CN119414616A

CN119414616A - An optical triode system, its control method and application

Info

Publication number: CN119414616A
Application number: CN202411549689.3A
Authority: CN
Inventors: 戴庆; 陈启田; 胡德波; 王丽艳
Original assignee: National Center for Nanosccience and Technology China
Current assignee: National Center for Nanosccience and Technology China
Priority date: 2024-11-01
Filing date: 2024-11-01
Publication date: 2025-02-11

Abstract

The invention provides a phototriode system, a regulating and controlling method and application thereof. The phototriode system comprises a light source module, a Van der Waals material layer, a micro-ring resonant cavity and a photoelectric detector. Aiming at the bottleneck faced by the development of an electronic transistor, the phototriode system based on the coupling of the Van der Waals semiconductor material and the silicon-based micro-ring resonant cavity improves the response speed and reduces the energy consumption by taking light waves and photons as signal carriers and utilizing the optical linear effect of the Van der Waals material and the resonance characteristic of the silicon-based micro-ring resonant cavity. The signal light is effectively amplified and regulated.

Description

Phototriode system, regulation and control method and application thereof

Technical Field

The invention belongs to the technical field of information communication, and particularly relates to a phototriode system, a regulating and controlling method and application thereof.

Background

In the continuous evolution of Information Communication Technology (ICT), the conventional electronic triode is taken as a key component, plays an irreplaceable role in signal amplification and logic operation, and forcefully promotes the progress of modern computing and communication systems. However, as the digital wave goes deep, particularly in the leading-edge fields of ultra-high-speed broadband communication, large-scale data center construction, high-performance computing, etc., electronic circuits based on conventional semiconductor materials gradually approach performance limits defined by basic laws of physics. The migration rate of electron carriers is limited by the nature and quantum effect of the material, and becomes a key factor for limiting the data processing speed and improving the energy efficiency. In this context, photonics is considered a critical path to break through the information technology bottleneck, with its high speed, low loss, high bandwidth, and inherent parallel processing capability.

The phototriode adopts light waves to replace electron flow, and uses photons as media to execute the tasks of signal scaling and regulation. The concept is deeply integrated with nonlinear optics, laser engineering and advanced material science, and aims to develop a new generation of light control device capable of effectively controlling the intensity and the phase of an optical signal so as to play a key role in the fields of optical communication, optical calculation, future quantum information processing and the like. Most of the phototriodes studied at present depend on second-order or third-order nonlinear effects, have high light intensity dependence, and can only become remarkable under a strong light field. In addition, further optimization is needed for the control of coherence and stability of light, the design of efficient optical coupling and conversion mechanism, and the precise control of nano-scale manufacturing process.

Van der Waals materials such as graphene, transition Metal Dichalcogenide (TMDs) and the like show remarkable application potential in the technical fields of silicon photonics and ultrafast light modulation by virtue of atomic-level thickness, strong light substance interaction, wide spectral response, mechanical robustness and heterogeneous integration capability. In research of exploring van der waals material all-optical triodes, graphene has been attracting attention as one of core materials due to its excellent electrical and optical characteristics. However, although graphene exhibits significant advantages in the preparation of modulation devices, its limitations are also significant in that the relatively low light absorptivity may limit modulation depth, thereby affecting the increase in signal strength, which is a major challenge in current research. In addition, graphene's performance is sensitive to temperature changes, which may lead to reduced stability and reliability under different environmental conditions, further limiting its wide application. In contrast, TMDs materials exhibit more desirable material properties in the all-optical triode field by virtue of their high light absorption, tunable optical bandgap, broad spectral response, and excellent light emission efficiency, and become a more potential choice.

Disclosure of Invention

Therefore, the invention aims to overcome the defects in the prior art and provide a phototriode system, a regulating method and application thereof.

Before setting forth the present disclosure, the terms used herein are defined as follows:

the term "TMDs" refers to a transition metal dichalcogenide.

To achieve the above object, a first aspect of the present invention provides a phototransistor system including:

The device at least comprises a light source module of a pumping light source and a signal light source, a Van der Waals material layer, a micro-ring resonant cavity and a photoelectric detector, wherein:

In the light source module, the pumping light source is used for exciting excitons in the van der Waals material to change the refractive index of the whole van der Waals material, and the signal light source is used for emitting signal light;

The Van der Waals material layer is used for absorbing the excitation light emitted by the pumping light source;

the micro-ring resonant cavity is used for amplifying or attenuating optical signals, and

The photoelectric detector is used for detecting and measuring the light intensity and/or the light power of the signal light output by the signal light source;

Preferably, the pump light is input to the van der waals material layer, the signal light is input to the micro-ring resonant cavity, and is modulated and then input to the photodetector.

The triac system according to the first aspect of the present invention, wherein,

The signal light output by the signal light source is coupled through the micro-ring resonant cavity and then is output, and the pumping light output by the pumping light source irradiates the van der Waals material layer to change the transmission intensity of the output signal light;

the wavelength of the pumping light is 400-800 nm, preferably 450-700 nm, more preferably 520-660 nm, and/or

The wavelength of the signal light is 1500-160 nm, preferably 1520-1580 nm, and more preferably 1530-1550 nm.

The band gap of the material of the Van der Waals material layer is 0 eV-2 eV, preferably 1 eV-1.8 eV, more preferably 1.2 eV-1.6 eV, and/or

The material of the van der Waals material layer is selected from one or more of graphene, TMDs, hexagonal boron nitride and transition metal carbide, preferably from one or more of graphene, TMDs and hexagonal boron nitride, more preferably graphene or TMDs;

Preferably, the TMDs is selected from one or more of molybdenum disulfide, molybdenum diselenide, tungsten disulfide, tungsten diselenide, tungsten ditelluride, molybdenum ditelluride, tungsten trioxide, molybdenum trisulfide, tungsten trisulfide, more preferably from one or more of molybdenum disulfide, molybdenum diselenide, tungsten disulfide, tungsten diselenide, tungsten ditelluride, molybdenum ditelluride, more preferably from one or more of molybdenum disulfide, molybdenum diselenide, tungsten disulfide, tungsten diselenide.

The phototriode system according to the first aspect of the present invention, wherein the micro-ring resonator comprises a straight waveguide, a micro-ring waveguide, a substrate, a waveguide layer, a silicon dioxide layer and a cladding layer, wherein,

The silicon dioxide layer is positioned on the substrate, the waveguide layer is positioned on the silicon dioxide layer, and the cladding layer covers the waveguide layer;

The straight waveguide and the micro-ring waveguide are positioned on the waveguide layer, and/or

And the Van der Waals material layer is partially covered above the micro-ring waveguide.

The width of the waveguide layer is 350-650 nm, preferably 400-600 nm, more preferably 450-550 nm;

the height of the waveguide layer is 150-300 nm, preferably 180-260 nm, more preferably 200-240 nm;

The micro-ring resonator has a micro-ring radius of 5-20 μm, preferably 6-15 μm, more preferably 8-12 μm, and/or

The gap width between the straight waveguide and the micro-ring waveguide is 60-120 nm, preferably 70-110 nm, and more preferably 80-100 nm.

The material of the straight waveguide and the micro-ring waveguide is selected from one or more of silicon, silicon nitride, silicon dioxide, preferably silicon or silicon nitride, most preferably silicon;

the material of the substrate is selected from one or more of silicon, germanium, gallium arsenide, indium phosphide, gallium nitride, silicon germanium, aluminum oxide, silicon nitride, boron nitride, preferably from one or more of silicon, gallium arsenide, indium phosphide, silicon nitride, aluminum oxide, most preferably silicon, and/or

The material of the coating layer is selected from one or more of silicon dioxide, aluminum oxide, silicon nitride, boron nitride, preferably silicon dioxide or aluminum oxide, most preferably silicon dioxide.

The photodetector is selected from one or more of Si photodetector, gaAs photodetector, inGaAs photodetector, pbS/PbSe photodetector, znO photodetector, organic photodetector, graphene photodetector, quantum dot photodetector, preferably from one or more of Si photodetector, gaAs photodetector, inGaAs photodetector, pbS/PbSe photodetector, znO photodetector, more preferably GaAs photodetector and/or InGaAs photodetector, and/or

The photoelectric detector is a visible light detector and/or a near infrared detector;

preferably, the wavelength of the visible light detector ranges from 400 to 1100nm, more preferably from 400 to 900nm, even more preferably from 400 to 700nm, and/or

Preferably, the wavelength range of the near infrared detector is 800-1800 nm, more preferably 1100-1700 nm, and even more preferably 1300-1650 nm.

A second aspect of the invention provides a method of modulating light, the method comprising modulating light using the phototriode system of the first aspect;

Preferably, the method includes the light source module emitting an optical signal that interacts with the van der Waals material layer and the micro-ring resonator to condition the optical signal.

The method according to the second aspect of the present invention, wherein the method further comprises:

the signal light source and the pumping light source in the light source module respectively emit signal light and pumping light, the signal light is input from a port at one end of the straight waveguide and is coupled through the micro-ring resonant cavity and is output from a port at the other end of the straight waveguide, and the pumping light irradiates on the van der Waals material layer so as to change the dielectric environment of the micro-ring waveguide and further change the transmission intensity of the output signal light.

A third aspect of the invention provides the use of a phototriode system according to the first aspect for the preparation of a device for performing an optical switching function and/or an optical amplifying function.

According to a preferred embodiment of the present invention, the present invention is a phototransistor system comprising:

The light source module comprises a pumping light source and a signal light source which are respectively used for exciting excitons in the Van der Waals material and emitting signal light.

Van der Waals material layer is mechanically stripped and transferred onto the micro-ring waveguide as photosensitive layer capable of generating excitons and changing their charge and polarization state in response to pump light.

The silicon-based micro-ring resonant cavity is coupled to the micro-ring resonant cavity after signal light is transmitted in the straight waveguide and interacts with TMDs material layers to realize amplification or attenuation of optical signals

And the photoelectric detector is used for detecting and measuring the light intensity or the light power of the output signal light.

The wavelength of the pump light is 400 to 800nm, preferably 450 to 700nm, more preferably 520 to 660nm, and generally, the exciton effect is optimal when the wavelength is selected to be close to the band gap of the material, in order to confirm the wavelength of the pump light according to the material TMDs used specifically.

Optionally, the phototriode system of the present invention may further comprise a control circuit for controlling the intensity, frequency, etc. of the pump light and processing the electrical signal output by the photodetector.

The specific connection mode of the light source module, the Van der Waals material layer and the micro-ring resonant cavity is that signal light is input into a straight waveguide of the micro-ring resonant cavity structure through a signal light source, a photoelectric detector and a computer are connected to the other end of the micro-ring resonant cavity after the signal light is modulated through the micro-ring structure, a modulation result is visualized, the Van der Waals material layer covers the micro-ring resonant cavity structure, excitons can be generated under the irradiation of a pumping light source, the refraction index is changed, the function of modulating the signal light is achieved, the pumping light irradiates the Van der Waals material, if a signal generator is externally connected to the pumping light source, different waveforms (such as square waves, sine waves, triangular waves and the like) can be generated, and therefore the capability of pumping light modulation signal light can be observed better.

The working principle is that the phototriode adopts light waves to replace electron flow, and uses photons as media to execute the tasks of signal scaling and regulation. When the pump light irradiates the van der Waals material layer, photons interact with electrons in the material, and excitons are excited to generate. The creation of excitons changes the charge distribution and polarization state within the van der waals material, thereby affecting its dielectric function. Meanwhile, the signal light interacts with the Van der Waals material layer through the silicon-based micro-ring resonant cavity. Due to the dielectric function change of the Van der Waals material layer, the transmission characteristic of the signal light in the resonant cavity is modulated, and the amplification or attenuation of the signal is realized. By adjusting the intensity and frequency of the pumping light, the generation and annihilation processes of excitons in the van der Waals material layer can be precisely controlled, so that the signal light can be effectively regulated and controlled.

The implementation method comprises the following steps:

1. Van der Waals material layer selection

Layers of van der waals materials having specific band gaps and optical properties are designed and prepared. Van der Waals materials include graphene, TMDs, and the like, and have extremely wide optical response ranges, covering the ultraviolet to terahertz and even extending to the microwave frequency range. Particularly TMDs materials, including molybdenum disulfide, molybdenum diselenide, tungsten disulfide, tungsten diselenide, etc., with band gaps between 1.0eV and 2.0eV, so that electrons can be excited by visible light in the near infrared band. Therefore, the function of the phototriode can be realized by selecting pump light with proper wavelength according to the band gap of the material. The invention mainly uses tungsten disulfide, but is not limited to this material, and Van der Waals materials can be used.

2. Design and optimize silicon-based micro-ring resonant cavity

The structural design of the micro-ring resonator requires comprehensive consideration of a plurality of key factors including the width of the waveguide, the radius of the micro-ring and the gap width between the straight waveguide and the micro-ring.

(1) In view of the compatibility of all-optical transistors in silicon-based photonic integrated circuits, the dimensions of the silicon waveguide are typically set to 500nm width and 220nm height, in order to ensure a seamless interface with existing integration techniques.

(2) The radius of the micro-ring is set to be 10 mu m, so that high-density integration is realized, and meanwhile, loss generated by the waveguide during bending can be effectively reduced, and the overall performance is improved.

(3) The gap width between the straight waveguide and the micro-ring is optimized. The gap width finally determined is 90nm, and the design can not only meet the precision requirement of the processing technology, but also obviously improve the coupling efficiency.

3. Optical triode structure design

The main structure of the triode is shown in fig. 1, and the main structure of the triode in fig. 1 comprises a light source module, a TMDs material layer and a silicon-based micro-ring resonant cavity, which together form a modulation area of the all-optical triode. The three components are added with the photoelectric detector to form the complete phototriode system. The straight waveguide and the micro-ring part are silicon waveguides, and the shadow part on the micro-ring waveguide is covered Van der Waals material. The optical signal has two beams, communication light and pump light. Communication light is input from one port of the straight waveguide, coupled through the micro-ring resonant cavity, and output from the other port. The pump excitation light irradiates on the van der Waals material for changing the dielectric environment of the micro-ring waveguide, thereby changing the transmission intensity of the output signal light.

A cross-sectional view of a device structure is shown in fig. 2, comprising a silicon substrate, a silicon dioxide layer on the substrate, a Si waveguide layer on the silicon dioxide layer, and a silicon dioxide cladding layer overlying the waveguide layer. The uppermost layer is a mechanically dry transferred van der Waals material (here tungsten disulfide).

Compared with the prior art, the phototriode system, the regulation and control method and the application thereof can have the following beneficial effects:

Aiming at the bottleneck faced by the development of an electronic transistor, the phototriode system based on the coupling of the Van der Waals semiconductor material and the silicon-based micro-ring resonant cavity improves the response speed and reduces the energy consumption by taking light waves and photons as signal carriers and utilizing the optical linear effect of the Van der Waals material and the resonance characteristic of the silicon-based micro-ring resonant cavity. The signal light is effectively amplified and regulated.

Drawings

Embodiments of the present invention are described in detail below with reference to the attached drawing figures, wherein:

fig. 1 shows a schematic view of a part of the structure of a phototriode system according to the present invention.

Fig. 2 shows a schematic cross-sectional structure of the inventive phototransistor system.

Fig. 3 shows the transmission spectrum simulation result of the micro-ring resonator of the triode system of the present invention.

Fig. 4 shows an optical microscope image of a micro-ring resonator of a phototransistor system of the present invention.

FIG. 5 is a graph showing the transmission spectrum of the micro-ring resonator of a triode system having a tungsten disulfide layer of the Van der Waals material of the present invention.

FIG. 6 shows a transmission spectrum of a micro-ring resonator of a triode system having a tungsten diselenide layer of the present invention.

FIG. 7 shows a transmission spectrum of a micro-ring resonator of a phototriode system having a layer of Van der Waals material of the present invention of molybdenum disulfide.

Fig. 8 shows a response test of the inventive phototransistor system.

Fig. 9 shows a schematic structural diagram of the phototransistor system of the present invention.

Detailed Description

The invention is further illustrated by the following specific examples in conjunction with the accompanying drawings, but it should be understood that these examples are for the purpose of more detailed description only and should not be construed as limiting the invention in any way.

This section generally describes the materials used in the test of the present invention and the test method. Although many materials and methods of operation are known in the art for accomplishing the objectives of the present invention, the present invention will be described in as much detail herein. It will be apparent to those skilled in the art that in this context, the materials and methods of operation used in the present invention are well known in the art, if not specifically described.

Example 1

This embodiment is an exemplary illustration of the present invention's phototriode system.

As shown in fig. 9, the phototransistor system of the present invention includes:

the light source module comprises a pumping light source and a signal light source which are respectively used for exciting excitons in the Van der Waals material and transmitting signal light to be processed.

And the silicon-based micro-ring resonant cavity is coupled to the micro-ring resonant cavity after signal light is transmitted in the straight waveguide and interacts with the TMDs material layer to amplify or attenuate an optical signal. And

The signal light is input into the straight waveguide of the micro-ring resonant cavity structure by the signal light source, the other end of the signal light is connected with the photoelectric detector and the computer after being modulated by the micro-ring structure, so that the modulation result is visualized, the Van der Waals material layer is covered above the micro-ring structure of the resonant cavity, excitons can be generated under the irradiation of the pumping light source, the refractive index is changed, the function of modulating the signal light is achieved, the pumping light irradiates on the Van der Waals material, if the pumping light source is externally connected with a signal generator, different waveforms (such as square waves, sine waves, triangular waves and the like) can be generated, and therefore the capability of pumping light modulation signal light can be observed better.

The preparation method of the phototriode system comprises the following steps:

1) Van der Waals material layer selection

A layer of van der waals material having specific band gaps and optical properties is selected and prepared. Van der Waals materials include graphene, TMDs, and the like, and have extremely wide optical response ranges, covering the ultraviolet to terahertz and even extending to the microwave frequency range. Particularly TMDs materials, including molybdenum disulfide, molybdenum diselenide, tungsten disulfide, tungsten diselenide, etc., with band gaps between 1.0eV and 2.0eV, so that electrons can be excited by visible light in the near infrared band. Therefore, the function of the phototriode can be realized by selecting pump light with proper wavelength according to the band gap of the material. The van der waals material of the present embodiment is exemplified by tungsten disulfide, but is not limited to this material, and other van der waals materials may be used. The wavelength of the pump light of this embodiment is exemplified by 520nm, and the wavelength of the signal light is exemplified by 1540 to 1545 nm.

2) Preparation and optimization of silicon-based micro-ring resonant cavity

As shown in fig. 2, the micro-ring resonator comprises a straight waveguide, a micro-ring waveguide, a substrate, a waveguide layer, a silicon dioxide layer and a cladding layer, wherein,

The silicon dioxide layer is arranged on the substrate, the waveguide layer is arranged on the silicon dioxide layer, the cladding layer covers the waveguide layer, the straight waveguide and the micro-ring waveguide are arranged on the waveguide layer, and the Van der Waals material (tungsten disulfide) transferred by a mechanical dry method is covered above the micro-ring waveguide. The materials of the straight waveguide and the micro-ring waveguide are exemplified by silicon, the materials of the substrate are exemplified by silicon, and the materials of the coating layer are exemplified by silicon dioxide.

The structure of the micro-ring resonator requires comprehensive consideration of a plurality of key factors including the width of the waveguide layer, the radius of the micro-ring waveguide, and the gap width between the straight waveguide and the micro-ring waveguide.

(1) In consideration of compatibility of the all-optical triode in the silicon-based photonic integrated circuit, the dimensions of the silicon waveguide layer in the embodiment are set to be 400nm in width and 220nm in height, so as to ensure seamless butt joint with the prior art.

(2) In the embodiment, the radius of the micro-ring waveguide is set to be 10 μm, so that high-density integration is realized, and meanwhile, loss generated when the waveguide is bent can be effectively reduced, and the overall performance is improved.

(3) The gap width between the straight waveguide and the micro-ring waveguide is optimized. The gap width finally determined by the embodiment is 90nm, so that the precision requirement of a processing technology can be met, and the coupling efficiency can be obviously improved.

3) Structure of phototriode

The main structure of the phototriode is shown in fig. 9, and the phototriode in fig. 9 comprises a light source module, a van der waals material layer and a silicon-based micro-ring resonant cavity, which together form a modulation area of the all-phototriode. The three components are added with the photoelectric detector to form the complete phototriode system. In this embodiment, the photodetector is exemplified by a visible light detector for receiving the pump light signal and a near infrared detector for receiving the output signal light, the straight waveguide and the micro-ring waveguide are exemplified by silicon waveguides, and the hatched portion on the micro-ring waveguide is a covered van der waals material. The optical signal has two beams, namely signal light and pump light. The signal light is input from the port at one end of the straight waveguide, coupled by the micro-ring resonant cavity, and output from the port at the other end of the straight waveguide. The pump light is irradiated on the van der Waals material for changing the dielectric environment of the micro-ring waveguide, thereby changing the transmission intensity of the output signal light.

Examples 2 to 4

This embodiment is another exemplary illustration of the present invention.

The phototriode systems of examples 2-4 were the same as example 1 except for the conditions listed in Table 1.

Table 1 the phototriode systems of examples 2-4

Example 5

This example illustrates the results of a micro-ring resonator transmission spectrum simulation of the present invention.

In order to prove that the change of the refractive index of the van der Waals material can effectively modulate the transmission characteristic of signal light in the resonant cavity, tungsten sulfide is constructed as a van der Waals material layer, the width and the height of a waveguide layer are respectively 400nm and 220nm of a composite micro-ring resonant cavity, the radius of a micro-ring is 10um, the gap between the micro-ring and a straight waveguide is 90nm, and transmission spectrum analysis is carried out on the designed silicon-based micro-ring resonant cavity by utilizing Lumerical software.

As shown in fig. 3, the transmission spectrum before and after the refractive index change of the van der waals material at the resonance peak center wavelength. Under the condition that the refractive index of the van der Waals material is unchanged (namely, pump light is not irradiated), the resonance wavelength of the micro-ring is 1544.2nm. When the inventors changed the refractive index of the van der Waals material from 4 to 4.1, the resonance wavelength of the micro-ring was red shifted to 1544.6nm, and the shift amount of the resonance wavelength was about 0.4nm. This demonstrates that the change in refractive index of the van der waals material can effectively change the transmission characteristics of the signal light in the resonator.

Example 6

This example illustrates the results of a micro-ring resonator test of a triode system of the present invention.

Van der Waals material-silicon-based waveguide composite micro-ring resonant cavities in examples 1-4 are prepared by using a micro-nano processing technology, and an optical microscope image of a device in example 1 is shown in FIG. 4. The device is subjected to light passing test, the wavelength of input signals is 1535-1550 nm, the optical power is 10mW, the wavelength of pumping excitation light is 520nm, and the optical power is 0.5mW. Fig. 5-7 show the change of the transmission spectrum of the device signal light before and after the pump light switch.

Table 2 micro-ring resonator test results for the triode systems of examples 2-4

As shown in table 2, fig. 4, and fig. 5-fig. 7, when pump light modulation is applied to the two-dimensional material, the corresponding formants will all shift by a certain magnitude, which means that the micro-ring resonant cavities of the triode systems prepared in embodiments 1-4 can all achieve the full light modulation effect, that is, the state of a beam of externally applied pump light beam is used to control the signal light.

Example 7

This embodiment illustrates the amplifying and attenuating effects of the present invention.

The present embodiment uses the phototriode systems of embodiments 1-4.

For the triode system of example 1, when the pump light is not turned on, the resonant wavelength of the micro-ring is 1538.98nm, the full width at half maximum is 0.41nm, and the corresponding frequency bandwidth is 56GHz. The signal light intensity in the range of 1538.77nm to 1539.19nm is attenuated to less than half of the usual level. When the pump light is turned on, the resonance wavelength of the micro-ring is changed from 1538.98nm to 1539.14nm, and 0.16nm red shift is generated, and at the moment, the light intensity of input signal light in the range of 1538.93-1539.35nm can be attenuated to be less than half of that of normal light. Therefore, when the input signal light is 1538.77-1538.93nm, the amplifying effect of the input signal light can be realized under the irradiation of the pumping light, and when the wavelength of the input signal light is 1539.19-1539.35 nm, the attenuation effect of the input signal light can be realized under the irradiation of the pumping light, and the two sections can realize the continuous modulation of the signal light. Especially when the input signal light is 1538.77-1538.93nm, the amplifying effect on the signal light can be realized.

TABLE 3 amplification effects of the triode systems of examples 2-4

Examples	Signal light wavelength	Wavelength of pump excitation light	Optical amplification
				2	1533nm	660nm	1550.8-1551.6
3	1540nm	660nm	1544.2-1544.8
				4	1542nm	520nm	1543.5-1544.2

As shown in table 3, when pump light is applied, the phototriodes prepared from the materials always have the function of amplifying light in the corresponding signal light wave bands, which indicates that the micro-ring resonant cavities of the phototriodes prepared in embodiments 1-4 can achieve the effect of amplifying signals.

Example 8

This embodiment illustrates the effect of the present invention of a phototransistor system.

The present embodiment uses the phototriode systems of embodiments 1-4. When the wavelength of the input signal is at the resonance wavelength 1538.98nm, the device can realize the function of an optical switch.

Specifically, for the triode system of example 1, as shown in fig. 5, when the pump light is turned on, the resonance peak changes from 1538.98nm to 1539.14nm, and the resonance wavelength is red shifted by 0.16nm. Meanwhile, the transmittance of the pump light at 1539nm is 37% in the state of being off, and the transmittance of the pump light at 1539nm is 22% after being on, and the extinction ratio is approximately 2dB. In summary, these two states may be defined as the on state and the off state of the micro-ring optical switch, respectively.

In this example, the switching function of the device was tested using pump light having a wavelength of 520nm, a power of 0.5mW and a frequency of 1KHz, and the results obtained are shown in FIGS. 6 and 7 (the phototransistors of example 2 and example 3). The result shows that the response of the signal light is not delayed. Given that the ultrafast optical response and carrier relaxation time of two-dimensional van der waals materials are in the range of a few picoseconds, an all-optical modulator based on two-dimensional van der waals materials would ideally be possible to achieve GHz fast modulation.

TABLE 4 response speed Effect of the triode systems of examples 2-4

Examples	Signal light wavelength	Wavelength of pump excitation light	Frequency of	Results
					2	1533nm	660nm	1KHz	Delay-free
3	1540nm	660nm	1KHz	Delay-free
					4	1542nm	520nm	1KHz	Delay-free

As shown in Table 4 and FIG. 5, the response results of the phototriodes prepared by the materials do not generate delay under the modulation of the pump light of 1KHz, which indicates that the micro-ring resonant cavities of the phototriodes prepared in examples 1-4 can achieve the effect of normal operation under the modulation frequency of 1 KHz.

Although the effects of some embodiments are shown above, it will be understood by those skilled in the art that, according to the inventive concept, the foregoing other embodiments not specifically showing effects or other technical solutions of the present invention not shown in the embodiments can also achieve the following technical effects, which are equivalent to the embodiments and are stated in the summary of the invention:

Although the present invention has been described to a certain extent, it is apparent that appropriate changes may be made in the individual conditions without departing from the spirit and scope of the invention. It is to be understood that the invention is not to be limited to the described embodiments, but is to be given the full breadth of the claims, including equivalents of each of the elements described.

Claims

1. A phototransistor system, the phototransistor system comprising:

2. The triac system of claim 1, wherein:

3. A phototransistor system according to claim 1 or 2, wherein:

4. The system of any of claims 1 to 3, wherein the micro-ring resonator comprises a straight waveguide, a micro-ring waveguide, a substrate, a waveguide layer, a silicon dioxide layer, and a cladding layer, wherein,

5. The triac system of claim 4, wherein:

6. The phototransistor system of claim 4 or 5 wherein:

7. The phototransistor system of any of claims 1 to 6 wherein:

8. A method of modulating light, the method comprising modulating light using the phototransistor system of any of claims 1 to 7;

9. The method according to claim 8, wherein the method further comprises:

10. Use of a phototriode system according to any one of claims 1 to 7 for the preparation of a device for implementing an optical switching function and/or an optical amplifying function.