CN111474803A - An All-optical XOR Optical Logic Gate Operation System Based on Time Lens Imaging - Google Patents

Abstract

An all-optical XOR optical logic gate operation system based on time lens imaging comprises a code expansion subsystem, a time lens imaging inversion subsystem and a code reduction subsystem, wherein the output end of the code expansion subsystem is connected with the input end of the time lens imaging inversion subsystem, the output end of the time lens imaging inversion subsystem is connected with the input end of the code reduction subsystem, and a single code is converted into a double code in the code expansion subsystem; in the time lens imaging inversion subsystem, the inversion of the double-pulse signal is realized when the pumping signal is a '1' code through the magnification factor of-1 times when M is equal to the magnification factor of-1 times; in the time lens imaging inversion subsystem, when the pumping signal is '0' code, the inversion of the double-pulse signal is not realized; in the code reduction subsystem, double codes are changed back to single codes. The invention not only greatly simplifies the arithmetic system of the exclusive-OR optical logic gate, but also greatly improves the arithmetic speed.

Description

An All-optical XOR Optical Logic Gate Operation System Based on Time Lens Imaging

technical field

The invention relates to an all-optical XOR optical logic gate operation system based on time lens imaging

Background technique

With the development of ultra-high-speed nonlinear optical signal processing technology, the traditional electrical signal processing technology has approached the electron rate bottleneck, and the use of optical logic gate circuits instead of electrical logic gate circuits has attracted widespread interest. All-optical communication will be the main communication method in the future, and all-optical logic technology makes complex electrical/optical and optical/electrical conversion systems no longer needed, and all-optical processing systems will be directly used. All-optical logic XOR optical logic gate operation system is an important basic element of optical logic operation, and an important device for realizing high-speed all-optical network.

闲置光E_idler相对于输入的信号光E_s而言引入了二次相移，这是FWM产生时间透镜效应的基本原理。A time lens refers to an optical device that can produce a secondary time phase shift for an optical signal. There are various implementations of time lenses, but they can be roughly classified into four categories: time lenses based on electro-optic phase modulators (EOPM), Time lenses based on cross-phase modulation (XPM), time lenses based on four-wave mixing (FWM), and time lenses based on nonlinear crystals, but due to the high requirements on materials due to the sum and difference frequency effects, such time lenses Lenses are rarely used in practice. For signal processing in the field of optical communication, Four-Wave Mixing (FWM) is the first choice to achieve the time-lens effect. The signal light with the electric field amplitudes E _s (t) and E _p (t), respectively, and the pump light undergo FWM action, and the resulting idle wave electric field amplitude

The idle light E _idler introduces a quadratic phase shift relative to the input signal light E _s , which is the basic principle of the time-lensing effect of the FWM.

时，就可以实现对输入光信号的放大或压缩，其中放大倍数M＝φ″₂/φ″₁。It consists of the input fiber (the second-order dispersion is φ″ ₁ =β _2s L _s ), the time lens (the focal length dispersion is φ″ _f =-φ″ _p /2=-β _2p L _p /2), and the output fiber ( The second-order dispersion amount is φ″ ₂ =β _{2i Li )} The three parts form a time lens imaging system. The chromatic dispersion of the front and rear optical fibers are respectively φ″ ₁ =β _2s L _s , φ″ ₂ =β _{2i Li ,} the focal length dispersion of the time lens is completely determined by the dispersion experienced by the pump light, φ″ _f =-φ " _p /2=-β _2p L _p /2, β _2s and β _2i are the second-order dispersion coefficients of the two optical fibers respectively, and β _2p is the second-order dispersion coefficient of the pump light transmission fiber; L _s and L _i are respectively The lengths of the front and rear optical fibers, L _p is the length of the optical fiber where the pump light undergoes dispersion broadening. When the imaging conditions are satisfied between the second-order dispersion φ″ ₁ , φ″ ₂ of the two optical fibers and the focal length dispersion φ″ _f of the time lens

, the amplification or compression of the input optical signal can be realized, wherein the amplification factor M=φ″ ₂ /φ″ ₁ .

SUMMARY OF THE INVENTION

In order to overcome the disadvantages of the prior art that the all-optical logic operation function is realized through the gain saturation characteristics of semiconductor materials, the process is complicated, the rate of the optical logic gate is not high, and the whole system is complex and tedious, the present invention provides an all-optical imaging based on time lens The XOR optical logic gate operation system not only simplifies the whole system, but also greatly improves the operation speed.

In order to solve the above-mentioned technical problems, the technical scheme adopted by the present invention is:

An all-optical XOR optical logic gate operation system based on time lens imaging, comprising a code spread subsystem, a time lens imaging inversion subsystem and a code reduction subsystem, wherein the output end of the code spread subsystem is connected to the time lens imaging inversion subsystem The output end of the time lens imaging inversion subsystem is connected to the input end of the code reduction subsystem, in the code code expansion subsystem, the single code is converted into a double code; the time lens imaging inversion subsystem In the subsystem, through the magnification of M=-1 times, the inversion of the double-pulse signal is realized when the pump light signal is "1" code; when the pump light signal is "0" code, the double-pulse signal will not be realized. Inversion; in the abbreviated code subsystem, the double code is restored back to the single code; the signal passes through the joint action of the three parts of the all-optical XOR optical logic gate operation system, which can realize that the pump light is a "1" code and the signal When the light is "1" code, the output signal light is "0" code, the pump light is "1" code, and when the signal light is "0" code, the output signal light is "1" code, and the pump light is "0" code And when the signal light is "1" code, the output signal light is "1" code, the pump light is "0" code, and when the signal light is "0" code, the output signal light is "0" code, that is, the logical XOR is realized. operation.

Further, the time lens imaging inversion subsystem is composed of three parts: the input fiber, the time lens and the output fiber. The second-order dispersion of the output fiber is φ″ ₂ and the second-order dispersion of the input fiber ₁ is the opposite, that is, φ″ ₂ =-φ″ ₁ ; the magnification of the time-lens imaging subsystem M=φ″ ₂ /φ″ ₁ =-1, during the duration of the pump light pulse of the time-lens imaging subsystem, Two signal light pulses can be covered at the same time, and the inversion of these two signal light pulses can be realized by M=-1, that is, "10" can be converted into "01", and "01" can be converted into "10".

Still further, in the time lens imaging inversion subsystem, the time lens effect is realized by generating FWM between the signal light and the pump light in a highly nonlinear medium.

Preferably, the pulse width of the pump light is controlled so that one pulse width of the pump light can cover the signal light pulse pairs of two durations, so as to realize the inversion of the double code.

Still further, in the spreading code subsystem, the single code is converted into a double code, that is, the signal light "1" is converted into "01", and "0" is converted into "10"; in the abbreviated code subsystem, the double code is converted into Change back to the single code again, that is, restore "01" to "1" and "10" to "0". Other single-code and double-code conversion methods can also be used.

In the time lens imaging inversion subsystem, the inversion of the double pulse signal is realized when the pump signal is a "1" code, that is, "10" is transformed into "01", and "01" is transformed into "10"; the In the time lens imaging inversion subsystem, the inversion of the double pulse signal is not realized when the pump signal is "0" code, that is, "10" is still "10" after transformation, and "01" is still "01" after transformation . Other inversions are also possible.

The technical idea of the present invention is as follows: firstly, the code spreading subsystem performs code spreading to convert the "1" code of the signal light into "01" and the "0" code into "10"; in the time lens imaging inversion subsystem , when φ" ₂ =-φ" ₁ , the magnification M = -1, so that the pulse width of the pump light can cover two signal light pulse widths. At this time, when the pump light pulse is "1" code, the double pulse width After the time lens imaging system, the time inversion is realized, that is, "10" is transformed into "01", and "01" is transformed into "10"; when the pump light pulse is "0" code, the double pulse elapsed time The lens imaging system does not have time inversion, that is, "10" is still "10" after the transformation, and "01" is still "01" after the transformation; finally, the double signal is returned to a single signal through the code reduction subsystem, which is about "01" is restored to "1" code, and "10" is restored to "0" code. In short, after the whole system conversion, the output signal obtained when the signal light and the pump light have the same pulse code is the "0" code, and when the signal light and the pump light have different pulse codes, the output signal is obtained. The output signal is "1" code. Based on the inversion characteristics of the time lens imaging system, as well as the two subsystems of spread code and code reduction, it provides a new implementation scheme for realizing all-optical XOR optical logic gate operation system.

The beneficial effects of the present invention are embodied in: after the optical signal passes through the code spreading subsystem, the time lens imaging inversion subsystem and the code reduction subsystem, the logical XOR operation of the signal and the pump light can be realized. Perform logical operations on ultra-high-speed optical signals.

Description of drawings

FIG. 1 is a system diagram of the present invention, which includes a code spread subsystem, a time lens imaging inversion subsystem, and a code reduction subsystem.

Fig. 2 is a schematic diagram of time lens inversion. When the magnification M=-1, a pair of light pulses obtain time inversion.

Figure 3 is a schematic diagram of the inversion of a pair of optical pulses (01) with a pulse width of 4ps when the pump optical pulse is "1" code after passing through the time lens imaging subsystem, wherein (a) is the input signal pulse "01" , (b) is the output signal pulse "10".

Figure 4 is a schematic diagram of the inversion of a pair of optical pulses (10) with a pulse width of 4ps passing through the time lens imaging subsystem when the pump optical pulse is "1" code, wherein (a) is the input signal pulse "10" , (b) is the output signal pulse "01".

Figure 5 is a schematic diagram of the inversion of a pair of optical pulses (01) with a pulse width of 4ps passing through the time lens imaging subsystem when the pump optical pulse is "0" code, wherein (a) is the input signal pulse "01" , (b) is the output signal pulse "01".

Figure 6 is a schematic diagram of the inversion of a pair of optical pulses (10) with a pulse width of 4ps passing through the time lens imaging subsystem when the pump optical pulse is "0" code, wherein (a) is the input signal pulse "10" , (b) is the output signal pulse "10".

Detailed ways

The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited thereto.

Referring to Figures 1 to 6, an all-optical XOR optical logic gate operation system based on time lens imaging includes a code spread subsystem, a time lens imaging inversion subsystem and a code reduction subsystem; the code spread subsystem converts the signal light ""1" is converted to "01", and signal light "0" is converted to "10". This method is very common in the current signal processing and communication fields, so its implementation process will not be repeated here; The performance system is composed of an input fiber, a time lens and an output fiber. The second-order dispersion of the output fiber φ" ₂ is opposite to the second-order dispersion of the input fiber φ" ₁ , that is, φ" ₂ =-φ "₁; the magnification of the time lens imaging subsystem M = φ" ₂ φ" ₁ =-1; the pulse width of the pump light is controlled so that its duration can cover two signal light pulses, so as to ensure that the pump light When the signal is a "1" code, a pair of optical pulses "10" can be inverted to "01", and "01" can be inverted to "10"; when the pump optical signal is a "0" code, no inversion occurs That is, a pair of optical pulses "10" are still "10" after conversion, and "01" is still "01" after conversion; the abbreviated code subsystem restores the double code to a single code, that is, restores "01" to "1", Restoring "10" to "0" is similar to spreading code, and its implementation process is not repeated here.

In the time lens imaging inversion subsystem, the time lens effect is realized by generating FWM between the signal light and the pump light in a highly nonlinear medium. Preferably, the pulse width of the pump light is controlled so that one pulse width of the pump light can cover the signal light pulse pair of two durations, so as to realize the inversion of the double code.

的成像条件，两个时间透镜成像子系统的参数均选择为：β_2s＝20ps²/km，L_s＝1km，β_2i＝-20ps²/km，L_i＝1km，β_2p＝20ps²/km，L_p＝1km。此时，φ″₂＝-φ″₁，M＝-1。Referring to Figure 2, in order to satisfy

, the parameters of the two time lens imaging subsystems are selected as: β _2s = 20ps ² /km, L _s = 1km, β _2i = _-20ps ² /km, Li = 1km, β _2p = 20ps ² / km, _Lp = 1 km. At this time, φ″ ₂ =-φ″ ₁ , and M=-1.

As shown in Figures 1 to 6 above, when the signal light and the pump light have the same pulse code, the output signal is a "0" code, and when the signal light and the pump light have different pulse codes, the output signal is obtained. The output signal is "1" code, which realizes the logical XOR operation. In the above embodiment, the optical pulse width is shortened, that is, the signal processing rate is increased, and the system performance is good, that is, the system can effectively process high-speed optical digital signals, and realize the logical XOR operation.

Claims (6)

1. An all-optical XOR optical logic gate operation system based on time lens imaging is characterized by comprising a code expansion subsystem, a time lens imaging inversion subsystem and a code reduction subsystem, wherein the output end of the code expansion subsystem is connected with the input end of the time lens imaging inversion subsystem, the output end of the time lens imaging inversion subsystem is connected with the input end of the code reduction subsystem, and a single code is converted into a double code in the code expansion subsystem; in the time lens imaging inversion subsystem, the inversion of the double-pulse signal is realized when the pumping signal is a '1' code through the magnification factor of-1 times when M is equal to the magnification factor of-1 times; in the time lens imaging inversion subsystem, when the pumping signal is '0' code, the inversion of the double-pulse signal is not realized; in the code reduction subsystem, double codes are changed back to single codes; the signals are subjected to the combined action of three parts of an all-optical exclusive-or optical logic gate operation system, so that the logic exclusive-or operation can be realized, namely, the signal light is a '0' code when the pump light is a '1' code and the signal light is a '1' code, the signal light is a '1' code when the pump light is a '1' code and the signal light is a '0' code, the signal light is a '1' code when the pump light is a '0' code and the signal light is a '0' code.

2. The all-optical XOR optical logic gate operation system based on time lens imaging as claimed in claim 1, wherein the time lens imaging inversion subsystem is composed of three parts of an input section optical fiber, a time lens and an output section optical fiber, and the second-order dispersion phi' of the output section optical fiber₂Second-order dispersion phi' with the input section optical fiber₁In contrast, i.e., "phi₂＝-φ″₁(ii) a The magnification M ═ phi ″' of the time lens imaging subsystem₂/φ″₁Two signal light pulses can be covered simultaneously during the duration of the pump light pulse of the time lens imaging subsystem, and the inversion of the two signal light pulses is realized by M-1.

3. An all-optical exclusive-or optical logic gate operating system based on time lens imaging as claimed in claim 1 or 2, characterized in that: in the time lens imaging inversion subsystem, the FWM of signal light and pump light occurs in a high nonlinear optical fiber to realize the time lens effect.

4. An all-optical exclusive-or optical logic gate operating system based on time lens imaging as claimed in claim 1 or 2, characterized in that: in the time lens imaging inversion subsystem, the width of a pump light pulse is controlled, so that one pump light pulse width can cover two signal light widths at the same time.

5. An all-optical exclusive-or optical logic gate operating system based on time lens imaging as claimed in claim 1 or 2, characterized in that: in the code spreading subsystem, a single code is converted into a double code, namely, a signal light 1 is converted into 01, and a signal light 0 is converted into 10; in the code reduction subsystem, double codes are changed back to single codes, namely, 01 is restored to 1, and 10 is restored to 0.

6. An all-optical exclusive-or optical logic gate operating system based on time lens imaging as claimed in claim 1 or 2, characterized in that: in the time lens imaging inversion subsystem, when a pump signal is a 1 code, the inversion of a double-pulse signal is realized, namely, the conversion from 10 to 01 and the conversion from 01 to 10 are realized; in the time lens imaging inversion subsystem, when a pumping signal is a '0' code, the inversion of a double-pulse signal is not realized, namely, the '10' is still '10' after the transformation of '10', and the '01' is still '01' after the transformation of '01'.

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