Photon integrated circuit, photon chip and method for monitoring modulator

Abstract

The invention provides a photonic integrated circuit, a photonic chip and a method for monitoring a modulator in the photonic integrated circuit. The photonic integrated circuit includes: a modulator including an optical output port; the light splitting device is provided with a light input port and at least two light output ports, and the light input port of the light splitting device is connected to the light output port of the modulator; and the polarization separation device comprises a first light output port and a second light output port, and a light input port of the polarization separation device is connected to one of the at least two light output ports of the light splitting device.

Description

Technical Field

[0001] The invention relates to the technical field of photonic semiconductors, and in particular to a photonic integrated circuit, a photonic chip and a method for monitoring a modulator in the photonic integrated circuit. Background Art

[0002] The modulator is an important device in photonic integrated circuits, and it is very important to monitor the performance of the modulator. Summary of the invention

[0003] The invention provides a photonic integrated circuit, a photonic chip and a method for monitoring a modulator in the photonic integrated circuit.

[0004] According to an embodiment of the present invention, there is provided a photonic integrated circuit, comprising:

[0005] a modulator comprising an optical output port;

[0006] An optical splitter device having an optical input port and at least two optical output ports, wherein the optical input port of the optical splitter device is connected to the optical output port of the modulator;

[0007] The polarization separation device comprises an optical input port, a first optical output port and a second optical output port. The optical input port of the polarization separation device is connected to one of the at least two optical output ports of the optical splitter device to obtain an optical signal from the optical splitter device.

[0008] In some embodiments of the present invention, the optical splitter comprises a directional coupler and a multimode interferometer. In some embodiments of the present invention, the optical splitter is configured to deliver 3% to 10% of its total output light to the polarization separation device.

[0009] In some embodiments of the present invention, the at least two optical output ports of the optical splitter device include a first optical output port and a second optical output port, wherein the light intensity output by the first optical output port of the optical splitter device is less than the light intensity output by the second optical output port of the optical splitter device, and the first optical output port of the optical splitter device is connected to the optical input port of the polarization separation device.

[0010] In some embodiments of the present invention, the polarization separation device includes a polarization beam splitter, a polarization rotation beam splitter or a polarization beam rotator.

[0011] In some embodiments of the present invention, the photonic integrated circuit further comprises a first photodetector and a second photodetector, wherein the first photodetector is connected to the first light output port of the polarization separation device, and the second photodetector is connected to the second light output port of the polarization separation device. In some embodiments of the present invention, the photonic integrated circuit further comprises a first optical coupler and a second optical coupler, wherein the first optical coupler is connected to the first light output port of the polarization separation device, and the second optical coupler is connected to the second light output port of the polarization separation device. In some embodiments of the present invention, the photonic integrated circuit comprises an optical computing unit, and the second light output port of the optical splitter device is connected to the optical computing unit.

[0012] According to another embodiment of the present invention, a photonic chip is provided, which has the photonic integrated circuit described in any one of the above embodiments.

[0013] In addition, an embodiment of the present invention provides a method for monitoring a modulator in a photonic integrated circuit, comprising:

[0014] receiving an output optical signal of a modulator as a monitoring object through an optical splitter;

[0015] The optical splitter inputs a part of the received optical signal to the polarization separation device through the first optical output port; the polarization separation device separates the light according to the polarization light component of the input optical signal and generates a first optical signal and a second optical signal;

[0016] The first optical signal and the second optical signal are monitored to obtain information of an output optical signal of the modulator.

[0017] In some embodiments of the present invention, the monitoring the first optical signal and the second optical signal to obtain information of the output optical signal of the modulator includes:

[0018] obtaining a modulated electrical signal corresponding to the light intensity extreme point of the first optical signal, and

[0019] A modulated electrical signal corresponding to the light intensity extreme point of the second optical signal is obtained.

[0020] In some embodiments of the present invention, the first optical signal includes TE light, and the second optical signal includes TM light.

[0021] In some embodiments of the present invention, the first optical output port of the spectrometer inputs a specified ratio of optical signals to the polarization separation device, and the specified ratio is the ratio of the light intensity of the optical signal output by the first optical output port to the total output light signal of the spectrometer, and the specified ratio is 3% to 10%.

[0022] The application of the present invention has at least one of the following advantages:

[0023] By using a light splitter to separate a specified proportion of the light signal from the output light signal of the modulator as the monitoring object, combined with the different intensity characteristics of the light signal associated with different polarization components output when modulating the modulated electrical signal, the polarization separation device separates two paths of light for monitoring, which can increase the amount of monitoring detection signals without occupying additional signal strength, and can ensure effective monitoring of the extremely strong point (optical bright state 1) and the extremely weak point (optical dark state 0) in the light intensity modulation. In addition, when the photonic integrated circuit is used for optical computing, light of appropriate intensity is still transmitted to the optical computing unit for normal computing.

[0024] Various aspects, features, advantages, etc. of the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. According to the following detailed description in conjunction with the accompanying drawings, the above aspects, features, advantages, etc. of the present invention will become more clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a block diagram of a photonic chip according to an exemplary embodiment of the present invention.

[0026] Figure 2 is a structural block diagram of a photonic chip according to another embodiment of the present invention.

[0027] Figure 3 is a structural block diagram of a photonic chip according to another embodiment of the present invention.

[0028] Figure 4 is a structural block diagram of a photonic chip according to another embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to facilitate understanding of various aspects, features and advantages of the technical solution of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the various embodiments described below are only for illustration and are not intended to limit the scope of protection of the present invention.

[0030] The terms used herein are for the purpose of describing specific embodiments and are not intended to limit the present invention. As used herein, the wording "one" is intended to include plural cases unless the context clearly indicates that it represents a single quantity. The terms "first", "second" or other similar expressions are used to distinguish objects and do not mean order or sequence unless it is clearly indicated that they represent the order. Similarly, the words "S1", "S2" and the like are intended to mark processes or steps or operations, and do not represent the execution order of these processes or steps or operations.

[0031] The embodiments of the present invention do not impose any particular limitation on the execution order of the steps, as long as the purpose or function of the invention can be achieved. Some steps or orders may be executed in parallel, sequentially, or alternately.

[0032] The inventor (or simply referred to as the inventor in this article) designs photonic integrated circuits for different scenarios, such as photon computing. The modulator is an important device in a photonic integrated circuit, and it is very important to monitor the performance of the modulator. The inventor realizes that it is necessary to accurately measure or detect the signal in the photonic integrated circuit. In the photonic integrated circuit designed by the inventor, the signal output by the modulator can be used for normal work (such as photon computing), and a part of the signal can be diverted for monitoring, so as to minimize the impact on the optical signal required for normal work. The signal used for monitoring can obtain sufficient information of the detector and can be used for monitoring real-time signals. A part of the optical signal is separated from the output optical signal of the modulator as the monitoring object by a splitter device, and two paths of light can be separated for monitoring by a polarization separation device according to the different intensity characteristics of the optical signal associated with different polarization components output when the modulated electrical signal is modulated. It can increase the amount of monitoring detection signal without occupying additional signal strength, and ensure effective monitoring of the extremely strong point (optical bright state 1) and the extremely weak point (optical dark state 0) in the light intensity modulation.

[0033] Figure 1An exemplary embodiment of the photonic chip of the present invention is shown. In an exemplary embodiment, the photonic chip 100 includes a photonic integrated circuit 110. The photonic integrated circuit 110 can be formed on a wafer by a semiconductor manufacturing process, and the wafer is cut to obtain the photonic chip. In an exemplary embodiment, the photonic integrated circuit 110 includes a modulator 111, a light splitting device 112, and a polarization beam splitter 113. Among them, the polarization beam splitter 113 is a polarization separation device, having a first light output port 113-1 and a second light output port 113-2, and the polarization separation device can also be a polarization rotation beam splitter or a polarization beam splitter rotator. The optical input port of the optical splitter 112 is connected to the optical output port of the modulator 111, and has at least a first optical output port 112-1 and a second optical output port 112-2. The first optical output port 112-1 is connected to the polarization beam splitter 113 to separate the monitoring optical signal from the input optical signal and send the monitoring optical signal to the polarization beam splitter 113. The second optical output port 112-2 outputs the main optical signal, which is used to realize the function of the photonic integrated circuit 110. For example, if the photonic integrated circuit 110 is used for photonic computing, the main optical signal is used for photonic computing. In an exemplary embodiment, the first optical output port 112-1 of the optical splitter 112 inputs a prescribed ratio of optical signals to the polarization beam splitter 113, and the prescribed ratio is the ratio of the light intensity of the optical signal output by the first optical output port 112-1 to the light intensity of the total output optical signal of the optical splitter 112. For example, the prescribed ratio is 5%, that is, the light output by the first optical output port 112-1 accounts for 5% of the total output optical signal of the optical splitter 112, and the main optical signal output by the second optical output port 112-2 accounts for 95% of the total output optical signal of the optical splitter 112. In some embodiments, the prescribed ratio is 3% to 10%. In some embodiments, the optical splitter 112 includes a directional coupler with a prescribed splitting ratio. The prescribed splitting ratio may include 95:5, wherein the directional coupler transmits 5% of the input light to the polarization beam splitter 113 through the corresponding optical output port.

[0034] In some embodiments, Figure 2 As shown, the photonic integrated circuit 110 also includes an optical computing unit 116. The second optical output port 112-2 of the optical splitter 112 can output a main optical signal to the optical computing unit 116. For example, the main optical signal can be used to represent the data to be calculated. Due to the presence of the polarization separation device, the two separated beams of light are guaranteed to be used for monitoring, and there can be two independent monitoring channels. In addition, light of appropriate intensity is still transmitted to the optical computing unit for normal calculation, which can be used for monitoring real-time signals.

[0035] The above description is based on the example of separating 5% of the optical signal for monitoring, and it should be understood that the present invention is not limited to this. Without affecting the power or signal strength of the main signal, any proportion of the optical signal can be separated for monitoring. For example, a signal with a light intensity of 3% or 10% can be separated from the total output optical signal of the optical splitter 112 for monitoring. In some embodiments, the ratio of the light intensity of the optical signal output by the first optical output port 112-1 to the light intensity of the input light (or total output light) of the optical splitter 112 is less than the ratio of the light intensity of the optical signal output by the second optical output port 112-2 to the light intensity of the input light (or total output light) of the optical splitter 112, and the first optical output port 112-1 is connected to the polarization beam splitter 113. The polarization beam splitter 113 is used to separate the different polarization light components of the input light, and the first optical output port 113-1 outputs a first optical signal having a first polarization light component, and the second optical output port 113-2 outputs a second optical signal having a second polarization light component.

[0036] In some embodiments, the polarization beam splitter 113 can be replaced by a polarization rotation beam splitter or a polarization beam splitter rotator, and the polarization beam splitter, polarization rotation beam splitter, or polarization beam splitter rotator can all be considered to belong to polarization separation devices. For example, the polarization beam splitter is used to separate the TE polarization light component and the TM polarization light component of the input light; for example, the polarization rotation beam splitter includes not only the function of polarization separation, but also the function of converting a certain polarization component in the input light, for example, the polarization rotation beam splitter is used to separate the TE polarization light component and the TM polarization light component in the input light to generate a first TE polarization light component, and convert the TM polarization light component into a second TE polarization light component.

[0037] In some embodiments, the polarization separation device may include a first optical output port and a second optical output port, and the photonic integrated circuit 110 may include a photodetector or an optical coupler connected to the first / second optical output port. The photodetector may detect the intensity of light, and the optical coupler may be used to output light from the photonic integrated circuit 110 to provide it to an external detection device. For example, the photonic integrated circuit 110 includes at least one of a first photodetector and a first optical coupler, and / or at least one of a second photodetector and a second optical coupler. The first optical output port may be connected to at least one of the first photodetector and the first optical coupler, and the second optical output port may be connected to at least one of the second photodetector and the second optical coupler. For example, in some embodiments, the photonic integrated circuit 110 includes a photodetector connected to the output port of the polarization beam splitter 113. Figure 3As shown, the photonic integrated circuit 110 includes a first photodetector 114 - 1 and a second photodetector 114 - 2 . The first photodetector 114 - 1 is connected to the first light output port 113 - 1 of the polarization beam splitter 113 , and the second photodetector 114 - 2 is connected to the second light output port 113 - 2 of the polarization beam splitter 113 .

[0038] The light output by the modulator 111 can be changed according to the applied electrical signal (referred to as the modulated electrical signal in this article). According to different modulated electrical signals, the modulator 111 will have different light intensity outputs. This process is the modulation of the light by the modulator. In addition, the light of different polarization components (such as TE component and TM component) in the optical signal output by the modulator 111 is related to the modulated electrical signal. The photodetector can reflect the light intensity information of the output port of the polarization beam splitter 113, wherein the first optical output port 113-1 of the polarization beam splitter 113 outputs the first optical signal, and the second optical output port 113-2 of the polarization beam splitter 113 outputs the second optical signal, and the light intensity information under different modulated electrical signals can be detected. Further, the functional relationship between the light intensity information and the modulated electrical signal can also be obtained. The above only takes the polarization beam splitter 113 as an example. In addition to using the polarization beam splitter 113 as a polarization separation device, the polarization separation device can also include a polarization rotation beam splitter or a polarization positive beam rotator. The polarization separation device can also include a polarization conversion (polarization rotation) of light of a certain polarization component before outputting it from the first optical output port or the second optical output port. For example, the polarization rotating beam splitter is used to separate the TE polarized light component and the TM polarized light component in the input light to generate a first TE polarized light component output (output as a first optical signal), and convert the TM polarized light component into a second TE polarized light component output (output as a second optical signal).

[0039] In another embodiment, the photonic integrated circuit 110 further includes an optical coupler, which is connected to the output port of the polarization beam splitter 113, so that a detector outside the chip can directly detect the chip through the optical coupler. Figure 4 As shown, the photonic integrated circuit 110 includes a first optical coupler 115-1 and a second optical coupler 115-2, wherein the first optical coupler 115-1 is connected to the first optical output port 113-1 of the polarization beam splitter 113, and the second optical coupler 115-2 is connected to the second optical output port 113-2 of the polarization beam splitter 113. In some embodiments, the optical coupler includes a vertical grating coupler or a lateral edge coupler.

[0040] In addition, an embodiment of the present invention provides a method for monitoring a modulator in a photonic integrated circuit. In an exemplary embodiment, the method includes: S1, receiving an output optical signal of a modulator as a monitoring object through an optical splitter; S2, the optical splitter inputs a part of the received optical signal to a polarization separation device through a first optical output port; S3, the polarization separation device separates the light according to the polarization light component of the input optical signal, and generates a first optical signal and a second optical signal; S4, monitoring the first optical signal and the second optical signal to obtain information of the output optical signal of the modulator. In some embodiments of the present invention, the first optical output port of the optical splitter inputs a prescribed proportion of optical signals to the polarization separation device, and the prescribed proportion is the ratio of the light intensity of the optical signal output from the first optical output port to the total light intensity of the optical signal output from the optical splitter, and the prescribed proportion is 3% to 10%, for example, it can be 5%, or it can be 3% or 10%. The present invention is not limited to this, and any proportion of optical signals can be separated for monitoring without affecting the power or signal strength of the main signal.

[0041] The present invention can increase the number of monitoring detection signals without occupying additional signal strength. Since the first optical signal and the second optical signal are detected, more abundant information to be monitored can be obtained to obtain relevant parameter data of the modulator.

[0042] The light intensity of the first optical signal and the second optical signal varies with the modulated electrical signal, and may have light intensity extreme points (maximum or minimum). In some embodiments, it includes obtaining the modulated electrical signal corresponding to the light intensity extreme point of the first optical signal, and obtaining the modulated electrical signal corresponding to the light intensity extreme point of the second optical signal.

[0043] In some embodiments of the present invention, the first optical signal includes TE light, and the second optical signal includes TM light.

[0044] In some embodiments of the present invention, the monitoring of the first optical signal and the second optical signal to obtain information of the output optical signal of the modulator includes: obtaining the modulated electrical signal corresponding to the light intensity extreme point of the first optical signal, such as the modulated electrical signal corresponding to the light intensity extreme point of the TE light; and obtaining the modulated electrical signal corresponding to the light intensity extreme point of the second optical signal, such as the modulated electrical signal corresponding to the light intensity extreme point of the TM light. Thus, the number of monitored detection signals is increased without occupying additional signal strength, and effective monitoring of the extreme point (optical bright state 1) and the weak point (optical dark state 0) in the light intensity modulation is ensured at the same time.

[0045] In some embodiments of the present invention, the possible optical signal output by the modulator includes a TE optical component and a TM optical component, and the TM light is separated from the output optical signal of the modulator and processed for monitoring.

[0046] Those skilled in the art should understand that what is disclosed above is only an implementation mode of the present invention, and it certainly cannot be used to limit the scope of rights for patent protection requested by the present invention. Equivalent changes made according to the implementation mode of the present invention are still within the scope covered by the claims of the present invention.

Claims

1. A photonic integrated circuit, comprising: a modulator comprising an optical output port; An optical splitter device having an optical input port and at least two optical output ports, wherein the optical input port of the optical splitter device is connected to the optical output port of the modulator; A polarization separation device comprises an optical input port, a first optical output port and a second optical output port, wherein the optical input port of the polarization separation device is connected to one of at least two optical output ports of the optical splitter device to obtain an optical signal from the optical splitter device.

2. The photonic integrated circuit according to claim 1, characterized in that: The optical splitter device includes a directional coupler and a multi-mode interferometer.

3. The photonic integrated circuit according to claim 2, characterized in that: The optical splitter device is configured to deliver 3% to 10% of its total output light to the polarization separation device.

4. The photonic integrated circuit according to claim 1, characterized in that: The at least two optical output ports of the optical splitter device include a first optical output port and a second optical output port, The light intensity outputted from the first light output port of the light splitter is smaller than the light intensity outputted from the second light output port of the light splitter. Furthermore, the first light output port of the light splitting device is connected to the light input port of the polarization separation device.

5. The photonic integrated circuit according to any one of claims 1 to 4, characterized in that: The polarization separation device includes a polarization beam splitter, a polarization rotation beam splitter or a polarization beam rotator.

6. The photonic integrated circuit according to claim 1, characterized in that: It also includes a first photodetector and a second photodetector. The first photodetector is connected to the first light output port of the polarization separation device, and the second photodetector is connected to the second light output port of the polarization separation device.

7. The photonic integrated circuit according to claim 1, characterized in that: It also includes a first optical coupler and a second optical coupler, wherein the first optical coupler is connected to the first optical output port of the polarization separation device, and the second optical coupler is connected to the second optical output port of the polarization separation device.

8. The photonic integrated circuit according to claim 7, characterized in that: The photonic integrated circuit comprises an optical computing unit, and the second optical output port of the optical splitter is connected to the optical computing unit.

9. A photonic chip, characterized in that: A photonic integrated circuit comprising the photonic integrated circuit according to any one of claims 1 to 8.

10. A method for monitoring a modulator in a photonic integrated circuit, comprising: receiving an output optical signal of a modulator as a monitoring object through an optical splitter; The optical splitter component inputs a part of the received optical signal to the polarization separation component through the first optical output port; The polarization separation device separates the light according to the polarization light component of the input optical signal, and generates a first optical signal and a second optical signal; The first optical signal and the second optical signal are monitored to obtain information of an output optical signal of the modulator.

11. The monitoring method according to claim 10, characterized in that: The monitoring of the first optical signal and the second optical signal to obtain information of the output optical signal of the modulator includes: obtaining a modulated electrical signal corresponding to the light intensity extreme point of the first optical signal, and A modulated electrical signal corresponding to the light intensity extreme point of the second optical signal is obtained.

12. The monitoring method according to claim 10 or 11, characterized in that: The first optical signal includes TE light, and the second optical signal includes TM light.

13. The monitoring method according to claim 10, characterized in that: The first optical output port of the optical splitter inputs a specified ratio of optical signals to the polarization separation device. The specified ratio is the ratio of the optical signal output by the first optical output port to the optical signal output by the optical splitter. The specified ratio is 3% to 10%.

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