High-extinction-ratio Fano resonance modulator based on multi-ring cascade

Abstract

The invention relates to the field of photonic neural mimicry computing chips and photoelectric devices, and discloses a multi-ring cascade-based high-extinction-ratio Fano resonance modulator, which comprises three micro-ring resonant cavity coupling bus waveguides, rectangular waveguides are respectively arranged in coupling areas of three micro-rings and the bus waveguides, light is input from an I < nput > port, and the I < nput > port is communicated with the I < nput > port; the rectangular waveguide is coupled into the micro-ring resonant cavity through a coupling area of the bus waveguide and the micro-ring resonant cavity, after resonance is carried out in the three micro-ring resonant cavities, through the bus waveguide, output is carried out, and the rectangular waveguide is used for introducing an extra phase factor and converting an output spectrum in the micro-ring resonant cavity from a Lorenz line type to a Fano resonance line type. Three micro-ring resonant cavities are adopted to be coupled with a bus waveguide, and a rectangular waveguide is arranged in the coupling area of each of three micro-rings and the bus waveguide and is used for introducing an additional phase factor, so that an output spectrum in the micro-ring resonant cavities can be converted from a Lorenz line type to a Fano resonance line type, and the linearity of a resonance peak of the output spectrum can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photonic neuromorphic computing chips and optoelectronic devices, and specifically to a high extinction ratio Fano resonance modulator based on multi-ring cascade. Background Art

[0002] In the booming and promising frontier field of photonic neuromorphic networks, in order to successfully achieve efficient, accurate and complex optical computing functions, it is urgently needed for a large number of silicon photonic devices with diverse types and excellent performance to participate and work together. Among these numerous silicon photonic devices, silicon photonic modulators undoubtedly occupy a pivotal and irreplaceable key position. It is like the core hub of the entire photonic neuromorphic network system, and plays a vital role in achieving accurate and efficient optical computing.

[0003] The extinction of the currently available micro-ring resonant cavity Fano resonance modulator is relatively low, the output spectrum resonance peak of the silicon optical modulator is relatively low, and the modulator performance is poor due to the low extinction ratio. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a high extinction ratio Fano resonance modulator based on multi-ring cascade, which solves the problem that the low extinction ratio is not conducive to the silicon optical modulator to realize the modulation function.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a high extinction ratio Fano resonance modulator based on multi-ring cascade, comprising: three micro-ring resonant cavities coupled to a bus waveguide, wherein the coupling regions of the three micro-rings and the bus waveguide are each provided with a rectangular waveguide, light is input from an input port, and then coupled into the micro-ring resonant cavity through the coupling region of the bus waveguide and the micro-ring resonant cavity, resonates in the three micro-ring resonant cavities, and then is output through the bus waveguide.

[0006] Preferably, the rectangular waveguide is used to introduce an additional phase factor to transform the output spectrum in the microring resonant cavity from a Lorenz line type to a Fano resonance line type, thereby improving the linearity of the output spectrum resonance peak.

[0007] Preferably, the modulator is manufactured based on an SOI platform, and the waveguide width is 450 nm and the thickness is 220 nm.

[0008] Preferably, the modulator adopts a transmission matrix method to analyze its transmission characteristics. The transmission matrix method regards the entire silicon photonic device as a black box with multiple input and output ports. The response characteristics of each port are linked to various parameters of the device to obtain the response characteristics of each port of the device under different parameters. The relationship between the input and output ports of the device is expressed by the following formula: Its transmission matrix is Indicates that, and t and k satisfy: t 2 +k 2 =1, where t and k are the transmission coefficient and coupling coefficient respectively.

[0009] Preferably, the transmission matrix method is used to analyze the transmission characteristics of a silicon-based multi-ring cascade Fano resonant device, the output spectrum of which is: Where: E out is the output light field, E0 is the input light field, t and κ1(κ2) are the transmission coefficient and coupling coefficient of the coupling region, Δφ is the phase introduced by the rectangular waveguide in the coupling region, κ 2 =κ1κ2=1-t 2 , α is the linear loss coefficient, n eff is the effective refractive index, λ is the operating wavelength, and R is the radius of the microring resonator.

[0010] Preferably, the modulator performs modulation based on the plasma dispersion effect. When the free carrier concentration in the semiconductor material is changed, the real and imaginary parts of the refractive index of the material itself change accordingly. The influence of the free carrier concentration on the imaginary part of the refractive index (absorption coefficient) Δα of the material is expressed by the following empirical formula: Δα(λ)=3.52×10 -6 λ 2 ΔN+2.4×10 -6 λ 2 ΔP

[0011] Δn(λ)=-3.64×10 -10 λ 2 ΔN-3.51×10 -6 λ 2 ΔP 0.8

[0012] Where Δn and ΔP are the concentrations of electrons and holes, respectively (cm-3).

[0013] A method for using a high extinction ratio Fano resonance modulator based on multi-ring cascade, the method comprising:

[0014] Step 1: Connect the high extinction ratio Fano resonance modulator based on multi-ring cascade to the corresponding optical communication system or optical experimental device to ensure that the light is accurately input from the designated Input port and output from the bus waveguide Through port;

[0015] Step 2: According to the specific application requirements and working environment, set the working parameters of the modulator, including adjusting the radius of the micro-ring resonant cavity, the phase factor introduced by the rectangular waveguide, and the coupling coefficient, start the optical communication system or optical experimental device, input the optical signal into the modulator from the input port, and resonate the light in the three micro-ring resonant cavities;

[0016] Step 3: Use the transmission matrix method to monitor and analyze the transmission characteristics of the modulator in real time. By measuring the optical field intensity, wavelength and other parameters at the input and output ports, the modulator performance is evaluated in combination with the transmission matrix formula and related theories.

[0017] Step 4: Perform modulation operation based on plasma dispersion effect, by controlling the free carrier concentration in the semiconductor material to change the real and imaginary parts of the material's refractive index, so as to achieve modulation of the optical signal, and accurately adjust the carrier concentration according to specific modulation requirements;

[0018] Step 5: During use, continuously monitor the output spectrum of the modulator to ensure that the linearity of the output spectrum resonance peak meets the application requirements. If performance deviation occurs, promptly check the parameter settings and external working conditions and make adjustments and optimizations.

[0019] The present invention provides a high extinction ratio Fano resonance modulator based on multi-ring cascade.

[0020] Beneficial effects:

[0021] 1. The present invention adopts three micro-ring resonant cavities coupled with a bus waveguide, and each of the three micro-rings and the bus waveguide has a rectangular waveguide in the coupling region, which is used to introduce an additional phase factor, thereby converting the output spectrum in the micro-ring resonant cavity from a Lorenz line type to a Fano resonance line type, thereby improving the linearity of the output spectrum resonance peak.

[0022] 2. The present invention adopts a three-ring cascade method to improve the extinction ratio of the device. Light is input from the Input port, and then coupled into the micro-ring resonant cavity through the coupling region of the bus waveguide and the micro-ring resonant cavity. After resonating in the three micro-ring resonant cavities, it is output through the bus waveguide Through. This method can achieve a Fano resonance peak with a high extinction ratio for each resonant wavelength, so that its structure can be applied to silicon optical modulators, greatly improving the performance of the modulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural diagram of a multi-ring cascade Fano resonance modulator with a high extinction ratio based on a multi-ring cascade of the present invention;

[0024] Figure 2 A schematic diagram of a transmission matrix of a two-input and two-output port device of a multi-ring cascaded high extinction ratio Fano resonance modulator according to the present invention;

[0025] Figure 3 A schematic diagram showing the spectrum comparison of a single-ring and a three-ring cascade Fano resonance device of a high extinction ratio Fano resonance modulator based on a multi-ring cascade according to the present invention;

[0026] Figure 4 A schematic diagram of the modulation spectrum of a modulator based on a multi-ring cascaded high extinction ratio Fano resonance modulator according to the present invention. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example:

[0029] Please see attached Figure 1 -Attached Figure 4 The embodiment of the present invention provides a high extinction ratio Fano resonance modulator based on multi-ring cascade, including: three micro-ring resonant cavities coupled to a bus waveguide, each of the coupling regions of the three micro-rings and the bus waveguide is provided with a rectangular waveguide, light is input from an input port, and then coupled into the micro-ring resonant cavity through the coupling region of the bus waveguide and the micro-ring resonant cavity, resonates in the three micro-ring resonant cavities, and then is output through the bus waveguide.

[0030] The optical path difference generated by the light in the microring resonator during one cycle of resonance in the microring must be an integer multiple of the wavelength to achieve resonance enhancement, that is, to satisfy the following microring resonance equation:

[0031] 2πRn c =mλ

[0032] In other words, only the light with a phase difference of an integer multiple of 2π generated when it circles the microring resonator can resonate and enhance in the microring. At this time, the microring resonance equation can be expressed as:

[0033] 2πRβ=2πm

[0034] Where, the radius of the microring is R, the effective refractive index of the waveguide is nc, the mode propagation constant is β, the wavelength of light in vacuum is λ, and the resonance order is m.

[0035] Preferably, the rectangular waveguide is used to introduce an additional phase factor to transform the output spectrum in the microring resonant cavity from a Lorenz line type to a Fano resonance line type, thereby improving the linearity of the output spectrum resonance peak.

[0036] Preferably, the modulator is manufactured based on an SOI platform, and the waveguide width is 450 nm and the thickness is 220 nm.

[0037] Preferably, the modulator adopts the transmission matrix method to analyze its transmission characteristics. The transmission matrix method regards the entire silicon photonic device as a black box with multiple input and output ports. The response characteristics of each port are linked to various parameters of the device to obtain the response characteristics of each port of the device under different parameters. The relationship between the input and output ports of the device is expressed by the following formula: Its transmission matrix is Indicates that, and t and k satisfy: t 2 +k 2 =1, where t and k are the transmission coefficient and coupling coefficient respectively.

[0038] Preferably, the transmission matrix method is used to analyze the transmission characteristics of a silicon-based multi-ring cascade Fano resonant device, the output spectrum of which is: Where: E out is the output light field, E0 is the input light field, t and κ1(κ2) are the transmission coefficient and coupling coefficient of the coupling region, Δφ is the phase introduced by the rectangular waveguide in the coupling region, κ 2 =κ1κ2=1-t 2 , α is the linear loss coefficient, n eff is the effective refractive index, λ is the operating wavelength, and R is the radius of the microring resonator.

[0039] Preferably, the modulator performs modulation based on the plasma dispersion effect. When the free carrier concentration in the semiconductor material is changed, the real and imaginary parts of the refractive index of the material itself change accordingly. The influence of the free carrier concentration on the imaginary part of the refractive index (absorption coefficient) Δα of the material is expressed by the following empirical formula: Δα(λ)=3.52×10 -6 λ 2 ΔN+2.4×10 -6 λ 2 ΔP

[0040] Δn(λ)=-3.64×10 -10 λ 2 ΔN-3.51×10 -6 λ 2 ΔP 0.8

[0041] Where Δn and ΔP are the concentrations of electrons and holes, respectively (cm-3).

[0042] Figure 4 As shown in the figure, when the voltage is applied to the multi-ring cascade structure modulator, the carrier concentration in the waveguide can be changed, thereby adjusting the effective refractive index of the waveguide to achieve the modulation function.

[0043] A method for using a high extinction ratio Fano resonance modulator based on multi-ring cascade, the method comprising:

[0044] Step 1: Connect the high extinction ratio Fano resonance modulator based on multi-ring cascade to the corresponding optical communication system or optical experimental device to ensure that the light is accurately input from the specified Input port and output from the bus waveguide Through port;

[0045] Step 2: According to the specific application requirements and working environment, set the working parameters of the modulator, including adjusting the radius of the micro-ring resonant cavity, the phase factor introduced by the rectangular waveguide, and the coupling coefficient, start the optical communication system or optical experimental device, input the optical signal into the modulator from the input port, and resonate the light in the three micro-ring resonant cavities;

[0046] Step 3: Use the transmission matrix method to monitor and analyze the transmission characteristics of the modulator in real time. By measuring the optical field intensity, wavelength and other parameters at the input and output ports, the modulator performance is evaluated in combination with the transmission matrix formula and related theories.

[0047] Step 4: Perform modulation operation based on plasma dispersion effect, by controlling the free carrier concentration in the semiconductor material to change the real and imaginary parts of the material's refractive index, so as to achieve modulation of the optical signal, and accurately adjust the carrier concentration according to specific modulation requirements;

[0048] Step 5: During use, continuously monitor the output spectrum of the modulator to ensure that the linearity of the output spectrum resonance peak meets the application requirements. If performance deviation occurs, promptly check the parameter settings and external working conditions and make adjustments and optimizations.

[0049] When the working mode or application scenario of the modulator is changed, the parameters of the modulator are reconfigured and optimized to adapt to the new requirements.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high extinction ratio Fano resonance modulator based on multi-ring cascade, characterized in that: include: Three micro-ring resonant cavities are coupled to a bus waveguide. A rectangular waveguide is provided in each coupling region between the three micro-rings and the bus waveguide. Light is input from an input port, and then coupled into the micro-ring resonant cavity through the coupling region between the bus waveguide and the micro-ring resonant cavity. After resonating in the three micro-ring resonant cavities, the light is output through the bus waveguide.

2. The high extinction ratio Fano resonance modulator based on multi-ring cascade according to claim 1, characterized in that: The rectangular waveguide is used to introduce an additional phase factor, transforming the output spectrum in the microring resonant cavity from a Lorenz line type to a Fano resonance line type, thereby improving the linearity of the output spectrum resonance peak.

3. The high extinction ratio Fano resonance modulator based on multi-ring cascade according to claim 1, characterized in that: The modulator is manufactured based on an SOI platform, and has a waveguide width of 450nm and a thickness of 220nm.

4. The high extinction ratio Fano resonance modulator based on multi-ring cascade according to claim 1, characterized in that: The modulator adopts the transmission matrix method to analyze its transmission characteristics. The transmission matrix method regards the entire silicon photonic device as a black box with multiple input and output ports. The response characteristics of each port are linked to various parameters of the device to obtain the response characteristics of each port of the device under different parameters. The relationship between the input and output ports of the device is expressed by the following formula: Its transmission matrix is Indicates that, and t and k satisfy: t 2 +k 2 =1, where t and k are the transmission coefficient and coupling coefficient respectively.

5. The high extinction ratio Fano resonance modulator based on multi-ring cascade according to claim 1, characterized in that: The transmission matrix method is used to analyze the transmission characteristics of silicon-based multi-ring cascade Fano resonant devices. The output spectrum of the device is: Where: E out is the output light field, E0 is the input light field, t and κ1(κ2) are the transmission coefficient and coupling coefficient of the coupling region, Δφ is the phase introduced by the rectangular waveguide in the coupling region, κ 2 =κ1κ2=1-t 2 , α is the linear loss coefficient, n eff is the effective refractive index, λ is the operating wavelength, and R is the radius of the microring resonator.

6. The high extinction ratio Fano resonance modulator based on multi-ring cascade according to claim 1, characterized in that: The modulator performs modulation based on the plasma dispersion effect. When the free carrier concentration in the semiconductor material is changed, the real and imaginary parts of the refractive index of the material itself change accordingly. The influence of the free carrier concentration on the imaginary part of the refractive index (absorption coefficient) Δα of the material is expressed by the following empirical formula: Δα(λ)=3.52×10 -6 λ 2 ΔN+2.4×10 -6 λ 2 ΔP Δn(λ)=-3.64×10 -10 l 2 ΔN-3.51×10 -6 l 2 ΔP 0.8 Where Δn and ΔP are the concentrations of electrons and holes, respectively (cm-3).

7. A method for using a high extinction ratio Fano resonance modulator based on multi-ring cascade, characterized in that: A high extinction ratio Fano resonance modulator based on multi-ring cascade as claimed in any one of claims 1 to 6, the method comprising: Step 1: Connect the high extinction ratio Fano resonance modulator based on multi-ring cascade to the corresponding optical communication system or optical experimental device to ensure that the light is accurately input from the specified Input port and output from the bus waveguide Through port; Step 2: According to the specific application requirements and working environment, set the working parameters of the modulator, including adjusting the radius of the micro-ring resonant cavity, the phase factor introduced by the rectangular waveguide, and the coupling coefficient, start the optical communication system or optical experimental device, input the optical signal into the modulator from the input port, and resonate the light in the three micro-ring resonant cavities; Step 3: Use the transmission matrix method to monitor and analyze the transmission characteristics of the modulator in real time. By measuring the optical field intensity, wavelength and other parameters at the input and output ports, the modulator performance is evaluated in combination with the transmission matrix formula and related theories. Step 4: Perform modulation operation based on plasma dispersion effect, by controlling the free carrier concentration in the semiconductor material to change the real and imaginary parts of the material's refractive index, so as to achieve modulation of the optical signal, and accurately adjust the carrier concentration according to specific modulation requirements; Step 5: During use, continuously monitor the output spectrum of the modulator to ensure that the linearity of the output spectrum resonance peak meets the application requirements. If performance deviation occurs, promptly check the parameter settings and external working conditions and make adjustments and optimizations.

Images