CN105676560A - Controllable full-light optical random logic gate - Google Patents

Abstract

The invention relates to photonic equipment and in particular relates to a controllable full-light optical random logic gate. The controllable full-light optical random logic gate comprises a tunable continuous laser device, a first optical isolator, an optical attenuator, a beam splitter, a main vertical cavity surface emission laser device, a second optical isolator, a first polarization beam splitter, a periodic pole lithium niobate crystal, a third optical isolator, a second polarization beam splitter, a third polarization beam splitter, an optical amplifier, a secondary vertical cavity surface emission laser device and a fourth polarization beam splitter, wherein a first plane mirror, a first half wave plate and a second half wave plate are further arranged between the beam splitter and the main vertical cavity surface emission laser device in parallel; a second plane mirror, a first Faraday rotator and a third half wave plate are further arranged between the first polarization beam splitter and the periodic pole lithium niobate crystal in parallel; a fourth half wave plate and a second Faraday rotator are further arranged between the second polarization beam splitter and the third polarization beam splitter in parallel; a transverse electric field E0 is applied to the periodic pole lithium niobate crystal. With the adoption of the logic gate, full-light optical random logic gate calculation and delayed storage of the calculation are realized.

Description

Controlled full light random logic door

Technical field

The present invention relates to photonic device, be specially controlled full light random logic door.

Background technology

Due to the cylinder that the active cavity of vertical cavity semiconductor laser (VCSEL) is symmetrical, it is easier two linearly polarized photons of lasing. Being called X polarized light when the polarization direction of light is along the X-direction of the coordinate axes of active cavity, polarization direction is called Y polarized light along the light Y-axis of Y-axis, and X polarized light is mutually perpendicular to Y polarized light. Change pumping current, Implantation Energy, or the luminous energy that injects changing off resonance causes the generation of polarization conversion and polarization bistability. In report relevant recently, making to use the polarization conversion in light injection laser and polarization bistability, different types of photoelectricity gate and all-optical logic gate computing can be obtained. Such as, in the VCSEL system of free-running operation, logic enters through pumping current and compiles, and logic output is decoded by VCSEL two linearly polarized photons launched, it is possible to obtain random logic OR-gate, NOR gate and NOT-AND gate; Injecting in VCSEL at coherent light, logic enters through injection light intensity and compiles, and logic output is decoded by VCSEL two linearly polarized photons launched, it is possible to obtain logical "and" door and OR-gate; Injecting in VCSEL in tunable optical, logic enters through exterior light frequency detuning and compiles, and two linearly polarized photons that logic output is exported by laser instrument decode, it is possible to achieve full light random logic OR-gate. But, in the methods described above, the slight change of some important parameters (such as pumping current, the injection light of light Implantation Energy and off resonance) can change the state of output polarization. Simultaneously as the instability of polarization conversion, result in gate in the above-mentioned methods has very poor stability. Further, since all-optical digital logical signal exists certain technical difficulty in time delay storage, therefore, above-mentioned basic logical gate operations can be only applied to combination logic photonic device, but can not be applied to sequential logic photonic device.

Summary of the invention

For above-mentioned technical problem, the present invention provides a kind of controlled full light random logic door, by controlling extra electric field and the logical relation of two logics input, controlled infull light random logic door can be realized, as inverter, AND gate, NOT-AND gate, OR-gate, partial sum gate, NOR gate, " XNOR " door computing and time delay thereof store.

The present invention is achieved through the following technical solutions:

Controlled full light random logic door, includes: tunable continuous wave laser, the first optoisolator, light successively Learn attenuator, beam splitter, main Vcsel, the second optoisolator, the first polarization beam apparatus, periodically pole lithium columbate crystal, the 3rd optoisolator, the second polarization beam apparatus, the 3rd polarization beam apparatus, optical amplifier, from Vcsel, the 4th polarization beam apparatus;

The first plane mirror, the first half-wave plate and the second half-wave plate also it is parallel with between described beam splitter and main Vcsel;

The second plane mirror, the first Faraday rotator, the 3rd half-wave plate also it is parallel with between the first described polarization beam apparatus and periodicity pole lithium columbate crystal;

The 4th half-wave plate, the second Faraday rotator also it is parallel with between the second described polarization beam apparatus and the 3rd polarization beam apparatus;

Periodically added with transverse electric field E on the lithium columbate crystal of pole₀。

Controlled full light random logic door provided by the invention, achieve full light random logic door computing and time delay storage thereof, be specifically capable of inverter, AND gate, NOT-AND gate, OR-gate, partial sum gate, NOR gate, " XNOR " door computing and time delay storage thereof. The arithmetic speed of this controlled full light random logic door is faster than the arithmetic speed of electric light gate, and these devices can be applied to time sequential photon logical device.

Accompanying drawing explanation

Fig. 1 is the structural representation of the present invention;

Fig. 2 is embodiment polarization bistability lag regression line under the effect of different extra electric fields;

Fig. 3 is embodiment logic inverter, partial sum gate, " XNOR " door computing and time delay storage thereof;

Fig. 4 is that embodiment sieve collects AND gate, NOT-AND gate, OR-gate and NOR gate computing and time delay storage thereof.

Detailed description of the invention

Below in conjunction with accompanying drawing, present invention is described further:

As shown in Figure 1, controlled full light random logic door, includes successively: tunable continuous wave laser the 1, first optoisolator 2, optical attenuator 3, beam splitter 4, main Vcsel the 5, second optoisolator the 6, first polarization beam apparatus 7, periodically pole lithium columbate crystal the 8, the 3rd optoisolator the 9, second polarization beam apparatus the 10, the 3rd polarization beam apparatus 11, optical amplifier 12, from Vcsel the 13, the 4th polarization beam apparatus 14;

The first plane mirror the 15, first half-wave plate 16 and the second half-wave plate 17 also it is parallel with between described beam splitter 4 and main Vcsel 5;

Second plane mirror the 18, first Faraday rotator the 19, the 3rd half-wave plate 20 also it is parallel with between the first described polarization beam apparatus 7 and periodicity pole lithium columbate crystal 8;

The 4th half-wave plate the 21, second Faraday rotator 22 also it is parallel with between described the second polarization beam apparatus 10 and the 3rd polarization beam apparatus 11;

Periodically added with transverse electric field E on pole lithium columbate crystal 8₀23。

Operation principle:

Main Vcsel 5 and the operation wavelength from Vcsel 13 are 850nm, and threshold current is 6.8mA, and its temperature is accurately controlled in ± 0.01 DEG C. The effect of the first optoisolator 2 is to ensure that the main Vcsel 5 of the unidirectional injection of light that tunable continuous wave laser 1 sends. The effect of the second optoisolator 6 is to avoid from the light feedback of the first polarization beam apparatus 7 to main Vcsel 5.3rd optoisolator 9 ensures to be injected into from Vcsel 13 from the light of periodicity pole lithium columbate crystal 8 output is unidirectional. It is placed on the energy that the optical attenuator 3 on the right of tunable continuous wave laser 1 injects for tuned light. Being placed on the left side optical amplifier 12 from Vcsel 13 is strengthen the injection light intensity from Vcsel 13. Additional transverse electric field E₀23 along the x-axis direction of periodicity pole lithium columbate crystal 8 coordinate system. Tunable continuous wave laser 1 sends x-polarisation light, it is separated into two-beam, a branch of being directly injected in main Vcsel 5, another bundle is changed into e polarized light by the first half-wave plate 16 and the second half-wave plate 17, is re-introduced in main Vcsel 5. Fixing certain pumping current, main Vcsel 5 lasing x-polarisation light and y-polarisation light, they are separated by the first polarization beam apparatus 7. The x-polarisation light separated from the first polarization beam apparatus 7 is considered as the initial input of 0 light periodicity pole lithium columbate crystal 8, because it is the polarization direction along 0 light. When by the first Faraday rotator 19 and the 3rd half-wave plate 20, when making the y-polarisation light that separates from the first polarization beam apparatus 7 parallel with the polarization direction of e light, it is thought of as in periodicity pole lithium columbate crystal 8 initial input of e light. At additional transverse electric field E₀Under the effect of 23, x and y-polarisation light experience electric light amplitude modulation(PAM) in periodicity pole lithium columbate crystal 8. Export 0 light from periodicity pole lithium columbate crystal 8, after time delay T, as x-polarisation light, after the 3rd polarization beam apparatus 11 and optical amplifier 12, be injected into from Vcsel 13. And it is considered logic output X₁. Output e light, after first passing through time delay T, again through the 4th half-wave plate 21 and the second Faraday rotator 22. At this moment, its polarization direction is along y-polarisation direction. Under these conditions, it is as y-polarisation light, after the 3rd polarization beam apparatus 11 and optical amplifier 12, is injected into from Vcsel 13. It addition, it is defined as logic output Y₁. From vertical cavity table The x-polarisation light of surface-emitting laser 13 output and y-polarisation light are thought of as logic output X respectively₂And Y₂。

Some important parameters of laser instrument are as follows: main Vcsel 5 with have identical pumping current from Vcsel 13, i.e. μ_M=μ_S=1.2; The X polarization of main Vcsel 5 and the injection light intensity of Y polarization: K_Mx=K_My=10ns^-1; Polarize and the injection light intensity of Y polarization: K from the X of laser instrument_Sx=K_Sy=5K_Mx; Exterior light amplitude: E_inj=0.6. Here, suppose that frequency detuning value Δ ω=d ω₁+dω₂(dω₁, d ω₂It is square wave), and be used for being compiled into two logic inputs. For frequency detuning d ω₁, logic input is defined as A₁; For off resonance d ω₂, logic input is defined as A₂. Under this condition, logic input has four sequences: (0,0), (0,1), (1,0) and (1,1). For (0,1) and (1,0), there is identical frequency detuning Δ ω_∏. Therefore, four logic list entries can with three standard frequency off resonance (Δ ω_I, Δ ω_∏, Δ ω_III) compile, here,Represent (0,0),Represent (1,1). Logic inverter is designed, logic input A₁With frequency detuning d ω₁Compile. Assuming that as d ω₁During=75GHz, A₁=1;If d ω₁=-140GHz, A₂=0. For other gate, Δ ω_∏It is set to-65radGHz,It is thought of as 215radGHz. Logic output decoding is as follows: periodically pole lithium columbate crystal 8 output X polarized light, remembers X₁=1, Y₁=0, export Y polarized light, then X₁=0, Y₁=1; X polarized light, X is only exported from VCSEL₂=1, Y₂=0, if exporting Y polarized light from Vcsel 13, then X₂=0, Y₂=1.

Spin flip conversion model based on well-known Vcsel, it is considered to external optical injection, the Rate equations obtaining main Vcsel is as follows:

$\begin{array}{c}\frac{{\mathrm{dE}}_{\mathrm{Mx}}\left(t\right)}{\mathrm{dt}}=k(1+\mathrm{ia})[N_M\left(t\right)E_{\mathrm{Mx}}\left(t\right)+{\mathrm{in}}_M\left(t\right)E_{\mathrm{My}}\left(t\right)-E_{\mathrm{Mx}}\left(t\right)]-i({\mathrm{\γ}}_p+\mathrm{\Δ\ω})E_{\mathrm{Mx}}\\ -{\mathrm{\γ}}_a{E}_{\mathrm{MX}}+\sqrt{{\mathrm{\β}}_{\mathrm{sp}}{\mathrm{\γ}}_e{N}_M}{\mathrm{\ξ}}_x+K_{\mathrm{Mx}}{E}_{\mathrm{inj}},\end{array}---\left(1\right)$

$\begin{array}{c}\frac{{\mathrm{dE}}_{\mathrm{My}}\left(t\right)}{\mathrm{dt}}=k(1+\mathrm{ia})[N_M\left(t\right)E_{\mathrm{My}}\left(t\right)-{\mathrm{in}}_M\left(t\right)E_{\mathrm{Mx}}\left(t\right)-E_{\mathrm{My}}\left(t\right)]-i({\mathrm{\γ}}_p+\mathrm{\Δ\ω})E_{\mathrm{Mx}}\\ +{\mathrm{\γ}}_a{E}_{\mathrm{My}}+\sqrt{{\mathrm{\β}}_{\mathrm{sp}}{\mathrm{\γ}}_e{N}_M}{\mathrm{\ξ}}_y+K_{\mathrm{My}}{E}_{\mathrm{inj}},\end{array}---\left(2\right)$

$\frac{{\mathrm{dN}}_M\left(t\right)}{\mathrm{dt}}=-{\mathrm{\γ}}_e\left[N_M(1+{\left|E_{\mathrm{Mx}}\right|}^2+{\left|E_{\mathrm{My}}\right|}^2)\right]+{\mathrm{\γ}}_e{\mathrm{\μ}}_M-{\mathrm{i\γ}}_e{n}_M(E_{\mathrm{My}}{E_{\mathrm{Mx}}}^{*}-E_{\mathrm{Mx}}{E_{\mathrm{My}}}^{*}),---\left(3\right)$

$\frac{{\mathrm{dn}}_M\left(t\right)}{\mathrm{dt}}=-{\mathrm{\γ}}_s{n}_M-{\mathrm{\γ}}_e{n}_M({\left|E_{\mathrm{Mx}}\right|}^2+{\left|E_{\mathrm{My}}\right|}^2)-{\mathrm{i\γ}}_e{N}_M(E_{\mathrm{My}}{E_{\mathrm{Mx}}}^{*}-E_{\mathrm{Mx}}{E_{\mathrm{My}}}^{*}),---\left(4\right)$

Here, subscript M refers to main Vcsel, and subscript x and y represents xandy linear polarization component respectively; E becomes amplitude slowly; N is at the inverted population being situated between band and conduction band; N be upper rotation and backspin radiation carrier number poor; K is a loss speed; γ_eIt it is the rate of decay of N; γ_sIt it is spin flip conversion relaxation rate; A linewidth enhancement factor; γ_aAnd γ_pRepresent anisotropy light field amplitude losses speed and active medium linear birefringence effect respectively; μ_MThe normalization pumping current of main Vcsel; Noise intensity parameter D is defined asβ_spIt it is sponta-neous emission factor; ξ_xAnd ξ_yRespectively two Gaussian noises, their time relationship is < ξ_i(t)ξ_j ^*(t) >=2 δ_ijδ(t-t’).K_Mx(K_My) it is that x (y) polarized component injects intensity; E_injIt it is injected field amplitude; Injected field off resonanceω_injIt it is the angular frequency of injected field; Reference frequencyIt is defined as (ω_x+ω_y)/2, ω_xA andIt is the angular frequency of the x of independent operating Vcsel and y-polarisation component respectively.

As it is shown in figure 1, x-polarisation component is propagated along periodic polarized lithium columbate crystal o light direction, y-polarisation component is by the first Faraday rotator 19 and the first half-wave plate 16 and e parallel light. Under these conditions, x and y-polarisation component are thought of as o light and the e light initial input of crystal. Therefore have

Here, U_xAnd U_yRepresent o light and e light amplitude respectively;It it is Planck constant; S_AIt it is the effective area of hot spot; V is Vcsel active layer volume; υ_cFor the light velocity in vacuum; T_L=2n_gυ_c/L_vIt it is light circulation time in laser cavity; ω₀It it is the mid frequency from main vertical cavity semiconductor laser laser pulse; n₁And n₂It is the intact refractive index of o light and e light respectively. Due to phase mismatch, second order nonlinear effect is very weak. Therefore, the analytic solutions of two linear polarization component linear electro-optic effect coupledwave equation in periodicity pole lithium columbate crystal 8 are:

U_{X, y}(L, t)=ρ_{X, y}(L, t) exp (i β₀L)exp[iφ_{X, y}(L, t)] (6)

Here:

${\mathrm{\&phi;}}_{x,y}(L,t)={\tan }^{-1}\left[\frac{\&PlusMinus;{\mathrm{\&gamma;U}}_{x,y}(0,t)-d_{\mathrm{1,3}}{U}_{y,x}(0,t)}{\mathrm{\&nu;}{U}_{x,y}(0,t)}\tan \left(\mathrm{\&nu;L}\right)\right],---\left(8\right)$

And:

${\mathrm{\&beta;}}_0=\frac{\mathrm{\&Delta;k}-d_2-d_4}{2},---\left(9\right)$

$\mathrm{\&nu;}=\sqrt{\frac{{(\mathrm{\&Delta;k}+d_2-d_4)}^2+4d_1{d}_3}{2}},---\left(10\right)$

$\mathrm{\&gamma;}=\frac{d_4-d_2-\mathrm{\&Delta;k}}{2},---\left(11\right)$

Here, coefficient d₁, d₂, d₃And d₄Refer to list of references: J.Zamora-Munt, andC.Masoller, " NumericalimplementationofaVCSEL-basedstochasticlogicgate viapolarizationbistability; " OptExpress18 (16), 16418-16429 (2010); L is crystal length; Wave vector mismatch Δ k=k_x-k_y+K₁, K₁=2 π/Λ is the first rank reciprocal lattice vector of crystal, and Λ is polarization cycle, k_xAnd k_yRepresent x and the y-polarisation component wave vector at mid frequency place respectively. Here, it is considered to K₁Close to wave vector amount of mismatch k_x-k_y, due to phase mismatch, which is ignored on linear electro-optic effect without the component affected.

As two polarized component first time delay τ experiencing linear electrooptic modulation, when being then injected into from Vcsel, have:

Wherein, E_pxAnd E_pyRespectively experience the x of Electro-optical Modulation and the amplitude of y-polarisation component.Under this condition, the Rate equations from Vcsel that time delay light injects is described as:

$\begin{array}{c}\frac{d{N}_S\left(t\right)}{\mathrm{dt}}=-{\mathrm{\&gamma;}}_e\{N_S\left(t\right)-{\mathrm{\&mu;}}_S+N_S\left(t\right)({\left|E_{\mathrm{Sx}}\left(t\right)\right|}^2+{\left|E_{\mathrm{Sy}}\right|}^2)\\ +{\mathrm{in}}_S\left(t\right)[E_{\mathrm{Sy}}\left(t\right){E^{*}}_{\mathrm{Sx}}\left(t\right)-E_{\mathrm{Sx}}\left(t\right){E^{*}}_{\mathrm{Sy}}\left(t\right)\},\end{array}---\left(14\right)$

$\begin{array}{c}\frac{d{N}_S\left(t\right)}{\mathrm{dt}}=-{\mathrm{\&gamma;}}_s{n}_S\left(t\right)-{\mathrm{\&gamma;}}_e\{n_S\left(t\right)({\left|E_{\mathrm{Sx}}\left(t\right)\right|}^2+{\left|E_{\mathrm{Sy}}\right|}^2)\\ +{\mathrm{iN}}_S\left(t\right)[E_{\mathrm{Sy}}\left(t\right){E^{*}}_{\mathrm{Sx}}\left(t\right)-E_{\mathrm{Sx}}\left(t\right){E^{*}}_{\mathrm{Sy}}\left(t\right)\},\end{array}---\left(15\right)$

Here subscript S refers to from Vcsel;It it is the mid frequency off resonance advocated peace between Vcsel; K_Sx(K_Sy) it is that x (y) polarized component injects intensity; μ_SIt it is normalization pump Pu electric current.

Can see that from Fig. 1, when being subject to coming from the injection of periodic polarized lithium columbate crystal output intensity from Vcsel, from Vcsel launch x (y) polarized component with have generalized chaotic synchronization with x (y) polarized component Delay injection light, namely

I_Sx(t)≈C₁I_Px(t-τ)(16)

I_Sy(t)≈C₂I_Py(t-τ)(17)

Wherein, I_Sx(t)=| E_Sx(t)|²; I_Sy(t)=| E_Sy(t)|²; I_px(t)=| E_px(t)|²; I_py(t)=| E_py(t)|²; C₁=< I_Sx(t)>/<I_Px(t-τ) >; C₂=< I_Sy(t)>/<I_Py(t-τ) >. when generalized chaotic synchronization equation (16) and (17) apply to logic gate design, it is possible to achieve the time delay of all-optical logic gate is deposited all.

As Fig. 2 gives for extra electric field E₀=0kV/mm and E₀=85kV/mm, polarization bistability lag regression line, this bistable state curve is the function between frequency detuning and two linear polarization light intensity. Wherein, dotted line is expressed as X polarized light, and solid line is Y polarized light. Track (a) represents under two different DC Electric Fields with (b), the polarization bistability ring of PPLN crystal output; Track (c) represents under two different DC Electric Fields with (d), from the polarization bistability ring of VCSEL output. Shown in arrow three frequency detuning d ω is used for logic compiler input.

Table 1 gives the input of logical not operation and the logical relation of output and the logical relation of extra electric field and logic input. Logic input frequency detuning d ω₁Compiling, it is defined as A₁. Extra electric field logical symbol e represents. When logical signal e is " 0 ", represent extra electric field E₀For 0kV/mm, when it is 1, extra electric field E₀For 85kV/mm; When logical signal e is identical with logic input A2, as shown in Table 1: $Y_1=\stackrel{\&OverBar;}{A_1},Y_2=\stackrel{\&OverBar;}{A_2}.$

Table 1

Table 2 gives logic XOR and the logical relation of the input of XNOR computing and output and the logical relation of extra electric field and logic input. Logic inputs with three standard frequency off resonance (Δ ω_I, Δ ω_∏, Δ ω_III) Compile, logic output X₁And Y₁Decoded by the PPLN certain proportion exported and time delay two linear polarization light intensity, logic output X₂And Y₂Decoded by the two linear polarization light intensity exported from VCSEL. As shown in Table 2:Y₁=A1 ⊙ A2, Y₂=A1 ⊙ A2.

Table 2

Fig. 3 shows logic " non-", distance, " XNOR " door computing and time delay storage thereof. Extra electric field, from X, Y intensity of polarization light of VCSEL output, and the time variation track of X, Y intensity of polarization light of the certain proportion of periodic polarized lithium columbate crystal output and time delay. (a): dotted line: logic input d ω 2; Imaginary point line: logic input d ω 1; Solid line: extra electric field E₀. (b) extra electric field E₀For 0kV/mm; Imaginary point line; Three standard frequency off resonance Δ ω_I, Δ ω_∏, Δ ω_III. (c) extra electric field E₀For 0kV/mm; Imaginary point line: three standard frequency off resonance Δ ω_I, Δ ω_∏, Δ ω_III。

Table 3 gives logical AND and the logical relation of logical AND non-input and output and the logical relation of extra electric field and logic input. Logic inputs with three standard frequency off resonance (Δ ω_I, Δ ω_∏, Δ ω_III) compile, logic output X₁And Y₁Decoded by the PPLN certain proportion exported and time delay two linear polarization light intensity, logic output X₂And Y₂Decoded by the two linear polarization light intensity exported from VCSEL.Can obtain from table 3: X₁=A1 A2, X₂=A1 A2,

Table 3

Table 4 gives logical AND and the logical relation of logical AND non-input and output and the logical relation of extra electric field and logic input. Logic inputs with three standard frequency off resonance (Δ ω_I, Δ ω_∏, Δ ω_III) compile Translate, logic output X₁And Y₁Decoded by the PPLN certain proportion exported and time delay two linear polarization light intensity, logic output X₂And Y₂Decoded by the two linear polarization light intensity exported from VCSEL. Can be obtained by table 4: X₁=A1+A2, X₂=A1+A2,

Table 4

Fig. 4 shows logical AND, with non-, or, and NOR-operation and time delay storage. Extra electric field, from X, Y intensity of polarization light of VCSEL output, and the time variation track of X, Y intensity of polarization light of the certain proportion of periodic polarized lithium columbate crystal output and time delay. In figure, imaginary point line: three standard frequency off resonance Δ ω_I, Δ ω_∏, Δ ω_III; Solid black lines: extra electric field E₀。

Claims (1)

1. controlled full light random logic door, it is characterized in that: include successively: tunable continuous wave laser (1), first optoisolator (2), optical attenuator (3), beam splitter (4), main Vcsel (5), second optoisolator (6), first polarization beam apparatus (7), periodically pole lithium columbate crystal (8), 3rd optoisolator (9), second polarization beam apparatus (10), 3rd polarization beam apparatus (11), optical amplifier (12), from Vcsel (13), 4th polarization beam apparatus (14),

The first plane mirror (15), the first half-wave plate (16) and the second half-wave plate (17) also it is parallel with between described beam splitter (4) and main Vcsel (5);

The second plane mirror (18), the first Faraday rotator (19), the 3rd half-wave plate (20) also it is parallel with between described the first polarization beam apparatus (7) and periodicity pole lithium columbate crystal (8);

The 4th half-wave plate (21), the second Faraday rotator (22) also it is parallel with between described the second polarization beam apparatus (10) and the 3rd polarization beam apparatus (11);

Periodically added with transverse electric field E on pole lithium columbate crystal (8)₀(23)。