TWI483016B - Optical switch - Google Patents

Description

light switch

The present invention relates to an optical switch, and more particularly to a 2 x 2 optical switch having a plurality of switching states.

Optical fiber communication technology is the best technical option in the current wired communication transmission system. Its transmission medium is through optical fiber. The optical fiber has low transmission loss, wide bandwidth, no electromagnetic interference, small size, light weight, high confidentiality, etc. advantage. Each communication node in the optical fiber communication network needs to have transmission and reception information corresponding to the upload path and the downlink path to achieve two-way information transmission. Under normal conditions, the upload path and the downlink path will be transmitted independently on one fiber. When the fiber is disconnected, the system switches the up/down transmission signal to the individual protection fiber through the optical switch according to the protection mechanism. The traditional optical switch is limited by the switching state of the switch. The network system of the optical fiber communication needs to set multiple fiber protection paths to maintain good communication.

FIG. 1A and FIG. 1B are schematic diagrams showing switching states of a conventional optical switch. As shown, U.S. Patent No. 5,724,165 discloses an optical switch. The optical switch 90 is a 2x2 optical switch having two input terminals 104, 108 and two output terminals 106, 110, and has two switching modes such as a parallel state (Bar state) of FIG. 1A and a staggered state of FIG. 1B (Cross). State). When in the parallel state of Figure 1A, the optical signals can be transmitted from the input 104 to the output 106 via the optical paths 100 and 102, and the reverse transmission can be transmitted from the output 110 to the input 108, as indicated by arrows 112 and 118. . another way Is the path as indicated by arrows 114 and 116.

When the optical switch 90 is in the interlaced state of FIG. 1B, the optical signal can be transmitted from the input 104 to the output 110 via the optical paths 100 and 102, as indicated by the arrow 112, and the reverse transmission can be transmitted by the output 106. To input 108, it is the path shown by arrow 116. Alternatively, when transmitted, it can be transmitted as indicated by arrows 114 and 118. As shown in FIGS. 1A and 1B, the bidirectional optical signals can be simultaneously transmitted on the same optical path in the optical switch, which is the reversible characteristic of the optical switch, that is, the direction can be reciprocal.

2A and 2B are schematic diagrams showing the switching function of another conventional optical switch. As shown in the figure, U.S. Patent No. 6,594,068 discloses another optical switch 120 having two states for transmitting optical signals by a unidirectional optical path 122 parallel state and a 124 interlaced state, as shown in Figures 2A and 2B. The two-way optical signal cannot be transmitted in the same optical path in the optical switch in the parallel state or the interlaced state, which is an irreversible characteristic of the optical switch, that is, the direction is not reciprocal.

The switching state of the optical switch affects the actual fiber network settings. Therefore, if the switch state of the optical switch is operable, the setting of the optical network can be simplified, the fiber network can be designed more flexibly, and the maintenance can be managed. Accordingly, FIGS. 3A to 3D illustrate a switching function diagram of still another conventional optical switch. As shown in the figure, the optical switch 150 having four switching states is proposed in the Republic of China Patent No. 1372270, wherein the 3A and 3B diagrams are the same as the directions of the 2A and 2B diagrams, and the The 3C diagram and the 3D diagram are states in which the optical paths are separated in different directions. However, none of the above four states has a reversible state that can be returned by the original optical path. Therefore, when an optical fiber is broken, the breakpoint position of the broken optical fiber cannot be directly detected by the optical switch, that is, when the optical fiber cannot be used. The Optical Time Domain Reflectometer (OTDR) detects breakpoints, so there are still some shortcomings in use.

In view of the above, an object of the present invention is to provide an optical switch that has a reciprocal bidirectional parallel switching state in addition to two non-reciprocal parallel and interleaved switching states, so that when the inter-node fiber line is broken When the point occurs, the OTDR photodetection signal can detect the fiber line breakpoint through the optical switch.

To achieve the above object, the optical switch provided by the present invention comprises two input terminals and two output terminals. The two inputs are used to input/output an optical signal. The two outputs are used for outputting/inputting the optical signal, wherein the optical signal can be transmitted unidirectionally to one of the two outputs by one of the two inputs, and can be reversely transmitted by one of the two outputs To one of the two inputs. In addition, the optical switch has three switching states, including: a first switching state, a parallel state in the forward optical transmission, and a reverse optical transmission in an interlaced state; and a second switching state in the forward optical transmission. In the interlaced state, and the reverse optical transmission is in a parallel state; and in a third switching state, both the forward optical transmission and the reverse optical transmission are in a parallel state.

Further, in the first switching state and the second switching state, the optical path of the optical signal transmitted between the two input ends and the two output ends is incompatible with each other. In the third switching state, the optical path of the optical signal transmitted between the two input ends and the two output ends is reciprocal.

In a preferred embodiment, the two input terminals and the two output terminals further include a polarization beam splitter, a Faraday rotator, a polarization combiner, and a magnetic field control element to be connected into a 2×2 optical switch.

In a preferred embodiment, the optical switch further includes a first four-turn reversible all-pass optical circulator and a second four-turn reversible all-pass optical circulator. The first four reversible all-pass The optical circulator has four first input/output ports. The second quadruple reversible all-pass optical circulator has four second input/output ports, wherein adjacent two turns of the four first input/output ports are adjacent to the four second input/output ports Two interleaved connections, the remaining two of the four first input/output ports are respectively one of the two inputs and one of the two outputs, and the remaining two of the four second input/output ports Then as one of the two inputs and one of the two outputs. In this embodiment, the first four-turn reversible all-pass optical circulator and the second four-turn reversible all-pass optical circulator have a forward cyclic direction state and a reverse cyclic direction state. Specifically, when the first four-turn reversible all-pass optical circulator and the second four-turn reversible all-pass optical circulator are in the same cyclic direction state, the optical open relationship is in the third switching state; The first four-turn reversible all-pass optical circulator and the second four-turn reversible all-pass optical circulator are in a different cyclic direction state, and the optical open relationship is in the first switching state or the second switching state .

In a preferred embodiment, the optical switch further includes a first non-reciprocal 2x2 optical switch and a second non-reciprocal 2x2 optical switch. The first non-reciprocal 2x2 optical switch has four first input/output ports. The second non-reciprocal 2x2 optical switch has four second input/output ports, wherein two adjacent ones of the four first input/output ports are interleaved with two adjacent ones of the four second input/output ports Connected, the remaining two ports of the four first input/output ports are respectively one of the two input terminals and one of the two output terminals, and the remaining two ports of the four second input/output ports are respectively One of the two inputs and one of the two outputs. Specifically, the first non-reciprocal 2x2 optical switch and the second non-reciprocal 2x2 optical switch both have two switching states, and include: a first state, which is a parallel state in forward optical transmission, and The transmission to the optical is an interlaced state; and a second state is an interlaced state in the forward optical transmission, and the reverse optical transmission is in a parallel state. In detail, when the first non-reciprocal 2x2 optical switch and the second non-reciprocal 2x2 optical switch are in different states, the light is turned on. The relationship is in the third switching state; when the first non-reciprocal 2x2 optical switch and the second non-reciprocal 2x2 optical switch are in the first state, the optical open relationship is in the first switching state; the first non- When the reciprocal 2x2 optical switch and the second non-reciprocal 2x2 optical switch are in the second state, the optical open relationship is in the second switching state.

In a preferred embodiment, the optical switch further includes a four-turn reversible all-pass optical circulator and a reciprocal 2x2 optical switch. The four-turn reversible all-pass optical circulator has four first input/output ports. The 2x2 optical switch has four second input/output ports, wherein two adjacent ones of the four first input/output ports are interleaved with two adjacent ones of the four second input/output ports, the four The remaining two ports of the first input/output port are respectively one of the two input terminals and one of the two output terminals, and the remaining two ports of the four second input/output ports are respectively used as the two input terminals. One and one of the two outputs. Specifically, the four-turn reversible all-pass optical circulator has a forward cyclic direction state and a reverse cyclic direction state. The reciprocal 2x2 optical switch has two switching states, including: a first state in which the forward optical transmission and the reverse optical transmission are parallel; and a second state in the forward optical transmission and the reverse optical The transmissions are all interlaced. In addition, when the reciprocal 2x2 optical switch is in the first state, the optical open relationship is in the third switching state; when the reciprocal 2x2 optical switch is in the second state, the optical open relationship is in the first switching state or The second switching state.

Compared with the prior art, the optical switch of the present invention has the third switching state that is mutually reciprocally bidirectionally paralleled, so that when the breakpoint of the optical fiber line between the nodes occurs, the OTDR optical detection signal can be detected by the optical switch through the optical switch. The purpose of the line breakpoint. In addition, the optical switch of the present invention can be composed of two four-turn reversible all-pass optical circulators, two second non-reciprocal 2x2 optical switches, or a four-turn reversible all-pass optical circulator and one reciprocal 2x2. The optical switch is composed of high flexibility in production.

The above and other objects, features, and advantages of the present invention will become more apparent and understood.

90, 120, 150‧‧‧ optical switch

100, 102, 122, 124‧‧‧ light paths

104, 108‧‧‧ input

106, 110‧‧‧ output

112, 114, 116, 118‧‧‧ arrows

200, 202‧‧‧ optical switch

222, 224‧‧‧ input

242, 244‧‧‧ output

300‧‧‧Four reversible all-pass optical circulator

301‧‧‧The first four reversible all-pass optical circulator

302‧‧‧Second four reversible all-pass optical circulator

401‧‧‧First non-reciprocal 2x2 optical switch

402‧‧‧Second non-reciprocal 2x2 optical switch

500‧‧‧Reciprocal 2x2 optical switch

1P1, 1P2, 1P3, 1P4‧‧‧ first input/output埠

2P1, 2P2, 2P3, 2P4‧‧‧ second input/output埠

Tx1, Tx1', Tx2, Tx2'‧‧‧ transmit end

Rx1, Rx1', Rx2, Rx2'‧‧‧ receiving end

FIG. 1A and FIG. 1B are schematic diagrams showing switching states of a conventional optical switch.

2A and 2B are schematic diagrams showing the switching function of another conventional optical switch.

3A to 3D are schematic diagrams showing another switching function of the existing optical switch.

4A to 4C are schematic diagrams showing three switching states of the optical switch according to a preferred embodiment of the present invention.

5A to 5C are schematic diagrams showing the architecture of a communication system using the optical switch of the embodiment.

6A and 6B are diagrams showing optical path meanings of two states of the four-turn reversible all-pass optical circulator according to the embodiment.

7A to 7D are schematic diagrams showing four switching states of an optical switch using two four-turn reversible all-pass optical circulators.

8A to 8D are schematic diagrams showing four switching states of an optical switch using two non-reciprocal 2x2 optical switches.

9A to 9D are diagrams showing four switching states of a combined optical switch using a four-turn reversible all-pass optical circulator and a reciprocal 2x2 optical switch.

The present invention has been described in detail with reference to the preferred embodiments in the

Please refer to FIG. 4A to FIG. 4C, and FIG. 4A to FIG. 4C illustrate one of the present inventions. A schematic diagram of three switching states of the optical switch of the preferred embodiment. The optical switch 200 includes two input terminals 222, 224 and two output terminals 242, 244. The two input terminals 222 and 224 are used for inputting/outputting an optical signal (not shown), and the two output terminals 242 and 244 are configured to output/input the optical signal. Specifically, the optical signal can be transmitted to one of the two output terminals 242, 244 by one of the two input terminals 222, 224, and can be reversely transmitted to the one of the two output terminals 242, 244. One of the two inputs 222, 224.

The three switching states of the optical switch 200 of the present embodiment will be described in detail below, and the three switching states are the first switching state, the second switching state, and the third switching state, respectively. It is worth noting that there is no sequential relationship between the above states. FIG. 4A is a schematic diagram showing the optical path of the first switching state. As shown in FIG. 4A, the optical signal is in a parallel state during forward light transmission, indicated by solid arrows; and the reverse optical transmission is in an interlaced state. It is indicated by a dotted arrow. FIG. 4B is a schematic diagram showing the optical path of the second switching state. As shown in FIG. 4B, the optical signal is in an interlaced state during forward optical transmission, indicated by solid arrows; and the reverse optical transmission is in a parallel state. It is indicated by a dotted arrow. That is, in the first switching state and the second switching state, the optical path of the optical signal transmitted between the two input ends 222, 224 and the two output ends 242, 244 is incompatible .

FIG. 4C is a schematic diagram showing the optical path of the third switching state. As shown in FIG. 4C, the optical signal is in a parallel state in both forward optical transmission and reverse optical transmission. That is to say, in the third switching state, the optical path of the optical signal transmitted between the two input terminals 222, 224 and the two output terminals 242, 244 is reciprocal.

5A to 5C are schematic diagrams showing the architecture of a communication system using the optical switch of the embodiment. Referring to FIG. 5A, two optical switches 200, 202 as shown in FIG. 4 are used for communication. On the two nodes, the input end 222 of the optical switch 200 is connected to the transmitting end Tx1 and the receiving end Rx1, and the other input end 224 is connected to the transmitting end Tx1' and the receiving end Rx1', notably, due to the optical switch 200 In the third state (bidirectional transmission), each input can be used as a transmitting terminal Tx and a receiving terminal Rx. The output end 242 of the optical switch 202 is connected to the transmitting end Tx2 and the receiving end Rx2, and the other output end 244 is connected to the transmitting end Tx2' and the receiving end Rx2'. It is also worth noting that since the optical switch 202 is in the third state ( Two-way transmission), so each output can be used as a transmitting terminal Tx and a receiving terminal Rx. Normal mode communication can be performed by setting the switching mode of the optical switches 200 and 202.

Referring to Figure 5B, when one of the paths is faulty, as shown, the path cannot communicate. At this time, by changing the switching mode of the optical switches 200 and 202, communication can be maintained by using only one path. Therefore, it is not necessary to set an alternate protection path. Referring to Fig. 5C, it is the same as the case of Fig. 5B, but it is another path failure. At this time, communication can be continued by changing the switching mode of the optical switches 200 and 202. Of course, the application of the optical switch 200 in the communication system of the optical network is not limited to the manner in which it is presented. The optical switch 200 can be applied where the optical system needs to perform path switching.

In addition to the flexible switching of the optical switch of this embodiment, when one of the paths is faulty, as shown in FIG. 5B, the OTDR can be connected to the input end 224 of the optical switch 200 of FIG. 5A for the breakpoint position. Measure. Similarly, when one of the paths is faulty, as shown in FIG. 5C, the OTDR can be connected to the input end 222 of the optical switch 200 of FIG. 5A for measurement of the breakpoint position. The switching modes of the optical switches 200 and 202 are then continued to maintain communication.

In order to achieve the switching function of FIG. 4, in the preferred embodiment, the optical switch is combined using two four-turn reversible all-pass optical circulators. As shown in Figures 6A and 6B, section 6A FIG. 6B is a diagram showing the optical path meanings of two states of the four-turn reversible all-pass optical circulator according to the embodiment. The four-way reversible all-pass optical circulator 300 has four output/input (IO) ports, called a first end point (Port 1), a second end point (Port 2), and a third end point (Port 3). The fourth end point (Port 4), FIG. 6A is a normal direction state, that is, the optical transmission path may be from the first end point to the second end point, and the second end point to the third end point a third endpoint to a fourth endpoint, and a fourth endpoint to the first endpoint. FIG. 6B illustrates a reverse direction state, that is, the optical transmission path may be from the fourth end point to the third end point, the third end point to the second end point, and the second end point to the first end point And the first to fourth endpoints. Preferably, the four-turn reversible all-pass optical circulator 300 is composed of a semi-hard magnetic material, and its forward or reverse state can be controlled by a magnetic field control element.

7A to 7D are schematic diagrams showing four switching states of an optical switch using two four-turn reversible all-pass optical circulators. As shown in FIG. 7A to FIG. 7D , specifically, the optical switch 200 of the embodiment includes a first four-turn reversible all-pass optical circulator 301 and a second four-turn reversible all-pass optical circulator. 302. The first four-turn reversible all-pass optical circulator 301 has four first input/output ports (I/O ports) 1P1, 1P2, 1P3, and 1P4. The second four-turn reversible all-pass optical circulator 302 has four second input/output ports P2P1, 2P2, 2P3, and 2P4, wherein the four first input/output ports 埠1P1, 1P2, 1P3, and 1P4 are adjacent to each other. Two 埠1P3 and 1P4 are interleaved with two adjacent 埠2P1 and 2P2 of the four second input/output ports 2P1, 2P2, 2P3, and 2P4, and the four first input/output ports P1P1, 1P2, 1P3, and 1P4 The remaining two ports 1P1 and 1P2 are respectively one of the two input terminals 222 and 224 (ie, 222) and one of the two output terminals 242 and 244 (ie, 242), and the four second input/output ports P2P1. The remaining two 2P3 and 2P4 of 2P2, 2P3, and 2P4 are respectively one of the two input terminals 222 and 224 (ie, 224) and one of the two output terminals 242 and 244 (ie, 244).

As shown in FIG. 7A and FIG. 7B, in this embodiment, the first four-turn reversible all-pass optical circulator 301 and the second four-turn reversible all-pass optical circulator 302 both have a forward loop. Direction state and a reverse cycle direction state. Specifically, as shown in FIG. 7C and FIG. 7D, the first four-turn reversible all-pass optical circulator 301 and the second four-turn reversible all-pass optical circulator 302 are all in the same cyclic direction state. The optical switch 200 is in the third switching state, that is, the states of the 7C and 7D are summarized into the same bidirectional parallel state.

As shown in FIGS. 7A and 7B, the first four-turn reversible all-pass optical circulator 301 and the second four-turn reversible all-pass optical circulator 302 are in different cyclic directions, respectively. The switch 200 is in the first switching state (as shown in FIG. 7A) or the second switching state (as shown in FIG. 7B). As can be seen from the above, the three switching states of the optical switch 200 can be switched by individually controlling the state of the cycle direction of the first four-turn reversible all-pass optical circulator 301 and the second four-turn reversible all-pass optical circulator 302.

In another preferred embodiment, the optical switch 200 is combined using two non-reciprocal 2x2 optical switches. 8A to 8D are schematic diagrams showing four switching states of an optical switch using two non-reciprocal 2x2 optical switches. As shown in FIG. 8A to FIG. 8D , specifically, the optical switch 200 of the embodiment includes a first non-reciprocal 2×2 optical switch 401 and a second non-reciprocal 2×2 optical switch 402 . The first non-reciprocal 2x2 optical switch 401 has four first input/output ports 1P1, 1P2, 1P3, 1P4. The second non-reciprocal 2x2 optical switch 402 has four second input/output ports 2P1, 2P2, 2P3, and 2P4, wherein the four first input/output ports 1P1, 1P2, 1P3, and 1P4 are adjacent to each other. And 1P4 are interleaved with two adjacent 2P1 and 2P2 of the four second input/output ports 2P1, 2P2, 2P3, and 2P4, and the remaining two of the four first input/output ports 1P1, 1P2, 1P3, and 1P4 1P1 and 1P2 respectively serve as one of the two inputs 222 and 224 (ie 222) and one of the two outputs 242 and 244 (ie 242), the remaining two ports 2P3 and 2P4 of the four second input/output ports 2P1, 2P2, 2P3, and 2P4 are respectively one of the two input terminals 222 and 224 (ie, 224) and the two output terminals 242 And one of 244 (ie 244).

Specifically, the first non-reciprocal 2x2 optical switch 401 and the second non-reciprocal 2x2 optical switch 402 both have two switching states, and include: a first state, which is a parallel state in the forward optical transmission, And the reverse optical transmission is in an interlaced state; and a second state is an interlaced state in the forward optical transmission, and the reverse optical transmission is in a parallel state. As shown in FIG. 8C and FIG. 8D, when the first non-reciprocal 2x2 optical switch 401 and the second non-reciprocal 2x2 optical switch 402 are in different states, the optical switch 200 is in the third switching. The states, that is, the states of the 8C and 8D are summarized into the same bidirectional parallel state.

As shown in FIG. 8A, when the first non-reciprocal 2x2 optical switch 401 and the second non-reciprocal 2x2 optical switch 402 are in the first state, the optical switch 200 is in the first switching state. As shown in FIG. 8B, when the first non-reciprocal 2x2 optical switch 401 and the second non-reciprocal 2x2 optical switch 402 are in the second state, the optical switch 200 is in the second switching state.

In another preferred embodiment, the optical switch 200 is combined using a four-turn reversible all-pass optical circulator and a conventional reciprocal 2x2 optical switch. 9A to 9D are diagrams showing four switching states of a combined optical switch using a four-turn reversible all-pass optical circulator and a reciprocal 2x2 optical switch. As shown in FIG. 9A to FIG. 9D, specifically, the optical switch 200 of the present embodiment includes a four-turn reversible all-pass optical circulator 300 and a reciprocal 2x2 optical switch 500. The four-turn reversible all-pass optical circulator 300 has four first input/output ports 1P1, 1P2, 1P3, and 1P4. The reciprocal 2x2 optical switch 500 has four second input/output ports P2P1, 2P2, 2P3, and 2P4, wherein the adjacent two 埠1P3 and 1P4 of the four first input/output ports P1P1, 1P2, 1P3, and 1P4 are The four second loses The adjacent two ports 2P1 and 2P2 of the input/output ports 2P1, 2P2, 2P3, and 2P4 are alternately connected, and the remaining two ports 1P1 and 1P2 of the four first input/output ports 1P1, 1P2, 1P3, and 1P4 serve as the two One of the input terminals 222 and 224 (ie, 222) and one of the two output terminals 242 and 244 (ie, 242), and the remaining two ports 2P3 of the four second input/output ports 2P1, 2P2, 2P3, and 2P4 2P4 acts as one of the two inputs 222 and 224 (ie 224) and one of the two outputs 242 and 244 (ie 244).

Specifically, the four-turn reversible all-pass optical circulator 300 has a forward cyclic direction state and a reverse cyclic direction state, as shown in FIGS. 6A and 6B. As shown in FIG. 1A and FIG. 1B, the reciprocal 2x2 optical switch 500 has two switching states, including: a first state in which both forward optical transmission and reverse optical transmission are parallel; and In the second state, both the forward optical transmission and the reverse optical transmission are in an interlaced state. In addition, when the reciprocal 2x2 optical switch 500 is in the first state, the optical switch 200 is in the third switching state, as shown in FIG. 9C and FIG. 9D. When the reciprocal 2x2 optical switch 500 is in the second state, the optical switch 200 is in the first switching state or the second switching state, as shown in FIGS. 9A and 9B.

It is worth mentioning that the components located between the two input terminals 222, 224 and the two output terminals 242, 244 may comprise a polarizing beam splitter, a Faraday Rotator, which is familiar to those skilled in the art. The composition of the polarization combiner, the magnetic field control element, etc., will not be described here. In addition, the optical switch 200 of the above three embodiments can integrate the above components by an integrated design, and can form a single commodity to reduce volume and cost. The optical path switching unit of the optical switch 200 may also be a birefringent crystal, a half-wave plate, a Faraday rotator, a semi-hard magnetic material, or a refractive index grading lens ( Gradient-index lens, GRIN lens) and other optical components and magnetic materials, by changing the magnetic pole direction and magnetic force of the semi-hard magnetic material, thereby changing the optical polarization of the Faraday rotator Rotating the angular direction allows the optical path of the optical switch 200 of the present invention to be resettable to achieve optical path switching.

In summary, the optical switch 200 of the present invention has a reciprocal bidirectional parallel third switching state, so that when the breakpoint of the fiber line between the nodes occurs, the OTDR photodetection signal can be detected by the optical switch through the optical switch. The purpose of the point. In addition, the optical switch 200 of the present invention may be composed of two four-turn reversible all-pass optical circulators 301, 302, two second non-reciprocal 2x2 optical switches 401, 402, or a four-turn reversible all-pass light. The circulator 300 and a reciprocal 2x2 optical switch 500 are combined to have high flexibility in production.

Although the present invention has been disclosed above in the preferred embodiments, it is not intended to limit the invention. Various changes and modifications may be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

200‧‧‧ optical switch

222, 224‧‧‧ input

242, 244‧‧‧ output

301‧‧‧The first four reversible all-pass optical circulator

302‧‧‧Second four reversible all-pass optical circulator

1P1, 1P2, 1P3, 1P4‧‧‧ first input/output埠

2P1, 2P2, 2P3, 2P4‧‧‧ second input/output埠

Claims (12)

An optical switch comprising: two input terminals for inputting/outputting an optical signal; and two output terminals for outputting/inputting the optical signal, wherein the optical signal can be transmitted in a forward direction by one of the two input terminals Up to one of the two outputs, and can be reversely transmitted to one of the two outputs by one of the two outputs; wherein the optical switch has three switching states, including: a first switching state, in the When transmitting to light, the state is parallel, and the reverse optical transmission is in an interlaced state; a second switching state is an interlaced state in the forward optical transmission, and the reverse optical transmission is in a parallel state; and a third switching state, Both the forward optical transmission and the reverse optical transmission are in a parallel state, wherein in the third switching state, the optical path of the optical signal transmitted between the two input ends and the two output ends is directional. The optical switch of claim 1, wherein in the first switching state and the second switching state, the optical path of the optical signal transmitted between the two input ends and the two output ends is The direction is not easy. The optical switch of claim 1, wherein the two input ends and the two output ends further comprise a polarization beam splitter, a Faraday rotator, a polarization combiner, and a magnetic field control element to be connected into one 2x2 optical switch. The optical switch of claim 1, further comprising: a first four-turn reversible all-pass optical circulator having four first input/output ports; and a second four-turn reversible all-pass light a circulator having four second input/output ports, wherein adjacent two turns of the four first input/output ports are interleaved with adjacent two turns of the four second input/output ports, the four The remaining two outputs of an input/output port are respectively one of the two inputs And one of the two outputs, the remaining two of the four second input/output ports are respectively one of the two inputs and one of the two outputs. The optical switch of claim 4, wherein the first four-turn reversible all-pass optical circulator and the second four-turn reversible all-pass optical circulator have a forward cyclic direction state and a reverse direction Cycle direction status. The optical switch of claim 5, wherein the first four-turn reversible all-pass optical circulator and the second four-turn reversible all-pass optical circulator are in the same cycle direction state, the light The open relationship is in the third switching state; when the first four-turn reversible all-pass optical circulator and the second four-turn reversible all-pass optical circulator are in different cycle direction states, the optical open relationship is in the The first switching state or the second switching state. The optical switch of claim 1, further comprising: a first non-reciprocal 2x2 optical switch having four first input/output ports; and a second non-reciprocal 2x2 optical switch having four a second input/output port, wherein two adjacent ones of the four first input/output ports are interleaved with two adjacent ones of the four second input/output ports, the four first input/output ports The remaining two ports are respectively one of the two inputs and one of the two outputs, and the remaining two ports of the four second input/output ports are respectively one of the two inputs and the two outputs One of the ends. The optical switch of claim 7, wherein the first non-reciprocal 2x2 optical switch and the second non-reciprocal 2x2 optical switch both have two switching states, and the first non-reciprocal 2x2 optical switch includes: a first state, in the When transmitting to light, it is in a parallel state, and the reverse optical transmission is in an interlaced state; and a second state is an interlaced state in the forward optical transmission, and the reverse optical transmission is in a parallel state. The optical switch of claim 8, wherein the first non-reciprocal 2x2 optical switch and the optical switch When the second non-reciprocal 2x2 optical switch is in a different state, the optical open relationship is in the third switching state; the first non-reciprocal 2x2 optical switch and the second non-reciprocal 2x2 optical switch are in the first In a state, the optical open relationship is in the first switching state; when the first non-reciprocal 2x2 optical switch and the second non-reciprocal 2x2 optical switch are in the second state, the optical open relationship is in the second state Switch status. The optical switch of claim 1, further comprising: a four-turn reversible all-pass optical circulator having four first input/output ports; and a reciprocal 2x2 optical switch having four seconds An input/output port, wherein two adjacent ones of the four first input/output ports are interleaved with two adjacent ones of the four second input/output ports, and the remaining two of the four first input/output ports埠 respectively as one of the two inputs and one of the two outputs, the remaining two of the four second input/output ports are respectively one of the two inputs and the two outputs One. The optical switch of claim 10, wherein the four-turn reversible all-pass optical circulator has a forward cyclic direction state and a reverse cyclic direction state, and the reciprocal 2x2 optical switch has two switching states, The method includes: a first state in which the forward optical transmission and the reverse optical transmission are in a parallel state; and a second state in which the forward optical transmission and the reverse optical transmission are in an interlaced state. The optical switch of claim 11, wherein the reciprocal 2x2 optical switch is in the first state, the optical open relationship is in the third switching state; and the reciprocal 2x2 optical switch is in the second state. The optical open relationship is in the first switching state or the second switching state.