CN1421719A - Optical switch using Faraday rotator - Google Patents

Abstract

An optical switch using Faraday rotor includes the first and the second receiving ends, the first and the second output ends, the first and the second beam splitters and the Faraday rotor. The first and second receiving terminals receive the first and second optical signals, respectively. The first optical splitter splits the first optical signal into first and second polarized lights, and splits the second optical signal into third and fourth polarized lights. The second optical splitter combines the first and second polarized lights into a first optical signal, and combines the third and fourth polarized lights into a second optical signal. The rotor is used for changing the polarization directions of the first polarized light, the second polarized light, the third polarized light and the fourth polarized light, and when the rotor is positioned at a first rotation angle, the first optical signal and the second optical signal synthesized by the second optical splitter are respectively output by the first output end and the second output end; when the rotor is at the second rotation angle, the first and second optical signals synthesized by the second optical splitter are output from the second and first output terminals, respectively. The invention can change the rotation of the polarized light only by changing the magnetic field of the rotor so as to change the traveling route of the optical signal, and the invention does not need to consider the displacement vector of the rotor, thereby reducing the tolerance generated by the rotor.

Description

Optical switch using Faraday rotator

technical field

The invention relates to an optical switch, in particular to an optical switch using a Faraday rotor to control the rotation of polarized light by changing the magnetic field applied to the Faraday rotor.

Background technique

In optical systems, signal data conversion or replacement is required in many cases. Therefore, optical switches play an extremely important role in optical communication systems. Among them, one of the most important functions of the optical switch is to change the optical path for transmitting data.

The current common 2-to-2 optical switch is to install a movable prism to switch the traveling route of the optical signal. As shown in Figure 1A, in a 2 to 2 optical switch 4, the first optical signal 43 received by the first receiving end 41 is transmitted to the first output end 45; at the same time, the second optical signal received by the second receiving end 42 The signal 44 is transmitted to a second output 46 . As shown in FIG. 1B, when an actuating mechanism 47 provides power to move a prism 48 to an appropriate position, the first optical signal 43 received by the first receiving end 41 changes the route through the prism 48, and then transmits to the second output. end 46 ; and the second signal 44 received by the second receiving end 42 is transmitted to the first output end 45 after being routed by the prism 48 . It changes the traveling route of the optical signal by moving the position of the prism 48 , that is, a 2-to-2 optical switch 4 is formed.

Contents of the invention

The object of the present invention is to provide an optical switch using a Faraday rotator, which changes the rotation of polarized light by changing the magnetic field applied to the Faraday rotator, and then controls the traveling route of the optical signal.

To achieve the above purpose, the present invention provides an optical switch using a Faraday rotator, which includes a first optical splitter, a second optical splitter and a Faraday rotator. Wherein, the first receiving end receives a first optical signal; the second receiving end receives a second optical signal. The first optical splitter divides the first optical signal into a first polarized light and a second polarized light, and divides the second optical signal into a third polarized light and a fourth polarized light. The second beam splitter synthesizes the first polarized light and the second polarized light into a first optical signal, and synthesizes the third polarized light and the fourth polarized light into a second optical signal. The Faraday rotator is used to change the polarization directions of the first polarized light, the second polarized light, the third polarized light and the fourth polarized light. When the Faraday rotator is at a first rotation angle, the first optical signal synthesized by the second beam splitter Output from the first output end, and the second optical signal is output from the second output end; when the Faraday rotator is at a second rotation angle, the first optical signal synthesized by the second optical splitter is output from the second output end, and the second optical signal is output from the second output end. The optical signal is output from the first output end.

According to an embodiment of the present invention, the first optical splitter and the second optical splitter may be polarized beam splitters (Polarized Beam Splitter, PBS). The first polarized light and the third polarized light are P polarized light, and the second polarized light and the fourth polarized light are S polarized light. When the Faraday rotator is at the second rotation angle, it can change the polarization direction of light, so that the S-polarized light is converted into P-polarized light, and the P-polarized light is converted into S-polarized light.

Compared with the prior art, the present invention provides an optical switch using a Faraday rotator. It only needs to change the magnetic field applied to the Faraday rotator to change its rotation of polarized light, so as to change the traveling route of the optical signal without The position of the Faraday rotator needs to be moved, and the displacement vector of the Faraday rotator does not need to be considered, which can reduce the tolerance generated when the Faraday rotator moves.

Description of drawings

An optical switch using a Faraday rotator according to a preferred embodiment of the present invention will be described below with reference to the relevant drawings, wherein the same components are denoted by the same reference symbols:

1A and 1B are schematic diagrams illustrating a conventional 2-to-2 optical switch;

2A and 2B are schematic diagrams illustrating an optical switch using a Faraday rotator in the first embodiment of the present invention;

3A and 3B are schematic diagrams illustrating an optical switch using a Faraday rotator in a second embodiment of the present invention;

4A and 4B are schematic diagrams illustrating an optical switch using a Faraday rotator in a third embodiment of the present invention.

Explanation of symbols in the figure:

1 Optical switch using Faraday rotator

11 The first beam splitter

12 second beam splitter

13 The first reflection unit

14 Second reflection unit

15 Faraday rotor

16 first collimator

17 Second collimator

18 The third collimator

19 The fourth collimator

20 first light signal

21 Second light signal

22 The first receiving end

23 Second receiving end

24 The first output terminal

25 Second output terminal

26 The first polarization splitter

27 Second polarization splitter

28 The first mirror surface

29 Second mirror surface

30 The first polarization splitter

31 Second polarization splitter

32 The first reflective layer

33 Second reflective layer

34 The first polarization layer

35 second polarization layer

36, 37 surfaces

38, 39 polarized filter membrane

4 optical switch

41 The first receiving end

42 Second receiving end

43 First light signal

44 Second signal

45 The first output terminal

46 Second output terminal

47 Actuating mechanism

48 Prisms

Detailed ways

Please refer to Fig. 2A and Fig. 2B, the optical switch 1 according to the preferred embodiment of the present invention comprises a first receiving end 22, a second receiving end 23, a first output end 24, a second output end 25, a first A beam splitter 11 , a second beam splitter 12 and a Faraday rotator 15 . Wherein, the first receiving end 22 receives a first optical signal 20 (the part of the solid line); the second receiving end 23 receives a second optical signal 21 (the part of the dotted line).

The first optical splitter 11 splits the first optical signal 20 into a first polarized light and a second polarized light, and splits the second optical signal 21 into a third polarized light and a fourth polarized light. The second beam splitter synthesizes the first polarized light and the second polarized light into the first optical signal 20 , and synthesizes the third polarized light and the fourth polarized light into the second optical signal 21 . The Faraday rotator 15 is used to change the polarization directions of the first polarized light, the second polarized light, the third polarized light and the fourth polarized light.

When the Faraday rotator 15 is at a first rotation angle, that is, when the angle is 0 degrees, the first optical signal 20 synthesized by the second optical splitter 12 is output from the first output end 24, and the second optical signal 21 is output from the second output end. 25 outputs. When the Faraday rotator 15 is at a second rotation angle, that is, when the angle is 90 degrees, the first optical signal 20 synthesized by the second optical splitter 12 is output from the second output end 25, and the second optical signal 21 is output from the first output end. 24 outputs. The first optical splitter 11 and the second optical splitter 12 are a first polarizing beam splitter 26 (Polarizing Beam Splitter, PBS) and a second polarizing beam splitter 27, respectively.

This embodiment also includes a first reflective unit 13, a second reflective unit 14, a first collimator 16, a second collimator 17, a third collimator 18 and a fourth collimator 19. Wherein, the first reflective unit 13 and the second reflective unit 14 are respectively a first reflective mirror 28 and a second reflective mirror 29 ; in addition, the collimator transforms the divergent light signal into a parallel light signal.

As shown in FIG. 2A, the first optical signal 20 enters the first polarized wave splitter 26 from the first receiving end 22, and the first optical signal 20 is separated into the first polarized light and the second polarized light by the first polarized wave splitter 26. Two polarized light, wherein the first polarized light (P polarized light; P-polarization) directly passes through the first polarization splitter 26, and the second polarized light (S polarized light; S-polarization) is reflected to the second reflective mirror 29.

In FIG. 2A, the rotation angle of the Faraday rotator 15 is the first rotation angle (0 degree), so the first polarized light and the second polarized light will not change the polarization direction when passing through the Faraday rotator 15, and the first polarized light passes through the Faraday rotator 15. The first reflective mirror surface 28 is reflected into the second polarized wave splitter 27 , and at the same time, the second polarized light is also reflected by the second reflective mirror surface 29 to reach the second polarized wave splitter 27 . The first polarized light directly passes through the second polarization splitter 27 to the first output end 24, while the second polarized light is reflected to the first output end 24, and the two beams are combined into the first optical signal 20, which is transmitted from the first output end 24 output.

The second optical signal 21 enters the first polarized wave splitter 26 from the second receiving end 23, and the second optical signal 21 is separated into a third polarized light and a fourth polarized light by the first polarized wave splitter 26, wherein The third polarized light (P polarized light) directly passes through the first polarization splitter 26, and is reflected into the Faraday rotator 15 through the second reflecting mirror 29, while the fourth polarized light (S polarized light) is reflected into the Faraday rotator 15 .

The fourth polarized light is reflected into the second polarized wave splitter 27 through the first reflective mirror surface 28 , and the third polarized light is reflected through the second reflective mirror surface 29 to reach the second polarized wave splitter 27 . The third polarized light directly passes through the second polarization splitter 27 to the second output end 25, and the fourth polarized light is reflected to the second output end 25, and the two light beams are synthesized into the second optical signal 21, which is transmitted from the second output end 25 outputs.

Next, please refer to FIG. 2B, the first optical signal 20 enters the first polarization splitter 26 from the first receiving end 22, and the first optical signal 20 is separated by the first polarization splitter 26 into first polarized light and The second polarized light, wherein the first polarized light (P polarized light) directly passes through the first polarization splitter 26 , and the second polarized light (S polarized light) is reflected to the second reflective mirror 29 .

In Fig. 2B, the rotation angle of the Faraday rotator 15 is the second rotation angle (90 degrees), so when passing through the Faraday rotator 15, the first polarized light (P polarized light) is converted into S polarized light, and the second polarized light ( S polarized light) into P polarized light. The first polarized light (converted into S polarized light) is reflected into the second polarized wave splitter 27 through the first reflective mirror surface 28 , and the second polarized light reaches the second polarized wave splitter 27 . Wherein the second polarized light (has been transformed into P polarized light) directly passes through the second polarization splitter 27 to the second output end 25, while the first polarized light (has been transformed into S polarized light) is reflected to the second output end 25 , the two light beams synthesize the first optical signal 20 and output it from the second output terminal 25 .

The second optical signal 21 enters the first polarized wave splitter 26 from the second receiving end 23, and the second optical signal 21 is separated into a third polarized light and a fourth polarized light by the first polarized wave splitter 26, wherein the second polarized light The three polarized lights (P polarized light) directly pass through the first polarization splitter 26 and are reflected into the Faraday rotator 15 through the second mirror 29 , while the fourth polarized light (S polarized light) is reflected into the Faraday rotator 15 . The Faraday rotator 15 converts the third polarized light into S polarized light, and converts the fourth polarized light into P polarized light. Then, the fourth polarized light (converted into P polarized light) is reflected into the second polarized wave splitter 27 through the first reflective mirror 28, and the third polarized light (converted into S polarized light) also reaches the second pole demultiplexer 27. Wherein the fourth polarized light directly passes through the second polarization splitter 27 to the first output end 24, and the third polarized light is reflected to the first output end 24, and the two light beams are synthesized into the second optical signal 21, which is transmitted from the first output end 24 outputs.

3A and 3B, in the second embodiment of the present invention, the first optical splitter 11 and the second optical splitter 12 are a trapezoidal first polarization splitter 30 and a second polarization splitter 31, and the first reflective mirror surface 28 and the second reflective mirror surface 29 in the first embodiment are replaced by a first reflective layer 32 and a second reflective layer 33 respectively, and the remaining components and features in this embodiment are all the same as those of the first The embodiment is the same. The first reflective layer 32 and the second reflective layer 33 are respectively arranged on the surface 36 of the first polarized wave splitter 30 and the surface 37 of the second polarized wave splitter 31, and its surface 36 and surface 37 are respectively connected to a polarized wave splitter. A filter membrane (Polarized filter) 38 and a polarized filter membrane 39 are parallel to each other. The functions of the first reflective layer 32 and the second reflective layer 33 are the same as the first reflective mirror surface 28 and the second reflective mirror surface 29 in the first embodiment, and the first reflective layer 32 changes the progress of the second polarized light and the third polarized light route, and the second reflective layer 33 changes the traveling route of the first polarized light and the fourth polarized light.

4A and 4B again, in the third embodiment of the present invention, the first polarization splitter 26 and the second polarization splitter 27 in the first embodiment respectively use a first polarization layer 34 and a second polarizing layer 35 instead, and the rest of the components and features are the same as those of the second embodiment. The functions of the first polarizing layer 34 and the second polarizing layer 35 are the same as those of the first polarized wave splitter 26 and the second polarized wave splitter 27, which are to divide the optical signal into P polarized light and S polarized light, and The polarized light is synthesized into an optical signal, and the polarization layers are respectively arranged on the sheet substrate with high light transmittance; and the first reflective layer 32 and the second reflective layer 33 are also respectively arranged on the sheet with high light transmittance. on top of the substrate. Here, the sheet substrate with high light transmittance can be a thin sheet, which is used to fix the polarization layer and the reflective layer.

The optical switch using the Faraday rotator provided by the present invention uses changing the magnetic field applied to the Faraday rotator 15 to switch the traveling route of the optical signal. The first receiving end 22, the second receiving end 23, the first output end 24, the second output end 25, and the Faraday rotator 15 are all fixed in one position, so the optical switch using the Faraday rotator provided by the present invention only needs to be The tolerances of the terminals and the Faraday rotator 15 are taken into account during manufacturing and assembly, and there is no need to take into account the tolerances due to movement during switching. Therefore, the optical switch using the Faraday rotator provided by the present invention does not need to consider the variation of component tolerances during actuation, so that the alignment between the receiving end and the output end is simpler and more accurate.

The above description is for illustration only, not for limitation. Any equivalent modification or change made without departing from the spirit and scope of the present invention shall be included in the protection scope of this patent.

Claims (10)

1. photoswitch that uses Faraday rotor comprises:

One first receiving end, it receives one first smooth signal;

One second receiving end, it receives one second smooth signal;

One first output terminal;

One second output terminal;

One first optical splitter, it is divided into one first polarized light and one second polarized light with one first smooth signal, and one second smooth signal is divided into one the 3rd polarized light and one the 4th polarized light;

One second optical splitter, it synthesizes this first smooth signal with this first polarized light and this second polarized light, and the 3rd polarized light and the 4th polarized light are synthesized this second smooth signal; And

One Faraday rotor, it can change the polarization direction of this first polarized light, this second polarized light, the 3rd polarized light and the 4th polarized light,

When this Faraday rotor was in one first anglec of rotation, this first smooth signal that this second optical splitter is synthesized was from this first output terminal output, and this second smooth signal is then exported by this second output terminal,

When this Faraday rotor was in one second anglec of rotation, this first smooth signal that this second optical splitter is synthesized was from this second output terminal output, and this second smooth signal is then by this first output terminal output.

2. the photoswitch of utilization Faraday rotor according to claim 1 is characterized in that: this first polarized light and the 3rd polarized light are the P polarized light, and this second polarized light and the 4th polarized light then are the S polarized light.

3. the photoswitch of utilization Faraday rotor according to claim 1 is characterized in that: this first optical splitter and this second optical splitter are the polarization channel-splitting filter.

4. the photoswitch of utilization Faraday rotor according to claim 1 is characterized in that: this optical splitter is a polarization layer, and it is arranged at one has on the flat substrates of high transmission rate.

5. according to the photoswitch of claim 3 or 4 described utilization Faraday rotors, it is characterized in that: also comprise:

One first reflector element and one second reflector element, it makes this first polarized light, this second polarized light, the 3rd polarized light and the 4th polarized light be incident to this second optical splitter by this first optical splitter in order to change the course of this first polarized light, this second polarized light, the 3rd polarized light and the 4th polarized light.

6. the photoswitch of utilization Faraday rotor according to claim 5 is characterized in that: this first reflector element and this second reflector element are mirror surface.

7. the photoswitch of utilization Faraday rotor according to claim 5 is characterized in that: this first reflector element and second reflector element are the reflection horizon, and it is arranged at respectively on the surface of this first polarization channel-splitting filter and the second polarization channel-splitting filter.

8. the photoswitch of utilization Faraday rotor according to claim 4 is characterized in that: this first reflector element and second reflector element are the reflection horizon, and it is arranged on this flat substrates with high transmission rate.

9. the photoswitch of utilization Faraday rotor according to claim 1, it is characterized in that: also comprise: four collimating apparatuss, be arranged at this first receiving end, second receiving end, first output terminal and second output terminal respectively, to collimate this first smooth signal and the second smooth signal.

10. the photoswitch of utilization Faraday rotor according to claim 1 is characterized in that: first anglec of rotation of this Faraday rotor and second anglec of rotation are respectively 0 degree and 90 degree.

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