JPS61261725A - By-pass optical switch having monitor function - Google Patents

Abstract

PURPOSE:To omit a mechanical movable part to expand the life of the title device and to reduce the consumption of electric body by using a liquid crystal cell as a switching element and changing voltage to be impressed to the liquid crystal to make the liquid crystal execute prescribed operation. CONSTITUTION:Signal light inputted from a terminal 1a is inputted to a beam splitter 9 of which the ratio of transmission to reflection is set up to a prescribed value and the reflected signal light is bent rectangularly at its optical path by a rectangular prism 13a and outputted to an output terminal 2a. The liquid crystal cell 11 sealing nematic liquid crystal rotates the polarizing surfaces of rectangular 2 polarized light rays separated by a polarizing splitter 10 for separating the incident signe light into rectangular 20 polarized light rays and synthesizing the separated light rays by 90 deg. in the going and returning ways in accordance with an externally impressed voltage and passes the rectangular 2 polarized light rays without rotation. A rectangular prism 12 having a reflecting film for returning the optical path, a prism 13b for bending one optical path out of the rectangular 2 polarized light rays rectangularly to synthesize the rectangular 2 polarized light rays separated by the splitter 10 and prism 13c for bending the optical poath of the signal light transmitted through the splitter 10 rectangularly are arranged on one end surface of the cell 11.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides communication terminals and information processing terminals to optical Noah7.
Communication and information processing τ゛□,...

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tical Local Area No “°′k）□
This article relates to a bypass optical switch with a monitor function used for accessing a bus from a terminal station in ``・, etc.''.

ξ ゛, [Prior art]);...: 1)1,..., Figures 3 (A) and (B) show a conventional bypass optical switch with a monitor function. FIG. 3 is a cross-sectional view showing two switching states, respectively. In the figure, (la) and (1b) represent the first and second input pairs']1 child, (3
a) and (3b) are first and second input terminal terminals;
(2a) and (2b) are the second and first output terminals 5
．． 1 ゛“””“゛”°°゛“”1゛”””°“6
″′″′11. Graded index rod lenses (4a) and (4b) are graded index rod lenses that condense parallel light onto the second and first output terminals (2a) and (2b); (5) is the 151st graded rod lens; ,1.
a semi-transparent mirror that transmits and reflects the signal light input from the input terminal (1a) of the
(6) is a mirror that totally reflects the input signal light from the second input terminal (1b); (7) is a mirror (6);
'+4-f Lte+L, v1.38,. ;!
[j+7+□, Yayu, 1.7°.

It is an electromagnet that moves.

In FIGS. 3(A) and (B), two gradient index rod lenses (3a) and (4a) are opposed to each other with a specific distance in the optical axis direction.
A one-to-one imaging optical system is formed in which a first input terminal (1a) and a second output terminal (2a) are connected to both ends of a) and (4a), and the above-mentioned gradient index rod lens Between (3a) and (4a) is a semi-transparent mirror (group) and mirror (6) that reflects 50% of the signal light converted into parallel light by the gradient index rod lens (3a) and transmits the remaining 50%. Insert the attached moving core (7).

As shown in FIG. 3(A), when a current is applied to the electromagnet (8) and the movable core (7) is moved to the upper position in the drawing, the signal light incident from the first input terminal (la) is converted into parallel light by the gradient index rod lens (3a), then 50% is reflected by the semi-transparent mirror 15), and the reflected light is input to the gradient index rod lens (4b) and sent to the first output terminal. (2b) and is used to constantly receive signal light. On the other hand, the signal light transmitted through the semi-transparent mirror (5) is
It is blocked by the moving core (7) and is not output to the second output terminal (2a). In this state, the second output terminal (2a)
The signal light enters from the second input terminal (1b) and is converted into parallel light by the gradient index rod lens (3b).The optical path is bent at right angles by the mirror (6) and the signal light enters the gradient index rod lens. (4a) is focused and output.

4. Next, as shown in Figure 3 (B), the current of the electromagnet (8) is cut off and the movable core (7) is moved to the lower position in the drawing, and in the λ-C state, the third In the same way as explained in Figure (A),
50% of the signal light incident from the first input terminal (1a) is output to the first output terminal (2b), and the other 50% is semi-transparent; ), then the gradient index rod lens -,! , , : (4a) is outputted to the second output terminal (2a). When ゛・i9♂, (, the signal light incident from the second input terminal (1b), 'H,':', i is the mirror (6)
The leading axis of the lens has a refractive index l: ( □1, pa; distributed rod lens (
From the optical axis passing between 3a) and (4a), 2;
No. 1. Output terminal 28) is not output.

[Problem that the invention seeks to solve]

The conventional bypass optical switch with a monitor function has a mechanical structure as shown below, so an electromagnet (8) is used to move a mirror (6) attached to a moving core (7). There were problems in that it was large, consumed a lot of power, and had a short operating life. Furthermore, semi-transparent mirror (5) and mirror (6)
Since the reflective film is exposed to the atmosphere, there are problems such as the reflective film corroding due to humidity and gas.

The present invention has been made to solve the above-mentioned problems, and aims to provide a bypass optical switch with a monitoring function that achieves lower power consumption, smaller size, and higher reliability.

[Means for solving problems]

The bypass optical switch with monitor function according to the present invention includes:
A beam splitter in which the ratio of transmission and reflection is set to a predetermined value for the signal light input from the first input terminal, and a beam splitter for outputting the signal light reflected by the beam splitter to the first output terminal. A first rectangular prism that bends the optical path at right angles, a one-light beam splitter for separating and combining the incident signal light into two orthogonal polarized lights, and a polarization plane of the two orthogonal polarized lights separated by this polarizing beam splitter. One part is rotated back and forth by 90 degrees depending on the applied voltage, or is not rotated to form a liquid crystal cell filled with a transparent material, and an optical path is formed on one end surface of this liquid crystal cell. A right-angle prism with a reflective film provided for folding back the beam; a second right-angle prism that bends the optical path of one of the two orthogonal polarized lights at a right angle for recombining the polarized light after M is polarized by the polarizing beam splitter; and a third right-angle prism that bends the optical path of the signal light transmitted through the splitter at a right angle.

[Effect]

The bypass optical switch with a monitoring function according to the present invention uses a nematic liquid crystal as an active medium and attaches a right-angle prism with a reflective film to one end surface of a liquid crystal cell sealed with the nematic liquid crystal, thereby folding the optical path and reciprocating the signal light. In addition to operating as a reflective liquid crystal cell, a polarizing beam splitter is used to separate the signal light into two orthogonal polarized lights, which are incident on the liquid crystal cell, and the applied voltage is controlled to polarize the plane of polarization by 90 degrees in a round trip. Either the signal light output from the second output terminal is converted into the signal light manually input from the first input terminal by rotating it or transmitting it without affecting the plane of polarization in any way. , or the signal light input from the second input terminal.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
In figure (A) or D), (1a) or 4b
) is the conventional monitor u shown in Fig. 3 (A) and (B).
This is the same as the one in the bypass optical switch. f9) 44 A beam splitter that deflects and transmits the signal light input from the first input terminal (1a) at a predetermined splitting ratio, 00) is a polarizing beam splitter for polarization separation and synthesis, and 0 Q21 is a rectangular prism with a reflective film used for returning and reciprocating the liquid crystal cell 0υ by returning the optical path, and Q21 is a rectangular prism (13a ), (13b) and (13c) are first to third rectangular prisms for bending the optical path at right angles, 04) is a substrate for attaching the above components, (1
5) is P-polarized light, which is linearly polarized light whose electric hectors are parallel to the plane of incidence of polarizing beam splitter 001, and θ6) is S-polarized light, which is linearly polarized light whose electric hectors are perpendicular to the plane of incidence of polarizing beam splitter 00). .

Next, the operation of the bypass optical switch of this embodiment configured as described above will be explained. Note that in FIGS. 1(A) to 1D), signal light is simultaneously input from the first and second input terminals (1a) and (lb), but in the following, for the sake of simplicity, each Each case in which signal light is input to input terminals (1a) and (lb) will be explained separately.

First, FIGS. 1A and 1B, in which a voltage is applied to the liquid crystal cell 0υ, will be described. In Fig. 1 (A), the signal light enters the gradient index rod lens (3a) from the first input terminal (1a) and is converted into parallel light, which is divided into predetermined branches by the beam splitter (9). The reflected light is reflected and transmitted by the first right angle prism (13a), and the optical path is bent at right angles and sent to the first output terminal (2b) via the gradient index rod lens (4b).
is output to. On the other hand, the optical path of the signal light transmitted through the beam splitter (9) is bent at a right angle by the second right-angle prism (13b), and is separated into P-polarized light 05) and S-polarized light 06) by the polarizing beam splitter 00). P polarized light θ5)
The optical path of the light is bent at a right angle by the third right angle prism (+3c), and the light is incident on the liquid crystal cell till along with the S polarized light 0θ. At this time, as will be explained in detail later in FIG. 2(A), the liquid crystal cell θ0 has a function of transmitting the incident linearly polarized light without rotating the plane of polarization when a voltage is applied. Therefore, even if the optical path is turned back by the right-angle prism 021 with a reflective film and it travels back and forth within the liquid crystal cell 01), the P-polarized light 05
) and S-polarized light 06) are transmitted unchanged, and P-polarized light (
15) leads to the polarizing beam splitter θ0). S polarization 0
The optical path of light 6) is bent at a right angle by the third right angle prism (13c), and the light beam 05) reaches the polarization beam splitter θ0) from a direction perpendicular to the P polarized light 05), where they are combined. The combined light enters the gradient index rod lens (4a) and is output to the second output terminal (2a).

Next, the state shown in FIG. 1(B) in which signal light is input from the second input terminal (1b) will be described. In the figure, light enters the second input terminal (1b) and is converted into parallel light by the gradient index rod lens (3b): l! , : ゛“1°“m′″′°−”;11”)y
9"°°゛1°゛1+i is separated into Q51 and S-polarized light Oe. S-polarized light 061 is separated into the third
, IJ , : Engineering (13c) t: Yo, Ekaya. □, 11
．． 7. The light is incident on the liquid crystal cell Qll together with the P-polarized light QSI. In this case, according to the same operating principle 1 as explained in FIG. 1(A),
Fold the optical path with a right-angle prism with a reflective film.

Even if the liquid crystal cell αυ is moved back and forth, each polarization 09 and OQ? The plane of polarization of ・, 1 photo is transmitted without rotation. S polarized light (+61 is polarized)', ll:): e -A
0, □3, + 77) i! jQ7'lJX” (
13c) g,=′″rtr *vs+*s°°16−
1, the polarized light beams '1', '1', and '001' arrive from the direction orthogonal to the S-polarized light α61, and the two are combined. The combined light is bent at a right angle by the second right-angle prism (13b).
・) is not output.

, 1 Next, the first state in which no voltage is applied to the liquid crystal cell θD
Figures (C) and (D) will be explained. First, 1,'',1 In Fig. 1(C),
As explained in A), the signal light incident from the first input terminal (1a) is reflected and transmitted by the beam splitter (9) at a predetermined splitting ratio, and the reflected light is transmitted to the first output terminal. (2b), and the transmitted light is separated into P-polarized light 05+ and S-polarized light OI by a polarizing beam splitter 00), and then enters the liquid crystal cell O11. At this time, the liquid crystal cell 00, as will be explained in detail later in FIG. 2(B),
When no voltage is applied, it has the function of rotating the plane of polarization of the linearly polarized light that enters back and forth by 90 degrees, so the optical path is turned around by a right-angle prism with a reflective film (JTL) and the liquid crystal cell a
Going back and forth through υ, p-polarized light a9 becomes S-polarized light (+51, and S
The polarized light 061 is converted into P polarized light θ. Of these, the S-polarized light 061 reaches the polarization beam splitter (lOl).

The optical path of the P-polarized light 0 is bent at a right angle by the third right-angle prism (i3c), and it reaches the polarization beam splitter 001 from a direction perpendicular to the S-polarized light aIil, where they are combined. Since the optical path of the combined light is bent at a right angle by the second right angle prism (13b), it is not output to the second output terminal (2a).

Next, the case of FIG. 1(D) in which the signal light is manually inputted from the second input terminal (1h) will be described. In the figure, signal light incident from the second input terminal (1b);
is separated into P-polarized light αQ and S-polarized light Qlfl by a polarizing beam (1,,,jl Musprinter 00), as explained in FIG. 1(B), and then the liquid crystal It is input to cell 0υ. At this time, the first room was 1°. . ) r
m I! Jl, L. Same. Movement 4. Hara. ,yo9
, when the optical path is turned back by the right-angle prism 02+ with a reflective film and the liquid crystal cell θ0 is moved back and forth, the P polarized light 0!9 becomes the S polarized light Oe.
In addition, the S-polarized light Oe is converted into the P-polarized light Q51.

Of these, the P-polarized light θ reaches the polarization beam splitter side. The optical path of the S-polarized light α0 is bent at a right angle by the third right-angle prism (13c) and becomes a P-polarized light (the one perpendicular to +51:
: The beam reaches the polarizing beam splitter from this direction, and the two beams are combined. The combined light enters the gradient index rod lens (4a) and is sent to the second output terminal (2a).
is output to.

Figures 2 (A) and (B) schematically show the configuration of a liquid crystal cell 00, which is a switching element of a bypass optical switch with monitor function according to the present invention. tt (7)
F9. . Li13! '1ilti, (180;J
:# ”r :1AtffE, am is a P-type nematic liquid crystal molecule. Fig. 2 (A) shows a state in which a voltage is applied to the liquid crystal cell OIl, and Fig. 2 (13) shows a state in which no voltage is applied to the liquid crystal cell θ0. This liquid crystal cell 00 has a transparent electrode 0η deposited on the surface of a glass substrate 0.
P is applied by diagonal deposition of SiOx and rubbing with cotton cloth.
It has a twisted nematec cell configuration with a twist angle of 45 degrees, in which the direction of the long axis of the shaped nematec liquid crystal molecules Os is twisted by 45 degrees between two glass substrates Oe.

In the state shown in FIG. 2(A), the long axes of the P-type nematic liquid crystal molecules are aligned parallel to the direction of the electric field.

Therefore, the plane of polarization of polarized light propagating parallel to the axis of the liquid crystal passes through without being rotated. In contrast, two electrodes 0
In the state shown in FIG. 2(B) in which no voltage is applied between 71, the alignment direction of the long axis of the P-type nematic liquid crystal molecules 01 is square or perpendicular to the polarization plane of the incident P-polarized light or S-polarized light. Therefore, the plane of polarization is rotated by 45 degrees on the output side due to the optical rotation of the nematec liquid crystal. When the optical path of this emitted light is turned around by the right-angle prism 021 with a reflective film described in FIGS. The plane of polarization will be rotated by 90 degrees.

2 (In the example described in L, the case was explained in which a non-polarizing beam splitter that reflects and transmits light at a predetermined splitting ratio is used as the beam splitter (9), but the splitting ratio is not limited to this, and the splitting ratio is 1:1. A similar effect can be achieved by using a polarizing beam splitter.

〔Effect of the invention〕

As described above, according to the present invention, a predetermined operation can be achieved simply by using a reflective liquid crystal cell as a switching element and switching the voltage applied to the liquid crystal.
Unlike mechanical types, there are no moving parts, so it has a long life, and the power consumption is about 10 μW at most, so it has the effect of providing low power consumption.

In addition, the length of each side of the component parts such as liquid crystal cells, polarizing beam splitters, and right-angle prisms can be reduced to about 50cm, and the total capacity is IOe11! The following effects can be achieved in small size.

Furthermore, since the above-mentioned components are bonded to each other with an adhesive whose refractive index is matched, there is an effect that the reflective film surface, etc. does not come into direct contact with the atmosphere, and excellent moisture and corrosion resistance can be obtained.

[Brief explanation of drawings]

1 (A) to (■)) are plan views respectively showing a bypass optical switch with a monitor function (-J) according to an embodiment of the present invention, and FIGS. 2 (A) and (B) are plan views of FIG. ) to D) are exploded perspective views schematically showing the configurations of the reflective liquid crystal cells, and FIG. 3 is a plan view showing a conventional bypass optical switch with a monitor function. (1a) and (1b) are input terminals, (2a) and (
2b) is an output terminal, (3a) or 4b) is a gradient index Rondo lens, (9) is a beam splitter, 00)
0υ is a polarizing beam splitter, 0υ is a liquid crystal cell, 04 is a right-angle prism with a reflective film, and (13a), (13b) and (13c) are right-angle prisms. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Figure 1 (C) □ ・1.1 Sound Figure 1 (D) , (・”;
11 Figure 2 (A) Figure 2 (B) Danhe Old Y 17Y Y? He & He+9 x \ × 1 //kuν■

Claims (2)

[Claims] (1) First and second input terminals and first and second input terminals
has an output terminal, and always outputs a part of the signal light input from the first input terminal from the first output terminal, and also outputs the remainder of the signal light input from the first input terminal. A bypass optical switch with a monitoring function that switches between the signal light input from the second input terminal and outputs the signal light to the second output terminal, which transmits and reflects the signal light input from the first input terminal. a beam splitter in which the ratio of the signal light to the beam splitter is set to a predetermined value, a first right-angle prism that bends the optical path at a right angle in order to output the signal light reflected by the beam splitter to the first output terminal, and an incident signal. A polarizing beam splitter for separating and combining light into two orthogonal polarized lights, and a polarization plane of the two orthogonal polarized lights separated by this polarizing beam splitter, with or without rotating the plane of polarization by 90 degrees in a round trip depending on an externally applied voltage. After polarization separation using a liquid crystal cell filled with nematic liquid crystal to transmit, a right-angle prism with a reflective film provided on one end of this liquid crystal cell to fold back the optical path, and the polarizing beam splitter,
A second right-angle prism that bends the optical path of one of the two orthogonal polarized lights at a right angle in order to recombine it, and a third right-angle prism that bends the optical path of the signal light that has passed through the beam splitter at a right angle. A bypass optical switch with a monitor function. (2) The liquid crystal cell has a twist angle of 45 degrees, which is parallel or perpendicular to the polarization plane of the linearly polarized light incident on the liquid crystal cell, and the long axes of the nematec liquid molecules are oriented in a state twisted by 45 degrees between the two glass substrates. A bypass optical switch with a monitor function according to claim 1, characterized in that a liquid crystal cell having a twisted nematic cell configuration is used.