Reconfigurable all-optical logic gate based on polarization modulator and method thereof

Abstract

The application discloses a reconfigurable all-optical logic gate implementation device and method based on a polarization modulator, and belongs to the field of optical communication and microwave technology. The device comprises a laser, a polarization modulator, an electric coupler, two PCs, a polarizer and a photodetector. The device and method are based on the microwave photon phase shift principle, and baseband data is introduced into the signal phase. Meanwhile, by using the polarization control technology, output photocurrents in different electric level states can be obtained. Due to the continuity of the polarization control, when six different adjustable phase differences are introduced, the system output electric level presents six different logic functions. The application has high practicability, and can be widely applied to high-speed optical computing, optical networks and optical signal processing and other optical systems.

Description

Technical Field

[0001] This invention relates to the fields of optical communication and microwave technology, and in particular to an implementation system of reconfigurable all-optical logic gates based on polarization modulators. Background Technology

[0002] With the advent of the Internet of Things (IoT) era, the volume of data processing required by businesses is growing exponentially, and the accompanying problems of computing power and power consumption urgently need to be addressed. Optical signals have characteristics such as high transmission speed, high frequency, and resistance to electromagnetic interference. Compared with existing semiconductor signal processing devices, all-optical processors or all-optical computing have advantages such as high-speed parallelism and low power consumption, and are considered a promising alternative in fields such as cloud computing and artificial intelligence computing. All-optical logic gates are the basic units of optical processing, relying on the modulation of one optical signal with another to simulate Boolean logic operations. Benefiting from the enormous development potential of all-optical computing, all-optical logic gates have received widespread attention from researchers in recent years.

[0003] Currently, the industry has conducted extensive research on all-optical logic gates, and the common approach to realizing optically controlled all-optical logic gates is based on nonlinear optical effects. Examples include devices based on semiconductor optical amplifiers, highly nonlinear optical fibers, and periodically polarized lithium niobate. However, conventional materials with low nonlinear sensitivity often require high optical power to operate, which hinders the further application of optical logic gates. Furthermore, most existing all-optical logic gates cannot simultaneously perform multiple logic operations in a single device and are difficult to interconnect with existing electronic devices. Summary of the Invention

[0004] This invention proposes an apparatus and method for implementing reconfigurable all-optical logic gates using a polarization modulator, an electrical coupler, a polarization controller (PC), a polarizer, and a photodetector.

[0005] The technical solution adopted in this invention is:

[0006] The reconfigurable all-optical logic gate device based on polarization modulator includes a laser, a polarization modulator, an electrical coupler, two PCs, a polarizer, and a photodetector.

[0007] The polarization modulator is a special phase modulator that supports phase modulation in both transverse electric wave (TE) and transverse magnetic wave (TM) modes, with opposite phase modulation indices for the two modes; the polarization modulator has an input terminal, an output terminal, and an RF terminal;

[0008] The output port of the laser is connected to the input port of PC1. After PC1 adjusts the angle between the input optical carrier and the principal axis of the polarization modulator, its output port is connected to the optical input port of the polarization modulator. The input end of the polarization modulator integrates a polarization beam splitter (PBS) to separate the two modes of the optical wave. The output end of the polarization modulator integrates a polarization beam combiner (PBC) to polarize and multiplex the modulated optical signals of the two modes. The output port of the polarization modulator is connected to the input port of PC2. After PC2 adjusts the polarization direction of the output signal of the polarization modulator and the phase difference between the two modes, its output port is connected to the input port of a polarizer. After the polarizer separates one polarization state of the signal, its output port is connected to the optical input port of the photodetector. Baseband signal 1 and baseband signal 2 are coupled to the radio frequency port of the polarization modulator via an electrocoupler.

[0009] The reconfigurable all-optical logic gate implementation method based on polarization modulator is as follows:

[0010] Step 1: Laser output signal E c (t), PC1 adjusts the input optical carrier E c After the angle between (t) and the main axis of the polarization modulator, the signal is connected to the optical input port of the polarization modulator;

[0011] Step 2: Baseband signal 1 and baseband signal 2 are coupled via an electrical coupler and then connected to the RF port of the polarization modulator;

[0012] Step 3: The polarization controller outputs optical signal E PolM (t):

[0013]

[0014] Among them, E c (t) represents the laser output signal; μ represents the modulator loss; s1(t) and s2(t) represent the normalized baseband signal 1 and the normalized baseband signal 2, respectively; m1 and m2 are the modulation indices of baseband signal 1 and baseband signal 2, respectively. and These represent the unit vectors of the TE and TM modes of the optical field, respectively.

[0015] Step 4: PC2 adjusts the output optical signal E of the polarization modulator. PolM The polarization direction of (t) and the phase difference between the two modes;

[0016] Step 5: The polarizer separates one of the polarization states of the signal to obtain the optical signal E. Pol (t):

[0017]

[0018] Where α represents the polarization control angle introduced by PC2; δ represents the adjustable phase difference introduced by PC2;

[0019] Step Six: Transmit the optical signal E Pol (t) is input to the photodetector, and the output photocurrent signal i(t) is obtained:

[0020]

[0021] Where η represents the responsivity of the photodetector; This represents the average output optical power of the laser.

[0022] When setting and Then, formula (3) can be further expressed as:

[0023]

[0024] Step 7: When the code elements of normalized baseband signal 1 and normalized baseband signal 2 are set to "0 0 1 1" and "01 0 1" respectively, formula (4) is expanded to:

[0025]

[0026] In formula (5), the system's output photocurrent signal i(t) is related to the adjustable phase difference δ introduced by PC2. Under different symbol combinations, the system has different output photocurrent level combinations. When the modulation indices m1, m2, and polarization control angle α are fixed, different logic functions can be achieved by adjusting PC2 to change the adjustable phase difference, as shown in the table below:

[0027] Table 1. Parameter configurations for six logic gates

[0028]

[0029]

[0030] As shown in Table 1, the adjustable phase difference δ required to achieve each logic function has a range of values, and any value within this range can achieve the required logic function. Among them, a set of special values ​​for δ that satisfy the six logic functions are 5π / 4 (225°), 3π / 4 (135°), 7π / 4 (315°), π / 2 (90°), π / 4 (45°), and 3π / 2 (270°).

[0031] Therefore, by rationally constructing the system structure and utilizing polarization control technology to achieve continuously adjustable optical phase shifting, it is possible to realize six different logic gate functions: AND, OR, NOR, XOR, NAND, and XNOR, providing solutions for high-speed optical signal processing, broadband optical networks, and other fields.

[0032] The advantage of this invention lies in constructing a reconfigurable all-optical logic gate device based on a polarization modulator. Based on the microwave photonic phase-shifting principle, baseband data is introduced into the signal phase. Simultaneously, by using polarization control technology, different output photocurrent levels can be obtained. Thanks to the continuity of polarization control, when six different adjustable phase differences are introduced, the system output level exhibits six different logic functions. This invention is highly practical and can be widely applied to optical systems such as high-speed optical computing, optical networks, and optical signal processing. Attached Figure Description

[0033] Figure 1 A diagram of a reconfigurable all-optical logic gate device based on a polarization modulator;

[0034] Figure 2 1Gbps baseband signal, polarization modulator output spectrum;

[0035] Figure 3 1Gbps baseband signal, original normalized baseband signal waveform: (a) s1(t); (b) s2(t);

[0036] Figure 4 The time-domain waveforms of the output after six logic gate operations for a 1Gbps baseband signal: (a) AND gate; (b) OR gate; (c) NOR gate; (d) XOR gate; (e) NAND gate; (f) XNOR gate.

[0037] Figure 5 2Gbps baseband signal, original normalized baseband signal waveforms: (a) s1(t); (b) s2(t);

[0038] Figure 6 The time-domain waveforms of the output after six logic gate operations for a 2Gbps baseband signal: (a) AND gate; (b) OR gate; (c) NOR gate; (d) XOR gate; (e) NAND gate; (f) XNOR gate. Detailed Implementation

[0039] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments:

[0040] In this example, the apparatus includes: a laser, a baseband signal source 1, a baseband signal source 2, a spectrometer, an oscilloscope, an electrical coupler, a PC, a polarizer, and a photodetector.

[0041] Step 1: Device Connection. Connect the laser's output port to the optical input port of PC1; connect the optical output port of PC1 to the input port of the polarization modulator; connect the polarization modulator's output port to the input port of PC2; connect the output port of PC2 to the input port of the polarizer; connect the polarizer's output port to the input port of the photodetector; connect the photodetector's output port to the oscilloscope.

[0042] Step 2: The laser generates an optical carrier with a working wavelength of 1552.5nm and an optical power of 16dBm; baseband signal source 1 generates a baseband signal with the symbol "0 0 1 1" and a bit rate of 1Gbps; baseband signal source 2 generates a baseband signal with the symbol "01 0 1" and a bit rate of 1Gbps; the half-wave voltage of the polarization modulator is 4V and the insertion loss is 3dB; the responsivity of the photodetector is 0.7A / W.

[0043] Step 3: Set the amplitude of both baseband signal 1 and baseband signal 2 to 1a.u; set the polarization control angle of PC1 to 45° and the tunable phase difference to 0°. Baseband signal source 1 and baseband signal source 2, after being coupled via an electrical coupler, serve as the RF drive signals to drive the polarization modulator. The output optical signal of the polarization modulator is as follows... Figure 2 As shown.

[0044] Step 4: Connect the outputs of baseband signal source 1 and baseband signal source 2 directly to the oscilloscope. Figure 3 (a) and Figure 3 (b) are the time-domain waveforms of baseband signal 1 and baseband signal 2 with a bit rate of 1Gbps, respectively, in the simulation.

[0045] Step 5: Connect the output of the polarization modulator sequentially to PC2, the polarizer, and the photodetector. Set the polarization control angle of PC2 to 45°, and adjust the phase difference to 225°, 135°, 315°, 90°, 45°, and 270° respectively. Connect the output signal of the photodetector directly to an oscilloscope for observation. Figure 4 (a) is the output time-domain waveform of the AND gate operation. It can be observed that when the symbol combinations of baseband signal 1 and baseband signal 2 are "0 0", "0 1", and "1 0" respectively, the system outputs a low level, defined as "0"; when the symbol combination of baseband signal 1 and baseband signal 2 is "1 1", the system outputs a high level, defined as "1", thus realizing the logic function of the dual-input AND gate. Similarly, Figure 4 (b) Figure 4 (c) Figure 4(d) Figure 4 (e) and Figure 4 (f) are the output time-domain waveforms of OR gate, NOT gate, XOR gate, NAND gate and XNOR gate operations at a bit rate of 1Gbps.

[0046] Step 6: Change the bit rate of baseband signal 1 and baseband signal 2 to 2Gbps, while keeping other parameters unchanged. Figure 5 (a) and Figure 5 (b) are the time-domain waveforms of baseband signal 1 and baseband signal 2 with a bit rate of 2Gbps, respectively, in the simulation.

[0047] Step 7: Same as in Step 5. Figure 6 (a) Figure 6 (b) Figure 6 (c) Figure 6 (d) Figure 6 (e) and Figure 6 (f) are the output time-domain waveforms of AND, OR, NOT, XOR, NAND, and XNOR operations at a bit rate of 2Gbps.

[0048] In summary, this scheme constructs a reconfigurable all-optical logic gate device based on a polarization modulator. Based on the microwave photonic phase-shifting principle, baseband data is introduced into the signal phase. Simultaneously, by using polarization control technology, output photocurrents at different voltage levels can be obtained. Thanks to the continuity of polarization control, the system output level exhibits different logic functions when different adjustable phase differences are introduced. This scheme can continuously implement six different logic functions, is easy to implement, and offers flexible operation, demonstrating potential application value in today's high-speed optical computing, optical networks, and optical signal processing optical systems.

[0049] In summary, the above-described embodiments are merely examples of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that those skilled in the art can make several equivalent modifications and substitutions based on the content disclosed in this invention. The modulator type, baseband data symbol type, baseband data modulation index, optical carrier wavelength, optical carrier power, polarization control angle, and adjustable phase difference type can all be changed. These equivalent modifications and substitutions, as well as adjustments to the baseband symbol rate, should also be considered within the scope of protection of this invention.

Claims

1. A reconfigurable all-optical logic gate device based on a polarization modulator, characterized in that, It includes a laser, a polarization modulator, an electrical coupler, two PCs, a polarizer, and a photodetector. The polarization modulator is a special phase modulator that supports phase modulation in both transverse electric wave (TE) and transverse magnetic wave (TM) modes, with opposite phase modulation indices for the two modes; the polarization modulator has an input terminal, an output terminal, and an RF terminal; The output port of the laser is connected to the input port of PC1. After PC1 adjusts the angle between the input optical carrier and the main axis of the polarization modulator, the output port of PC1 is connected to the optical input port of the polarization modulator. The input end of the polarization modulator integrates a polarization beam splitter (PBS) to separate the two modes of the optical wave. The output end of the polarization modulator integrates a polarization beam combiner (PBC) to polarize and multiplex the modulated optical signals of the two modes. The output port of the polarization modulator is connected to the input port of PC2. After PC2 adjusts the polarization direction of the output signal of the polarization modulator and the phase difference between the two modes, the output port of PC2 is connected to the input port of the polarizer. After the polarizer separates one of the polarization states of the signal, the output port of the polarizer is connected to the optical input port of the photodetector. Baseband signal 1 and baseband signal 2 are connected to the radio frequency port of the polarization modulator after being coupled via an electrical coupler; Among them, the polarization controller outputs optical signals. : in, This is the laser output signal; μ For modulator losses; s 1(t), s 2(t) represent normalized baseband signal 1 and normalized baseband signal 2, respectively; m 1. m 2 are the modulation indices of baseband signal 1 and baseband signal 2, respectively; and These represent the unit vectors of the TE and TM modes of the optical field, respectively. Among them, baseband signal 1 and baseband signal 2 are coupled by an electric coupler and used as radio frequency drive signals to drive the polarization modulator.

2. A method for implementing reconfigurable all-optical logic gates based on the device described in claim 1, characterized in that, The process is as follows: Step 1: Laser output signal PC1 adjusts the input optical carrier. After the angle between the signal and the main axis of the polarization modulator, the signal is connected to the optical input port of the polarization modulator. Step 2: Baseband signal 1 and baseband signal 2 are coupled via an electrical coupler and then connected to the RF port of the polarization modulator; Step 3: The polarization controller outputs an optical signal. : （1） in, This is the laser output signal; μ For modulator losses; s 1(t), s 2(t) represent normalized baseband signal 1 and normalized baseband signal 2, respectively; m 1. m 2 are the modulation indices of baseband signal 1 and baseband signal 2, respectively; and These represent the unit vectors of the TE and TM modes of the optical field, respectively. Step 4: PC2 adjusts the output optical signal of the polarization modulator. The polarization direction and the phase difference between the two modes; Step 5: The polarizer separates one of the polarization states of the signal to obtain the optical signal. : （2） in, α This represents the polarization control angle introduced by PC2; δ This indicates the adjustable phase difference introduced by PC2; Step Six: Transmit the optical signal Input to photodetector, obtain output photocurrent signal : （3） in, η Indicates the responsivity of the photodetector; This represents the average output optical power of the laser. When setting and Then, formula (3) can be further expressed as: （4） Step 7: When the code elements of normalized baseband signal 1 and normalized baseband signal 2 are set to "0 0 1 1" and "0 1 01" respectively, formula (4) is expanded to: （5） In formula (5), the system's output photocurrent signal Adjustable phase difference introduced by PC2 δ Related; under different symbol combinations, the system has different output photocurrent level combinations; when the modulation index is fixed. m 1. m 2 and polarization control angle α In the future, by adjusting PC2 to change the adjustable phase difference, different logic functions can be achieved, as shown in the table below: Table 1. Parameter configuration of six logic gates As shown in Table 1, the adjustable phase difference required to implement each logic function is... δ Each has a range of values, and any value within that range can achieve the corresponding logical function.

3. The method for implementing reconfigurable all-optical logic gates as described in claim 2, characterized in that, In step seven, the functions of six different logic gates are satisfied: AND, OR, NOR, XOR, NAND, and XNOR. δ A set of special values ​​are 5π / 4 (225°), 3π / 4 (135°), 7π / 4 (315°), π / 2 (90°), π / 4 (45°) and 3π / 2 (270°).

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