each other such that the other component from the second polarizing element is incident on the polarization separation film of the second polarizing element, and the incident light to the first polarizing element is incident from a direction perpendicular to the two components, and the second polarizing element The first isosceles right prism is incident on the polarization separation film obliquely, or the first isosceles right prism and reflected at the other side face are incident on the polarization separation film obliquely, When the light emitted from the second polarizing element is emitted in a direction perpendicular to the two components, and the polarization planes of the two components are not rotated by the Faraday rotator and the wave plate,
Emitted from either the first right-angled isosceles prism or the second right-angled isosceles prism of the second polarizing element as an output light in which both the components are combined from the polarization separation film of the second polarizing element. However, when the plane of polarization is rotated, the combined output light is emitted from the other of the first isosceles right prism or the second isosceles right prism, and This is achieved by an optical switch characterized in that when the light is emitted from an equilateral prism, it is reflected by the other side and emitted.

(6) Embodiments of the invention Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings.

FIG. 2 shows an optical switch constructed using the device of the present invention. 1 and 2 are polarizing elements of the present invention, and 3 is a polarizing element of the present invention.
It is a Faraday rotator such as YIG. Reference numeral 4 denotes a wave plate that is provided when a polarization angle of 90° cannot be obtained between the polarization planes of the output light of the Faraday rotator 3. 5,
6 is an input optical system, and 7 and 8 are output optical systems.

The polarizing elements 1 and 2 are transparent flat plates 9 having parallel planes.
A light reflecting film 11 is sandwiched between one surface of the first rectangular prism 10 and one of the perpendicular surfaces of the first rectangular prism 10,
The other side of the transparent flat plate 9 and the second right angle prism 12
A polarization separation film 13 is sandwiched between the polarization separation film 13 and the surface facing at right angles. The distance d between the output lights of the polarizing element 1 can be approximately 1 mm, and the wavelength plate 4
may be attached to the entrance surface of the right-angle prism 12 of the polarizing element 2.

The operation of an optical switch using a polarizing element configured as described above will be explained.

The vertically polarized component of the light entering from the input optical system 5 is reflected by the polarization separation film 13 and output as output light, and the horizontally polarized component is transmitted through the polarization separation film 13 and then reflected by the light reflection film 11. It is reflected and emitted as emitted light. In this way, both of the above components are separated by the polarizing element and emitted, and the distance between them is 1.
It is narrow, about mm.

Both of these components pass through the Faraday rotator 3 and the wave plate 4;
If the plane of polarization is not rotated by the wave plate 4, the light propagates to the output optical system 7 as shown by the solid line in FIG. However, due to the Faraday rotator 3 and the wave plate 4, the plane of polarization of each component is 90°.
When rotated, each component entering the polarizing element 2 is a vertically polarized component that becomes a horizontally polarized component, and a horizontally polarized component that becomes a vertically polarized component. Each component propagates as shown by the dotted line. In this way, the input light is switched and outputted from the optical switch to the output optical system 8.

Similarly, the input light from the input optical system 6 is separated into a vertically polarized component and a horizontally polarized component by the polarizing element 1, and is separated into a vertically polarized component and a horizontally polarized component depending on whether or not the plane of polarization is rotated by the Faraday rotator 3 and the wave plate 4. It propagates as shown by the dotted line or the solid line, and when the plane of polarization is rotated by the Faraday rotator 3 and the wave plate 4, it is propagated to the output optical system 7, and when the rotation is not applied, it is propagated to the output optical system 8 ( (See Figure 4). Therefore, in this case as well, the input light is switched by the optical switch and output.

According to such an optical switch, as is clear from the above description, the input optical systems 5 and 6 and the output optical systems 7 and 8 can be arranged in two directions,
It is possible to simplify the optical system, and in particular, to solve problems related to the routing of optical fibers when it is desired to construct an equivalent optical switch using a conventional optical switch.

In the above embodiment, as can be seen from the figure, the first rectangular prism 10 is twice as large as the second rectangular prism 12, but inside the first prism 10, It is not limited to this as long as it can be totally reflected.

(7) Effects of the Invention As described above, according to the present invention, it is possible to provide the ability to arrange two optical systems in parallel directions for both input light and output light. Therefore, it is useful for compactly configuring optical switches and the like.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an optical switch as a prior art, FIG. 2 is a diagram showing an optical switch constructed using the polarizing element of the present invention, and FIGS.
FIG. 3 is a diagram for explaining the operation of a picture light switch. In the figure, 9 is a transparent flat plate, 10 is a first right-angle prism, 11 is a light reflection film, 12 is a second right-angle prism, and 13 is a polarization separation film.

Claims (1)

[Scope of Claims] 1. A first polarizing element that separates incident light into a vertically polarized component and a horizontally polarized component that are parallel and close to each other and outputs the same; an optical switch comprising: a second polarizing element that emits light as a polarizing element; and a Faraday rotator and a wavelength plate disposed between the first and second polarizing elements so that both the components pass; The polarizing element has first and second right-angled isosceles prisms, and a slope facing a right angle of the second isosceles right prism and one side surface of the first isosceles right prism that intersects at a right angle. a transparent flat plate having a parallel plane sandwiched between the faces thereof, and a transparent flat plate having a parallel plane sandwiched between the surfaces thereof, and a transparent flat plate sandwiched in a partial area between the slope of the second right-angled isosceles prism and one plane of the transparent flat plate, and one of the two components. a polarized light separating film that reflects the other component and transmits the other component;
The polarization separation film is sandwiched between one side of the right-angled isosceles prism and the other plane of the transparent flat plate in a partial area shifted from the polarization separation film, and reflects the other component that has passed through the polarization separation film and the transparent flat plate. a light reflecting film, the second polarizing element includes first and second isosceles right prisms, one of the right-angled side surfaces of the first isosceles right prism, and the second isosceles right prism. A transparent flat plate having a parallel plane sandwiched between the faces facing the right-angled slope of the equilateral prism, and a partial area between the slope of the second right-angled isosceles prism and one plane of the transparent flat plate. a polarization separation film which is sandwiched between the two components and reflects one of the components and transmits the other;
The polarized light separating film is sandwiched between one side of the right-angled isosceles prism and the other plane of the transparent flat plate in a partial region that is misaligned, and the one side that passes through the second isosceles right-angled prism and the transparent flat plate The wavelength plate has a light reflecting film that passes the components through a transparent flat plate again and then reflects them toward the polarization separation film, and the wavelength plate has one of the sides of the second right-angled isosceles prism that intersects at right angles with the two components. an incident surface, and is provided between the incident surface and the Faraday rotator, and the first polarizing element and the second polarizing element each have a transparent flat plate tilted in the same direction with respect to the two components so as to be parallel to each other. At the same time, the one component from the polarization separation film of the first polarization element enters the light reflection film of the second polarization element via the Faraday rotator and the wavelength plate, and the polarization separation film of the first polarization element enters the light reflection film of the second polarization element. are arranged to face each other so that the other component from the light reflecting film is incident on a polarization separation film of a second polarizing element, and the incident light on the first polarizing element is incident from a direction perpendicular to both of the components, That said second
The first isosceles right prism is incident on the polarized light separating film obliquely, or the first isosceles right prism is reflected at the other side and the polarized light is incident obliquely on the polarized light separating film. The light emitted from the second polarizing element is emitted in a direction perpendicular to the two components, and when the polarization planes of the two components are not rotated by the Faraday rotator and the wave plate, the light emitted from the second polarizing element Output light in which the two components are combined from the polarization separation film is output from either the first isosceles right prism or the second isosceles right prism of the second polarizing element, and the plane of polarization is rotated. In this case, the combined emitted light is emitted from the other of the first isosceles right prism or the second isosceles right prism, and
An optical switch characterized in that when the light is emitted from a right-angled isosceles prism, it is reflected on the other side and emitted.