CN108802908B - Dual-input dual-output optical switch based on defect-containing nonlinear photonic lattice - Google Patents

Abstract

The invention provides a double-input double-output optical switch based on a defect-containing nonlinear photonic lattice, which includes a first waveguide layer and a second waveguide layer, and the first waveguide layer is arranged on the upper part of the second waveguide layer; the first waveguide layer includes Including N+m waveguides, wherein the N waveguides with serial numbers from v ₁ to v _N are nonlinear waveguides, and N+m waveguides are arranged on the same horizontal plane, where m is a positive integer; the second waveguide layer includes N‑1 A linear waveguide, wherein the N-1 linear waveguides are arranged on the same horizontal plane; wherein the linear waveguide with the sequence number u ₁ has a positive defect, and the linear waveguide with the sequence number u _N-1 has a negative defect; the double-input double-output optical switch also includes Two input ports and two output ports. The present invention has non-linearly dependent optical switch transmittance, and different light intensities at different input ends have different light-through states, can flexibly regulate the opening and closing of the optical path, and can realize optical path protection under the condition of high input light intensity.

Description

Dual-input dual-output optical switch based on defect-containing nonlinear photonic lattice

technical field

The invention belongs to the field of optical communication and optical logic calculation, and relates to an optical switch, in particular to a double-input double-output optical switch based on a defect-containing nonlinear photon lattice.

Background technique

With the continuous improvement of traditional integration processes, transistor circuits are gradually approaching the physical limit, and Moore's Law will no longer apply. Replacing electrical signals with optical signals has become a new way to develop integrated technology, and all-optical switches play an important role in optical computing and optical information processing.

Traditional mechanical optical switches are bulky and difficult to integrate, and have a slow response speed; although microelectronic optical switches have good process compatibility, they have large insertion loss, unstable switches, and response speeds of only on the order of microseconds. With the development of photonic technology, photonic lattice appears in front of people as a brand-new all-optical platform, but the general all-optical photonic lattice optical switch only has a single input/single output, which is not conducive to the flexible regulation of optical signals. In addition, with the introduction of nonlinear effects, high-power-density optical signals will inevitably damage optical devices, so the protection of the optical path is also one of the problems to be solved urgently.

Contents of the invention

Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a dual-input dual-output optical switch based on a defect-containing nonlinear photonic lattice, which solves the problem of high-power The optical signal of the concentration will cause damage to the optical device.

In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve:

A double-input double-output optical switch based on a defect-containing nonlinear photonic lattice, comprising a first waveguide layer and a second waveguide layer, and the second waveguide layer is arranged on the upper part of the first waveguide layer;

The first waveguide layer is denoted as v _n and includes N+m waveguides, wherein the N waveguides with serial numbers from v ₁ to v _N are nonlinear waveguides, and the N+m waveguides are arranged on the same horizontal plane, where m is a positive integer;

The second waveguide layer is denoted as u _n , including N-1 linear waveguides, and the N-1 linear waveguides are arranged on the same horizontal plane; wherein the linear waveguide with serial number u ₁ has a positive defect, and the serial number is u _N- A linear waveguide of ₁ has negative defects;

The dual-input dual-output optical switch also includes two input ports (ports 1 and 2) and two output ports (ports 3 and 4).

Further, the linear waveguide is located directly above the midpoint of the connecting line between the two nonlinear bands.

Further, there is an intralayer coupling coefficient κ ₁ between every two adjacent nonlinear waveguides, and an interlayer coupling coefficient κ ₂ between adjacent linear waveguides and nonlinear waveguides; where, κ ₁ : κ ₂ is Greater than or equal to 2 and less than or equal to 3.

Further, the two input ports are respectively arranged on the left side of the first waveguide layer (port 1) or the right linear waveguide region (port 2), and the two output ports are respectively arranged on the left side of the first waveguide layer (port 3) or the right linear waveguide region (port 4).

Further, both the linear waveguide and the nonlinear waveguide are linear waveguides. Compared with the prior art, the present invention has the following technical effects:

The present invention is provided with dual-port input and output ports, and the on-off of the optical switch depends on the light intensity and the selection of the input port, which can realize the protection of the optical path under the condition of high input light intensity;

The present invention is sawtooth-shaped, has non-linearly dependent optical switch transmittance, different light intensities at different input ends have different same-light states, can flexibly regulate and disconnect the optical path, and can realize optical path protection in the case of high input light intensity;

The invention has the advantages of small size, simple structure, easy integration and low insertion loss.

Description of drawings

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

Fig. 2 is the sectional view of structure of the present invention;

When Fig. 3 (a) N is 2, under the self-focus nonlinear effect, the transmittance curve of the present invention; Fig. 3 (b) N is 3, under the self-focus nonlinear effect, the transmittance curve of the present invention Curve; Figure 3 (c) N is 2, under the self-defocus nonlinear effect, the transmittance curve of the present invention; Fig. 3 (d) is when N is 3, under the self-defocus nonlinear effect, the transmittance curve of the present invention Invented transmittance curve; where the triangle and the solid line represent the case of small defects (|β _1,2 |=0.1) two ports (k=π/2 represents the incident from port 1, k=-π/2 represents the secondary port 2 incident), the dotted line and the star-shaped line represent the transmittance of the two ports in the case of strong defects (|β _1,2 |=1);

Fig. 4 is a numerical simulation transmission diagram under different light intensity inputs under the condition of N=3, |β _1,2 |=1, κ ₂ /κ ₁ =2.

The specific content of the present invention will be further explained in detail below in conjunction with the accompanying drawings.

Detailed ways

It should be noted that as shown in FIG. 1 , left and right in this application refer to left and right in FIG. 1 .

Specific embodiments of the present invention are provided below, and it should be noted that the present invention is not limited to the following specific embodiments, and all equivalent transformations done on the basis of the technical solutions of the present application all fall within the scope of protection of the present invention.

Example 1:

As shown in Figures 1 and 2, this embodiment provides a double-input double-output optical switch based on a defect-containing nonlinear photonic lattice, including a first waveguide layer and a second waveguide layer, and the second waveguide layer is arranged on the first waveguide layer. The upper part of the waveguide layer;

The first waveguide layer includes N+m waveguides, wherein the _N waveguides whose serial numbers are v1 to _vN are nonlinear waveguides, and the N+m waveguides are arranged on the same horizontal plane, where m is a positive integer;

The second waveguide layer includes N-1 linear waveguides, and the N-1 linear waveguides are arranged on the same horizontal plane; wherein the linear waveguide with the serial number u ₁ has a positive defect, and the linear waveguide with the serial number u _N-1 has a negative defect ;

Wherein, the linear waveguide is located directly above the midpoint of the connecting line of the two nonlinear wavebands.

There is an intralayer coupling coefficient κ ₁ between every two adjacent nonlinear waveguides, and there is an interlayer coupling coefficient κ ₂ between adjacent linear waveguides and nonlinear waveguides; wherein, κ ₁ :κ ₂ is 2:1 .

The dual-input dual-output optical switch also includes two input ports and two output ports. Among them, as shown in Figure 1, the two input ports are respectively arranged on the left side of the first waveguide layer (port 1) or the right linear waveguide area (port 2), and the two output ports are respectively arranged on the left side of the first waveguide layer (port 2). 3) or the right linear waveguide region (port 4).

Both the linear waveguide and the nonlinear waveguide in this embodiment are linear waveguides. When N=2, As shown in Figure 3(a) and Figure 3(c).

When N=3, As shown in Figure 3(b) and Figure 3(d).

in:

V ₂ =ε(β ₂ )T ₀ e ^3ik +ρ(β ₂ )T ₀ e ^4ik ;

ω=-2κ ₁ cosk;

V ₁ =e ^ik R ₀ +e ^-ik R;

In the formula, T ₀ is the transmission amplitude, R is the reflection amplitude, R ₀ is the incident amplitude, β _1,2 is the defect size, and k is the optical wave vector.

As shown in Fig. 3(d), when α=-1, N=3, |β _1,2 |=1, both curves first increase and then decrease with the increase of light intensity. In the case of low light, the transmittance of the optical switch at both input terminals is very low, most of the energy is reflected, and there is no obvious difference between the two curves, indicating that the two inputs should have the same switching state - only one The output port is open; at medium light intensity, the light waves input from ports 1 and 2 have high transmittance, but there are obvious differences between the two curves, indicating that the optical switch input from ports 1 and 2 will have a high transmittance. Different switching states realize the optical switch of dual-port input/output. In the case of strong light, the transmittance curves of the optical switches input from ports 1 and 2 are greatly reduced, indicating that most of the energy is reflected and the optical path protection is realized. From the above analysis, it can be seen that the present invention can be implemented in a system with self-defocusing nonlinear effect and strong defects.

The dual-input dual-output optical switch proposed in the present invention can be prepared by diffusing iron and magnesium in different layers in lithium niobate at high temperature. The nonlinear layer waveguide can be formed by diffusing Fe ₂ O ₃ at high temperature, and the linear layer can suppress the photorefractive effect by diffusing MgO at high temperature, thereby preparing a linear waveguide; changing the doping concentration can realize positive and negative defects, so that the defect refractive index is n ₀ ±(10 ^-3 ~ 10 ^-4 ) (n ₀ is the refractive index of the linear layer common waveguide). The coupling coefficient is proportional to the distance between the waveguides, so the coupling coefficient can be adjusted by adjusting the distance between the waveguides, assuming κ ₁ = 0.15mm ^-1 , κ ₂ = 0.3mm ^-1 , then the distance between the nonlinear waveguides d = 17μm , the distance between the nonlinear layer and the linear layer is d=34μm.

In this embodiment, the number of nonlinear waveguides is N=3, the defect depth is |β|=n ₀ ±10 ^-3 , κ ₁ =0.15mm ^-1 , and κ ₂ =0.3mm ^-1 . The numerical simulation results are shown in Figure 4. In the case of weak light, the input at port 1 will get the output signal at port 3, and port 4 is closed; when the input at port 2 will get the output signal at port 4, and port 3 will be closed. state; continue to increase the light intensity, the signal input from port 1 can pass through the optical switch with low loss, and the signal output is obtained at port 4. At this time, port 4 is open and port 3 is closed; the signal input from port 2 passes through the optical switch. In the semi-transparent and semi-reflective state, there are output signals on ports 3 and 4, and the optical switch is open for both ports; in the case of strong light, the input of port 1 can only be output from port 3, and the port 4 is closed , to achieve the protection of the optical path in port 4; the input from port 2 will also have a similar phenomenon, which can realize the protection of the optical path in port 3.

Claims (4)

1. A double-input double-output optical switch based on a defect-containing nonlinear photonic lattice, characterized in that it includes a first waveguide layer and a second waveguide layer, and the second waveguide layer is arranged on the top of the first waveguide layer; The first waveguide layer is denoted as v _n and includes N+m waveguides, wherein the N waveguides with serial numbers from v ₁ to v _N are nonlinear waveguides, and the N+m waveguides are arranged on the same horizontal plane, where m is a positive integer; The second waveguide layer is denoted as u _n , including N-1 linear waveguides, and the N-1 linear waveguides are arranged on the same horizontal plane; wherein the linear waveguide with serial number u ₁ has a positive defect, and the serial number is u _N- A linear waveguide of ₁ has negative defects; The double-input double-output optical switch also includes two input ports and two output ports, the two input ports are respectively arranged in the linear waveguide area on the left or right side of the first waveguide layer, and the two output ports are respectively arranged in the first waveguide layer A linear band region on the left or right side of the waveguide layer. 2. The dual-input dual-output optical switch based on a defect-containing nonlinear photonic lattice according to claim 1, wherein the linear waveguide is located directly above the midpoint of the connecting line between two nonlinear wavebands. 3. The double-input double-output optical switch based on the defect-containing nonlinear photonic lattice according to claim 2, wherein there is an intralayer coupling coefficient κ ₁ between every two adjacent nonlinear waveguides, There is an interlayer coupling coefficient κ ₂ between adjacent linear waveguides and nonlinear waveguides; wherein, κ ₁ : κ ₂ is greater than or equal to 2 and less than or equal to 3. 4 . The dual-input dual-output optical switch based on a defect-containing nonlinear photonic lattice according to claim 1 , wherein both the linear waveguide and the nonlinear waveguide are linear waveguides.