Wavelength-selective all-optical switch based on surface plasmons

Abstract

The wavelength selective all-optical switch based on surface plasmons of the present invention belongs to the field of micro-nano optoelectronic technology; the wavelength selective all-optical switch is composed of a substrate layer and a rectangular metal layer, the rectangular metal layer is closely attached to the substrate layer, and a first straight waveguide, a second straight waveguide, a third straight waveguide, a fourth straight waveguide and an equilateral triangle resonant cavity which are equal in height to the rectangular metal layer are etched on the rectangular metal layer, wherein the second straight waveguide and the fourth straight waveguide are in the same direction as the long side of the rectangular metal layer, and the angles between the first straight waveguide and the third straight waveguide and the long side of the rectangular metal layer are both 60°; in the equilateral triangle resonant cavity, a rectangular metal block which is equal in height to the rectangular metal layer and whose center coincides with the center of the equilateral triangle resonant cavity is also arranged; the wavelength selective all-optical switch based on surface plasmons of the present invention has a simple structure, has the technical advantages of wavelength selectability and high extinction ratio, and can be applied to large-scale integrated optical communication devices in the future.

Description

Technical Field

[0001] The invention discloses a wavelength selective all-optical switch based on surface plasmons and belongs to the technical field of micro-nano optoelectronics. Background Art

[0002] Surface plasmon is an electromagnetic evanescent wave that propagates along the interface between metal and dielectric and decays exponentially in the direction perpendicular to the interface. This electromagnetic wave has the properties of breaking through the traditional diffraction limit and electric field confinement.

[0003] As a typical waveguide structure based on surface plasmon filters, the metal-dielectric-metal structure has the characteristics of high light confinement and easy manufacturing. Therefore, the metal-dielectric-metal structure based on surface plasmon polaritons has been used in different photonic components, such as sensors, Mach-Zehnder interferometers, filters, etc.

[0004] In high-speed optical communication systems, optical switches are used as key node devices to realize functions such as optical cross-connection, optical switching, optical add / drop multiplexing, and network self-healing protection. At present, with the development of highly integrated all-switch devices, the demand for all-optical switches with anti-electromagnetic interference and fast response speed is becoming more and more obvious. However, most existing all-optical switches are used to switch single-wavelength optical signals, the wavelength is not selectable, the structure is complex, and the extinction ratio is low. It is particularly important to realize a multi-channel optical switch with selectable wavelength, simple structure, and high extinction ratio. Summary of the invention

[0005] In order to achieve the above object, the present invention discloses a wavelength selective all-optical switch based on surface plasmons. The all-optical switch realizes wavelength selectivity by incident on different straight waveguides, has a simple structure and a high extinction ratio.

[0006] The object of the present invention is achieved in that:

[0007] The wavelength selective all-optical switch based on surface plasmon polaritons is composed of a substrate layer and a rectangular metal layer, wherein the rectangular metal layer is closely attached to the substrate layer, and a first straight waveguide, a second straight waveguide, a third straight waveguide, a fourth straight waveguide and an equilateral triangle resonant cavity which are equal in height to the rectangular metal layer are etched on the rectangular metal layer, wherein the second straight waveguide and the fourth straight waveguide are in the same direction as the long side of the rectangular metal layer, and the angles between the first straight waveguide and the third straight waveguide and the long side of the rectangular metal layer are both 60°; and a rectangular metal block which is equal in height to the rectangular metal layer and whose center coincides with the center of the equilateral triangle resonant cavity is also arranged in the equilateral triangle resonant cavity.

[0008] The dimensions of the above-mentioned wavelength selective all-optical switch based on surface plasmon are limited as follows:

[0009] The size of the rectangular metal layer is 1160nm×530nm×75nm;

[0010] The width of the first straight waveguide is 50 nm, and the distance from the equilateral triangle resonant cavity is d1=18 nm;

[0011] The width of the second straight waveguide is 50nm, and the distance from the equilateral triangle resonant cavity is d2=20nm~50nm;

[0012] The width of the third straight waveguide is 50 nm, and the distance between the third straight waveguide and the equilateral triangle resonant cavity is d3=18 nm;

[0013] The width of the fourth straight waveguide is 50 nm, and the distance between the fourth straight waveguide and the equilateral triangle resonant cavity is d4=10 nm to 40 nm;

[0014] The side length of the equilateral triangle resonant cavity is 484 nm;

[0015] The rectangular metal block has a length h=200 nm and a width w=20 nm to 50 nm.

[0016] Furthermore, the base layer is made of silicon dioxide material, the rectangular metal layer and the rectangular metal block are made of silver material, and the first straight waveguide, the second straight waveguide, the third straight waveguide, the fourth straight waveguide and the equilateral triangle resonant cavity are connected to the air.

[0017] Beneficial effects:

[0018] First, the wavelength selective all-optical switch based on surface plasmon polaritons of the present invention only includes three physical structures: a substrate layer, a rectangular metal layer and a rectangular metal block, and five etched structures: a first straight waveguide, a second straight waveguide, a third straight waveguide, a fourth straight waveguide and an equilateral triangle resonant cavity. Compared with other all-optical switches, it has the technical advantage of a simple structure.

[0019] Second, the wavelength-selective all-optical switch based on surface plasmon polaritons of the present invention can switch and modulate optical signals of different wavelengths by injecting them into different straight waveguides. Compared with other all-optical switches, it has the technical advantage of wavelength selectability.

[0020] Third, the wavelength-selective all-optical switch based on surface plasmon polaritons of the present invention can achieve a maximum extinction ratio of 11.7 dB. Compared with other all-optical switches, it has the technical advantage of high extinction ratio.

[0021] Fourthly, the wavelength selective all-optical switch based on surface plasmon of the present invention can be applied to large-scale integrated optical communication devices in the future due to its simple structure, selectable wavelength and high extinction ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1It is a schematic structural diagram of the wavelength selective all-optical switch based on surface plasmon of the present invention.

[0023] Figure 2 It is the transmittance curve when the distance d2 between the second straight waveguide and the equilateral triangle resonant cavity changes.

[0024] Figure 3 It is the transmittance curve when the distance d4 between the fourth straight waveguide and the equilateral triangle resonant cavity changes.

[0025] Figure 4 The transmittance curve of the rectangular metal block as the width w changes.

[0026] Figure 5 Transmittance curves when optical signals are input from different straight waveguides.

[0027] In the figure: 1 substrate layer, 2 rectangular metal layer, 3 first straight waveguide, 4 second straight waveguide, 5 third straight waveguide, 6 fourth straight waveguide, 7 equilateral triangle resonant cavity, 8 rectangular metal block. DETAILED DESCRIPTION

[0028] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings. Specific implementation method 1

[0030] The wavelength selective all-optical switch based on surface plasmon in this specific implementation mode has a structural schematic diagram as shown in FIG. Figure 1 As shown, it is composed of a base layer 1 and a rectangular metal layer 2, wherein the rectangular metal layer 2 is closely attached to the base layer 1, and a first straight waveguide 3, a second straight waveguide 4, a third straight waveguide 5, a fourth straight waveguide 6 and an equilateral triangle resonant cavity 7 which are equal in height to the rectangular metal layer 2 are etched on the rectangular metal layer 2, wherein the second straight waveguide 4 and the fourth straight waveguide 6 are in the same direction as the long side of the rectangular metal layer 2, and the angles between the first straight waveguide 3 and the third straight waveguide 5 and the long side of the rectangular metal layer 2 are both 60°( Figure 1 α and β in the resonance cavity 7 are both 60°); in the equilateral triangle resonance cavity 7, a rectangular metal block 8 is also provided, which is equal in height to the rectangular metal layer 2 and whose center coincides with the center of the equilateral triangle resonance cavity 7. Specific implementation method 2

[0032] The wavelength selective all-optical switch based on surface plasmon in this specific implementation is further defined on the basis of the specific implementation method 1:

[0033] The size of the rectangular metal layer 2 is 1160nm×530nm×75nm;

[0034] The width of the first straight waveguide 3 is 50 nm, and the distance between the first straight waveguide 3 and the equilateral triangle resonant cavity 7 is d1=18 nm;

[0035] The width of the second straight waveguide 4 is 50 nm, and the distance between the second straight waveguide 4 and the equilateral triangle resonant cavity 7 is d2 = 20 nm to 50 nm;

[0036] The width of the third straight waveguide 5 is 50 nm, and the distance between the third straight waveguide 5 and the equilateral triangle resonant cavity 7 is d3=18 nm;

[0037] The width of the fourth straight waveguide 6 is 50 nm, and the distance between the fourth straight waveguide 6 and the equilateral triangle resonant cavity 7 is d4=10 nm to 40 nm;

[0038] The side length of the equilateral triangle resonant cavity 7 is 484 nm;

[0039] The rectangular metal block 8 has a length h=200 nm and a width w=20 nm to 50 nm. Specific implementation method three

[0041] The wavelength selective all-optical switch based on surface plasmon under this specific implementation is further defined on the basis of specific implementation method one or specific implementation method two: the base layer 1 is made of silicon dioxide material, the rectangular metal layer 2 and the rectangular metal block 8 are made of silver material, and the first straight waveguide 3, the second straight waveguide 4, the third straight waveguide 5, the fourth straight waveguide 6 and the equilateral triangle resonant cavity 7 are connected to the air. Specific implementation method four

[0043] In this specific embodiment, the wavelength selective all-optical switch based on surface plasmon is simulated and tested for the distance d2 between the second straight waveguide 4 and the equilateral triangle resonant cavity 7. When the distance d2 changes from 50nm to 20nm, the transmittance curve is as follows: Figure 2 As shown, it can be seen that in the range of 400nm to 700nm, as d2 decreases, the transmittance of the two resonance peaks increases, and a slight red shift occurs, while the waveform remains basically unchanged. Specific implementation method five

[0045] In this specific embodiment, the wavelength selective all-optical switch based on surface plasmon is simulated and tested for the distance d4 between the fourth straight waveguide 6 and the equilateral triangle resonant cavity 7. When the distance d4 changes from 40nm to 10nm, the transmittance curve is as follows: Figure 3 As shown, it can be seen that in the range of 400nm to 700nm, as d4 decreases, the transmittance of the two resonance peaks increases, and a slight red shift occurs, while the waveform remains basically unchanged. Specific implementation method 6

[0047] In the wavelength selective all-optical switch based on surface plasmon in this specific embodiment, the width w of the rectangular metal block 8 is simulated and tested. When the width w changes from 50nm to 20nm, the transmittance curve is as follows: Figure 4 As shown, it can be seen that in the range of 400nm to 700nm, as w decreases, the transmittance of resonance peak 1 increases, the transmittance of resonance peak 2 remains basically unchanged, and a blue shift occurs, while the waveform remains basically unchanged. Specific implementation method seven

[0049] The wavelength selective all-optical switch based on surface plasmon in this specific implementation mode inputs optical signals to the first straight waveguide 3, the second straight waveguide 4, and the third straight waveguide 5, and the combination is as follows:

[0050] Combination 1: inputting the second straight waveguide 4 alone;

[0051] Combination 2: inputting the second straight waveguide 4 and the first straight waveguide 3 simultaneously;

[0052] Combination 3: inputting the second straight waveguide 4 and the third straight waveguide 5 at the same time;

[0053] Combination 4: inputting the second straight waveguide 4, the first straight waveguide 3 and the third straight waveguide 5 at the same time;

[0054] The change of transmittance curve is as follows Figure 5 As shown, it can be seen that in the range of 400nm to 550nm, combination 4 will make the extinction ratio of combination 1 to resonance peak 1 reach 4.5dB, and combination 2 and combination 3 will make the extinction ratio of combination 1 to resonance peak 2 reach 11.7dB, verifying the technical advantage of high extinction ratio compared with other all-optical switches.

Claims

1. A wavelength-selective all-optical switch based on surface plasmons, characterized in that: The invention comprises a base layer (1) and a rectangular metal layer (2), wherein the rectangular metal layer (2) is closely attached to the base layer (1), and a first straight waveguide (3), a second straight waveguide (4), a third straight waveguide (5), a fourth straight waveguide (6) and an equilateral triangular resonant cavity (7) are etched on the rectangular metal layer (2) at the same height as the rectangular metal layer (2), wherein the second straight waveguide (4) and the fourth straight waveguide (6) have the same long side direction as the rectangular metal layer (2), and the angles between the first straight waveguide (3) and the third straight waveguide (5) and the long side direction of the rectangular metal layer (2) are both 60°; and a rectangular metal block (8) is also provided in the equilateral triangular resonant cavity (7), which has the same height as the rectangular metal layer (2) and whose center coincides with the center of the equilateral triangular resonant cavity (7); The base layer (1) is made of silicon dioxide material, the rectangular metal layer (2) and the rectangular metal block (8) are made of silver material, and the first straight waveguide (3), the second straight waveguide (4), the third straight waveguide (5), the fourth straight waveguide (6) and the equilateral triangle resonant cavity (7) are connected to the air.

2. The wavelength selective all-optical switch based on surface plasmon according to claim 1, characterized in that: The dimensions are limited to the following: The size of the rectangular metal layer (2) is 1160nm×530nm×75nm; The width of the first straight waveguide (3) is 50 nm, and the distance d1 between the first straight waveguide (3) and the equilateral triangle resonant cavity (7) is 18 nm; The width of the second straight waveguide (4) is 50 nm, and the distance d2 between the second straight waveguide (4) and the equilateral triangle resonant cavity (7) is 20 nm to 50 nm; The width of the third straight waveguide (5) is 50 nm, and the distance d3 between the third straight waveguide (5) and the equilateral triangle resonant cavity (7) is 18 nm; The width of the fourth straight waveguide (6) is 50 nm, and the distance d4 between the fourth straight waveguide (6) and the equilateral triangle resonant cavity (7) is 10 nm to 40 nm; The side length of the equilateral triangle resonant cavity (7) is 484 nm; The rectangular metal block (8) has a length h=200nm and a width w=20nm-50nm.

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