An optical switch and optical switch array

Abstract

This application provides an optical switch and an optical switch array, achieving polarization insensitivity and improving signal transmission quality. The optical switch includes an optical splitter, a first waveguide, a second waveguide, a first phase adjustment device, an optical combiner, and a first driving device disposed on a substrate. The first phase adjustment device is disposed along the extension direction of the first waveguide, and a gap exists between the first phase adjustment device and the first waveguide. The optical splitter splits an input optical signal to obtain a first optical signal and a second optical signal. The first optical signal is transmitted through the first waveguide, and the second optical signal is transmitted through the second waveguide. The first driving device drives the first phase adjustment device to move, thereby adjusting the phase of the first optical signal. The optical combiner combines the phase-adjusted first and second optical signals and outputs the combined optical signal through a first port or a second port.

Description

Technical Field

[0001] This application relates to the field of optical communication, and more particularly to an optical switch and an optical switch array. Background Technology

[0002] With the development of technologies such as Dense Wavelength Division Multiplexing (DWDM), the speed and capacity of information transmission in optical fiber communication links are increasing daily. This has led to a growing demand for faster and more efficient information exchange in optical communication networks (such as metropolitan area networks and data centers), making all-optical switching a development trend. Optical switches are key components in realizing all-optical switching systems, enabling functions such as routing, wavelength selection, optical cross-connection, and self-healing protection across the entire optical layer.

[0003] The continuous expansion of telecommunications network backbone transmission capacity and the continuous improvement of speed have made optical fiber communication the main transmission means of modern information networks. When an optical switch is connected to an optical fiber, the polarization state of the optical signal entering the optical switch from the optical fiber is uncertain due to the non-perfect circular cross-section of the fiber and the influence of stress and other factors. During the phase adjustment of the optical signal by the optical switch, the effective refractive index change of the transverse electric (TE) mode optical signal differs significantly from that of the transverse magnetic (TM) mode optical signal. This makes the optical switch sensitive to polarization, resulting in polarization dependent loss (PDL) and polarization mode dispersion (PMD), thereby reducing the signal transmission quality. Summary of the Invention

[0004] This application provides an optical switch and an optical switch array, which realizes that the optical switch is insensitive to polarization and improves the signal transmission quality.

[0005] In a first aspect, embodiments of this application provide an optical switch. The optical switch includes an optical splitter, a first waveguide, a second waveguide, a first phase adjustment device, an optical combiner, and a first driving device, all disposed on a substrate. The two ends of the first waveguide are respectively connected to the optical splitter and the optical combiner, and the two ends of the second waveguide are also respectively connected to the optical splitter and the optical combiner. The first phase adjustment device is disposed along the extension direction of the first waveguide, and a gap exists between the first phase adjustment device and the first waveguide in a first direction or a second direction. The first direction is perpendicular to the substrate, and the second direction is perpendicular to the first direction and also perpendicular to the extension direction of the first waveguide.

[0006] Specifically, the optical splitter is used to split the input optical signal into a first optical signal and a second optical signal. The first optical signal is transmitted through a first waveguide, and the second optical signal is transmitted through a second waveguide. A first driving device is used to drive a first phase adjustment device to move, thereby adjusting the phase of the first optical signal. Specifically, the length difference between the first waveguide and the first phase adjustment device is greater than a first preset value in a first direction, and / or the length difference between the first waveguide and the first phase adjustment device is greater than the first preset value in a second direction. This ensures that during the movement of the first phase adjustment device, the effective refractive index change of the transverse electric TE mode optical signal in the first optical signal is Δn1, the effective refractive index change of the transverse magnetic TM mode optical signal in the first optical signal is Δn2, and Δn1-Δn2 / Δn1 is less than a second preset value and / or Δn1-Δn2 / Δn2 is less than a second preset value. An optical combiner is used to combine the phase-adjusted first and second optical signals and output the combined optical signal through a first port or a second port.

[0007] In this embodiment, the first waveguide is significantly larger than the first phase adjustment device in thickness and / or width. During its movement, the first phase adjustment device only disturbs the phase of the first signal and does not generate excessive energy transfer with the first waveguide. Therefore, during phase adjustment, the effective refractive index change Δn1 of the TE mode optical signal and the effective refractive index change Δn2 of the TM mode optical signal will not differ significantly. This achieves polarization insensitivity of the optical switch and improves signal transmission quality.

[0008] In some possible implementations, during the movement of the first phase adjustment device, the optical field energy in the first phase adjustment device is less than 50% of the optical field energy in the first waveguide. While ensuring phase adjustment capability, this avoids the concentration of optical field energy in the first phase adjustment device, making it easier to achieve polarization insensitivity of the optical switch.

[0009] In some possible implementations, a range of values ​​for the second preset value is provided, namely 0 < the second preset value ≤ 10%, which enhances the feasibility of this solution.

[0010] In some possible implementations, the first waveguide is a straight waveguide, which has a simpler structure.

[0011] In some possible implementations, the first waveguide is a folded waveguide, and the first phase adjustment device can be positioned above the first waveguide so that it can cover the folded first waveguide. This design enhances the phase adjustment effect and improves the efficiency compared to a first waveguide with a straight waveguide structure.

[0012] In some possible implementations, the first driving device is used to drive the first phase adjustment device to move in a first direction or a second direction, so as to move the first phase adjustment device closer to or further away from the first waveguide, thereby improving the flexibility of the solution.

[0013] In some possible embodiments, a second phase adjustment device and a second driving device are further disposed on the substrate. The second phase adjustment device is disposed along the extension direction of the first waveguide, and a gap exists between the second phase adjustment device and the first waveguide in either a first or second direction. The second driving device is further used to adjust the phase of the first optical signal by driving the second phase adjustment device to move. Specifically, the length difference between the first waveguide and the second phase adjustment device is greater than a first preset value in the first direction, and / or the length difference between the first waveguide and the second phase adjustment device is greater than the first preset value in the second direction. In this embodiment, the phase change of the first optical signal after passing through the first waveguide is the sum of the phase adjustments performed on the first optical signal by the first and second phase adjustment devices, resulting in a larger range of phase adjustment.

[0014] In some possible embodiments, a second phase adjustment device and a second driving device are further disposed on the substrate. The second phase adjustment device is disposed along the extension direction of the second waveguide, and a gap exists between the second phase adjustment device and the second waveguide in either the first or second direction. The second driving device is used to drive the second phase adjustment device to move, so as to adjust the phase of the second optical signal. Wherein, the length difference between the second waveguide and the second phase adjustment device in the first direction is greater than a first preset value, and / or, the length difference between the second waveguide and the second phase adjustment device in the second direction is greater than the first preset value. This ensures that during the movement of the second phase adjustment device, the effective refractive index change of the transverse electric TE mode optical signal in the second optical signal is Δn3, the effective refractive index change of the transverse magnetic TM mode optical signal in the second optical signal is Δn4, and Δn3-Δn4 / Δn3 is less than the second preset value and / or Δn3-Δn4 / Δn4 is less than the second preset value. The optical combining device is specifically used to combine the phase-adjusted first optical signal and the phase-adjusted second optical signal, and output the combined optical signal. In this embodiment, a second phase adjustment device can also be provided above or to the side of the second waveguide to adjust the phase of the second optical signal, thus expanding the implementation methods of the optical switch.

[0015] In some possible implementations, the second driving device is used to drive the second phase adjustment device to move in the first direction or the second direction, so as to move the second phase adjustment device closer to or further away from the second waveguide, thereby improving the flexibility of the solution.

[0016] In some possible implementations, the optical switch further includes a stop structure. The stop structure is used to fix the position of the first phase adjustment device during movement, thereby controlling the distance between the first phase adjustment device and the first waveguide. The stop structure allows for flexible control of the distance between the first phase adjustment device and the first waveguide to maintain the desired phase adjustment state.

[0017] In some possible implementations, the first driving device is used to drive the first phase adjustment device to move by electrostatic driving, piezoelectric driving, thermoelectric driving or electromagnetic driving, which improves the scalability of this solution.

[0018] In some possible implementations, the optical switch further includes a thermal adjustment device for adjusting the temperature of the first waveguide to phase-modulate the first optical signal. This allows it to work in conjunction with the phase adjustment device described above to adjust the phase of the optical signal transmitted in the waveguide, resulting in better phase adjustment performance.

[0019] In some possible implementations, optical splitting devices include, but are not limited to, beam splitters, multimode interferometers (MMIs), and directional couplers (DCs). Optical combining devices include, but are not limited to, beam combiners, MMIs, and DCs.

[0020] Secondly, embodiments of this application provide an optical switch. The optical switch includes an optical splitter, a first waveguide, a second waveguide, a first phase adjustment device, a second phase adjustment device, an optical combiner, and a first driving device, all disposed on a substrate. The two ends of the first waveguide are connected to the optical splitter and the optical combiner, respectively, and the two ends of the second waveguide are also connected to the optical splitter and the optical combiner, respectively. Both the first and second phase adjustment devices are disposed along the extension direction of the first waveguide. A gap exists between the first phase adjustment device and the first waveguide in a first direction, and a gap exists between the second phase adjustment device and the first waveguide in a second direction. The first direction is perpendicular to the substrate, and the second direction is perpendicular to both the first and the extension direction of the first waveguide.

[0021] Specifically, the optical splitter is used to split the input optical signal into a first optical signal and a second optical signal. The first optical signal is transmitted through a first waveguide, and the second optical signal is transmitted through a second waveguide. A first driving device is used to drive a first phase adjustment device and a second phase adjustment device to simultaneously move closer to or further away from the first waveguide to adjust the phase of the first optical signal. The difference between the distance moved by the first phase adjustment device and the distance moved by the second phase adjustment device is less than a first preset value. The effective refractive index change of the transverse electric TE mode optical signal in the first optical signal is Δn1, and the effective refractive index change of the transverse magnetic TM mode optical signal in the first optical signal is Δn2. Δn1-Δn2 / Δn1 is less than a second preset value and / or Δn1-Δn2 / Δn2 is less than a second preset value. The optical combiner is used to combine the phase-adjusted first and second optical signals and output the combined optical signal through a first port or a second port.

[0022] In this embodiment, the movement of the phase adjustment device in different directions has different effects on the effective refractive index of the TE mode optical signal and the TM mode optical signal. For example, when the first phase adjustment device moves in the first direction, the effective refractive index of the TE mode optical signal changes significantly, while the effective refractive index of the TM mode optical signal does not change significantly. When the second phase adjustment device moves in the second direction, the effective refractive index of the TM mode optical signal changes significantly, while the effective refractive index of the TE mode optical signal does not change significantly. Therefore, when the first and second phase adjustment devices move synchronously, the change in effective refractive index Δn1 of the TE mode optical signal and the change in effective refractive index Δn2 of the TM mode optical signal will not differ significantly. This design approach allows for polarization insensitivity of the optical switch even without constraints on the thickness or width of the phase adjustment device, and the waveguide structure does not necessarily have to be a square cross-section, allowing for the adaptation of waveguides with more cross-sectional shapes.

[0023] In some possible implementations, a range of values ​​for the second preset value is provided, namely 0 < the second preset value ≤ 10%, which enhances the feasibility of this solution.

[0024] In some possible implementations, the first driving device is used to drive the first phase adjustment device to move in a first direction or a second direction. The first driving device is also used to drive the second phase adjustment device to move in the first direction or the second direction.

[0025] In some possible implementations, a third phase adjustment device, a fourth phase adjustment device, and a second driving device are also disposed on the substrate. Both the third and fourth phase adjustment devices are disposed along the extension direction of the first waveguide. A gap exists between the third phase adjustment device and the first waveguide in a first direction. A gap exists between the fourth phase adjustment device and the first waveguide in a second direction. The second driving device is used to drive the third and fourth phase adjustment devices to simultaneously approach or move away from the first waveguide to adjust the phase of the first optical signal. The difference between the distance moved by the third phase adjustment device and the distance moved by the fourth phase adjustment device is less than a first preset value. In this implementation, the first and second phase adjustment devices can be considered as one set of phase adjustment devices, and the third and fourth phase adjustment devices can be considered as another set of phase adjustment devices. The phase change of the first optical signal after passing through the first waveguide is the sum of the phase adjustments performed by the two sets of phase adjustment devices on the first optical signal, resulting in a larger range of phase adjustment.

[0026] In some possible implementations, a third phase adjustment device, a fourth phase adjustment device, and a second driving device are also disposed on the substrate. Both the third and fourth phase adjustment devices are disposed along the extension direction of the second waveguide. A gap exists between the third phase adjustment device and the second waveguide in a first direction. A gap exists between the fourth phase adjustment device and the second waveguide in a second direction. The second driving device is used to drive the third and fourth phase adjustment devices to synchronously approach or move away from the second waveguide to adjust the phase of the second optical signal. The difference between the distance moved by the third and fourth phase adjustment devices is less than a first preset value. The effective refractive index change of the transverse electric TE mode optical signal in the second optical signal is Δn3, and the effective refractive index change of the transverse magnetic TM mode optical signal in the second optical signal is Δn4. Δn3-Δn4 / Δn3 is less than the second preset value and / or Δn3-Δn4 / Δn4 is less than the second preset value. The optical combining device is specifically used to combine the phase-adjusted first optical signal and the phase-adjusted second optical signal, and output the combined optical signal. In this embodiment, a third phase adjustment device and a fourth phase adjustment device can be respectively provided above and to the side of the second waveguide to adjust the phase of the second optical signal, thereby expanding the implementation methods of the optical switch.

[0027] In some possible implementations, the second driving device is used to drive the third phase adjustment device to move in a first direction or a second direction. The second driving device is also used to drive the fourth phase adjustment device to move in the first direction or a second direction.

[0028] In some possible implementations, the optical switch further includes a first stop structure and a second stop structure. The first stop structure is used to fix the position of the first phase adjustment device during movement, thereby controlling the distance between the first phase adjustment device and the first waveguide. The second stop structure is used to fix the position of the second phase adjustment device during movement, thereby controlling the distance between the second phase adjustment device and the first waveguide.

[0029] In some possible implementations, the optical switch also includes a thermal adjustment device. The thermal adjustment device is used to adjust the temperature of the first waveguide to phase-adjust the first optical signal. This allows it to work in conjunction with the phase adjustment device described above to adjust the phase of the optical signal transmitted in the waveguide, resulting in better phase adjustment performance.

[0030] In some possible implementations, the first driving device is used to drive the first phase adjustment device to move by electrostatic driving, piezoelectric driving, thermoelectric driving or electromagnetic driving, and the second driving device is used to drive the second phase adjustment device to move by electrostatic driving, piezoelectric driving, thermoelectric driving or electromagnetic driving.

[0031] Thirdly, embodiments of this application provide an optical switch array, which includes a plurality of optical switches. Each optical switch can be an optical switch as described in any of the embodiments of the first or second aspect above. The optical switch array is used to transmit optical signals between every two adjacent optical switches.

[0032] In this embodiment, the effective refractive index of the TE mode optical signal or the TM mode optical signal in the first optical signal can be disturbed during the movement of the first phase adjustment device, but the change in effective refractive index Δn1 of the TE mode optical signal and the change in effective refractive index Δn2 of the TM mode optical signal will not differ significantly. In this way, the optical switch can be made insensitive to polarization during phase adjustment, improving the signal transmission quality. Furthermore, compared to changing the refractive index of the waveguide through thermo-optical adjustment to adjust the phase of the optical signal in the waveguide, this application only requires moving the phase adjustment device to achieve phase adjustment of the optical signal in the waveguide, resulting in higher efficiency and no heat generation issues. In addition, compared to changing the refractive index of the waveguide through carrier dispersion effects to adjust the phase of the optical signal in the waveguide, the method provided in this application does not require a carrier injection process, thus eliminating the problem of carrier absorption loss. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of one application scenario of the optical switch in this application;

[0034] Figure 2(a) is a schematic diagram of an optical switch array in this application;

[0035] Figure 2(b) is a schematic diagram of the path switching of the optical switch in this application;

[0036] Figure 3 This is a schematic diagram of the first structure of the optical switch in this application;

[0037] Figure 4 A schematic diagram showing the first phase adjustment device moving in a first direction;

[0038] Figure 5 This diagram illustrates the effective refractive index changes of TE mode and TM mode optical signals.

[0039] Figure 6 This is a schematic diagram of the second structure of the optical switch in this application;

[0040] Figure 7 This is a schematic diagram of the third structure of the optical switch in this application;

[0041] Figure 8 This is a schematic diagram of another phase adjustment method in this application;

[0042] Figure 9(a) is a schematic diagram of the first structure of the drive device in this application;

[0043] Figure 9(b) is a schematic diagram of the second structure of the drive device in this application;

[0044] Figure 9(c) is a schematic diagram of the third structure of the drive device in this application;

[0045] Figure 9(d) is a schematic diagram of the fourth structure of the drive device in this application. Detailed Implementation

[0046] This application provides an optical switch and an optical switch array, achieving polarization insensitivity of the optical switch and improving signal transmission quality. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0047] Figure 1 This is a schematic diagram illustrating one application scenario of the optical switch in this application. For example... Figure 1 The diagram shows an optical crossconnect (OXC) device. This OXC device has multiple ports at both ends for transmitting optical signals from different sources to a designated destination, thus achieving routing functionality. The core component of this OXC device is an optical switch array. For example, an optical signal output by user 1 is input through port 7. The optical switch array can change the transmission path of the optical signal, causing it to be output from the designated port 11 to the destination.

[0048] Figure 2(a) is a schematic diagram of an optical switch array according to this application. As shown in Figure 2(a), the optical switch array has multiple rows and columns of optical switches. One optical switch can be placed at the intersection of each of two transmission paths, and each pair of adjacent optical switches is used for transmitting optical signals. Figure 2(b) is a schematic diagram of the path switching of the optical switches according to this application. As shown in Figure 2(b), the optical switches adopt a "cross-bar" design, and the optical signal will have two path states after passing through the optical switches. The "bar" state is a straight-through state, where the optical signal continues to transmit along the previous transmission direction. The "cross" state is a cross-connected state, where the optical signal turns 90° before continuing transmission. By controlling the state of each optical switch, routing from any input port to any output port can be achieved.

[0049] The optical switch provided in this application is described below.

[0050] It should be noted that the optical switch provided in this application is designed based on the Mach-Zehnder interferometer (MZI) principle, primarily utilizing the phase characteristics of light. The input optical signal is split into two paths and transmitted in two independent waveguides, then the two optical signals are combined before output. By setting a phase adjustment device on at least one waveguide to adjust the phase of at least one optical signal, constructive or destructive interference occurs after the two optical signals are combined, achieving the effect of path switching. For example, by controlling the phase adjustment device, constructive interference occurs at the through port of the optical switch, and destructive interference occurs at the cross port, meaning the optical switch is in a through state. Alternatively, by controlling the phase adjustment device, destructive interference occurs at the through port of the optical switch, and constructive interference occurs at the cross port, meaning the optical switch is in a cross state.

[0051] It should be noted that this application does not limit the material of the waveguide in the optical switch. For example, the waveguide material can be silicon, or silicon doped materials such as silicon nitride or silicon oxide. This application also does not limit the specific thickness of the waveguide. For example, a thin waveguide of 220nm-300nm or a thick waveguide of 3µm can be used.

[0052] Figure 3 This is a schematic diagram of the first structural design of the optical switch in this application. (See attached diagram.) Figure 3 As shown, the optical switch includes: a substrate 10, an optical splitter 20, a first waveguide 301, a second waveguide 302, a first phase adjustment device 401, a first driving device 501, and an optical combiner 60. The two ends of the first waveguide 301 are connected to the optical splitter 20 and the optical combiner 60, respectively, and the two ends of the second waveguide 302 are also connected to the optical splitter 20 and the optical combiner 60, respectively. The first phase adjustment device 401 extends along the extension direction of the first waveguide 301 (i.e.,...). Figure 3 The first phase adjustment device 401 and the first waveguide 301 are positioned in a first direction perpendicular to the substrate 10 (i.e., the X direction shown), and there is a gap between the first phase adjustment device 401 and the first waveguide 301. In one possible embodiment, the first phase adjustment device 401 and the first waveguide 301 are positioned in a first direction perpendicular to the substrate 10 (i.e., the X direction shown), and there is a gap between the first phase adjustment device 401 and the first waveguide 301. Figure 3 It has a gap in the Z direction (as shown), that is, as Figure 3 The first phase adjustment device 401 shown is disposed above the first waveguide 301. In another possible embodiment, the first phase adjustment device 401 and the first waveguide 301 are in the second direction (i.e., Figure 3 The second direction (shown in the Y direction) has a gap. This second direction is perpendicular to the first direction and is also perpendicular to the extension direction of the first waveguide 301. That is, the first phase adjustment device 401 can also be set on the side of the first waveguide 301. No further drawings are provided here.

[0053] Specifically, the optical splitter 20 splits the input optical signal to obtain a first optical signal and a second optical signal. The first optical signal is transmitted through a first waveguide 301, and the second optical signal is transmitted through a second waveguide 302. The first driving device 501 drives the first phase adjustment device 401 to move closer to or further away from the first waveguide 301, thereby adjusting the phase of the first optical signal. The optical combiner 60 combines the phase-adjusted first and second optical signals and outputs the combined optical signal through a first port or a second port. The first port can be considered a through port of an optical switch, and the second port can be considered a cross port of an optical switch. The output of the combined optical signal from the first port or the second port can be controlled by adjusting the phase of the first optical signal; for details, please refer to the above description of the optical switch path switching principle, which will not be repeated here. It should be noted that the first phase adjustment device 401 can move in either a first direction or a second direction; this is not specifically limited here. Figure 4 The diagram shown is a schematic representation of the first phase adjustment device moving in a first direction.

[0054] It should be understood that the first optical signal includes both transverse electric (TE) mode optical signals and transverse magnetic (TM) mode optical signals. This application designs the optical switch so that, during phase adjustment, the difference in the effective refractive index change between the TE mode optical signal and the TM mode optical signal is small, thus achieving polarization insensitivity. Specifically, the length difference between the first waveguide 301 and the first phase adjustment device 401 in the first and / or second directions is greater than a first preset value. That is, the thickness of the first waveguide 301 is significantly greater than the thickness of the first phase adjustment device 401, or the width of the first waveguide 301 is significantly greater than the width of the first phase adjustment device 401, or both the thickness and width of the first waveguide 301 are significantly greater than the thickness and width of the first phase adjustment device 401. In this way, the first phase adjustment device 401, during its movement, only disturbs the phase of the first signal and does not generate excessive energy transfer with the first waveguide 301. Therefore, during phase adjustment, the effective refractive index change Δn1 of the TE mode optical signal and the effective refractive index change Δn2 of the TM mode optical signal will not differ significantly. This allows the optical switch to be insensitive to polarization, thus improving the signal transmission quality.

[0055] As an example, the above design allows the optical field energy in the first phase adjustment device 401 to be less than 50% of the optical field energy in the first waveguide 301. This, in turn, makes Δn1-Δn2 / Δn1 less than a second preset value and / or Δn1-Δn2 / Δn2 less than a second preset value, where 0 < the second preset value ≤ 10%. It should be understood that the values ​​of 50% and 10% mentioned above are merely specific examples provided in this application; in practical applications, these values ​​can be flexibly adjusted through design, and no specific limitations are imposed here.

[0056] Figure 5 This diagram illustrates the effective refractive index changes for TE mode and TM mode optical signals. Figure 5 As shown, the first driving device 501 drives the first phase adjustment device 401 to move closer to the first waveguide 301. The effective refractive index change Δn1 of the TE mode optical signal is 2.2431 - 2.214 = 0.0291, and the effective refractive index change Δn2 of the TM mode optical signal is 2.0768 - 2.0475 = 0.0293. If the second preset value is 5%, it satisfies that Δn1 - Δn2 / Δn1 is less than the second preset value and / or Δn1 - Δn2 / Δn2 is less than the second preset value.

[0057] It should be noted that in practical applications, only at least one set of phase adjustment devices and drive devices needs to be set around the first waveguide 301; the specific number of phase adjustment devices and drive devices is not limited here. For example Figure 3 As shown, a second phase adjustment device 402 and a second driving device 502 may also be disposed on the substrate 10. The second phase adjustment device 402 is also disposed along the extension direction (X direction) of the first waveguide, and there is a gap between the second phase adjustment device 402 and the first waveguide 301 in the first direction (Z direction) or the second direction (Y direction), that is, the second phase adjustment device 402 can be disposed above or to the side of the first waveguide 301. The second driving device 502 is used to drive the second phase adjustment device 402 to move in the first direction (Z direction) or the second direction (Y direction) to adjust the phase of the first optical signal. It should be understood that the phase change of the first optical signal after passing through the first waveguide 301 is the sum of the phase adjustments performed on the first optical signal by the first phase adjustment device 401 and the second phase adjustment device 402, and the phase adjustment range is larger. Similarly, in order to achieve polarization insensitivity of the optical switch, the length difference between the first waveguide 301 and the second phase adjustment device 402 in the first direction and / or the second direction must be greater than a first preset value. It should also be understood that in some scenarios, multiple phase adjustment devices can share the same drive device for driving, without the need to configure a separate drive device for each phase adjustment device.

[0058] In some possible implementations, at least one set of phase adjustment devices and driving devices may also be provided around the second waveguide 302, and the specific number of phase adjustment devices and driving devices is not limited here. Figure 6 This is a schematic diagram of a second structural design for the optical switch in this application. (See attached diagram.) Figure 6As shown, a third phase adjustment device 403, a fourth phase adjustment device 404, a third driving device 503, and a fourth driving device 504 are also disposed on the substrate. The third phase adjustment device 403 and the fourth phase adjustment device 404 are both disposed along the extension direction (X direction) of the second waveguide 302. A gap exists between the third phase adjustment device 403 and the second waveguide 302 in either the first direction (Z direction) or the second direction (Y direction), meaning the third phase adjustment device 403 can be disposed above or to the side of the second waveguide 302. Similarly, a gap exists between the fourth phase adjustment device 404 and the second waveguide 302 in either the first direction (Z direction) or the second direction (Y direction), meaning the fourth phase adjustment device 404 can be disposed above or to the side of the second waveguide 302. Similarly, in order to make the optical switch insensitive to polarization, the length difference between the second waveguide 302 and the third phase adjustment device 403 in the first direction and / or the second direction must be greater than the first preset value, and the length difference between the second waveguide 302 and the fourth phase adjustment device 404 in the first direction and / or the second direction must be greater than the first preset value.

[0059] Specifically, the third driving device 503 is used to drive the third phase adjustment device 403 to move in the first direction (Z direction) or the second direction (Y direction) to adjust the phase of the second optical signal. The fourth driving device 504 is used to drive the fourth phase adjustment device 404 to move in the first direction (Z direction) or the second direction (Y direction) to adjust the phase of the second optical signal. Based on the above design, the effective refractive index change Δn3 of the TE mode optical signal and the effective refractive index change Δn4 of the TM mode optical signal in the second optical signal will not be significantly different, that is, Δn3-Δn4 / Δn3 is less than the second preset value and / or Δn3-Δn4 / Δn4 is less than the second preset value.

[0060] It should be noted that the optical switch described above can also include at least one stop structure. This stop structure is used to fix the position of the phase adjustment device during its movement, thereby controlling the distance between the phase adjustment device and the waveguide, and thus fixing the phase adjustment capability of the phase adjustment device. For example, if a 90° phase adjustment capability is required, the stop structure can control the distance between the phase adjustment device and the waveguide to L1. Similarly, if a 180° phase adjustment capability is required, the stop structure can control the distance between the phase adjustment device and the waveguide to L2. By flexibly adjusting the distance between the phase adjustment device and the waveguide, the phase of the signal transmitted in the waveguide can be changed, thus controlling the optical signal output from different ports. A specific example will illustrate this below.

[0061] Taking the optical switch structure shown in Figure 6 above as an example, the first phase adjustment device 401, the second phase adjustment device 402, the third phase adjustment device 403, and the fourth phase adjustment device 404 all have a 90° phase adjustment capability. Table 1 below shows the state of the optical switch under different settings. "+" indicates that the phase adjustment device adjusts the phase by 90°, and "-" indicates that the phase adjustment device adjusts the phase by 0°. It can be seen that when the first phase adjustment device 401 and the second phase adjustment device 402 work together, the phase of the first optical signal deflects by 180°, while the phase of the second optical signal remains unchanged; in this case, the optical switch is in a through state. When the third phase adjustment device 403 and the fourth phase adjustment device 404 work together, the phase of the first optical signal remains unchanged, while the phase of the second optical signal deflects by 180°; in this case, the optical switch is in a crossover state.

[0062] Table 1

[0063]

[0064] Figure 7 This is a schematic diagram of the third structure of the optical switch in this application. For example... Figure 7 As shown, the first waveguide 301 can be a folded waveguide. For example, the first waveguide 301 is folded twice, and can be divided into three segments according to the transmission direction of the first optical signal. The first optical signal output from the optical splitter 20 first transmits along the first waveguide 301 from left to right, then after the first fold, it transmits along the first waveguide 301 from right to left, and after the second fold, it transmits along the first waveguide 301 from left to right to the optical combiner 60. Based on Figure 7 The structure of the first waveguide 301 shown allows both the first phase adjustment device 401 and the second phase adjustment device 402 to be positioned above the first waveguide 301, so that both devices can cover this folded first waveguide 301. This design enhances the phase adjustment effect and improves the efficiency compared to a first waveguide 301 with a straight waveguide structure.

[0065] In some possible implementations, a thermal adjustment device can also be incorporated into the optical switch. Since the refractive index of waveguide materials varies at different temperatures, adjusting the waveguide temperature using a thermal adjustment device can change the effective refractive index and phase of the transmitted optical signal within the waveguide. This allows for better phase adjustment in conjunction with the phase adjustment device described above. For example, if a 100° phase change is needed for the optical signal transmitted in the waveguide, a 90° phase change can be achieved by driving the phase adjustment device. Then, the thermal adjustment device can be used for fine-tuning the phase to achieve a 100° phase change. In other words, the thermal adjustment device can serve as an auxiliary means to supplement the phase adjustment capability of the phase adjustment device.

[0066] It should be noted that the optical splitter 20 includes, but is not limited to, a beam splitter, a multimode interferometer (MMI), and a directional coupler (DC). The power of the two optical signals output by the optical splitter 20 can be the same or different. In practical applications, any optical splitter 20 capable of achieving adjustable output optical power is within the scope of protection of this application. The optical combiner 60 includes, but is not limited to, a beam combiner, an MMI, and a DC. In practical applications, any optical combiner 60 capable of achieving optical signal combining is within the scope of protection of this application.

[0067] In the optical switches described above, the phase adjustment device is placed either above or to the side of the waveguide. In another possible implementation, a phase adjustment device can be placed both above and to the side of the waveguide. Figure 8 This is a schematic diagram of another phase adjustment method in this application. (For example...) Figure 8 As shown, the first phase adjustment device 401 is disposed above the first waveguide 301, and the second phase adjustment device 402 is disposed to the side of the first waveguide 301. It should be noted that in this embodiment, the first phase adjustment device 401 and the second phase adjustment device 402 must move synchronously under the action of the driving device. It should be understood that synchronous movement here means that the first phase adjustment device 401 and the second phase adjustment device 402 must simultaneously approach or move away from the first waveguide 301, and the first phase adjustment device 401 and the second phase adjustment device 402 must move at similar or equal distances. For example, while the first phase adjustment device 401 approaches the first waveguide 301 in the first direction (Z direction), the second phase adjustment device 402 must simultaneously approach the first waveguide 301 in the second direction (Y direction). It should be understood that, for ease of controlling the synchronous movement of the first phase adjustment device 401 and the second phase adjustment device 402, it is best to use the same driving device for driving.

[0068] It should be noted that the movement of the phase adjustment device in different directions has different effects on the effective refractive index of the TE mode optical signal and the TM mode optical signal. For example, when the first phase adjustment device 401 moves in the first direction (Z direction), the effective refractive index of the TE mode optical signal changes significantly, while the effective refractive index of the TM mode optical signal does not change significantly. When the second phase adjustment device 402 moves in the second direction (Y direction), the effective refractive index of the TM mode optical signal changes significantly, while the effective refractive index of the TE mode optical signal does not change significantly. Therefore, when the first phase adjustment device 401 and the second phase adjustment device 402 move synchronously, the change in effective refractive index Δn1 of the TE mode optical signal and the change in effective refractive index Δn2 of the TM mode optical signal will not differ significantly. This design approach allows for polarization insensitivity of the optical switch even without constraints on the thickness or width of the phase adjustment device, and the waveguide structure does not necessarily have to be a square cross-section, allowing for the adaptation of waveguides with more cross-sectional shapes.

[0069] The following provides several specific structures of driving devices. It should be understood that the driving device structures described below are only examples of several implementations. In practical applications, driving devices that can drive the phase adjustment device to move in the first or second direction are all within the scope of protection of this application. It should be noted that the driving device in this application can specifically use electrostatic driving, piezoelectric driving, thermoelectric driving, or electromagnetic driving, etc., to drive the phase adjustment device to move. The specific method is not limited here. The following mainly describes the structure of the driving device.

[0070] Figure 9(a) is a schematic diagram of the first structure of the driving device in this application. As shown in Figure 9(a), the first phase adjustment device 401 is disposed above the first waveguide 301, and one end of the first phase adjustment device 401 is connected to the first driving device 501. The first driving device 501 is fixed on the substrate 10, and the end of the first driving device 501 connected to the first phase adjustment device 401 is movable. Specifically, the first driving device 501 can adopt a cantilever beam structure. Therefore, the first driving device 501 can drive the first phase adjustment device 401 to move in the first direction (Z direction).

[0071] Figure 9(b) is a schematic diagram of a second structure of the driving device in this application. As shown in Figure 9(b), the first phase adjustment device 401 is disposed on the side of the first waveguide 301, and one end of the first phase adjustment device 401 is connected to the first driving device 501. Similar to Figure 9(a) above, the first driving device 501 can specifically adopt a cantilever beam structure, thereby driving the first phase adjustment device 401 to move in the first direction (Z direction).

[0072] Figure 9(c) is a schematic diagram of a third structure of the driving device in this application. As shown in Figure 9(c), the first phase adjustment device 401 is disposed above the first waveguide 301, and both ends of the first phase adjustment device 401 are connected to the first driving device 501. The first driving device 501 is fixed on the substrate 10, and the first driving device 501 can adopt a spring structure. The first driving device 501 can drive the first phase adjustment device 401 to move in the first direction (Z direction) by moving itself in the first direction (Z direction). It should be understood that, based on the structure shown in Figure 9(c), the first driving device 501 can also drive the first phase adjustment device 401 to move in the second direction (Y direction) by changing the direction of movement of the first driving device 501. The specific details are not shown in the accompanying drawings here.

[0073] Figure 9(d) is a schematic diagram of the fourth structure of the driving device in this application. As shown in Figure 9(d), the first phase adjustment device 401 is disposed above the first waveguide 301, and both ends of the first phase adjustment device 401 are connected to the first driving device 501. The first driving device 501 adopts a comb structure, and can be moved in the first direction (Z direction) by electrostatic driving, thereby driving the first phase adjustment device 401 to move in the first direction (Z direction). It should be understood that, based on the structure shown in Figure 9(d), the first driving device 501 can also drive the first phase adjustment device 401 to move in the second direction (Y direction) by changing the direction of movement of the first driving device 501. The specific details are not shown in the accompanying drawings here.

[0074] In this embodiment, through the design described above, the effective refractive index of the TE mode optical signal or the TM mode optical signal in the first optical signal can be disturbed during the movement of the first phase adjustment device, but the change in effective refractive index Δn1 of the TE mode optical signal and the change in effective refractive index Δn2 of the TM mode optical signal will not differ significantly. In this way, the optical switch can be made polarization-insensitive during phase adjustment, improving the signal transmission quality. Furthermore, compared to changing the refractive index of the waveguide through thermo-optical adjustment to adjust the phase of the optical signal in the waveguide, this application only requires moving the phase adjustment device to achieve phase adjustment of the optical signal in the waveguide, resulting in higher efficiency and no heat generation issues. Moreover, compared to changing the refractive index of the waveguide through carrier dispersion effects to adjust the phase of the optical signal in the waveguide, the method provided in this application does not require a carrier injection process, thus eliminating the problem of carrier absorption loss.

[0075] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An optical switch, characterized by The device includes an optical splitter, a first waveguide, a second waveguide, a first phase adjustment device, an optical combiner, and a first driving device, all disposed on a substrate. The two ends of the first waveguide are respectively connected to the optical splitter and the optical combiner. The two ends of the second waveguide are also respectively connected to the optical splitter and the optical combiner. The first phase adjustment device is disposed along the extension direction of the first waveguide. A gap exists between the first phase adjustment device and the first waveguide in a first direction or a second direction. The first direction is perpendicular to the substrate, and the second direction is perpendicular to both the first and the extension direction of the first waveguide. The optical splitter is used to split the input optical signal to obtain a first optical signal and a second optical signal, wherein the first optical signal is transmitted through the first waveguide and the second optical signal is transmitted through the second waveguide; The first driving device is used to drive the first phase adjustment device to move in order to adjust the phase of the first optical signal. In the first direction, the length difference between the first waveguide and the first phase adjustment device is greater than a first preset value, and / or, in the second direction, the length difference between the first waveguide and the first phase adjustment device is greater than the first preset value. This is so that during the movement of the first phase adjustment device, the effective refractive index change of the transverse electric TE mode optical signal in the first optical signal is Δn1, the effective refractive index change of the transverse magnetic TM mode optical signal in the first optical signal is Δn2, and Δn1-Δn2 / Δn1 is less than a second preset value and / or Δn1-Δn2 / Δn2 is less than a second preset value. The optical combiner is used to combine the phase-adjusted first optical signal and the second optical signal, and output the combined optical signal through the first port or the second port.

2. The optical switch of claim 1, wherein, During the movement of the first phase adjustment device, the optical field energy in the first phase adjustment device is less than 50% of the optical field energy in the first waveguide.

3. The optical switch according to claim 1 or 2, characterized in that, 0 < the second preset value ≤ 10%.

4. The optical switch according to any one of claims 1 to 3, characterized in that, There is a gap between the first phase adjustment device and the first waveguide in the first direction, and the first waveguide is a folded waveguide.

5. The optical switch according to any one of claims 1 to 4, characterized in that, The first driving device is used to drive the first phase adjustment device to move in the first direction or the second direction.

6. The optical switch according to any one of claims 1 to 5, characterized in that, The substrate is further provided with a second phase adjustment device and a second driving device. The second phase adjustment device is arranged along the extension direction of the first waveguide, and there is a gap between the second phase adjustment device and the first waveguide in the first direction or the second direction. The second driving device is further configured to adjust the phase of the first optical signal by driving the second phase adjustment device to move, wherein the length difference between the first waveguide and the second phase adjustment device in the first direction is greater than the first preset value, and / or the length difference between the first waveguide and the second phase adjustment device in the second direction is greater than the first preset value.

7. The optical switch according to any one of claims 1 to 5, characterized in that, The substrate is further provided with a second phase adjustment device and a second driving device. The second phase adjustment device is arranged along the extension direction of the second waveguide, and there is a gap between the second phase adjustment device and the second waveguide in the first direction or the second direction. The second driving device is used to drive the second phase adjustment device to move in order to adjust the phase of the second optical signal. In the first direction, the length difference between the second waveguide and the second phase adjustment device is greater than the first preset value, and / or, in the second direction, the length difference between the second waveguide and the second phase adjustment device is greater than the first preset value, so that during the movement of the second phase adjustment device, the effective refractive index change of the transverse electric TE mode optical signal in the second optical signal is Δn3, the effective refractive index change of the transverse magnetic TM mode optical signal in the second optical signal is Δn4, and Δn3-Δn4 / Δn3 is less than the second preset value and / or Δn3-Δn4 / Δn4 is less than the second preset value. The optical combining device is specifically used to combine the phase-adjusted first optical signal and the phase-adjusted second optical signal, and output the combined optical signal.

8. The optical switch according to claim 6 or 7, characterized in that, The second driving device is used to drive the second phase adjustment device to move in the first direction or the second direction.

9. The optical switch according to any one of claims 1 to 8, characterized in that, The optical switch also includes a stop structure; The stop structure is used to fix the position of the first phase adjustment device during the movement of the first phase adjustment device, so as to control the distance between the first phase adjustment device and the first waveguide.

10. The optical switch according to any one of claims 1 to 9, characterized in that, The optical switch also includes a thermal adjustment device; The thermal adjustment device is used to adjust the temperature of the first waveguide in order to perform phase adjustment on the first optical signal.

11. An optical switch, characterized in that, The device includes an optical splitter, a first waveguide, a second waveguide, a first phase adjustment device, a second phase adjustment device, an optical combiner, and a first driving device, all disposed on a substrate. The two ends of the first waveguide are respectively connected to the optical splitter and the optical combiner, and the two ends of the second waveguide are also respectively connected to the optical splitter and the optical combiner. The first phase adjustment device and the second phase adjustment device are both disposed along the extension direction of the first waveguide. In a first direction, there is a gap between the first phase adjustment device and the first waveguide, and in a second direction, there is a gap between the second phase adjustment device and the first waveguide. The first direction is perpendicular to the substrate, and the second direction is perpendicular to the first direction and also perpendicular to the extension direction of the first waveguide. The optical splitter is used to split the input optical signal to obtain a first optical signal and a second optical signal, wherein the first optical signal is transmitted through the first waveguide and the second optical signal is transmitted through the second waveguide; The first driving device is used to drive the first phase adjustment device and the second phase adjustment device to synchronously approach or move away from the first waveguide to adjust the phase of the first optical signal. The difference between the distance moved by the first phase adjustment device and the distance moved by the second phase adjustment device is less than a first preset value. The effective refractive index change of the transverse electric TE mode optical signal in the first optical signal is Δn1, and the effective refractive index change of the transverse magnetic TM mode optical signal in the first optical signal is Δn2. Δn1-Δn2 / Δn1 is less than a second preset value and / or Δn1-Δn2 / Δn2 is less than the second preset value. The optical combiner is used to combine the phase-adjusted first optical signal and the second optical signal, and output the combined optical signal through the first port or the second port.

12. The optical switch according to claim 11, characterized in that, 0 < the second preset value ≤ 10%.

13. The optical switch according to claim 11 or 12, characterized in that, The first driving device is used to drive the first phase adjustment device to move in the first direction or the second direction, and the first driving device is used to drive the second phase adjustment device to move in the first direction or the second direction.

14. The optical switch according to any one of claims 11 to 13, characterized in that, The substrate is further provided with a third phase adjustment device, a fourth phase adjustment device and a second driving device. The third phase adjustment device and the fourth phase adjustment device are both arranged along the extension direction of the first waveguide. In the first direction, there is a gap between the third phase adjustment device and the first waveguide, and in the second direction, there is a gap between the fourth phase adjustment device and the first waveguide. The second driving device is used to drive the third phase adjustment device and the fourth phase adjustment device to move synchronously closer to the first waveguide or move synchronously away from the first waveguide to adjust the phase of the first optical signal, wherein the difference between the distance moved by the third phase adjustment device and the distance moved by the fourth phase adjustment device is less than the first preset value.

15. The optical switch according to any one of claims 11 to 13, characterized in that, The substrate is further provided with a third phase adjustment device, a fourth phase adjustment device and a second driving device. The third phase adjustment device and the fourth phase adjustment device are both arranged along the extension direction of the second waveguide. In the first direction, there is a gap between the third phase adjustment device and the second waveguide, and in the second direction, there is a gap between the fourth phase adjustment device and the second waveguide. The second driving device is used to drive the third phase adjustment device and the fourth phase adjustment device to synchronously move closer to the second waveguide or synchronously move away from the second waveguide to adjust the phase of the second optical signal. The difference between the distance moved by the third phase adjustment device and the distance moved by the fourth phase adjustment device is less than the first preset value. The effective refractive index change of the transverse electric TE mode optical signal in the second optical signal is Δn3, and the effective refractive index change of the transverse magnetic TM mode optical signal in the second optical signal is Δn4. Δn3-Δn4 / Δn3 is less than the second preset value and / or Δn3-Δn4 / Δn4 is less than the second preset value. The optical combining device is specifically used to combine the phase-adjusted first optical signal and the phase-adjusted second optical signal, and output the combined optical signal.

16. The optical switch according to claim 14 or 15, characterized in that, The second driving device is used to drive the third phase adjustment device to move in the first direction or the second direction, and the second driving device is used to drive the fourth phase adjustment device to move in the first direction or the second direction.

17. The optical switch according to any one of claims 11 to 16, characterized in that, The optical switch also includes a first stop structure and a second stop structure; The first stop structure is used to fix the position of the first phase adjustment device during the movement of the first phase adjustment device, so as to control the distance between the first phase adjustment device and the first waveguide. The second stop structure is used to fix the position of the second phase adjustment device during the movement of the second phase adjustment device, so as to control the distance between the second phase adjustment device and the first waveguide.

18. The optical switch according to any one of claims 11 to 16, characterized in that, The optical switch also includes a thermal adjustment device; The thermal adjustment device is used to adjust the temperature of the first waveguide in order to perform phase adjustment on the first optical signal.

19. An optical switch array, characterized in that, It includes a plurality of optical switches as described in any one of claims 1 to 18, wherein every two adjacent optical switches are used to transmit optical signals.

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