Method and system for calibrating the switching point voltage of an optical switch

Abstract

A method and system for calibrating the switching point voltage of an optical switch. The method includes: providing an optical switch link, the optical switch link including an optical switch to be measured and an adjacent optical switch, there being a first optical transmission path and a second optical transmission path between the optical switch to be measured and the adjacent optical switch, and there being a preset optical path difference between the first optical transmission path and the second optical transmission path; inputting an optical signal into the optical switch link, and applying a plurality of control voltages with a preset step size to the optical switch to be measured to determine the spectral diagrams of the optical switch link under the respective control voltages; calculating and determining the free spectral range value according to the optical path difference, and determining the optical power of the optical signal to be measured under the respective control voltages according to the respective spectral diagrams; using the control voltage when the optical power of the optical signal to be measured is at a minimum value as the switching point voltage of the optical switch to be measured. Through the solution of the present invention, the switching point voltage of the optical switch to be measured in the optical switch link can be simply and accurately calibrated.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic technologies, and in particular, to a method and system for calibrating the switching point voltage of an optical switch. Background Art

[0002] Currently, at the nodes of optical networks, electronic signal processing and electronic switching methods are still adopted, which have problems such as the "optical - electrical - optical" conversion bottleneck and high energy consumption, and it is difficult to meet the requirements of future optical networks. The all - optical switching technology directly completes the exchange of information between optical channels in the optical domain without going through the "optical - electrical - optical" conversion, improving the data transmission rate. The optical switch is the most basic and core device in the optical switching module, and its basic function is to control the switching of optical signals transmitted on different optical transmission paths.

[0003] In practical applications, multiple optical switches are usually integrated on an integrated optical device. Due to the influence of manufacturing errors, the actual switching point voltage of the optical switch usually has a certain deviation from the switching point voltage in the ideal state. In order to ensure the performance of the optical switch and the integrated optical device, it is necessary to calibrate the switching point voltage of the optical switch on the integrated optical device to find the actual switching point voltage of the optical switch. Therefore, there is an urgent need for a method that can accurately calibrate the switching point voltage of the optical switch. Summary of the Invention

[0004] The technical problem solved by the present invention is to provide a method that can accurately calibrate the switching point voltage of an optical switch.

[0005] To solve the above - mentioned technical problem, an embodiment of the present invention provides a method for calibrating the switching point voltage of an optical switch. The method includes: providing an optical switch link, where the optical switch link includes a to - be - measured optical switch and an adjacent optical switch, the adjacent optical switch is an optical switch adjacent to the to - be - measured optical switch, and there is a first optical transmission path and a second optical transmission path between the to - be - measured optical switch and the adjacent optical switch, and there is a preset optical path difference between the first optical transmission path and the second optical transmission path; inputting an optical signal into the optical switch link, and applying a plurality of control voltages with a preset step size to the to - be - measured optical switch to determine the spectral diagram of the optical switch link under each control voltage, where the abscissa of the spectral diagram of the optical switch link is the free spectral range and the ordinate is the optical power; calculating and determining the free spectral range value according to the optical path difference, and determining the optical power of the to - be - measured optical signal under each control voltage according to each spectral diagram, where the to - be - measured optical signal is a part of the optical signal output from the optical switch link that has the free spectral range value; taking the control voltage when the optical power of the to - be - measured optical signal is the minimum as the switching point voltage of the to - be - measured optical switch.

[0006] Optionally, determining the spectrogram of the optical switch link at each control voltage includes: when applying each control voltage with a preset step size to the optical switch under test, inputting optical signals with different wavelengths into the optical switch link to obtain a wave-domain sweep spectrum of the optical switch link, where the abscissa of the wave-domain sweep spectrum is the wavelength and the ordinate is the optical power; determining the spectrogram of the optical switch link according to the wave-domain sweep spectrum of the optical switch link.

[0007] Optionally, determining the spectrogram of the optical switch link according to the wave-domain sweep spectrum of the optical switch link includes: performing a Fourier transform on the wave-domain sweep spectrum to obtain the spectrogram of the optical switch link.

[0008] Optionally, the optical switch link includes N optical switches, the optical switch under test is the first optical switch in the optical switch link, the adjacent optical switch is the second optical switch, there are a third optical transmission path and a fourth optical transmission path between the i-th optical switch and the (i + 1)-th optical switch in the optical switch link, there is a preset i-th optical path difference between the third optical transmission path and the fourth optical transmission path, the value of the i-th optical path difference is different from the value of the optical path difference, and when i takes different values, the value of the i-th optical path difference is also different; the method further includes: sequentially determining the switching point voltages of the second optical switch to the (N - 1)-th optical switch; where determining the switching point voltage of the i-th optical switch includes: applying the switching point voltage of each optical switch before the i-th optical switch; applying a plurality of control voltages with a preset step size to the i-th optical switch to determine the i-th spectrogram of the optical switch link at each control voltage; determining the i-th free spectral range value according to the i-th optical path difference, and determining the optical power of the i-th optical signal to be measured at each control voltage according to each i-th spectrogram, where the i-th optical signal to be measured is a part of the optical signals output from the optical switch link that has the i-th free spectral range value; using the control voltage when the optical power of the i-th optical signal to be measured is the minimum as the switching point voltage of the i-th optical switch; where the abscissa of the i-th spectrogram of the optical switch link is the free spectral range and the ordinate is the optical power; i and N are positive integers, i ≥ 2, N ≥ 3, i < N.

[0009] Optionally, the optical switch link includes M optical switches, the optical switch under test is the first optical switch in the optical switch link, the adjacent optical switch is the second optical switch, the method further includes: applying the switching point voltage of each optical switch before the M-th optical switch; applying a plurality of control voltages to the M-th optical switch to obtain the optical power of the optical signals output from the optical switch link at each control voltage; using the control voltages when the optical power of the optical signals output from the optical switch link is the maximum and the minimum as the switching point voltages of the M-th optical switch, where M is a positive integer, M ≥ 2.

[0010] Optionally, the first optical transmission path is an optical waveguide, the second optical transmission path is an optical waveguide, and the first optical transmission path and the second optical transmission path satisfy one or more of the following: different materials, different shapes, different dimensions.

[0011] Optionally, when the materials, shapes, widths, and heights of the first optical transmission path and the second optical transmission path are the same but the lengths are different, the following formula is used to calculate the free spectral range value:

[0012]

[0013] where FSR is the free spectral range value, λ is the preset wavelength, n g is the group refractive index of the first optical transmission path or the second optical transmission path, and ΔL is the optical path difference.

[0014] Optionally, each optical switch in the optical switch link has multiple switching point voltages, and the method further includes: selecting any one of the multiple switching point voltages of each optical switch as the first voltage of each optical switch; sequentially determining the state of the j-th optical switch at its first voltage and determining the state of the M-th optical switch at its first voltage, where j is a positive integer and j < M; sequentially determining the state of the j-th optical switch at its first voltage includes: applying the first voltage of each optical switch to each optical switch respectively, and measuring and determining the first transmission time of the j-th optical switch; applying the respective second voltages to the j-th optical switch and the (j + 1)-th optical switch respectively while the control voltages of other optical switches remain their respective first voltages, and measuring and determining the second transmission time of the j-th optical switch, where the second voltage is a switching point voltage adjacent in value to the first voltage among the multiple switching point voltages of the same optical switch; comparing the first transmission time and the second transmission time of the j-th optical switch, and determining the output interface through which the optical signal outputs from the j-th optical switch when the control voltage of the j-th optical switch is its first voltage according to the comparison result; determining the state of the j-th optical switch at its first voltage according to the input interface through which the optical signal inputs to the j-th optical switch and the output interface through which the optical signal outputs from the j-th optical switch when the control voltage of the j-th optical switch is its first voltage; determining the state of the M-th optical switch at its first voltage includes: applying the first voltage of each optical switch to each optical switch respectively; determining the input interface through which the optical signal inputs to the M-th optical switch at its first voltage according to the state of each optical switch before the M-th optical switch at their respective first voltages and the input interface through which the optical signal inputs to the first optical switch; determining the state of the M-th optical switch at its first voltage according to the input interface through which the optical signal inputs to the M-th optical switch and the output interface through which the optical signal outputs from the M-th optical switch at the first voltage of the M-th optical switch.

[0015] Optionally, the optical switch to be measured is an optical switch based on a Mach-Zehnder interferometer or an optical switch based on a microelectromechanical device.

[0016] To solve the above technical problems, an embodiment of the present invention further provides a system for calibrating the switching point voltage of an optical switch. The system includes: an optical switch link, which includes an optical switch to be measured and an adjacent optical switch. The adjacent optical switch is an optical switch adjacent to the optical switch to be measured. There is a first optical transmission path and a second optical transmission path between the optical switch to be measured and the adjacent optical switch, and there is a preset optical path difference between the first optical transmission path and the second optical transmission path; an optical switch controller for applying a plurality of control voltages with a preset step size to the optical switch to be measured; a light source for inputting an optical signal into the optical switch link; a terminal for determining the spectrum diagram of the optical switch link under each control voltage according to the plurality of control voltages applied by the optical switch controller. The abscissa of the spectrum diagram of the optical switch link is the free spectral range, and the ordinate is the optical power. Determine the free spectral range value according to the optical path difference, and determine the optical power of the optical signal to be measured under each control voltage according to each spectrum diagram. Take the control voltage when the optical power of the optical signal to be measured is the minimum as the switching point voltage of the optical switch to be measured. Wherein, the optical signal to be measured is a part of the optical signal output from the optical switch link that has the free spectral range value.

[0017] Optionally, the light source is further configured to input optical signals with different wavelengths into the optical switch link when applying each control voltage with a preset step size to the optical switch to be measured, so as to obtain a wavelength-domain sweep spectrum diagram of the optical switch link. The abscissa of the wavelength-domain sweep spectrum diagram is the wavelength, and the ordinate is the optical signal intensity; wherein, the terminal is further configured to determine the spectrum diagram of the optical switch link according to the wavelength-domain sweep spectrum diagram of the optical switch link.

[0018] Optionally, the system further includes: an optical detector for measuring the optical power of the optical signal output from the optical switch link.

[0019] Optionally, the optical switch link includes M optical switches, and each optical switch in the optical switch link has multiple switching point voltages; the optical switch controller is further configured to select any one of the multiple switching point voltages of each optical switch as the first voltage of each optical switch, apply the first voltage of the optical switch to each optical switch respectively, and apply the respective second voltages to the j-th optical switch and the (j + 1)-th optical switch respectively; the terminal is further configured to measure and determine the first transmission time and the second transmission time of the j-th optical switch; compare the first transmission time and the second transmission time of the j-th optical switch, and determine the output interface from which the optical signal outputs from the j-th optical switch when the control voltage of the j-th optical switch is its first voltage according to the comparison result; determine the state of the j-th optical switch at its first voltage according to the input interface to which the optical signal inputs to the j-th optical switch and the output interface from which the optical signal outputs from the j-th optical switch when the control voltage of the j-th optical switch is its first voltage; determine the input interface to which the optical signal inputs to the M-th optical switch at its first voltage according to the state of each optical switch before the M-th optical switch at its respective first voltage and the input interface to which the optical signal inputs to the first optical switch; determine the state of the M-th optical switch at its first voltage according to the input interface to which the optical signal inputs to the M-th optical switch and the output interface from which the optical signal outputs from the M-th optical switch at the first voltage of the M-th optical switch; wherein, the first voltage is any one of the multiple switching point voltages of each optical switch, and the second voltage is the switching point voltage adjacent to the first voltage in terms of value among the multiple switching point voltages of the same optical switch.

[0020] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0021] In the embodiment of the present invention, when applying a control voltage to the optical switch to be measured in the optical switch link, a spectrogram of the optical switch link under the control voltage can be obtained. The spectrogram contains the interference information of the optical signal. After calculating and determining the free spectral range value according to the preset optical path difference, the optical power of the optical signal to be measured can be determined in the spectrogram. By applying control voltages with multiple preset step lengths to the optical switch to be measured in the optical switch link, the optical power of the optical signal to be measured under each control voltage can be obtained respectively, and the control voltage when the optical power is the minimum can be determined, so that the switching point voltage of the optical switch to be measured can be obtained. Thus, in the embodiment of the present invention, the switching point voltage of the optical switch to be measured is calibrated based on the interference of the optical signal, and the accuracy is higher.

[0022] Further, in the embodiment of the present invention, when each control voltage with a preset step is applied to the optical switch to be measured, optical signals with different wavelengths are used to scan the optical switch link to obtain a spectral scan diagram of the optical switch link, and then a Fourier transform is performed on the spectral scan diagram to obtain a frequency spectrum diagram of the optical switch link.

[0023] Further, in the embodiment of the present invention, when determining the switching point voltage of the i-th optical switch, first apply the switching point voltage to each optical switch before the i-th optical switch, and then determine the optical power of the i-th optical signal under each control voltage. The control voltage at which the optical power is minimized is used as the switching point voltage of the i-th optical switch. Since the control voltage of each optical switch before the i-th optical switch is its switching point voltage, when determining the switching point voltage of the i-th optical switch, the influence of the control voltage of the previous optical switch on optical switching in the optical switch link can be avoided, making the determined switching point voltage of the i-th optical switch more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. is a schematic structural diagram of an optical switch applicable to a method for calibrating the switching point voltage of an optical switch in an embodiment of the present invention.

[0025] Figure 2 FIG. is a schematic scenario diagram of a method for calibrating the switching point voltage of an optical switch in an embodiment of the present invention.

[0026] Figure 3 FIG. is a schematic flowchart of a method for calibrating the switching point voltage of an optical switch in an embodiment of the present invention.

[0027] Figure 4 FIG. is a schematic diagram of the spectral scan diagram in an embodiment of the present invention.

[0028] Figure 5 FIG. is a schematic flowchart of another method for calibrating the switching point voltage of an optical switch in an embodiment of the present invention.

[0029] Figure 6 FIG. is a schematic diagram of the frequency spectrum diagram in an embodiment of the present invention.

[0030] Figure 7 FIG. is a schematic diagram of the "voltage - optical power" response curve of the optical switch link in an embodiment of the present invention.

[0031] Figure 8 FIG. is a schematic structural diagram of a system for calibrating the switching point voltage of an optical switch in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] As described in the background art, there is an urgent need for a method that can accurately calibrate the switching point voltage of an optical switch.

[0033] The inventors of the present invention have found through research that in the prior art, the method for determining the switching point voltage of an optical switch mainly measures the optical power at the output port of the optical switch to be measured through a photodetector. That is, the photodetector needs to be connected to the optical output port of the optical switch to be measured. For an optical switch link integrated with multiple optical switches, using this method means that multiple output ports need to be added, which will increase the test difficulty and also cause additional optical losses when the optical signal is transmitted in the optical switch link.

[0034] In addition, when it is necessary to measure the switching point voltages of multiple optical switches in the optical switch link, this method requires connecting photodetectors to the optical output ports of the multiple optical switches to be measured. This method will cause relatively large optical losses during the optical transmission process. Since the optical switch link is usually located on an optical chip, this method will cause the chip size to increase and the packaging cost to rise due to the need for multiple photodetectors.

[0035] To solve the above technical problems, an embodiment of the present invention provides a method for calibrating the switching point voltage of an optical switch. The method includes: providing an optical switch link, the optical switch link includes an optical switch to be measured and an adjacent optical switch, there is a first optical transmission path and a second optical transmission path between the optical switch to be measured and the adjacent optical switch, and there is a preset optical path difference between the first optical transmission path and the second optical transmission path; inputting an optical signal into the optical switch link, and applying a plurality of control voltages with a preset step size to the optical switch to be measured to determine the spectrogram of the optical switch link under each control voltage; calculating and determining the free spectral range value according to the optical path difference, and determining the optical power of the optical signal to be measured under each control voltage according to each spectrogram; using the control voltage when the optical power is the minimum value as the switching point voltage of the optical switch to be measured. In the embodiment of the present invention, when applying a control voltage to the optical switch to be measured in the optical switch link, the spectrogram of the optical switch link under this control voltage can be obtained. The free spectral range value is calculated and determined according to the preset optical path difference. Since the abscissa of the spectrogram is the free spectral range and the ordinate is the optical power, the optical power of the optical signal to be measured can be determined in the spectrogram. By applying a plurality of control voltages with a preset step size to the optical switch to be measured in the optical switch link, the optical power of the optical signal to be measured under each control voltage can be obtained respectively, and the control voltage when the optical power is the minimum is determined, so that the switching point voltage of the optical switch to be measured can be obtained.

[0036] To make the above objects, features, and beneficial effects of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings.

[0037] Refer to Figure 1 , Figure 1 which is a schematic structural diagram of an optical switch applicable to the method for calibrating the switching point voltage of an optical switch in an embodiment of the present invention. More specifically,Figure 1 This is a top view of the optical switch 11. The following will be combined with Figure 1 to make a non-limiting description of the optical switch 11 applicable to the method for calibrating the switching point voltage of an optical switch in an embodiment of the present invention.

[0038] The optical switch 11 applicable in the embodiment of the present invention includes a first optical input port 12, a second optical input port 13, a first power splitter 14, a second power splitter 15, a first transmission waveguide 16, a second transmission waveguide 17, a first optical output port 18, a second optical output port 19, a first phase shifter 20, and a second phase shifter 21.

[0039] Further, there are two optical transmission paths for the optical signal input into the optical switch 11. Specifically, the optical signal can be input into the optical switch 11 from the first optical input port 12. The optical signal input from the first optical input port 12 can all be output from the first optical output port 18, or all be output from the second optical output port 19, or part of it can be output from the first optical output port 18 and part from the second optical output port 19. The optical signal can also be input into the optical switch 11 from the second optical input port 13. The optical signal input from the second optical input port 13 can all be output from the first optical output port 18, or all be output from the second optical output port 19, or part of it can be output from the first optical output port 18 and part from the second optical output port 19.

[0040] It should be noted that the optical signal can also be input into the optical switch 11 from the first optical output port 18 and / or the second optical output port 19 and output from the first optical input port 12 and / or the second optical input port 13. The embodiment of the present invention does not impose any restrictions on the transmission direction of the optical signal in the optical switch 11. That is, the ports in the optical switch 11 can be used as optical input ports or optical output ports.

[0041] Further, the first power splitter 14 is used to divide the optical signal input into the optical switch 11 into two paths; the two optical signals are respectively transmitted into the first transmission waveguide 16 and the second transmission waveguide 17. The first power splitter can be a directional coupler or a multi-mode interferometer (Multi-Mode Interferometer), but is not limited thereto.

[0042] Further, the second power splitter 15 is used to combine the optical signals in the first transmission waveguide 16 and the second transmission waveguide 17 and transmit them to the first optical output port 18 and / or the second optical output port 19. The second power splitter can be a directional coupler or a multi-mode interferometer (Multi-mode Interferometer), but is not limited thereto.

[0043] Further, a first phase shifter 20 is placed on the first transmission waveguide 16, and a second phase shifter 21 is placed on the second transmission waveguide 17. By changing the voltage applied to the first phase shifter 20, the phase of the light transmitted in the first transmission waveguide 16 can be changed. By changing the voltage applied to the second phase shifter 21, the phase of the light transmitted in the second transmission waveguide 17 can be changed. Furthermore, the phase difference between the light in the first transmission waveguide 16 and the second transmission waveguide 17 can be changed, thereby changing the optical switching state. That is, the amount of optical signals output from the two optical output ports of the optical switch 11 can be changed. More specifically, taking the first phase shifter 20 as an example, the first phase shifter 20 is a heating resistor that can heat the first transmission waveguide 16. When the temperature of the first transmission waveguide 16 changes, the phase of the light transmitted in the first transmission waveguide 16 also changes.

[0044] In a non-limiting embodiment of the present invention, the voltage applied to the second phase shifter 21 remains unchanged. By changing the voltage applied to the first phase shifter 20, the optical switching state is changed. At this time, the voltage applied to the first phase shifter 20 can be referred to as the control voltage of the optical switch 11. By adjusting the control voltage, the amount of optical signals output from the two optical output ports of the optical switch 11 can be changed. It should be noted that the voltage applied to the first phase shifter 20 can also remain unchanged, and the optical switching state can be changed by changing the voltage applied to the second phase shifter 21. At this time, the voltage applied to the second phase shifter 21 can be referred to as the control voltage of the optical switch 11. The embodiments of the present invention do not limit this.

[0045] Further, when the phase difference between the light transmitted in the first transmission waveguide 16 and the second transmission waveguide 17 is (2π×X) (X is a natural number), the optical switch 11 is in the cross state. That is, the light input from the first optical input port 12 is all output from the second optical output port 19, and the light input from the second optical input port 13 is all output from the first optical output port 18. When the phase difference between the light transmitted in the first transmission waveguide 16 and the second transmission waveguide 17 is (π + 2π×X) (X is a natural number), the optical switch 11 is in the through state. That is, the light input from the first optical input port 12 is all output from the first optical output port 18, and the light input from the second optical input port 13 is all output from the second optical output port 19. When the optical switch 11 is in the cross state or the through state, the control voltage of the optical switch 11 is its switching point voltage. It should be noted that under multiple control voltages, the optical switch 11 can be in the cross state or the through state. When the optical switch 11 is in the cross state or the through state, the optical switch 11 is at the switching point. At this time, the control voltage of the optical switch 11 is the switching point voltage.

[0046] It should be noted that Figure 1Only one type of optical switch applicable to the embodiments of the present invention is shown. Figure 1 The optical switch 11 shown in Figure 1 is an optical switch based on a Mach-Zehnder interferometer. The optical switch in the embodiments of the present invention may also be an optical switch based on a Micro-Electro-Mechanical System (MEMS), but is not limited thereto. The embodiments of the present invention do not impose any restrictions on the type of the optical switch 11.

[0047] Reference Figure 2 , Figure 2 is a schematic diagram of a scenario of a method for calibrating the switching point voltage of an optical switch in the embodiments of the present invention.

[0048] Figure 2 An optical switch link including multiple optical switches is shown. Each optical switch is directly connected to an adjacent optical switch through an optical transmission path. The light source 201 provides an optical signal for the optical switch link. The optical signal is input from at least one optical input port of the first optical switch 21 of the optical switch link, and passes through the second optical switch 22, the third optical switch 23, the fourth optical switch 24, and the fifth optical switch 25, and is output from at least one optical output port of the fifth optical switch 25.

[0049] Furthermore, there are two optical transmission paths between two adjacent optical switches. For example, there are a first optical transmission path 211 and a second optical transmission path 212 between the first optical switch 21 and the second optical switch 22, and there is an optical path difference between the first optical transmission path 211 and the second optical transmission path 212.

[0050] Furthermore, the light source 201 can output light of different wavelengths. For example, the light source 201 can be a laser, and the wavelength of the output light can be adjusted; the light source 201 can also be a broadband light source, but is not limited thereto.

[0051] In a non-limiting embodiment of the present invention, the light source 201 can output an optical signal with a wavelength having a fixed step size. For example, the wavelength range of the optical signal is 1550 - 1560 nm, and the fixed step size is 0.1 nm. That is, the wavelength of the optical signal output by the light source 201 can be 1550 nm, 1550.1 nm, 1550.2 nm, ……

[0052] Furthermore, the optical detector 202 is connected to any optical output port of the fifth optical switch, and can measure and determine the optical power of the optical signal output after passing through the entire optical switch link. The optical signal output from the optical switch link is the optical signal output by the light source 201. The optical detector 202 can be an optical power meter or a spectrometer, but is not limited thereto.

[0053] Both the light source 201 and the optical detector 202 are connected to the terminal 204. The terminal can obtain the wavelength of the optical signal input into the optical switch link, and can also obtain the optical power of the optical signal output after the optical signal of each wavelength passes through the optical switch link.

[0054] Furthermore, each optical switch in the optical switch link is connected to the optical switch controller 203. The optical switch controller 203 includes multiple voltage sources. Each optical switch can be connected to different voltage sources of the optical switch controller. By changing the output voltage of each voltage source by the optical switch controller 203, the control voltage of each optical switch can be changed. The optical switch controller 203 can also be connected to the terminal 204, and can transmit the control voltage of each optical switch to the terminal 204, so that the terminal 204 can obtain the control voltage of each optical switch, and the optical power of the optical signal output from the optical switch link under each control voltage.

[0055] It should be noted that the embodiment of the present invention does not impose any restrictions on the number of optical switches in the optical switch link.

[0056] Reference Figure 3 , Figure 3 is a schematic flowchart of a method for calibrating an optical switch in an embodiment of the present invention.

[0057] Step S301: Provide an optical switch link, where the optical switch link includes a to-be-tested optical switch and an adjacent optical switch. The adjacent optical switch is an optical switch adjacent to the to-be-tested optical switch. There is a first optical transmission path and a second optical transmission path between the to-be-tested optical switch and the adjacent optical switch, and there is a preset optical path difference between the first optical transmission path and the second optical transmission path;

[0058] Step S302: Input an optical signal into the optical switch link, and apply multiple control voltages with a preset step size to the to-be-tested optical switch to determine the spectrogram of the optical switch link under each control voltage. The abscissa of the spectrogram of the optical switch link is the free spectral range, and the ordinate is the optical power;

[0059] Step S303: Calculate and determine the free spectral range value according to the optical path difference, and determine the optical power of the to-be-tested optical signal under each control voltage according to each spectrogram, where the to-be-tested optical signal is a part of the optical signal output from the optical switch link that has the free spectral range value;

[0060] Step S304: Use the control voltage when the optical power of the to-be-tested optical signal is the minimum as the switching point voltage of the to-be-tested optical switch.

[0061] In the specific implementation of step S301, the provided optical switch link may include an optical switch to be measured, and the optical switch to be measured may be any suitable optical switch. The optical switch to be measured may be an optical switch based on a Mach-Zehnder interferometer (MZI type optical switch), or may also be an optical switch including a silicon-based micro-ring resonator (MRR type optical switch), but is not limited thereto. In a non-limiting example, the optical switch to be measured may be Figure 1 the optical switch 11 shown, and specific reference may be made to Figure 1 the relevant description, which will not be elaborated herein.

[0062] Further, the optical switch link further includes an adjacent optical switch, and the adjacent optical switch refers to an optical switch adjacent to the optical switch to be measured. There are a first optical transmission path and a second optical transmission path between the optical switch to be measured and the adjacent optical switch, and an optical signal can be output from the optical switch to be measured and transmitted to the adjacent optical switch via the first optical transmission path and / or the second transmission path.

[0063] Wherein, there is a preset optical path difference between the first optical transmission path and the second optical transmission path, and the optical path difference can be set during the design process of the optical switch link.

[0064] Further, the first optical transmission path may be an optical waveguide, and the second optical transmission path may also be an optical waveguide. The first optical transmission path and the second optical transmission path may satisfy one or more of the following: different materials, different shapes, different sizes. More specifically, the different sizes of the first optical transmission path and the second optical transmission path may refer to the different lengths of the first optical transmission path and the second optical transmission path.

[0065] Further, in the specific implementation of step S302, the optical switch to be measured may be connected to any one of the voltage sources in the optical switch controller. Since the optical switch controller can change the control voltage of the optical switch to be measured, through the optical switch controller, a plurality of control voltages with a preset step size are applied to the optical switch to be measured. The preset step size may be a plurality of different values, or the preset step size may also be the same value, and the preset step size may be determined in advance.

[0066] Further, when applying each control voltage to the optical switch to be measured, an optical signal with a fixed step size wavelength output by a light source is used to scan the optical switch link, and the optical power of the optical signal after the optical signal of each wavelength passes through the optical switch link is determined by an optical detector. Since both the light source and the optical detector are connected to the terminal, a wave domain sweep spectrum diagram of the optical switch link can be obtained at the terminal. Figure 4A schematic diagram showing the spectral scan diagram in the optical domain of an optical switch link is presented. The abscissa of the spectral scan diagram in the optical domain is the wavelength of the optical signal output by the light source, and the ordinate is the optical power of the optical signal output after passing through the optical switch link. Each wavelength value in the spectral scan diagram in the optical domain corresponds one-to-one with the optical power value. That is, the spectral scan diagram in the optical domain describes the law of the optical power of the optical signal output from the optical switch link varying with the wavelength of the optical signal input into the optical switch link.

[0067] Furthermore, the spectral diagram of the optical switch link can be obtained based on the spectral scan diagram in the optical domain. The abscissa of the spectral diagram is the free spectral range, and the ordinate is the optical power. The free spectral range and the optical power in the spectral diagram correspond one-to-one. In a non-limiting embodiment, the terminal can perform a Fourier transform on the spectral scan diagram in the optical domain to obtain the spectral diagram of the optical switch link.

[0068] It should be noted that the abscissa of the spectral diagram obtained by performing a Fourier transform on the spectral scan diagram in the optical domain is 1 / FSR. In the embodiments of the present invention, the abscissa after the Fourier transform is further inverted to obtain the spectral diagram of the optical switch link in the embodiments of the present invention. The abscissa of the spectral diagram of the optical switch link is the free spectral range (FSR).

[0069] It should be noted that for each control voltage of the optical switch to be measured, the spectral diagram can be obtained through the above method. Thus, by sequentially applying multiple control voltages to the optical switch to be measured, multiple spectral diagrams of the optical switch link can be obtained at the terminal.

[0070] Continue to refer to Figure 3 , in the specific implementation of step S303, the free spectral range value of the optical signal to be measured can be determined according to the preset optical path difference first, and then the optical power of the optical signal to be measured can be determined in each spectral diagram.

[0071] It should be noted that the optical signals output from the two output ports of the optical switch to be measured are respectively transmitted to the adjacent optical switch through the first optical transmission path and the second optical transmission path. Due to the preset optical path difference between the first optical transmission path and the second optical transmission path, the optical signals transmitted to the adjacent optical switch through the first optical transmission path and the optical signals transmitted to the adjacent optical switch through the second optical transmission path will interfere. The optical signal generated by the interference is the optical signal to be measured. The optical signal to be measured has a specific free spectral range value, and the specific free spectral range value can be determined by the preset optical path difference.

[0072] Furthermore, since there is a corresponding relationship between the free spectral range value and the optical power in the spectral diagram, the optical power of the optical signal to be measured under each control voltage can be determined.

[0073] In a non-limiting embodiment, when the materials, shapes, widths, and heights of the first optical transmission path and the second optical transmission path are the same but the lengths are different, the following formula can be used to calculate the free spectral range value of the optical signal to be measured:

[0074]

[0075] where FSR is the free spectral range value of the optical signal to be measured, λ is the preset wavelength, n g is the group refractive index of the first optical transmission path and / or the second optical transmission path, and ΔL is the optical path difference between the first optical transmission path and the second optical transmission path. Among them, the preset wavelength λ can be the average wavelength of the light in the scanning optical switch link, but is not limited thereto.

[0076] Further, after calculating the free spectral range value of the optical signal to be measured, the optical power of the optical signal to be measured at each control voltage can be determined in the spectrogram obtained at each control voltage.

[0077] In the specific implementation of step S304, when the optical power of the optical signal to be measured is at the minimum value, the control voltage of the optical switch to be measured is the switching point voltage of the optical switch to be measured.

[0078] It should be noted that when the optical switch to be measured is at the switching point, the optical switch to be measured is in the cross or through state, and there is only one transmission path with optical signal transmission in the first transmission path and the second transmission path. Ideally, interference does not occur in adjacent optical switches. Therefore, the control voltage when the optical power of the optical signal to be measured is at the minimum value is the switching point voltage. It should be noted that due to the periodicity of the optical signal, the optical power of the optical signal to be measured is at the minimum value at multiple control voltages of the optical switch to be measured, that is, the optical switch to be measured has multiple switching point voltages.

[0079] It should also be noted that the "minimum value" referred to in the embodiments of the present invention refers to the optical power value of the optical signal to be measured when the switching point voltage is applied to the optical switch to be measured. Theoretically, the optical power of the optical signal to be measured at different switching point voltages should be the same, all being the "minimum value". However, in the actual calibration process, due to reasons such as operation errors and device errors, the optical power values of the optical signal to be measured at different switching point voltages may not be the same. The "minimum value" referred to in the embodiments of the present invention does not refer to the minimum value of the optical power at different switching point voltages, but refers to the minimum value of the optical power during the calibration of a switching point voltage.

[0080] As described above, in the embodiments of the present invention, there is no need to provide an optical detector after the optical switch to be measured, and only an optical detector needs to be provided at the output port of the optical switch link. Therefore, while accurately calibrating the switching point voltage of the optical switch to be measured, optical loss generated during the transmission of the optical signal in the optical switch link is avoided.

[0081] Refer to Figure 5 , Figure 5 which shows another method for calibrating the switching point voltage of an optical switch in an embodiment of the present invention. Among them, the optical switch link includes N optical switches, where N is a positive integer and N≥3. There is a third optical transmission path and a fourth optical transmission path between the i-th optical switch and the (i + 1)-th optical switch in the optical switch link. There is a preset i-th optical path difference between the third optical transmission path and the fourth optical transmission path, and when i takes different values, the values of the i-th optical path difference are also different. That is, the i-th optical path differences between every two optical switches in the optical switch link are different from each other.

[0082] Further, each optical switch in the optical switch link is respectively connected to a plurality of voltage sources of an optical switch controller. The voltage sources correspond to the optical switches one by one. For each optical switch, the optical switch controller can change the output voltage of its corresponding voltage source, thereby changing the control voltage of the optical switch. By Figure 5 the method shown, the switching point voltages of each optical switch in the optical switch link can be accurately calibrated in sequence.

[0083] In step S501, determine the switching point voltage of the first optical switch in the optical switch link and let i = 2. Specifically, the method shown in Figure 3 can be used to determine the switching point voltage of the first optical switch. For the specific content, reference can be made to the relevant description about Figure 3 and will not be elaborated here.

[0084] In step S502, apply the switching point voltage of each optical switch before the i-th optical switch to its control voltage. For example: when i = 2, that is, when determining the switching point voltage of the second optical switch, apply the switching point voltage of the first optical switch to its control voltage. When i = 3, when determining the switching point voltage of the third optical switch, apply the switching point voltage of the first optical switch and apply the switching point voltage of the second optical switch.

[0085] Since the control voltage of each optical switch before the i-th optical switch is its switching point voltage, that is, each optical switch before the i-th optical switch is in a through state or a cross state. Therefore, the optical signal input to the i-th optical switch is input from any one optical input port of the i-th optical switch, rather than being input from multiple optical input ports. Thus, the solution of the embodiment of the present invention can avoid the influence of the control voltages of the previous optical switches on the optical switching in the optical switch link when determining the switching point voltage of the i-th optical switch, making the determined switching point voltage of the i-th optical switch more accurate.

[0086] If \(i < N\), then steps S503 to S505 are sequentially executed. Specifically, in step S503, a plurality of control voltages with a preset step size are applied to the \(i\)-th optical switch to determine the \(i\)-th spectrogram of the optical switch link under each control voltage; in step S504, according to the \(i\)-th optical path difference, the free spectral range value of the \(i\)-th optical signal to be measured is determined, and the optical power of the \(i\)-th optical signal to be measured under each control voltage is determined according to each \(i\)-th spectrogram, where the \(i\)-th optical signal to be measured is a part of the optical signals output from the optical switch link and having the \(i\)-th free spectral range value; in step S505, the control voltage when the optical power of the \(i\)-th optical signal to be measured is the minimum value is used as the switching point voltage of the \(i\)-th optical switch.

[0087] Reference Figure 6 , Figure 6 shows the spectrogram of an optical switch link including 5 optical switches. Among them, there are two optical transmission paths between the first optical switch and the second optical switch, and there is a preset first optical path difference \(\Delta L1\) between the two optical transmission paths; there is a preset second optical path difference \(\Delta L2\) between the two optical transmission paths between the second optical switch and the third optical switch; there is a preset third optical path difference \(\Delta L3\) between the two optical transmission paths between the third optical switch and the fourth optical switch; there is a preset fourth optical path difference \(\Delta L4\) between the two optical transmission paths between the fourth optical switch and the fifth optical switch. And the first optical path difference, the second optical path difference, the third optical path difference, and the fourth optical path difference are not the same as each other. The \(i\)-th free spectral range value can be calculated and determined respectively according to the \(i\)-th optical path difference, and then the optical power of the \(i\)-th optical signal can be determined from the \(i\)-th spectrogram. Figure 5 The optical power 1 of the first optical signal to be measured, the optical power 2 of the second optical signal to be measured, the optical power 3 of the third optical signal to be measured, and the optical power 4 of the fourth optical signal to be measured are reflected in the shown spectrogram. When determining the switching point voltage of the \(i\)-th optical switch, the \(i\)-th free spectral range value can be calculated and determined according to the \(i\)-th optical path difference. The first optical path difference, the second optical path difference, the third optical path difference, and the fourth optical path difference are not the same as each other. Therefore, the optical power of the \(i\)-th optical signal to be measured with the \(i\)-th free spectral range value can be accurately determined in the spectrogram, and then the optical power of the \(i\)-th optical signal to be measured is determined in the spectrogram under each different control voltage.

[0088] For more specific content about steps S503 to S505, reference can be made to the relevant descriptions of steps S302 to S304 above, which will not be elaborated here.

[0089] Continue to refer to Figure 5 , after executing step S505, the switching point voltage of the \(i\)-th optical switch can be obtained, where \(i\geq2\) and \(i < N\).

[0090] Further, let i = i + 1, return to step S502, and repeat the above steps S502 to S505 to sequentially determine the switching point voltages of each optical switch in the optical switch link except the Nth optical switch.

[0091] Further, when i = N, steps S506 to S507 can be sequentially executed. In the specific implementation of step S506, a plurality of control voltages are applied to the Nth optical switch to obtain the optical power of the optical signal passing through the optical switch link and output from any output port of the Nth optical switch under each control voltage. The optical signal passing through the optical switch link and output from the output port of the Nth optical switch is the optical signal output from the optical switch link. In the specific implementation of step S607, the control voltages when the optical power of the optical signal output from the optical switch link is at a maximum value and a minimum value are used as the switching point voltages of the Nth optical switch.

[0092] Reference Figure 7 , Figure 7 shows a schematic diagram of the "voltage - optical power" response curve of the optical signal output from the optical switch link. Specifically, the optical detector can measure and determine the optical power of the optical signal output from the optical switch link under each control voltage. Since both the optical detector and the optical switch controller are connected to the terminal, the terminal can obtain the "voltage - optical power" response curve of the optical signal output from the optical switch link, where the abscissa is the control voltage of the Nth optical switch and the ordinate is the optical power of the optical signal output from the optical switch link. By adjusting the control voltage of the Nth optical switch, the optical power of the optical signal output from the optical switch link under each control voltage can be obtained. The control voltages when the optical power is at a maximum value and a minimum value are the switching point voltages of the Nth optical switch.

[0093] It should be noted that when the optical switch link includes only two optical switches, the first optical switch can be used as the optical switch to be measured, and the method shown in Figure 3 is used to calibrate the switching point operating voltage of the first optical switch, and then the steps S506 to S507 in Figure 5 are used to calibrate the switching point operating voltage of the second optical switch. Specifically, the switching point voltage of each optical switch before the first optical switch is applied; a plurality of control voltages are applied to the second optical switch to obtain the optical power of the optical signal output from the optical switch link under each control voltage, and the control voltages when the optical power of the optical signal output from the optical switch link is at a maximum value and a minimum value are used as the switching point voltages of the second optical switch.

[0094] Thus, through Figure 5The method for calibrating the switching point voltage of an optical switch shown can accurately determine the switching point voltage of each optical switch in an optical switch link. Compared with the prior art, the embodiment of the present invention only needs to measure the optical power of the optical signal output from the optical switch link, that is, only needs to set an optical detector at the output interface of the last optical switch in the optical switch link, without setting an optical detector behind each optical switch, reducing the operation difficulty of calibrating the switching point voltage and avoiding additional optical loss when the optical signal is transmitted in the optical switch link.

[0095] Further, after determining the multiple switching point voltages of each optical switch in the optical switch link, the states of the respective optical switches at their respective switching point voltages can also be determined. It should be noted that the state refers to whether the optical switch is in a cross state or a through state. It should also be noted that due to the periodicity of the optical signal, for the multiple switching point voltages of each optical switch, the cross state and the through state of the optical switch alternate at adjacent switching point voltages. Only by determining the state of the optical switch at one of the switching point voltages, the states of the optical switch at all switching point voltages can be determined.

[0096] Specifically, any one of the multiple switching point voltages of each optical switch is selected as the first voltage of the optical switch, and the first voltage is applied to each optical switch.

[0097] Further, the state of the first optical switch can be determined first.

[0098] Specifically, when the control voltage of each optical switch is the first voltage, the transmission time of the optical signal through the optical switch link is measured and recorded as the first transmission time of the first optical switch. That is, the first transmission time is the transmission time of the optical signal in the optical switch link when the control voltage of each optical switch is its respective first voltage.

[0099] Further, the second voltage of the first optical switch and the second optical switch is applied, and the transmission time of the optical signal in the optical switch link at this time is measured and recorded as the second transmission time of the first optical switch. Wherein, the second voltage refers to the switching point voltage adjacent to the first voltage in value among the multiple switching point voltages for the same optical switch. It should be noted that the control voltages of the other optical switches in the optical switch link remain unchanged at this time and are still their respective first voltages.

[0100] Further, compare the first transmission time and the second transmission time of the first optical switch. It should be noted that when measuring the first transmission time and the second transmission time of the first optical switch, the control voltages of other optical switches are all their respective first voltages. Therefore, the states of other optical switches remain unchanged. Since when the control voltage of the first optical switch is adjusted to the second voltage of the first optical switch, the control voltage of the second optical switch also changes from the first voltage of this optical switch to the second voltage, the output interface from which the optical signal is output from the second optical switch remains unchanged. Thus, the transmission path of the optical signal in the optical switch link after being output from the second optical switch remains unchanged. Therefore, the change in the first transmission time and the second transmission time of the first optical switch only depends on whether the optical signal is transmitted in the first optical transmission path or in the second optical transmission path.

[0101] Specifically, if the first transmission time is greater than the second transmission time, it indicates that the optical signal passes through the longer one of the first transmission path and the second transmission path under the first voltage. Since the lengths of the first transmission path and the second transmission path are preset, the output interface from which the optical signal is output from the first optical switch under the first voltage can be determined.

[0102] Further, determine the input interface to which the optical signal is input to the first optical switch, that is, determine the input interface where the first optical switch is connected to the light source. According to the input interface to which the optical signal is input to the first optical switch and the output interface from which the optical signal is output from the first optical switch under its first voltage, the state of the first optical switch under its first voltage can be determined. Thus, the state of the first optical switch under its second voltage can be determined. If the first voltage is the switching point voltage in the cross state, then the second voltage is the switching point voltage in the through state; if the first voltage is the switching point voltage in the through state, then the second voltage is the switching point voltage in the cross state.

[0103] Further, referring to the above method, the states of the first to the (M - 1)th optical switches in the optical switch link under their respective first voltages can be determined in sequence.

[0104] Specifically, the respective first voltages can be applied to each optical switch, and the first transmission time of the jth optical switch can be measured. Then, the control voltages of the jth optical switch and the (j + 1)th optical switch are adjusted to their respective second voltages, the control voltages of other optical switches remain unchanged, and the second transmission time of the jth optical switch is measured. That is, the second transmission time is the transmission time of the optical signal in the optical switch link when the control voltages of the jth optical switch and the (j + 1)th optical switch are their respective second voltages and the control voltages of other optical switches are still their respective first voltages.

[0105] Further, compare the first transmission time and the second transmission time of the j-th optical switch. Since the control voltages of other optical switches are always the first voltage, the input interface where the optical signal is input to the j-th optical switch and the output interface where the optical signal is output from the (j + 1)-th optical switch remain unchanged. The changes in the first transmission time and the second transmission time of the j-th optical switch only depend on the change in the transmission path between the j-th optical switch and the (j + 1)-th optical switch. Since the length of the optical transmission path between the j-th optical switch and the (j + 1)-th optical switch is preset, the output interface where the optical signal is output from the j-th optical switch can be determined.

[0106] Further, according to the states of each optical switch before the j-th optical switch under their respective first voltages and the input interface where the optical signal is input to the optical switch link, the input interface where the optical signal is input to the j-th optical switch under the first voltage can be determined. Thus, according to the input interface where the optical signal is input to the j-th optical switch under the first voltage and the output interface where the optical signal is output from the j-th optical switch, the state of the j-th optical switch under the first voltage can be determined.

[0107] Further, for the M-th optical switch, apply the respective first voltages to each optical switch of the optical switch link. Since the states of the first optical switch to the (M - 1)-th optical switch under their respective first voltages have been determined, according to the input interface where the optical signal is input to the optical switch link, the input interface where the optical signal is input to the M-th optical switch can be determined.

[0108] Further, determine the output interface where the optical signal is output from the optical switch link when the first voltage is applied to the M-th optical switch, and the state of the M-th optical switch under the first voltage can be determined.

[0109] Thus, through the method of the embodiment of the present invention, it can be determined whether each optical switch in each optical switch link is in the through state or the cross state under each switching point voltage.

[0110] It should be noted that the embodiment of the present invention does not impose any restrictions on the measurement method of the first transmission time and the second transmission time.

[0111] Refer to Figure 8 , Figure 8 which is a schematic structural diagram of a system for calibrating the switching point voltage of an optical switch in the embodiment of the present invention. The system for calibrating the switching point voltage of an optical switch includes:

[0112] An optical switch link 81, where the optical switch link includes an optical switch under test and an adjacent optical switch. The adjacent optical switch is an optical switch adjacent to the optical switch under test. There is a first optical transmission path and a second optical transmission path between the optical switch under test and the adjacent optical switch, and there is a preset optical path difference between the first optical transmission path and the second optical transmission path;

[0113] An optical switch controller 82, configured to apply a plurality of control voltages with a preset step size to the optical switch under test;

[0114] A light source 83, configured to input an optical signal into the optical switch link;

[0115] A terminal 84, configured to determine a spectrogram of the optical switch link under each control voltage according to the plurality of control voltages applied by the optical switch controller. The abscissa of the spectrogram of the optical switch link is the free spectral range, and the ordinate is the optical power. Determine the free spectral range value according to the optical path difference, and determine the optical power of the optical signal under test under each control voltage according to each spectrogram. Use the control voltage when the optical power of the optical signal under test is the minimum as the switching point voltage of the optical switch under test. Among them, the optical signal under test is a part of the optical signal output from the optical switch link that has the free spectral range value. The terminal includes a processor. The terminal can be a calculator, a server, etc., but is not limited thereto.

[0116] Further, the light source 83 can also be configured to input optical signals with different wavelengths into the optical switch link when applying each control voltage with a preset step size to the optical switch under test, so as to obtain a wavelength-domain sweep spectrogram of the optical switch link. Among them, the abscissa of the wavelength-domain sweep spectrogram is the wavelength, and the ordinate is the optical power. The light source can be a laser or a broadband light source, but is not limited thereto.

[0117] Further, the system further includes: an optical detector (not shown in the figure), and the optical detector is configured to measure the optical power of the optical signal output from the optical switch link 81. The optical detector can be a spectrometer or an optical power meter, but is not limited thereto. After measuring the optical power, the optical detector can transmit the optical power to the terminal in real time.

[0118] Further, the terminal 84 is further configured to determine a spectrogram of the optical switch link according to the wavelength-domain sweep spectrogram of the optical switch link.

[0119] Further, the terminal 84 may also be integrated with a vector network analyzer (not shown in the figure). The optical switch controller 82 is further configured to select any one of the multiple switching point voltages of each optical switch as the first voltage of each optical switch, apply the first voltage of each optical switch respectively, and apply the respective second voltages to the j-th optical switch and the (j + 1)-th optical switch; the terminal 84 is further configured to measure and determine the first transmission time and the second transmission time of the j-th optical switch; compare the first transmission time and the second transmission time of the j-th optical switch, and determine the output interface through which the optical signal outputs from the j-th optical switch when the control voltage of the j-th optical switch is its first voltage according to the comparison result; determine the state of the j-th optical switch at its first voltage according to the input interface through which the optical signal inputs to the j-th optical switch and the output interface through which the optical signal outputs from the j-th optical switch when the control voltage of the j-th optical switch is its first voltage; determine the input interface through which the optical signal inputs to the M-th optical switch at its first voltage according to the state of each optical switch before the M-th optical switch at its respective first voltage and the input interface through which the optical signal inputs to the first optical switch; determine the state of the M-th optical switch at its first voltage according to the input interface through which the optical signal inputs to the M-th optical switch and the output interface through which the optical signal outputs from the M-th optical switch at the first voltage of the M-th optical switch; wherein, the first voltage is any one of the multiple switching point voltages of each optical switch, and the second voltage is the switching point voltage adjacent to the first voltage in terms of value among the multiple switching point voltages of the same optical switch.

[0120] It should be noted that the first transmission time and the second transmission time may also be measured and determined by a vector network analyzer external to the terminal 84, and then the first transmission time and the second transmission time are transmitted to the terminal 84, and then the terminal 84 compares the first transmission time and the second transmission time.

[0121] It can be understood that the terminal in the embodiment of the present invention may include a memory and a processor. A computer program capable of running on the processor is stored on the memory. When the processor runs the computer program, it executes the steps of the above method. The terminal includes, but is not limited to, terminal devices such as computers, tablet computers, and servers.

[0122] For more information about the principle, specific implementation, working mode, and beneficial effects of the system for calibrating the switching point voltage of the optical switch, reference may be made to the relevant description of the method for calibrating the switching point voltage of the optical switch described above, and details are not repeated here.

[0123] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A method for calibrating the switching point voltage of an optical switch, characterized in that, The method includes: Providing an optical switch link, the optical switch link including an optical switch to be measured and an adjacent optical switch, the adjacent optical switch being an optical switch adjacent to the optical switch to be measured, there being a first optical transmission path and a second optical transmission path between the optical switch to be measured and the adjacent optical switch, and there being a preset optical path difference between the first optical transmission path and the second optical transmission path; Inputting an optical signal into the optical switch link and applying a plurality of control voltages with a preset step size to the optical switch to be measured to determine the spectrogram of the optical switch link under each control voltage, the abscissa of the spectrogram of the optical switch link being the free spectral range and the ordinate being the optical power; Calculating and determining the free spectral range value according to the optical path difference, and determining the optical power of the optical signal to be measured under each control voltage according to each spectrogram, wherein the optical signal to be measured is a part of the optical signal output from the optical switch link and having the free spectral range value; Taking the control voltage when the optical power of the optical signal to be measured is at a minimum as the switching point voltage of the optical switch to be measured.

2. The method for calibrating the switching point voltage of an optical switch according to claim 1, characterized in that Determining the spectrogram of the optical switch link under each control voltage includes: When applying each control voltage with a preset step size to the optical switch to be measured, inputting optical signals with different wavelengths into the optical switch link to obtain a wave domain sweep spectrogram of the optical switch link, wherein the abscissa of the wave domain sweep spectrogram is the wavelength and the ordinate is the optical power; Determining the spectrogram of the optical switch link according to the wave domain sweep spectrogram of the optical switch link.

3. The method for calibrating the switching point voltage of an optical switch according to claim 2, wherein Determining the spectrogram of the optical switch link according to the wave domain sweep spectrogram of the optical switch link includes: Performing a Fourier transform on the wave domain sweep spectrogram to obtain the spectrogram of the optical switch link.

4. The method for calibrating the switching point voltage of an optical switch according to claim 1, characterized in that The optical switch link includes N optical switches, the optical switch to be measured being the first optical switch in the optical switch link, the adjacent optical switch being the second optical switch, there being a third optical transmission path and a fourth optical transmission path between the i-th optical switch and the (i + 1)-th optical switch in the optical switch link, there being a preset i-th optical path difference between the third optical transmission path and the fourth optical transmission path, the value of the i-th optical path difference being different from the value of the optical path difference, and when i takes different values, the value of the i-th optical path difference is also different; the method further includes: sequentially determining the switching point voltages of the second optical switch to the (N - 1)-th optical switch; Wherein, determining the switching point voltage of the i-th optical switch includes: Applying the switching point voltage of each optical switch before the i-th optical switch to it; Applying a plurality of control voltages with the preset step size to the i-th optical switch to determine the i-th spectrogram of the optical switch link under each control voltage; Determining the i-th free spectral range value according to the i-th optical path difference, and determining the optical power of the i-th optical signal to be measured under each control voltage according to each i-th spectrogram, wherein the i-th optical signal to be measured is a part of the optical signal output from the optical switch link and having the i-th free spectral range value; Taking the control voltage when the optical power of the i-th optical signal to be measured is at a minimum as the switching point voltage of the i-th optical switch; Among them, the abscissa of the i-th spectrogram of the optical switch link is the free spectral range, and the ordinate is the optical power; i and N are positive integers, i≥2, N≥3, i<N.

5. The method for calibrating the switching point voltage of an optical switch according to claim 1, wherein The optical switch link includes M optical switches, the optical switch to be measured is the first optical switch in the optical switch link, and the adjacent optical switch is the second optical switch. The method further includes: Applying the switching point voltage to each optical switch before the M-th optical switch; Applying a plurality of control voltages to the M-th optical switch to obtain the optical power of the optical signal output from the optical switch link under each control voltage; Taking the control voltages when the optical power of the optical signal output from the optical switch link is at a maximum value and a minimum value as the switching point voltage of the M-th optical switch, where M is a positive integer and M≥2.

6. The method for calibrating the switching point voltage of an optical switch according to claim 1, characterized in that, The first optical transmission path is an optical waveguide, the second optical transmission path is an optical waveguide, and the first optical transmission path and the second optical transmission path satisfy one or more of the following: Different materials, different shapes, different sizes.

7. The method for calibrating the switching point voltage of an optical switch according to claim 1, wherein When the materials, shapes, widths, and heights of the first optical transmission path and the second optical transmission path are the same but the lengths are different, the following formula is used to calculate the free spectral range value: where FSR is the free spectral range value, λ is the preset wavelength, n g is the group refractive index of the first optical transmission path or the second optical transmission path, and ΔL is the optical path difference.

8. The method for calibrating the switching point voltage of an optical switch according to claim 5, characterized in that, Each optical switch in the optical switch link has a plurality of switching point voltages, and each optical switch has at least one input interface and at least one output interface. The method further includes: Selecting any switching point voltage from the plurality of switching point voltages of each optical switch as the first voltage of each optical switch; Sequentially determining the state of the j-th optical switch at its first voltage and determining the state of the M-th optical switch at its first voltage, where j is a positive integer and j<M; Sequentially determining the state of the j-th optical switch at its first voltage includes: Applying the first voltage of each optical switch to each optical switch respectively, and measuring and determining the first transmission time of the j-th optical switch; Adjusting the control voltages of the j-th optical switch and the j+1-th optical switch to their respective second voltages, and measuring and determining the second transmission time of the j-th optical switch. The second voltage is the switching point voltage adjacent to the first voltage value among the plurality of switching point voltages of the same optical switch; Comparing the first transmission time and the second transmission time of the j-th optical switch, and determining the output interface through which the optical signal outputs from the j-th optical switch when the control voltage of the j-th optical switch is its first voltage according to the comparison result; Determining the state of the j-th optical switch at its first voltage according to the input interface through which the optical signal inputs to the j-th optical switch and the output interface through which the optical signal outputs from the j-th optical switch when the control voltage of the j-th optical switch is its first voltage; Determining the state of the M-th optical switch at its first voltage includes: Applying the first voltage of each optical switch to each optical switch respectively; Determining the input interface through which the optical signal inputs to the M-th optical switch at its first voltage according to the state of each optical switch before the M-th optical switch at their respective first voltages and the input interface through which the optical signal inputs to the first optical switch; Determine the state of the Mth optical switch at its first voltage based on the optical signal input to the input interface of the Mth optical switch and output from the output interface of the Mth optical switch at the first voltage of the Mth optical switch.

9. The method for calibrating the switching point voltage of an optical switch according to claim 1, characterized in that The optical switch to be measured is an optical switch based on a Mach-Zehnder interferometer or an optical switch based on a microelectromechanical system.

10. A system for calibrating the switching point voltage of an optical switch, characterized in that, The system includes: An optical switch link, the optical switch link including an optical switch to be measured and an adjacent optical switch, the adjacent optical switch being an optical switch adjacent to the optical switch to be measured, and there being a first optical transmission path and a second optical transmission path between the optical switch to be measured and the adjacent optical switch, and a preset optical path difference between the first optical transmission path and the second optical transmission path; An optical switch controller for applying a plurality of control voltages with a preset step size to the optical switch to be measured; A light source for inputting an optical signal into the optical switch link; A terminal for determining the spectrogram of the optical switch link at each control voltage according to the plurality of control voltages applied by the optical switch controller, the abscissa of the spectrogram of the optical switch link being the free spectral range, the ordinate being the optical power, determining the free spectral range value according to the optical path difference, and determining the optical power of the optical signal to be measured at each control voltage according to each spectrogram, and taking the control voltage when the optical power of the optical signal to be measured is the minimum as the switching point voltage of the optical switch to be measured, where the optical signal to be measured is a partial optical signal having the free spectral range value among the optical signals output from the optical switch link.

11. The system for calibrating the switching point voltage of an optical switch according to claim 10, characterized in that: The light source is further configured to input optical signals with different wavelengths into the optical switch link when applying each control voltage with the preset step size to the optical switch to be measured, so as to obtain a wavelength-domain sweep spectrogram of the optical switch link, where the abscissa of the wavelength-domain sweep spectrogram is the wavelength and the ordinate is the optical power; Wherein, the terminal is further configured to determine the spectrogram of the optical switch link according to the wavelength-domain sweep spectrogram of the optical switch link.

12. The system for calibrating the switching point voltage of an optical switch according to claim 10, wherein The system further includes: an optical detector, and the optical detector is configured to measure the optical power of the optical signal output from the optical switch link.

13. The system for calibrating the switching point voltage of an optical switch according to claim 10, characterized in that, The optical switch link includes M optical switches, and each optical switch in the optical switch link has a plurality of switching point voltages; The optical switch controller is further configured to select any one of the plurality of switching point voltages of each optical switch as the first voltage of each optical switch, apply the first voltage of each optical switch to each optical switch respectively, and apply the respective second voltages to the jth optical switch and the j + 1th optical switch respectively; The terminal is further configured to measure and determine the first transmission time and the second transmission time of the jth optical switch; compare the first transmission time and the second transmission time of the jth optical switch, and determine the output interface from which the optical signal outputs from the jth optical switch when the control voltage of the jth optical switch is its first voltage according to the comparison result; determine the state of the jth optical switch at its first voltage according to the input interface to which the optical signal is input to the jth optical switch and the output interface from which the optical signal outputs from the jth optical switch when the control voltage of the jth optical switch is its first voltage. Determine the input interface of the M-th optical switch for the optical signal according to the states of each optical switch before the M-th optical switch at their respective first voltages and the input interface of the optical signal input to the first optical switch; determine the state of the M-th optical switch at its first voltage according to the input interface of the optical signal input to the M-th optical switch and the output interface output from the M-th optical switch at the first voltage of the M-th optical switch; Wherein, the first voltage is any one of the multiple switching point voltages of each optical switch, and the second voltage is the switching point voltage adjacent in value to the first voltage among the multiple switching point voltages of the same optical switch.

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