CN109491175B - Reconfigurable steering logic device based on mode multiplexing - Google Patents
Reconfigurable steering logic device based on mode multiplexing Download PDFInfo
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Abstract
The invention provides a reconfigurable steering logic device based on mode multiplexing, which comprises a demultiplexer, a micro-ring array and a multiplexer which are sequentially connected; the demultiplexer comprises three S-shaped waveguides and four straight waveguides which are connected in sequence, and adjacent straight waveguides are connected through a heat insulation cone; the micro-ring array comprises four straight waveguides which are arranged side by side and have the same width, each straight waveguide is coupled with a group of micro-ring groups, and each micro-ring group consists of a first micro-ring and a second micro-ring which are arranged at intervals; the multiplexer (3) comprises three S-shaped waveguides and four straight waveguides which are connected in sequence; adjacent straight waveguides are connected through an adiabatic taper. The logic device can solve the problem that a common guide logic device can only realize single logic operation, can also solve the problem that a reconfigurable guide logic device based on wavelength division multiplexing needs a plurality of lasers, can realize arbitrary logic operation, greatly reduces the cost from the source, and has good application prospect in optical information processing.
Description
Technical Field
The invention belongs to the technical field of optical information processing, and relates to a reconfigurable guide logic device based on mode multiplexing.
Background
From the birth of the first transistor in 1947 to the rise of artificial intelligence in the early 21 st century, the rapid development of the first transistor is as short as several decades, and the microelectronic technology has penetrated into the point drop in our lives. However, with the development of information technology in recent years, there is an increasing demand for high-capacity, high-rate communication. The number of cores of the CPU based on the ARM architecture is increasing, the number of transistors integrated on a single core is increasing, the size of the transistors is decreasing, the problems of on-chip metal interconnection, power consumption and heat dissipation are becoming more and more troublesome, and moore's law is becoming more and more difficult to continue. There are various indications that the use of information technology using photons as carriers instead of electronic information technology is imminent. The optical fiber and various optical elements constitute an integrated optical circuit, which can greatly improve the data operation and transmission capability. Reconfigurable steering logic is an important component of optical information processing. Compared with the common logic device, the guide logic device has expandability in structure and is more perfect in function. The common guide logic device can only realize single logic function and has no universality.
Currently, the developed steering logic devices are generally based on wavelength division multiplexing technology. As early as 2011, Q, Xu et al first published the article "configurable optical direct-localized circuits using micro-responder-based optical switches" (Optics Express, Vol. 19, Issue 6, pp. 5244-. Since the concept of reconfigurable logic is put forward for the first time, q, Xu and the like firstly use an 8-bit priority encoder to verify the idea, but a photoelectric converter is required to be used in the device, so that the device is more complicated, the cost is increased, and the large-scale integration is not facilitated. Furthermore, Y. Tian et al, which utilizes wavelength division multiplexing technology, implement reconfigurable steering logic devices capable of producing arbitrary logic combinations, and the science and technology article "Experimental evaluation of area configurable electronic-oriented logic circuit using modeled carrier-injection micro-ring detectors" (Scientific Reports, Vol. 7, Issue 1, pp:6410 (2017)), and so on. However, the guide logic device based on wavelength division multiplexing needs a plurality of laser light sources, and the cost is high; furthermore, wavelength division multiplexing is also becoming a bottleneck due to the limited wavelength range of the available C-band, which results in the limited channels available for wavelength division multiplexing. To solve this problem, a new optical signal multiplexing method, i.e., mode multiplexing, has been proposed. The mode multiplexing technology is a technology of multiplexing different modes of light onto a multimode fiber or a few-mode fiber for transmission, and demultiplexing the different modes into corresponding signals at a receiving end.
Disclosure of Invention
The invention aims to provide a reconfigurable guide logic device based on mode multiplexing, which can realize the operation of any logic function and bring great convenience to the realization of various complex logic operations.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a reconfigurable steering logic device based on mode multiplexing comprises a demultiplexer, a micro-ring array and a multiplexer which are sequentially connected;
the demultiplexer comprises a first S-shaped waveguide, a second S-shaped waveguide, a third S-shaped waveguide, a first straight waveguide, a second straight waveguide, a third straight waveguide and a fourth straight waveguide which are connected in sequence, wherein two adjacent straight waveguides are connected through a heat insulation cone; the width of the first straight waveguide is greater than that of the second straight waveguide, the width of the second straight waveguide is greater than that of the third straight waveguide, and the width of the third straight waveguide is greater than that of the fourth straight waveguide;
the widths of the first S-shaped waveguide, the second S-shaped waveguide, the third S-shaped waveguide and the fourth straight waveguide are the same;
one end of the first S-shaped waveguide is coupled with the first straight waveguide, one end of the second S-shaped waveguide is coupled with the second straight waveguide, and one end of the third S-shaped waveguide is coupled with the fourth straight waveguide; the other end of the first S-shaped waveguide, the other end of the third straight waveguide, the other end of the second S-shaped waveguide and the other end of the third S-shaped waveguide are connected with the micro-ring array;
the micro-ring array comprises a fifth straight waveguide, a sixth straight waveguide, a seventh straight waveguide and an eighth straight waveguide which are arranged side by side and have the same width, one end of the fifth straight waveguide is connected with the other end of the second S-shaped waveguide, one end of the sixth straight waveguide is connected with the other end of the fourth straight waveguide, one end of the seventh straight waveguide is connected with the other end of the third S-shaped waveguide, and one end of the eighth straight waveguide is connected with one end of the first S-shaped waveguide; the other end of the fifth straight waveguide, the other end of the sixth straight waveguide, the other end of the seventh straight waveguide and the other end of the eighth straight waveguide are connected with the multiplexer;
a group of micro-ring groups are coupled on the fifth straight waveguide, the sixth straight waveguide, the seventh straight waveguide and the eighth straight waveguide, and each micro-ring group consists of a first micro-ring MRR and a second micro-ring MRR which are arranged at intervals; the size and the width of the first micro-ring MRR are the same as those of the second micro-ring MRR, and the coupling distances between all the micro-rings MRR and the straight waveguides coupled with the micro-rings MRR are the same;
the multiplexer comprises a fourth S-shaped waveguide, a fifth S-shaped waveguide, a sixth S-shaped waveguide, a ninth straight waveguide, a tenth straight waveguide, an eleventh straight waveguide and a twelfth straight waveguide which are connected in sequence; two adjacent straight waveguides are connected through a heat insulation cone; one end of the fourth S-shaped waveguide is coupled with the ninth straight waveguide, one end of the fourth S-shaped waveguide is connected with the other end of the eighth straight waveguide, one end of the fifth S-shaped waveguide is coupled with the tenth straight waveguide, the other end of the fifth S-shaped waveguide is connected with the other end of the fifth straight waveguide, one end of the sixth S-shaped waveguide is coupled with the eleventh straight waveguide, the other end of the sixth S-shaped waveguide is connected with the other end of the seventh straight waveguide, and the other end of the twelfth straight waveguide is connected with the other end of the sixth straight waveguide. The fourth S-shaped waveguide, the fifth S-shaped waveguide, the sixth S-shaped waveguide and the twelfth straight waveguide have the same width
The reconfigurable steering logic device has the following advantages:
1. the natural characteristics of light are utilized, and high-speed and high-capacity information processing can be realized; the mature CMOS process technology is utilized, so that the device has high integration level, small volume, low power consumption and good expansibility, is convenient to integrate with electrical elements, greatly reduces the manufacturing cost of the device, and plays an important role in optical information processing in the future. The method has the characteristics of easy integration, low power consumption and compatibility with a CMOS (complementary metal oxide semiconductor) process, and fundamentally solves the problem of information capacity in the development of modern integrated circuits.
2. Each optical switch based on the microring resonator in the reconfigurable guided logic device structure is independent, and all the switches work simultaneously and in parallel, which means that the delay of each switch is not accumulated, and the final result is output in the form of light beams at the optical output end, so that the processing speed of the whole device is much higher than that of an electric device.
3. The reconfigurable guiding logic device based on wavelength division multiplexing can not only solve the problem that a common guiding logic device can only realize single logic operation, but also solve the problem that the reconfigurable guiding logic device based on wavelength division multiplexing needs a plurality of lasers, and can realize arbitrary logic operation. Therefore, the method has good application prospect in optical information processing in the future.
4. Only one wavelength is needed to be input at the input end, a plurality of laser light sources are not needed, and the cost is greatly reduced from the source.
Drawings
FIG. 1 is a schematic diagram of a reconfigurable steering logic device of the present invention.
Figure 2 is a schematic diagram of a demultiplexer in the reconfigurable steering logic device of the present invention.
Figure 3 is a schematic diagram of a micro-ring array in a reconfigurable steering logic device of the present invention.
Figure 4 is a schematic diagram of a multiple loop single waveguide structure forming a micro-loop array in a reconfigurable guided logic device of the present invention.
Figure 5 is a schematic diagram of a multiplexer in the reconfigurable steering logic device of the present invention.
Fig. 6 is a graph of the spectral response of a microring resonator, using silicon-based electro-optic modulation as an example.
Fig. 7 is a schematic cross-sectional structure diagram of a silicon-based thermo-optically modulated micro-ring resonator or straight waveguide.
Fig. 8 is a schematic cross-sectional structure diagram of a silicon-based electro-optically modulated micro-ring resonator or straight waveguide.
Fig. 9 is a specific example illustrating the working principle of the present invention.
Fig. 10 is a waveform diagram of an input signal and an output signal.
Figure 11 is a block diagram of the operation of the reconfigurable steering logic device of the present invention.
In the figure: 1. the optical fiber coupler comprises a demultiplexer, 2. a microring array, 3. a multiplexer, 1-1. a first straight waveguide, 1-2. a first S-type waveguide, 1-3. a second straight waveguide, 1-4. a second S-type waveguide, 1-5. a third straight waveguide, 1-6. a third S-type waveguide, 1-7. a fourth straight waveguide, 2-1. a first microring MRR, 2-2. a second microring MRR, 2-3. a fifth straight waveguide, 2-4. a sixth straight waveguide, 2-5. a seventh straight waveguide, 2-6. an eighth straight waveguide, 3-1. a ninth straight waveguide, 3-2. a fourth S-type waveguide, 3-3. a tenth straight waveguide, 3-4. a fifth S-type waveguide, 3-5. an eleventh straight waveguide, 3-6. a sixth S-type waveguide, and 3-7. a twelfth straight waveguide.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, the reconfigurable steering logic device of the present invention includes a demultiplexer 1, a micro-ring array 2 and a multiplexer 3 connected in sequence.
As shown in fig. 2, a demultiplexer 1 in the reconfigurable guided logic device of the present invention includes a first S-type waveguide 1-2, a second S-type waveguide 1-4, a third S-type waveguide 1-6, and a first straight waveguide 1-1, a second straight waveguide 1-3, a third straight waveguide 1-5, and a fourth straight waveguide 1-7 connected in sequence, where two adjacent straight waveguides are connected by an Adiabatic Taper (Adiabatic Taper); the width of the first straight waveguide 1-1 is larger than that of the second straight waveguide 1-3, the width of the second straight waveguide 1-3 is larger than that of the third straight waveguide 1-5, and the width of the third straight waveguide 1-5 is larger than that of the fourth straight waveguide 1-7.
The first S-shaped waveguide 1-2, the second S-shaped waveguide 1-4, the third S-shaped waveguide 1-6 and the fourth straight waveguide 1-7 have the same width.
One end of a first S-shaped waveguide 1-2 is coupled with a first straight waveguide 1-1, one end of a second S-shaped waveguide 1-4 is coupled with a second straight waveguide 1-3, and one end of a third S-shaped waveguide 1-6 is coupled with a fourth straight waveguide 1-7; the other end of the first S-shaped waveguide 1-2, the other end of the third straight waveguide 1-7, the other end of the second S-shaped waveguide 1-4 and the other end of the third S-shaped waveguide 1-6 are all connected with the micro-ring array 2.
As shown in fig. 3, the micro-ring array 2 in the reconfigurable guiding logic device of the invention includes a fifth straight waveguide 2-3, a sixth straight waveguide 2-4, a seventh straight waveguide 2-5 and an eighth straight waveguide 2-6 which are arranged side by side and have the same width, wherein one end of the fifth straight waveguide 2-3 is connected with the other end of the second S-shaped waveguide 1-4, one end of the sixth straight waveguide 2-4 is connected with the other end of the fourth straight waveguide 1-7, one end of the seventh straight waveguide 2-5 is connected with the other end of the third S-shaped waveguide 1-6, and one end of the eighth straight waveguide 2-6 is connected with one end of the first S-shaped waveguide 1-2; the other end of the fifth straight waveguide 2-3, the other end of the sixth straight waveguide 2-4, the other end of the seventh straight waveguide 2-5 and the other end of the eighth straight waveguide 2-6 are all connected with the multiplexer 3.
A space or an insulator which can prevent the two micro-rings MRR from generating thermal crosstalk is arranged between the two adjacent micro-rings MRR.
A group of micro-ring groups are coupled on the fifth straight waveguide 2-3, the sixth straight waveguide 2-4, the seventh straight waveguide 2-5 and the eighth straight waveguide 2-6, and each micro-ring group consists of a first micro-ring MRR2-1 and a second micro-ring MRR2-2 which are arranged at intervals; the size and width of the first microring MRR2-1 are the same as those of the second microring MRR2-2, and the coupling pitches between all the microrings MRRs and the straight waveguides to which the microrings MRRs are coupled are the same. One micro-ring group and a straight waveguide coupled to the micro-ring group constitute a multi-ring single waveguide structure shown in fig. 4, and a plurality of multi-ring single waveguide structures arranged in parallel constitute a micro-ring array 2.
As shown in fig. 5, the multiplexer 3 in the reconfigurable guided logic device of the present invention includes a fourth S-shaped waveguide 3-2, a fifth S-shaped waveguide 3-4, a sixth S-shaped waveguide 3-6, and a ninth straight waveguide 3-1, a tenth straight waveguide 3-3, an eleventh straight waveguide 3-5, and a twelfth straight waveguide 3-7 connected in sequence; two adjacent straight waveguides are connected through an adiabatic cone. One end of a fourth S-shaped waveguide 3-2 is coupled with the ninth straight waveguide 3-1, one end of the fourth S-shaped waveguide 3-2 is connected with the other end of the eighth straight waveguide 2-6, one end of a fifth S-shaped waveguide 3-4 is coupled with the tenth straight waveguide 3-3, the other end of the fifth S-shaped waveguide 3-4 is connected with the other end of the fifth straight waveguide 2-3, one end of a sixth S-shaped waveguide 3-6 is coupled with the eleventh straight waveguide 3-5, the other end of the sixth S-shaped waveguide 3-6 is connected with the other end of the seventh straight waveguide 2-5, and the other end of the twelfth straight waveguide 3-7 is connected with the other end of the sixth straight waveguide 2-4. The fourth S-shaped waveguide 3-2, the fifth S-shaped waveguide 3-4, the sixth S-shaped waveguide 3-6 and the twelfth straight waveguide 3-7 have the same width.
The demultiplexer 1 and the multiplexer 3 are implemented by using a directional coupler, a micro-ring resonator, a Y-branch or a grating coupler, and the like.
The mode input to the first straight waveguide 1-1 includes TEm···TE2,TE1,TE0And (5) molding. TE in the first straight waveguide 1-1mModes and TE supported by the first S-shaped waveguide 1-20The mode satisfies the index matching condition, therefore TEmThe mode is coupled down into the first S-shaped waveguide 1-2 and converted into a fundamental mode TE0. In addition, some of the TE in the first straight waveguide 1-1 are not completely coupledmThe mode, which is dissipated while continuing to propagate forward through the Adiabatic Taper (Adiabatic Taper), does not cause any interference with the mode coupling of the next order. Similarly, TE in the second straight waveguide 1-32Modes and TE supported by the second S-shaped waveguide 1-40The mode satisfies the index matching condition, therefore TE2The mode is coupled down to the second S-shaped waveguide 1-4 and converted to TE0And (5) molding. Therefore, after coupling for several times, all the straight waveguides entering the module two-microring array 2 are the fundamental mode TE0。
The micro-ring array 2 is formed by arranging m × n micro-rings and m straight waveguides, the coupling pitches of the micro-rings and the straight waveguides are the same, and the basic structure of the micro-ring array is an MRR-based optical switch. The two working modes adopted by the device are a bar/cross state and a cross/bar state respectively, as shown in fig. 6, the device represents an optical signal through state after the micro-ring is loaded with a high level and an optical signal blocked state after the micro-ring is loaded with the high level. The straight waveguides in the micro-ring array 2 comprise a fifth straight waveguide 2-3, a sixth straight waveguide 2-4, a seventh straight waveguide 2-5 and an eighth straight waveguide 2-6, and all the straight waveguides are used for transmitting fundamental mode TE0. The resonance wavelength of each micro-ring MRR is changed by modulating each micro-ring MRR by using an electric signal, including changing the group refractive index of the annular waveguide by generating heat or changing the carrier concentration in a material, and the logic operation obtained by the output of each straight waveguide after passing through the micro-ring array 2 is
Wherein
And
the dynamic voltage signal loaded on the micro-ring is called the number to be operated, and will directly participate in logic operationNumber (n). And is
And
micro-rings corresponding to two different resonance states, the former representing the bar/cross state and the latter representing the cross/bar state, i.e.
When the micro-ring is loaded with high level, the optical signal is in a direct connection state,
the optical signal is directly connected when the low level is loaded. Since all the micro-rings are the same and have the same resonance wavelength, to obtain two different resonance wavelengths, a pre-modulation voltage needs to be loaded on one of the micro-rings.
The micro-ring array 2 inputs into the fourth S-shaped waveguide 3-2, the fifth S-shaped waveguide 3-4, the sixth S-shaped waveguide 3-6 and the twelfth straight waveguide 3-7, and all of the fundamental mode TE carrying the AND operation result0A signal. After mode coupling, the fundamental mode TE of the sixth S-shaped waveguide 3-60And TE supported by the eleventh straight waveguide 3-51The refractive index matching condition is satisfied, and thus the fundamental mode TE of the sixth S-type waveguides 3 to 60Is coupled down to the eleventh straight waveguide 3-5 and converted into TE1Mode(s). Similarly, TE of the fifth S-shaped waveguide 3-40The fundamental mode is coupled down into the tenth waveguide 3-3 and converted into TE2Mode(s). After multiple times of coupling downloading, the OR operation is finally completed in the ninth straight waveguide 3-1 at the total output end, and Y = Y is obtained1+y2+···ym。
The narrow waveguide and the wide waveguide in the demultiplexer 1 and the multiplexer 3 are connected by an Adiabatic Taper (Adiabatic Taper) with a sufficient length, the width of the Adiabatic Taper (Adiabatic Taper) is linearly changed from the width of the narrow waveguide to the width of the wide waveguide, and the Adiabatic Taper (Adiabatic Taper) is sufficiently long, so that the expansion of the side edge of the Adiabatic Taper (Adiabatic Taper) waveguide is slower than the diffraction expansion of the optical mode, thereby ensuring that the fundamental mode is not subjected to mode conversion when passing through, and reducing crosstalk between modes.
The reconfigurable guiding logic device inputs an electric signal sequence to be processed and a multimode single-wavelength continuous optical signal, outputs an optical signal after the electric signal operation, wherein the basic unit of each micro-ring MRR is a micro-ring resonator MRR optical switch with a thermal modulation mechanism or an electric modulation mechanism, and the processing process is as follows: inputting multimode single wavelength continuous laser including TE at an optical port of a reconfigurable guided logic devicem···TE2,TE2,TE0Mode, the demultiplexer process is TE in the first straight waveguide 1-1mMode and TE supported by the first S-shaped waveguide 1-20The mode satisfies the index matching condition (i.e., effective refractive index)N eff1 =N eff2 Effective coupling of light in the two waveguides when the effective refractive indices of the two waveguides are matched for light in different modes, otherwise no coupling occurs), TEmThe mode is downloaded into the first S-shaped waveguide 1-2 and converted to the fundamental mode TE0And continuing to transmit. Similarly, TE in the second straight waveguide 1-32The mode is downloaded into the second S-shaped waveguide 1-4 and converted to TE0And continuing to transmit. Thus, the modes input into the straight waveguides in the microring array 2 are all fundamental mode TE0The n-bit binary electrical signal to be calculated acts on m × n MRRs in the form of a voltage signal, and a second micro-ring MRR2-2 in fig. 3 indicates that when the micro-ring is loaded with a high level, the micro-ring resonates at the operating wavelength, and when the micro-ring is loaded with a low level, the micro-ring does not resonate at the operating wavelength; the first micro-ring MRR2-1 indicates that when the micro-ring is loaded with high level, the micro-ring is not resonant at the working wavelength, when the micro-ring is loaded with low level, the micro-ring is resonant at the working wavelength, the other end of each straight waveguide in the micro-ring array outputs the logical AND operation result of the electrical signals input by n bits in the form of optical logic, and the basic mode TE carrying the AND operation result0Transmitting to S-shaped waveguide again, downloading to corresponding straight waveguide to complete OR operation, and outputting TE at output endm···TE2,TE1,TE0And carrying out modulo operation on any logic function.
The micro-ring MRR structure can also be realized by SOI, SIN and III-V materials. The optimized scheme of the invention is realized based on SOI material, and has the outstanding advantages that; the technology utilizes the existing CMOS technology, so that the device has small volume, low power consumption and good expansibility, and is convenient to integrate with electrical elements.
The performance advantage of the invention is closely related to the material property and the structure of the device.
In terms of materials: the present invention uses Silicon-On-Insulator (SOI) material On an insulating substrate. SOI refers to the formation of SiO2A monocrystalline silicon film with a certain thickness is grown on the insulating layer, and the process is compatible with the CMOS process widely applied in the field of microelectronics at present. Silicon waveguide made of SOI material, with Si (refractive index of 3.45) as core layer and SiO as cladding layer2(refractive index 1.44) so that the difference between the refractive indices of the cladding and core layers is large, the waveguide has a strong confinement capability to the optical field so that the bend radius can be small.
The following is a brief description of the working principle of the micro-ring MRR shown in fig. 4 by analyzing the transmission process of optical signals:
demorgen's Law in terms of Boolean algebra:
then, any one of the logic functions can be represented in the form of a logical operation "and", i.e., Y = Y1+y2+···ym，Wherein
. That is, the expression of any one logical operation can be set to Y = Y1+y2+···ymA form of (1), wherein ymThe output result representing each straight waveguide in the micro-ring array is an and operation of n operands (e.g.:
). The principle of designing the structure of the device is that multipath signals simultaneously complete AND operation and then OR operation is realized, so that the operation of any logic function is realized.
The modulation principle is illustrated by taking fig. 6 (electro-optical modulation of carrier injection) as an example: lambda [ alpha ]1，λ2Respectively shows the positions of the resonance wavelengths of the first micro-ring MRR2-1 and the second micro-ring MRR2-2 when no voltage is applied, and the working wavelength lambdawIs selected at lambda1To (3). The working principle of the electro-optical modulation scheme of the plasma dispersion effect is explained. After passing through the demultiplexer 1, the light input to the micro-ring array 2 has a wavelength of an operating wavelength λ1TE of basic model0Signal, input to the input of fig. 4. When the second micro-ring MRR2-2 is at the high level deltaVAt a resonance wavelength from λ2Move to λ1(when a high level is applied, carriers are injected into the waveguide region, the refractive index of the waveguide becomes small, and the resonance wavelength shifts from long wavelength to short wavelength), by this definition, for the first microring MRR2-1, the optical signal is 0 when the electrical signal is 0, and the optical signal is 1 when the electrical signal is 1, and for the second microring MRR2-2, the optical signal is 1 when the electrical signal is 0, and the optical signal is 0 when the electrical signal is 1. So that logical operation can be obtained at the output port of the straight waveguide
Wherein
Representing the number of pending operations loaded on the first micro-ring MRR2-1 and the second micro-ring MRR 2-2.
The tuning electrode of the reconfigurable steering logic device of the present invention may be a thermal modulation mechanism or an electrical modulation mechanism. The cross-sectional structure of the silicon-based thermo-optically modulated micro-ring resonator or the straight waveguide is shown in FIG. 7, and comprises a substrate Si on which SiO is arranged2Layer of SiO2The layer is provided with a Si waveguide core region and a tuning electrode, and SiO is surrounded around the waveguide and the tuning electrode2. The width of the Si waveguide core region is W, and the height of the Si waveguide core region is H; distance between top surface of Si waveguide core region and bottom surface of tuning electrodeIs dSiO2(ii) a The cross-sectional structure of a silicon-based electro-optically modulated micro-ring resonator or straight waveguide is shown in fig. 8.
The MRR with the thermal modulation mechanism or the electric modulation mechanism can adopt thermal modulation under the condition of low requirement on signal transmission rate (below M magnitude), and adopts electric modulation in a high-speed (G magnitude) transmission system.
For a clearer description of the working principle of the reconfigurable steering logic device of the present invention, the following description will be given by taking the generation of logic functions as
By way of illustration, specific examples of (c):
it is easy to know that the required logic signal is generated by three different dynamic signal types, so that three different light modes are required to be input, and the corresponding micro-ring array 2 is also a 3 × 3 micro-ring switch array. TE is input at the input end of the second straight waveguide 1-3 as shown in FIG. 90，TE1And TE2Three modes, after being demultiplexed, are input to the fifth straight waveguide 2-3, the sixth straight waveguide 2-4 and the seventh straight waveguide 2-5 which are all of the fundamental mode TE0A signal. In the micro-ring array, a constant voltage signal is applied to the following micro-ringsA 2=0,A 3=1,B 3=1, then to other microringsA 1,B 1,B 2,C 1 ,C 2 ,C 3 Applying dynamic voltage modulation signalsa 1,b 1,b 2,c 1,c 2,c 3After passing through the multiplexer 3, the TE carrying the calculation result can be obtained from the tenth waveguide 3-30，TE1And TE2The multimode signal of (1). The corresponding waveform diagram is shown in FIG. 10, and the output end is the logic function
。
The operational schematic of the reconfigurable steering logic device of the present invention is shown in FIG. 11, the blocks of FIG. 11The first is a demultiplexer 1, the second module is a micro-ring array 2, and the third module is a multiplexer 3. The demultiplexer 1 is implemented based on the structure of a directional coupler. The reconfigurable guiding logic device can complete any logic operation. The input is the electric signal to be operated and a multimode continuous optical signal, the output is the optical signal after the logical operation to the electric signal, wherein the basic unit of each micro-ring resonator MRR is the micro-ring resonator MRR optical switch with thermal modulation mechanism or electric modulation mechanism, the operation process is: inputting multi-mode single wavelength continuous laser at one optical port (main waveguide) of the device, firstly, demultiplexing the multi-mode in the main waveguide by using the mode coupling principle, and changing the mode coupled to the micro-ring array waveguide into a fundamental mode TE0The electrical signal to be calculated is loaded on each micro-ring MRR in high and low levels according to the states of 1 and 0, respectively, and the fundamental mode TE is output in the form of optical logic at the end port of each straight waveguide0And finally, multiplexing the modes to a main waveguide by using the mode coupling principle again to complete OR logic operation so as to complete the operation of any logic function.
The reconfigurable guide logic device based on mode multiplexing has good expandability, and the functions of guide logic operation can be expanded into the following steps by only correspondingly increasing the number of directional couplers in the mode multiplexing/demultiplexing device and the number of optical switches in the micro-ring array: implementing input of TE at input0-TEm(fundamental mode to arbitrary higher order mode) resulting in a logical operation Y = Y at the output1+y2+···ym（
) That is, an arbitrary logical operation is completed.
In the present invention, the sequence of electrical signals to be computed (the electrical signals applied to the microring) needs to be precisely synchronized in time. In the high-speed operation mode, special design and electromagnetic compatibility analysis and simulation of the electrodes are required.
In the invention, the optical signal can be transmitted in the optical fiber and directly enters the next stage for processing.
Claims (3)
1. A reconfigurable steering logic device based on mode multiplexing is characterized by comprising a demultiplexer (1), a micro-ring array (2) and a multiplexer (3) which are connected in sequence;
the demultiplexer (1) comprises a first S-shaped waveguide (1-2), a second S-shaped waveguide (1-4), a third S-shaped waveguide (1-6) and a first straight waveguide (1-1), a second straight waveguide (1-3), a third straight waveguide (1-5) and a fourth straight waveguide (1-7) which are connected in sequence, wherein two adjacent straight waveguides are connected through an adiabatic cone; the width of the first straight waveguide (1-1) is larger than that of the second straight waveguide (1-3), the width of the second straight waveguide (1-3) is larger than that of the third straight waveguide (1-5), and the width of the third straight waveguide (1-5) is larger than that of the fourth straight waveguide (1-7);
the widths of the first S-shaped waveguide (1-2), the second S-shaped waveguide (1-4), the third S-shaped waveguide (1-6) and the fourth straight waveguide (1-7) are the same;
one end of the first S-shaped waveguide (1-2) is coupled with the first straight waveguide (1-1), one end of the second S-shaped waveguide (1-4) is coupled with the second straight waveguide (1-3), and one end of the third S-shaped waveguide (1-6) is coupled with the third straight waveguide (1-5); the other end of the first S-shaped waveguide (1-2), the other end of the fourth straight waveguide (1-7), the other end of the second S-shaped waveguide (1-4) and the other end of the third S-shaped waveguide (1-6) are connected with the micro-ring array (2);
the micro-ring array (2) comprises fifth straight waveguides (2-3), sixth straight waveguides (2-4), seventh straight waveguides (2-5) and eighth straight waveguides (2-6) which are arranged side by side and have the same width, one end of each fifth straight waveguide (2-3) is connected with the other end of each second S-shaped waveguide (1-4), one end of each sixth straight waveguide (2-4) is connected with the other end of each fourth straight waveguide (1-7), one end of each seventh straight waveguide (2-5) is connected with the other end of each third S-shaped waveguide (1-6), and one end of each eighth straight waveguide (2-6) is connected with one end of each first S-shaped waveguide (1-2); the other end of the fifth straight waveguide (2-3), the other end of the sixth straight waveguide (2-4), the other end of the seventh straight waveguide (2-5) and the other end of the eighth straight waveguide (2-6) are all connected with the multiplexer (3);
a group of micro-ring groups are coupled on the fifth straight waveguide (2-3), the sixth straight waveguide (2-4), the seventh straight waveguide (2-5) and the eighth straight waveguide (2-6), and each micro-ring group consists of a first micro-ring MRR (2-1) and a second micro-ring MRR (2-2) which are arranged at intervals; the size and the width of the first micro-ring MRR (2-1) are the same as those of the second micro-ring MRR (2-2), and the coupling distances between all the micro-rings MRRs and the straight waveguides coupled with the micro-rings MRRs are the same;
the multiplexer (3) comprises a fourth S-shaped waveguide (3-2), a fifth S-shaped waveguide (3-4), a sixth S-shaped waveguide (3-6), and a ninth straight waveguide (3-1), a tenth straight waveguide (3-3), an eleventh straight waveguide (3-5) and a twelfth straight waveguide (3-7) which are sequentially connected; two adjacent straight waveguides are connected through a heat insulation cone; one end of a fourth S-shaped waveguide (3-2) is coupled with a ninth straight waveguide (3-1), the other end of the fourth S-shaped waveguide (3-2) is connected with the other end of an eighth straight waveguide (2-6), one end of a fifth S-shaped waveguide (3-4) is coupled with a tenth straight waveguide (3-3), the other end of the fifth S-shaped waveguide (3-4) is connected with the other end of the fifth straight waveguide (2-3), one end of a sixth S-shaped waveguide (3-6) is coupled with an eleventh straight waveguide (3-5), the other end of the sixth S-shaped waveguide (3-6) is connected with the other end of a seventh straight waveguide (2-5), and the other end of a twelfth straight waveguide (3-7) is connected with the other end of the sixth straight waveguide (2-4); the widths of the fourth S-shaped waveguide (3-2), the fifth S-shaped waveguide (3-4), the sixth S-shaped waveguide (3-6) and the twelfth straight waveguide (3-7) are the same.
2. The reconfigurable steering logic device based on mode multiplexing according to claim 1, wherein a space or an insulator for preventing thermal crosstalk between the first microring MRR (2-1) and the second microring MRR (2-2) adjacent to each other is provided between the two microrings MRRs.
3. A reconfigurable steering logic device based on mode multiplexing according to claim 1, characterized in that the demultiplexer (1) and the multiplexer (3) employ directional couplers, microring resonators, Y-branches or grating couplers.
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