WO2019109816A1

WO2019109816A1 - Wavelength alignment method, apparatus and system for silicon-based dual microring optical switch

Info

Publication number: WO2019109816A1
Application number: PCT/CN2018/117121
Authority: WO
Inventors: 李丹萍; 李彦波; 邱辞源; 朱庆明; 张红霞
Original assignee: 华为技术有限公司
Priority date: 2017-12-06
Filing date: 2018-11-23
Publication date: 2019-06-13
Also published as: CN109884809A; CN109884809B

Abstract

A wavelength alignment method, apparatus (100) and system for a silicon-based dual micro-ring optical switch (1021). The method comprises: first, determining one microring of a dual microring as a primary ring, and the other microring as a secondary ring, wherein an input optical power of the primary ring is not less than an input optical power of the secondary ring; and then executing the following two steps at least once to complete wavelength alignment: determining a first thermal adjustment power of the primary ring, wherein the first thermal adjustment power is a thermal adjustment power that maximizes a monitoring optical power of the primary ring, and setting a thermal adjustment electrode corresponding to the primary ring to be the first thermal adjustment power; and determining a second thermal adjustment power of the secondary ring, wherein the second thermal adjustment power is a thermal adjustment power that minimizes the monitoring optical power of the primary ring, and setting a thermal adjustment electrode corresponding to the secondary ring to be the second thermal adjustment power. The wavelength alignment method is flexible and suitable for a variety of scenarios comprising a plurality of optical signal inputs.

Description

Wavelength alignment method, device and system for silicon-based dual micro-ring optical switch

This application claims to be submitted to the State Intellectual Property Office of China on December 6, 2017, application number 201711278862.0, and the Chinese patent application titled "Wavelength Alignment Method, Device and System for Silicon-based Dual Micro-ring Optical Switch" is preferred. The entire contents are hereby incorporated by reference.

Technical field

This invention relates to the field of optics, and more particularly to wavelength alignment techniques for silicon based dual microring optical switches.

Background technique

As the volume of data centers continues to grow, traditional electrical switches have problems of limited bandwidth and high power consumption, which has become a bottleneck in the development of large-scale data centers. Microring-based silicon-based optical switches have the advantage of mentioning small, low power consumption. In addition, the high-order microring structure can further increase the bandwidth and out-of-band rejection ratio of the optical switch. Therefore, microring-based silicon-based switches are considered an ideal alternative to large-scale data center applications. However, the operating wavelength of the microring (ie, the resonant wavelength) is extremely sensitive to process errors and changes in the external environment such as temperature. Microrings, especially high-order microrings, require real-time resonant wavelength alignment to ensure that the microrings are always operating near the input wavelength.

At present, the microring structure applied to the optical switch is mainly a second-order microring, which is also called a double microring. Currently, for dual micro-ring optical switches, the current wavelength alignment method requires the input signal to be a single-ended input (ie, only a single input optical signal), and the port position of the input signal is known. Second, the current wavelength alignment method accomplishes the alignment of the wavelengths by the following two steps:

First, the thermal power of the two micro-rings is adjusted one by one to the maximum monitoring optical power of each ring, so that the resonant wavelengths of the two micro-rings are consistent with the input wavelength;

Then, according to the relationship between the phase of the input optical signal and the micro-ring monitoring optical power corresponding to the non-optical input end (ie, the sum of the phases of the input optical signals in the two micro-rings is equal to the average of the differences between their phases and both When it is equal to zero, the monitoring optical power of the micro-ring corresponding to the input end of the optical signal is the largest. By repeatedly adjusting the thermal power of the two micro-rings to change the phase of the optical signal in the micro-ring, the input of the optical signal is corresponding. The micro-ring optical power is the largest, and the thermal power of the two micro-rings is set to correspond to two thermal power values;

By repeatedly performing the above two steps, the resonant wavelengths of the two microrings are always maintained near the input wavelength.

This existing method is not flexible enough to meet the optical switch requirements in data center applications. For example, there are variations in the input or multiple input signals at the same time.

Summary of the invention

Embodiments of the present invention provide a wavelength alignment method, apparatus, and system for aligning a resonant wavelength of a silicon-based dual micro-ring optical switch to solve the problem in the prior art that the input terminal cannot be applied. Problems with multiple scenes.

In a first aspect, an embodiment of the present invention provides a wavelength alignment method. The method comprises the following steps:

First, it is determined that one microring of the dual microring is a primary ring, and the other microring is a secondary ring, and an input optical power of the primary ring is not less than an input optical power of the secondary ring;

Then, execute sequentially:

A1: determining a first thermal power of the primary ring, where the first thermal power is a thermal power value that maximizes a monitoring optical power of the primary ring, and setting a thermal adjustment electrode corresponding to the primary ring For the first thermal power;

A2: determining a second thermal power of the secondary ring, where the second thermal power is a thermal power value that minimizes a monitoring optical power of the primary ring, and setting a thermal adjustment electrode corresponding to the secondary ring For the second heat regulation power.

The method utilizes the law that the monitoring optical power corresponding to the relatively high power microring in the double microring structure changes with the phase shift of the two microrings, and the heat of the two microrings is adjusted through a series of steps. The power is adjusted such that the phase shift of the two microrings approaches zero or even zero. Thereby the resonant wavelengths of the two microrings are as close as possible to the input wavelength value, even equal to the input wavelength. The method provided by the present invention does not limit the number of input optical signals, and is also applicable to the case where the input port changes from one port to another.

The above steps A1 and A2 can be performed in different specific ways.

In a possible implementation, the primary ring is thermally tuned with a set of thermal power values, and the thermal power value of the set of thermal power values that maximizes the monitored optical power of the primary ring is determined. The first thermal power (ie, performing the A1 step); thermally adjusting the secondary ring with another set of thermal power values, and determining that the monitoring of the primary ring is performed in the other set of thermal power values The minimum thermal power value of the optical power is the second thermal power (ie, the A2 step is performed). Optionally, after the steps A1 and A2 are performed, the A1 and A2 steps are performed one or more times to improve the accuracy of wavelength alignment. It should be noted that the precise alignment of the wavelength can be achieved usually by two to three repetitions. The present invention does not limit the number of actual repetitions.

In another possible implementation, a set of thermal power values are used to simultaneously thermally adjust the primary ring and the secondary ring, and determine a monitoring optical power of the primary ring in the set of thermal power values. The maximum thermal power value is the first thermal power (ie, performing the A1 step); the other set of thermal power values are used to thermally modulate the secondary ring, and determining the set of thermal power values The minimum thermal power value of the monitoring optical power of the primary ring is the second thermal power (ie, performing the A2 step); and the set of thermal power values is used to thermally adjust the primary ring, and determining the The thermal power value of the set of thermal power values that maximizes the monitoring optical power of the primary ring is the third thermal power (ie, the A1 step is performed again by using different thermal modulation modes). This way, by first coarse tuning the primary and secondary rings, the resonant wavelengths of the two microrings are close to the target wavelength (ie, the input wavelength). Then, the primary ring and the secondary ring are separately adjusted to further make the resonant wavelengths of the two microrings substantially close to each other, even equal to the target wavelength. In order to improve the accuracy, step A1 or A1 and A2 may be repeatedly executed. When the adjustment step size of the adjustment power value is specifically selected, a consistent step size can be adopted. It is also possible to perform different adjustment steps in such a way that the adjustment step size is smaller and smaller, that is to say, the adjustment step selected by the current execution step is smaller than the adjustment step length selected in the previous step. Doing so can reduce the time it takes for the wavelength alignment method.

In a second aspect, an embodiment of the present invention provides a wavelength aligning device. The apparatus includes a processor, a transmitter, and a receiver. The receiver is configured to acquire monitoring optical power of the silicon-based dual micro-ring optical switch. The processor is configured to perform the steps of determining a primary ring and a secondary ring in the method of the first aspect, and adjusting a thermal power of the primary ring and the secondary ring. The transmitter is configured to send a control command to the silicon-based dual micro-ring optical switch, so that the thermal adjustment electrode of the primary or secondary ring is set to a certain thermal power. That is, the transmitter and receiver are used to perform information interaction between the wavelength aligning device and the silicon-based dual micro-ring optical switch. For example, monitor optical power information. Another example is the thermal power setting control command. It should be noted that the silicon-based dual micro-ring optical switch is not part of the aligning wavelength device, but is the object of the wavelength aligning device interaction. Specifically, the silicon-based dual micro-ring optical switch can be a single dual micro-ring optical switch, or can be an optical switch structure composed of multiple double micro-rings. The processor is operative to perform all of the steps of the first aspect or any one of the implementations of the first aspect other than the transmitting and receiving actions.

In a third aspect, an embodiment of the present invention provides a computer storage medium, configured to store computer software instructions for use in the second aspect of the aligning apparatus, comprising: performing any of the foregoing second aspect or the second aspect The program designed.

In a fourth aspect, an embodiment of the present invention provides a wavelength alignment system. The system includes a silicon based chip and a wavelength alignment device. Wherein, the silicon-based chip comprises a plurality of silicon-based dual micro-ring optical switches. The wavelength aligning device is the wavelength aligning device of the second aspect or any implementation thereof. Specifically, the wavelength aligning device receives the monitor optical power of the plurality of silicon-based dual micro-ring optical switches of the silicon-based chip through a receiver, and sends one or more control commands to the silicon-based chip through the transmitter. A plurality of silicon-based dual micro-ring optical switches, the one or more control commands being used to set the thermal power. Further, the processor in the wavelength aligning device is further configured to: determine a wavelength alignment order for the plurality of silicon-based dual micro-ring optical switches according to a structure of the silicon-based chip. By determining the microrings that need to be aligned and the alignment sequence, the efficiency and accuracy of the alignment can be improved.

DRAWINGS

1 is a possible hardware structure diagram of a wavelength alignment system provided by the present invention;

2 is a schematic structural view of the dual micro-ring switch 1021 of FIG. 1;

3 is a schematic flow chart of wavelength alignment provided by the present invention;

4 is a schematic diagram showing a relationship between a possible primary ring monitoring optical power and a dual microring phase according to the present invention;

FIG. 5 is a schematic flowchart of wavelength alignment provided by Embodiment 1 of the present invention; FIG.

FIG. 6 is a schematic diagram of changes in monitoring optical power of a primary ring according to Embodiment 1 of the present invention; FIG.

FIG. 7 is a schematic flowchart of wavelength alignment according to Embodiment 2 of the present invention; FIG.

FIG. 8 is a schematic diagram of changes in monitoring optical power of a primary ring according to Embodiment 2 of the present invention; FIG.

FIG. 9 is a schematic flowchart of wavelength alignment provided by Embodiment 3 of the present invention; FIG.

FIG. 10 is a structural diagram of a possible device according to an embodiment of the present invention.

Detailed ways

The network architecture and the service scenario described in the embodiments of the present invention are intended to more clearly illustrate the technical solutions of the embodiments of the present invention, and do not constitute a limitation of the technical solutions provided by the embodiments of the present invention. A person skilled in the art can understand that the technical solutions provided by the embodiments of the present invention are applicable to similar technical problems as the network architecture evolves and new service scenarios appear.

General overview:

An optical switch (OS) is an optical device having one or more selectable transmission windows for mutually converting or logically operating optical signals in an optical transmission line or an integrated optical path. The basic form of the optical switch is 2×2, that is, the input end and the output end each have two optical fibers (input terminal I ₁ , input terminal I ₂ , output terminal O ₁ , and output terminal O ₂ ), which can complete two connections. status. One is a parallel connection, ie two incident optical signals are input from I ₁ and I ₂ , respectively output by O ₁ and O ₂ . The other is a cross-connect, ie two incident optical signals are input from I ₁ and I ₂ , respectively output by O ₂ and O ₁ .

Optical switches play an important role in optical networks. For example, in a Wavelength Division Multiplexing (WDM) transmission system, an optical switch can be used for wavelength adaptation, regeneration, and clock extraction. In an Optical Time Division Multiplexing (OTDM) system, an optical switch is available. In de-multiplexing; in all-optical switching systems, optical switches are key components of optical cross-connect (OXC) and are important components for wavelength conversion. According to the number of input and output ports of the optical switch, it can be divided into 1×1, 1×2, 1×N, 2×2, 2×N, M×N, etc., which have different uses in different occasions. For example, it can be used in a data center, or used to construct a backbone optical network device, etc., for spatially exchange data so that the wavelengths carrying the data can be exchanged to the correct port.

There are many types of optical switches, such as mechanical optical switches, electro-optic switches, and silicon-based optical switches. The wavelength alignment technique described in the present invention is applicable to silicon-based dual micro-ring optical switches of various structures. It should be noted that the present invention does not impose any limitation on the specific scenario in which the silicon-based dual micro-ring optical switch is used.

FIG. 1 is a diagram showing a possible hardware structure of the wavelength alignment system described in the present invention. Specifically, the wavelength aligning device 100 includes two parts, a control subsystem 101 and a silicon-based chip 102. The control subsystem 101 is also referred to as a wavelength aligning device, and the system includes a controller (Micro Control Unit, MCU) 1011, an analog-to-digital converter (ADC) 1012, and a transimpedance amplifying circuit ( Trans-impedance amplifiers, TIAs 1013, PIN diodes 1014, drivers 1015 and Digital-to-analog converters (DACs) 1016. The connection relationship of these components is shown in Figure 1. Specifically, the controller 1011 is connected to the DAC 1016 and the ADC 1012 via a serial interface (not numbered), respectively. The DAC 1016 is configured to convert the wavelength control information of the controller into a corresponding instruction (for example, a power control signal), and then amplified by the driver 1015 and sent to the silicon-based chip 102. The ADC 1012 is configured to convert the monitor optical power of the silicon-based chip 102 into a digital signal and then send it to the controller 1011. Specifically, the control subsystem 101 is connected to the monitoring output end of each micro-ring of the silicon-based chip 102 through a plurality of optical fibers, and the optical power of the monitoring output of the plurality of micro-rings in the silicon-based chip is passed through the plurality of PIN diodes 1014. It is converted into a current and amplified into a voltage by TIAs 1013, and then converted to a controller 1011 after being converted by the ADC 1012. Silicon based chip 102 includes one or more dual micro-ring silicon based optical switches 1021, as well as a plurality of input ports and output ports. Taking the example of the silicon-based chip 102 of FIG. 1 as an example, the interface of the silicon-based chip includes: 4 optical signal input ports, 4 optical signal output ports, and electrical input ports P ₁ , P connected to the control subsystem 101. ₂ ,..., P ₁₂ and monitoring ports M ₁ , M ₂ ,..., M ₁₂ . Wherein, a dual micro-ring silicon-based optical switch 1021 includes two electrical input ports and two monitoring ports. It should be noted that the PIN diode 1014 can also be integrated in a silicon-based chip. Then, the control subsystem 101 and the silicon-based chip 102 can be interconnected using electrical connections without the use of optical fibers. It should also be noted that the port is also referred to as an interface. To simplify the description, the invention is collectively referred to as a port.

It should also be noted that the specific design of the silicon-based chip 102 shown in FIG. 1 may be of various structures. For example: the BENES structure shown in Figure 1, or the CrossBar structure or the Switch-and-Select structure. The BENES structure shown in Figure 1 includes six dual micro-ring silicon based optical switches 1021, namely S1, S2, ..., S6. The present invention does not limit the specific design structure of the silicon-based chip, and only requires the basic unit used in the chip to be a dual micro-ring silicon-based optical switch, and the double-micro-ring is a parallel structure. The number of optical signal ports per silicon-based chip, as well as the number of ports (or interfaces) connected to the control subsystem, depends on the specific structural design. It should also be noted that the above described control subsystem 1011 and silicon based chip 102 may be provided by different manufacturers, wherein the control subsystem 1011 uses the wavelength alignment techniques provided by the present invention.

It should also be noted that the external environment in which the silicon-based chip is used is constantly changing, such as the wavelength and temperature of the input optical signal. Therefore, the control subsystem needs to repeatedly use the wavelength alignment technique to ensure that the optical switch operates at the resonant wavelength. Repeated wavelength alignment is sometimes used as a wavelength tracking technique. To simplify the description, the present invention is collectively referred to as wavelength alignment for wavelength alignment and wavelength tracking.

FIG. 2 is a schematic view showing the structure of a double micro-ring silicon-based optical switch 1021 of FIG. In particular, the structure has two parallel micro-rings, two heating electrodes H ₁ and H _2, and 8 ports. Among them, I ₁ and I ₂ are two optical signal input ports, O ₁ and O ₂ are two optical signal output ports, M ₁ and M ₂ are two monitoring output ports, and the other two ports TO ₁ and TO ₂ are Connect the port of the heating electrode. Ports TO ₁ and TO _{2 are} used to change the power applied to the heating electrode (hereinafter referred to as thermal power) to achieve the purpose of adjusting the operating wavelength (or resonant wavelength) of the microring. In the figure, t ₁ , t ₂ and t ₃ are the transmission coefficients of three coupling regions (for example, directional couplers). It should also be noted that TO ₁ and TO ₂ in FIG. 2 are the P ports in FIG. 1 (for example, P ₁ and P ₂ ports). The control subsystem 1011 of FIG. 1 applies different voltages to the heating electrodes of the silicon-based optical switches through TO ₁ and TO ₂ , thereby changing the temperature of the micro-rings to change its operating wavelength, which is sometimes referred to as TO ₁ and TO ₂ for control. port.

The wavelength alignment technique described in the present invention will now be described in conjunction with more drawings.

FIG. 3 is a flow chart showing a wavelength alignment provided by the present invention. It should be noted that this step is only for one double micro-ring silicon-based optical switch. For example, for the optical switch 1021 in FIG.

S301: Determine a primary ring and a secondary ring.

Specifically, the primary ring and the secondary ring can be determined by acquiring the input optical power of the two microrings. The microring in which the input optical power is large is determined to be the main ring, and the other microring is the secondary ring. If the power of the two micro-rings is the same, then you can specify any one of the micro-rings as the primary ring and the other as the secondary ring. It should be noted that the input optical power is proportional to the monitored optical power obtained by M ₁ /M ₂ . Therefore, the primary ring and the secondary ring can also be determined by obtaining the monitor optical power.

S302: Determine a first thermal power of the primary ring, where the first thermal power increases a maximum monitoring optical power of the primary ring, and sets a thermal electrode corresponding to the primary ring to the first thermal Adjust power

Specifically, the thermal power of a primary ring can be determined by individually adjusting the thermal power of the primary ring multiple times or by adjusting the thermal power of the primary and secondary rings multiple times. The thermal power is such that the monitored optical power of the primary ring is at a maximum. Then, the thermal adjustment electrode corresponding to the main ring is adjusted through the control port, that is, the power is set to the aforementioned thermal power value, so that the monitoring optical power of the main ring is maximized.

S303: Determine a second heat modulation power of the secondary ring, where the second heat modulation power minimizes a monitoring optical power of the primary ring, and set a thermal adjustment electrode corresponding to the secondary ring to the second thermal modulation power.

Specifically, the thermal power of a secondary loop can be determined by individually adjusting the thermal power of the secondary loop multiple times. The thermal power is such that the monitored optical power of the primary ring is at a minimum. Then, the thermal adjustment electrode corresponding to the secondary ring is adjusted by the control port to be the thermal power adjustment value, so that the monitoring optical power of the primary ring is minimized.

It should be noted that the first thermal power, the second thermal power, and the third thermal power and the fourth thermal power mentioned later are all specific values. It should also be noted that in order to minimize the difference between the operating wavelength and the input wavelength of the microring, or to reduce the error of wavelength alignment, the above steps may be improved by using one or more of the following methods:

First: When the thermal power of the primary ring is separately adjusted in the step S302, a similar adjustment step (also referred to as scanning granularity) may be employed to perform the steps S302 and S303. And improve the alignment accuracy by repeatedly performing these two steps;

The second type: when the heat regulation power of the primary ring and the secondary ring are simultaneously adjusted when the step S302 is performed for the first time, the coarse adjustment step size and the thermal power adjustment of the primary ring and the secondary ring may be adjusted first, and step S302 is performed. Then, step S303 is performed with a smaller adjustment step size, and then step S302 is performed with a smaller adjustment step size and only adjusting the thermal power of the main ring. Optionally, step S303 may also be performed by continuing to lower the adjustment step value. Then, the alignment accuracy is improved by performing S302 with a smaller adjustment step or by performing S302 and S303.

For a description of the adjustment step size (or the scanning granularity) and a specific selection manner, refer to the detailed description of the embodiment 1-3, and no further details are provided herein.

The following is a detailed description of the theory of how to determine the resonant wavelength of a dual microring silicon-based switch involved in the above method.

Taking the input optical power of the micro-ring from the input port I ₁ as a large example (ie, the primary ring is the micro-ring 1), according to the transmission matrix theory of the micro-ring, it can be inferred that the optical signals of the input port I ₁ are respectively transmitted to the monitoring end. The transmission equations for M ₁ and M ₂ are as follows:

In equations (1) and (2), t ₁ , t ₂ and t ₃ are the transmission coefficients of the three directional couplers, respectively, and k ₁ , k ₂ and k ₃ are the couplings of the three directional couplers, respectively. Coefficient, j is the imaginary unit of the complex number;

a _i is the transmission coefficient of the microring i (i = 1 or 2), which can be obtained by the following formula:

a _i =exp(-αL-jφ _i ),i=1,2 (3)

In formula (3), L is the perimeter of the microring waveguide (ie, the microring), α is the microring transmission loss coefficient, and φ _i is the phase shift of the optical signal transmitted in the microring for one week. φ _i can be obtained by the following formula:

φ _i =2πn _g LΔλ _i /λ ₀ ² (i=1,2) (4)

In the formula (4), n _g is the waveguide transmission loss coefficient, λ ₀ is the wavelength of the input optical signal, and Δλ _i is the offset of the resonance wavelength (also referred to as the resonance peak) of the microring i from the input wavelength λ ₀ . It should be noted that when the resonant wavelengths of the two microrings are both λ ₀ , φ ₁ = φ ₂ =0.

According to the above formula (1) and (2) can be seen, when the optical input signal is input while two uncorrelated, the optical power monitor terminal M PM (hereafter referred to monitor the optical power of the main ring) _1, and φ1 and φ2 ₁ The relationship can be expressed as follows:

In equation (5), E _i represents the optical field distribution of the incident optical signal I _i , and P _i is the optical power of the incident optical signal, i=1 or 2. The introduction of f ₁ and f ₂ is to simplify equation (5), which can be obtained by the following equation:

It can be seen from the formula (5) that the monitor optical power PM ₁ (φ1, φ2) of the main loop changes as the phase shift amounts of the two micro-rings change. Figure 4 shows a schematic diagram of the change in optical power value as a function of microring phase shift. It should be noted that the optical power value is normalized in FIG. 4, that is, all the values are divided by the maximum optical power value to ensure that the value in FIG. 4 fluctuates between 0-1. . In addition, the phase is also normalized and divided by π. It should also be noted that, in Figure 4, only one input has an optical signal input (ie, P _{I1 is} not 0, and P _I2 is 0), and the optical signal input changes at both ends as shown in Figure 6 or Figure 8 shows that (ie, both P _I1 and P _{I2 are} not zero). It can be seen from Fig. 4 that the monitoring optical power distribution of the main loop is “saddle type” distribution, and when φ ₁ = φ ₂ =0, the corresponding point on the graph is called the saddle point S, that is, when the resonance of the two microrings When the offset of the wavelength is 0, the corresponding point is the saddle point. At this saddle point, the main ring's monitor optical power is the largest in the horizontal axis direction, and the main ring's monitor optical power is the smallest on the vertical axis. As can be seen from the figure, the saddle point is unique. It should be noted that, according to formula (5), whether the two optical signal inputs or the single optical signal input, and/or the difference of other parameter settings, the monitoring optical power distribution law of the primary ring is similar. , that is, there is a unique saddle point.

Based on this finding, the method illustrated in FIG. 3 performs a saddle point search by the steps to achieve wavelength alignment. This method provides greater flexibility and can be applied to scenarios where the input port changes, or to scenes that are simultaneously input by both ends. In addition, the accuracy of wavelength alignment can be improved by repeatedly performing some of the steps.

The embodiments of the present invention will be further described in detail below based on the common aspects of the wavelength alignment technique described above. It should be noted that the terms "first", "second" and the like in the following embodiments of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or order. It is to be understood that the data so used may be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than what is illustrated or described herein.

Example 1:

This embodiment provides a method, apparatus and system for wavelength alignment. The system includes the control subsystem shown in FIG. 1 and an optical switch including a dual micro-ring silicon-based optical switch, wherein the method of wavelength alignment is performed by a control subsystem and is performed by a dual micro-ring silicon-based optical switch. Interact to complete wavelength alignment.

Figure 5 shows the detailed steps, including:

S501: setting initial parameters;

Specifically, the initial parameters may include the number of executions of the steps that need to be repeatedly performed (ie, the number of cycles or the number of repetitions), the initial thermal dimming power value, the size of each adjustment of the thermal power (ie, the adjustment step size), and the like. If the number of loops is set to 1, it means that only S503 and S504 need to be executed once, and it is not necessary to perform multiple times. Or you can increase the accuracy of wavelength alignment by setting a higher value. It should be noted that this step is an optional step. The specific parameters can be set to the default values, so there is no need to set them again before performing wavelength alignment. Generally, the number of repetitions is three times to achieve better alignment accuracy. The present invention does not impose any limitation on the specific number of repetitions.

S502: Determine a primary ring and a secondary ring.

This step is similar to S301 in FIG. 3 and will not be described again here. As a possible implementation method, two micro-rings can be simultaneously thermally adjusted through a set of linearly increasing thermal power values, and the input optical powers of the two micro-rings are obtained. Among them, there are various methods for obtaining input optical power. For example, connect a coupled waveguide at the input to directly obtain this information. For another example, by setting a corresponding monitoring terminal on the micro ring, the input optical power information is indirectly obtained through the output current of the monitoring terminal. Taking the monitoring terminal as an example, the average of the plurality of monitoring optical powers acquired by each micro ring is averaged. Then, the average optical power of the two microrings is compared, and the power is larger as the primary ring, and the other is the secondary ring. It should be noted that the range of the above-mentioned thermal power needs to cover a region near the resonance wavelength of the microring, for example, ±1 nm (nanometer). The number of this set of thermal power (also known as the number of thermal steps) is small, for example: 4-6 (steps). For example, if the thermal power is 2mW, the thermal wavelength can be adjusted to 1nm, then the set of thermal power can be set to {1, 2, 3, 4}, the unit is mW.

Table 1 further shows a possible specific implementation process of this step, which is described as follows:

A specific implementation process of step S502 in Table 1

It should be noted that the monitoring current of the monitoring terminal obtained in the monitoring of Table 1 is proportional to the monitoring power of the monitoring terminal, and the monitoring power of the monitoring terminal is also proportional to the optical power of the input terminal. Therefore, the magnitude of the power value can be indirectly determined by comparing the magnitude of the current value. It should also be noted that waiting for a certain period of time to measure the monitoring current is to obtain more stable data. It should be noted that if the input optical power can be accurately obtained, it is not necessary to obtain the optical power value multiple times, and there is no need to perform averaging processing, and the obtained input optical power value can be directly compared. The method given in Table 1 improves the accuracy of power value comparison by multiple measurements and averaging.

S503: Determine a first thermal power of the primary ring, where the first thermal power maximizes a monitoring optical power of the primary ring, and sets a thermal electrode corresponding to the primary ring to the first thermal Adjust power

This step is similar to S302 in FIG. 3 and will not be described again here. Specifically, the primary loop can be thermally tuned by a set of linearly increasing thermal power values to determine the thermal power at which the monitored optical power of the primary loop can be maximized. It should be noted that the range of the set of thermal power in this step is required to cover the entire Free Space Range (FSR), and the number of steps is large. That is, in the FSR range, a fine scan of the thermal power is performed. For example, if the thermal power transfer termination (also known as the maximum heat transfer power) is P _max, it can be set to P _step1 _{_{(P max -P start) / 64}} , where P _max -P _start the FSR must be able to cover the entire, wherein P _start is the minimum thermal power (or initial thermal power).

Table 2 further shows a possible specific implementation process of this step, which is described as follows:

A specific implementation process of step S503 in Table 2

S504: Determine a second heat modulation power of the secondary ring, where the second heat modulation power minimizes a monitoring optical power of the primary ring, and set a thermal adjustment electrode corresponding to the secondary ring to the second thermal modulation power.

This step is similar to S303 in FIG. 3 and will not be described here. The thermal tuning method of this step can adopt the fine scanning method of S503, see Table 2. The main difference is that this step is to perform a thermal power sweep for the secondary loop. In addition, the power value (P _s ) that minimizes I _PDm is obtained, and the thermal power of the secondary loop is set to this value.

S505: Is the number of cycles reached?

It is judged whether or not the number of loops of step S503 and step S504 reaches a predetermined number of times.

S506: The method ends.

Fig. 6 shows a possible search path that can be realized by the method of the present embodiment on the distribution pattern of PM ₁ (φ ₁ , φ ₂ ). As shown in Fig. 6, Init represents the initial position where the optical switch is located, and the saddle point S is the target position at which the light opening should be reached. By performing step S503, the position at which the optical switch is located changes along the horizontal axis due to the change in the phase shift amount of the main ring, reaching the maximum value of the main loop monitoring power, as shown in step (i) of FIG. By performing S504, the position of the optical switch changes along the vertical axis as the phase shift of the secondary ring changes, reaching the minimum value of the monitoring power of the primary loop, thereby substantially approaching the saddle point, thereby achieving the purpose of wavelength quasi-alignment, as shown in the figure. Step (ii) of 6. Further, as S503 and S504 are repeatedly performed a plurality of times, the accuracy of wavelength alignment can be further improved. For example, if step (ii) is performed in FIG. 6 only to reach the vicinity of point S, this may perform S503 and S504 again to finally reach point S. In general, S points can be achieved by performing fewer times, for example: 2-3 times. It should be noted that, in order to further improve the alignment accuracy, it may also be implemented by repeatedly performing the steps S502-S505.

It should be noted that a set of thermal power values used in various embodiments of the present invention may be thermally tuned using a set of values having a typical law, such as the linear increments mentioned in Embodiments 1 and 2. Or linearly decreasing, nonlinearly increasing or decreasing. The present invention does not impose any restrictions on how to select this set of thermal power values.

Example 2:

This embodiment provides another method, apparatus and system for wavelength alignment. The system includes the control subsystem shown in FIG. 1 and an optical switch including a dual micro-ring silicon-based optical switch, wherein the method of wavelength alignment is performed by a control subsystem and is performed by a dual micro-ring silicon-based optical switch. Interact to complete wavelength alignment.

Figure 7 shows the detailed steps, including:

S701: setting initial parameters;

This step is similar to S501 and will not be described here. The main difference is that the steps that need to be cycled are different, specifically step S704, or S704 and S705. Further, the steps of steps S703 and S705 are similar, but the adjustment steps of the thermal power are different.

S702: Determine a primary ring and a secondary ring.

This step is similar to S502 in FIG. 3, and details are not described herein again.

S703: Determine a first thermal power of the primary ring, where the first thermal power increases a maximum monitoring optical power of the primary ring, and sets a thermal electrode corresponding to the primary ring to the first thermal Adjust power

Specifically, the step is to find the target thermal power value by simultaneously thermally tuning the primary ring and the secondary ring. It should be noted that, similar to Embodiment 1, the range of the set of thermal power in this step is also required to cover the entire FSR. That is, the thermal power sweep is performed within the FSR range. The difference is that this step is to perform a coarse scan, that is, the power adjustment step value is relatively large. For example, if the maximum thermal power is P _max , the adjustment step is P _max /16.

Table 3 further shows a possible specific implementation process of this step, which is described as follows:

A specific implementation process of step S703 in Table 2

S704: Determine a second heat modulation power of the secondary ring, where the second heat modulation power minimizes a monitoring optical power of the primary ring, and set a thermal adjustment electrode corresponding to the secondary ring to the second thermal modulation power.

This step is similar to step 504 of FIG. 5 and will not be described again here. It should be noted that the thermal power range P _range and the thermal modulation step P _{step used in this step} are both smaller than that in step S703. For example, the thermal power range of step S704 is only 1/8 of step S703, and P _step is only 1/2.

S705: Determine a third thermal power of the primary ring, where the third thermal power maximizes a monitoring optical power of the primary ring, and sets a thermal electrode corresponding to the primary ring to the third thermal Adjust power

This step is similar to step S703. The main difference is the following three points:

First: determining the third thermal power by separately adjusting the thermal power of the primary ring;

Second: the P _range and P _step used in this step are both smaller than that of step S704. For example, the thermal power range of step S705 is only 1/8 of step S704, and P _step is only 1/2 of step S704.

S706: Is the number of loops reached?

It is judged whether or not the number of loops of step S707 has reached a predetermined number of times. It should be noted that if the number of loops is set to 0, step S707 need not be performed.

S707: Determine a fourth thermal power of the secondary ring, where the fourth thermal power minimizes a monitoring optical power of the primary ring, and sets a thermal electrode corresponding to the secondary ring to the fourth thermal Adjust power

This step root step 704 is similar. The only difference is that this step is smaller than the P _range and P _step values used in the previous step. This can reduce the number of scans and increase the speed at which the microring adjusts the wavelength alignment.

It should be noted that the adjustment ranges and steps in the above steps 704, 705 and 707 can also remain the same.

It should also be noted that the step requiring a loop may further include step S703. For example, step S707 in FIG. 7 is replaced with step 703. For another example, S703 is further added based on step S707.

S708: The method ends.

Fig. 8 shows a possible search path that can be realized by the method of the present embodiment on the distribution pattern of PM ₁ (φ ₁ , φ ₂ ). As shown in Figure 8, Init represents the initial position of the optical switch, and the saddle point is the target position that the optical opening should reach. By performing step S703, the position at which the optical switch is located changes due to the simultaneous change in the phase shift amounts of the primary ring and the secondary ring, approaching the saddle point, as in step (i) of FIG. By performing S704, the position at which the optical switch is located changes along the vertical axis as the phase shift of the secondary loop changes, approaching the minimum value of the primary loop monitoring power, thereby being closer to the saddle point, as in step (ii) of FIG. By performing S705, the position where the optical switch is located changes along the horizontal axis as the phase shift of the main ring changes, approaching the maximum value of the main loop monitoring power, as in step (iii) of FIG. By performing S707, the position at which the optical switch is placed changes along the vertical axis as the phase shift of the secondary ring changes, thereby achieving the purpose of wavelength alignment, as in step (iv) of FIG. It should be noted that the example of FIG. 8 is one that achieves wavelength alignment by one coarse adjustment (step S703) and three fine step adjustments. Among them, the adjustment of the three finer steps respectively adjusts the thermal power of the microring so that the optical switch moves the horizontal axis and the two vertical axes at the position where the PM ₁ (φ ₁ , φ ₂ ) distribution pattern is located. In practical applications, this fine-grained adjustment can be performed only twice or more times, for example: 4 times. The invention is not limited in any way. In addition, the position of the optical switch on the distribution pattern of PM ₁ (φ ₁ , φ ₂ ) is first to change the horizontal axis or the vertical axis, and the present invention is not limited. Further, by repeatedly performing S707 or S707 and S705 a plurality of times, the accuracy of wavelength alignment can be further improved. It should be noted that, in order to further improve the alignment precision, it is also possible to perform the steps S702-S708 repeatedly.

Example 3:

This embodiment provides yet another method, apparatus and system for wavelength alignment. Taking the system including the system shown in Fig. 1 as an example, a silicon-based chip composed of six silicon-based light-emitting devices is included. Wherein the method of wavelength alignment is performed by a control subsystem and wavelength alignment is accomplished by interaction with a dual micro-ring silicon based optical switch.

Figure 9 shows the execution steps, which are described in detail below.

S901: Determine an adjustment sequence of the optical switch.

Specifically, since a silicon-based chip contains a plurality of switches, it is necessary to determine the order of adjustment for each of the optical switches. Generally, the adjustment order is determined based on the flow direction of the optical signal. Taking the silicon-based chip in FIG. 1 as an example, the order of the wavelength alignment operations is adjusted from left to right. Specifically, it is possible to simultaneously adjust the optical switches S1 and S2, and then simultaneously adjust S3 and S4, and finally adjust the order of S5 and S6 at the same time. Alternatively, S1 and S2 are separately adjusted in either order, and both optical switches are adjusted and then processed according to S3 and S4. For example, in the order of S1, S2, S4, S3, S5, S6 or the order of S1, S2, S3, S4, S6, S5. It should be noted that the present invention does not limit the silicon-based chip structure (that is, the number and configuration of the optical switches specifically included) that need to be wavelength-aligned. S902: Perform wavelength alignment on one or more optical switches according to the determined optical switch adjustment sequence.

Specifically, the method of Embodiment 1 or Embodiment 2 is applied to each or each group of optical switches to perform wavelength alignment on each of the optical switches.

It should be noted that it is also possible to perform wavelength alignment on only a part of the optical switches included in one silicon-based chip. The selection of the part of the optical switch depends on the specific application scenario of the silicon-based chip. For example: if only S1, S3 and S5 shown in Figure 1 need to be adjusted. Then, if the adjustment order is determined according to the flow direction of the optical signal, it can be determined that the adjustment order is S1, S3, S5.

The wavelength alignment method provided in this embodiment is used to adjust a set of silicon-based optical switches. Fast wavelength alignment can be achieved by making reasonable adjustments to the sequence. In addition, the method is suitable for multiple inputs, or single input but the input is constantly changing, with great flexibility to meet the corresponding needs.

Example 4:

Figure 10 is a block diagram showing the hardware structure of a possible wavelength aligning device. The network device includes a processing unit 1001, a transmitting unit 1002, and a receiving unit 1003. It should be noted that the device can be used to implement the different behaviors mentioned in the above embodiments 1-3, by interacting with the optical switch to achieve simple and flexible wavelength alignment. Some examples will be given below. It should also be noted that there are multiple transmitting units, generally circuits; and there are multiple receiving units, usually light receiving diodes.

In one possible implementation, the apparatus is used to implement the method illustrated in FIG. Specifically, the processing unit 1001 is configured to perform the internal processing step in FIG. 5, the sending unit 1002 is configured to send control information for adjusting the hot-tuned power to the optical switch, and the receiving unit 1003 is configured to receive the monitoring optical power information of the optical switch. .

In another possible implementation, the apparatus is used to implement the method illustrated in FIG. Specifically, the processing unit 1001 is configured to perform the internal processing step in FIG. 7, the sending unit 1002 is configured to send control information for adjusting the hot-tuned power, and the receiving unit 1003 is configured to receive the monitoring optical power information.

In yet another possible implementation, the apparatus is used to implement the method illustrated in FIG. Specifically, the processing unit 1001 is configured to perform the internal processing step in FIG. 9, the sending unit 1002 is configured to send control information for adjusting the hot-tuned power, and the receiving unit 1003 is configured to receive the monitoring optical power information.

It should be noted that the device shown in FIG. 10 is the control subsystem shown in FIG. 1 , and the object of control and interaction is an optical switch. The components that may be included in the device and the specific related descriptions are shown in FIG. 1 for the description of the control subsystem, and details are not described herein again. It should also be noted that the above processing unit, transmitting unit and receiving unit may also be replaced by a processor, a transmitter and a receiver.

A person skilled in the art may understand that all or part of the steps of implementing the above embodiments may be completed by hardware, or may be instructed by a program to execute related hardware, and the program may be stored in a computer readable storage medium. The storage medium mentioned may be a read only memory, a random access memory or the like. Specifically, for example, the processing unit or processor may be a central processing unit, a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device. , transistor logic, hardware components, or any combination thereof. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods for implementing the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present invention.

When implemented in software, the method steps described in the above embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in accordance with embodiments of the present invention are generated in whole or in part. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be from a website site, computer, server or data center Transfer to another website site, computer, server, or data center by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL), or wireless (eg, infrared, wireless, microwave, etc.). The computer readable storage medium can be any available media that can be accessed by a computer or a data storage device such as a server, data center, or the like that includes one or more available media. The usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (such as a solid state disk (SSD)).

Finally, it should be noted that the above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, and any person skilled in the art can easily within the technical scope disclosed by the present invention. Any changes or substitutions are contemplated as being within the scope of the invention. Therefore, the scope of the invention should be determined by the scope of the appended claims.

Claims

A wavelength alignment method for a silicon-based dual micro-ring optical switch, characterized in that the method comprises:

Determining that one microring of the dual microring is a primary ring, and the other microring is a secondary ring, and an input optical power of the primary ring is not less than an input optical power of the secondary ring;

Order execution:

A1: determining a first thermal power of the primary ring, the first thermal power is to maximize a monitoring optical power of the primary ring, and setting a thermal electrode corresponding to the primary ring to the first thermal Adjust power

A2: determining a second thermal power of the secondary ring, the second thermal power is to minimize a monitoring optical power of the primary ring, and setting a thermal electrode corresponding to the secondary ring to the second thermal Adjust the power.
The wavelength alignment method according to claim 1, wherein the determining the first thermal power of the primary ring comprises: thermally adjusting the primary ring with a set of thermal power values, and determining the The thermal power value of the set of thermal power values that maximizes the monitored optical power of the primary ring is the first thermal power.
The wavelength alignment method according to claim 1 or 2, wherein the determining the second thermal power of the secondary ring specifically comprises: thermally adjusting the secondary ring with another set of thermal power values, And determining, in the another set of thermal power values, a thermal power value that minimizes a monitoring optical power of the primary ring is the second thermal power.
The wavelength alignment method according to any one of claims 1 to 3, characterized in that the method further comprises performing the steps A1 and A2 at least once after the steps A1 and A2 are sequentially performed.
The method of wavelength alignment according to claim 1, wherein the method further comprises:

A3: determining a third thermal power of the primary ring, the third thermal power is to maximize the monitoring optical power of the primary ring, and setting a thermal electrode corresponding to the primary ring to the third thermal Adjust the power.
The wavelength alignment method according to claim 5, wherein the determining the first thermal power of the primary ring comprises: thermally adjusting the primary ring and the a secondary loop, and determining, in the set of thermal power values, a thermal power value that maximizes a monitoring optical power of the primary loop is the first thermal power.
The wavelength alignment method according to any one of claims 5-6, wherein the determining the second thermal power of the secondary ring comprises: thermally adjusting the time by another set of thermal power values. Looping, and determining, in the set of thermal power values, a thermal power value that minimizes a monitoring optical power of the primary ring is the second thermal power.
The wavelength alignment method according to any one of claims 5-7, wherein the determining the third thermal power of the secondary ring specifically comprises: thermally adjusting the primary with a further set of thermal power values Looping, and determining, in the further set of thermal power values, a thermal power value that maximizes a monitoring optical power of the primary ring is the third thermal power.
A wavelength aligning method according to any one of claims 5-7, wherein said method comprises: performing said step A2 at least once after said sequence of steps A1-A3 is performed.
A wavelength aligning device for a silicon-based dual micro-ring optical switch, characterized in that the device comprises: a processor, a transmitter and a receiver, wherein:

The receiver is configured to acquire monitoring optical power of the silicon-based dual micro-ring optical switch;

The processor is configured to perform the following steps:

Determining that one microring of the dual microring is a primary ring, and the other microring is a secondary ring, and an input optical power of the primary ring is not less than an input optical power of the secondary ring;

Order execution:

A1: determining a first thermal power of the primary ring, where the first thermal power increases a maximum monitoring optical power of the primary ring;

A2: determining a second thermal power of the secondary ring, where the second thermal power minimizes a monitoring optical power of the primary ring;

The transmitter is configured to:

Sending a control command to the silicon-based dual micro-ring optical switch, so that the thermal adjustment electrode of the main ring is set to the first thermal power;

Sending another control command to the silicon-based dual micro-ring optical switch such that the thermal adjustment electrode of the secondary ring is set to the second thermal power.
The wavelength aligning device of claim 10, wherein the determining the first thermal power of the primary ring comprises: thermally adjusting the primary ring with a set of thermal power values, and determining The thermal power value of the set of thermal power values that maximizes the monitored optical power of the primary ring is the first thermal power.
The wavelength aligning device according to claim 10 or 11, wherein the determining the second thermal power of the secondary ring comprises: thermally adjusting the secondary ring with another set of thermal power values, And determining, in the another set of thermal power values, a thermal power value that minimizes a monitoring optical power of the primary ring is the second thermal power.
A wavelength aligning apparatus according to any one of claims 10 to 12, wherein said processor performs said steps A1 and A2 at least once after said steps A1 and A2 are sequentially performed.
A wavelength aligning device for a silicon-based dual micro-ring optical switch, characterized in that the device comprises: a processor, a transmitter and a receiver, wherein:

The receiver is configured to acquire monitoring optical power of the silicon-based dual micro-ring optical switch;

The processor is configured to perform the following steps:

Determining that one microring of the dual microring is a primary ring, and the other microring is a secondary ring, and an input optical power of the primary ring is not less than an input optical power of the secondary ring;

Order execution:

A1: determining a first thermal power of the primary ring, where the first thermal power increases a maximum monitoring optical power of the primary ring;

A2: determining a second thermal power of the secondary ring, where the second thermal power minimizes a monitoring optical power of the primary ring;

A3: determining a third thermal power of the primary ring, where the third thermal power increases a maximum monitoring optical power of the primary ring;

The transmitter is configured to:

Sending a control command to the silicon-based dual micro-ring optical switch, the hot-tuning electrode of the main ring is set to the first thermal power;

Sending another control command to the silicon-based dual micro-ring optical switch, wherein the thermal modulation electrode of the secondary ring is set to the second thermal power;

Sending another control command to the silicon-based dual micro-ring optical switch, and the thermal adjustment electrode of the main ring is set to the third thermal power.
The wavelength aligning apparatus according to claim 14, wherein the determining the first thermal power of the main ring comprises: thermally adjusting the main ring and the a secondary loop, and determining, in the set of thermal power values, a thermal power value that maximizes a monitoring optical power of the primary loop is the first thermal power.
The wavelength aligning apparatus according to any one of claims 14-15, wherein the determining the second thermal power of the secondary ring specifically comprises: thermally adjusting the time by another set of thermal power values Looping, and determining, in the set of thermal power values, a thermal power value that minimizes a monitoring optical power of the primary ring is the second thermal power.
The wavelength aligning apparatus according to any one of claims 14-16, wherein the determining the third thermal power of the secondary ring specifically comprises: thermally adjusting the main body with another set of thermal power values Looping, and determining, in the further set of thermal power values, a thermal power value that maximizes a monitoring optical power of the primary ring is the third thermal power.
The wavelength aligning apparatus according to any one of claims 14-17, wherein said processor performs said step A2 at least once after said sequence of performing A1-A3.
A wavelength alignment system comprising a silicon based chip and a wavelength alignment device, wherein:

The silicon-based chip includes a plurality of silicon-based dual micro-ring optical switches;

The wavelength aligning device is the wavelength aligning device of any one of claims 10-18;

The wavelength aligning device receives the monitor optical power of the plurality of silicon-based dual micro-ring optical switches of the silicon-based chip through the receiver, and sends one or more control commands to the silicon-based chip through the transmitter A plurality of silicon-based dual micro-ring optical switches, the one or more control commands being used to set the thermal power.
The system of claim 19, wherein the processor in the wavelength aligning device is further configured to: determine a wavelength alignment order for the plurality of silicon-based dual micro-ring optical switches according to a structure of the silicon-based chip .