CN217181269U

CN217181269U - 2X 2 optical waveguide switch based on phase change material

Info

Publication number: CN217181269U
Application number: CN202123229488.XU
Authority: CN
Inventors: 张桂菊; 汪成根; 王笑笑
Original assignee: Suzhou University
Current assignee: Suzhou University
Priority date: 2021-12-21
Filing date: 2021-12-21
Publication date: 2022-08-12
Anticipated expiration: 2031-12-21

Abstract

The utility model discloses a 2X 2 optical waveguide switch based on phase change material. On a silicon dioxide substrate, two silicon waveguides are distributed in an axisymmetric manner, two ends of each silicon waveguide are bent, one end of each silicon waveguide is an input port, the other end of each silicon waveguide is an output port, a middle coupling area of each silicon waveguide is linear, and a phase-change film material covers the coupling area. The switch unit is controlled by a phase-change material covered on the waveguide of the coupling area, the double-channel selection input, the double-channel gating and the mode switching functions can be completed on the transverse electric basement membrane (TE0) by switching the phase state of the phase-change material, and the input function and the output function of the same side port of the transverse electric basement membrane (TM0) are met. The utility model provides an optical waveguide switch can realize the function of mode separation switch to the TE0 mould and the TM0 mould of mixing the input.

Description

2X 2 optical waveguide switch based on phase change material

Technical Field

The utility model belongs to the technical field of optoelectronics, in particular to 2 x 2 optical waveguide switch based on phase change material.

Background

An optical switch is a core unit for mode multiplexing and data exchange, and at present, a silicon-based optical waveguide switch is mainly of a Mach-Zehnder interferometer type (see the literature: Lin Y, Zhou T, Hao J, et al. General architecture for on-chip optical space and mode switching [ J ]. Optica, 2018, 5(2): 180.) based on the principle of optical interference, and the phase difference is formed mainly by refractive index change caused by applying voltage to an interference arm through electro-optical modulation. However, the refractive index modulation is weak, which causes the device to be oversized, and the state needs continuous voltage maintenance, which causes the device to be volatile.

With the search for optical switching devices, optical switches based on phase change materials have emerged. The phase-change material is covered on the waveguide to form a composite waveguide, the phase-change material can perform reversible phase change in a crystalline state and an amorphous state, and a great refractive index difference can be formed before and after the phase change to change the propagation path of the optical signal. Most of the current common 2 × 2 optical switches are mechanical, and have large volume, large insertion loss and unstable optical path switching. Although the common 2X 2 optical switch based on phase change material solves these problems, the coupling region is designed based on three waveguide coupling (see the literature: Zhang Q, Zhang Y, Li J, et al. Broadband and non-volatile optical switching materials: beyond the structural configuration-of-polymer [ J ]. Optics Letters, 2018, 43(1):94.), the phase change material is covered on the intermediate waveguide, which increases the experimental difficulty of the device. The input port of the optical switch device which is researched at present only supports the input of a single transverse electric mode or transverse magnetic mode basically, and the switch effect cannot be formed for the mixed mode input of the transverse electric mode and the transverse magnetic mode, so that the application of the switch is limited.

Disclosure of Invention

The utility model discloses the purpose is not enough to prior art existence, provides a small in size, switching rate is fast, and the accessible changes phase change material's phase on the composite waveguide, realizes the binary channels and selects the 2 x 2 optical waveguide switch of the function of input and double-circuit gating, mixed mode separation.

The technical scheme for realizing the purpose of the utility model is to provide a 2 x 2 optical waveguide switch based on phase change material, on the silicon dioxide substrate, two silicon waveguides are distributed in axial symmetry, two ends of the silicon waveguides are in bending shape, one end is input port, the other end is output port, the middle coupling area of the silicon waveguides is in straight line shape, the coupling area covers the phase change film material; the cross section of the silicon waveguide is rectangular, the width of the silicon waveguide is 0.25-0.4 micrometer, and the height of the silicon waveguide is 0.25-0.4 micrometer; the length of the coupling region is 15-20 micrometers; the covering width of the phase change film is equal to the width of the silicon waveguide, and the thickness of the phase change film is 10-300 nanometers.

The technical scheme of the utility model in, the interval of the straightway of two silicon waveguides is 100~500 nanometers.

In the technical scheme of the utility model, phase change material can be binary, ternary or quaternary compound that Ge, Sb, Te or Se constitute, for example GeTe ₂ 、Ge ₂ Sb ₂ Te ₅ Or Ge ₂ Sb ₂ Se ₄ Te ₁ Etc.; the incident light source adopts a communication band (1530-1565 nm).

The utility model discloses based on phase change material, formed two symmetrical waveguide formula photoswitch structures that advance-two play, when phase change material is the low-loss amorphous state of low-emissivity, and when satisfying best coupling length, the light wave mode can take place the coupling and then can selective switching output port in the coupling region of two wave guides.

Compared with the prior art, the utility model discloses owing to adopted two waveguide structures, its beneficial effect lies in: incident light can be selectively input from the input port, and the phase state of one phase change material can be selectively switched according to the difference of the input port, so that the transmission path of the base film in different modes can be changed. The utility model provides a 2X 2 optical waveguide switch, the accessible changes phase change material's phase state on the composite waveguide, realizes the function of binary channels selection input and double-circuit gating, mixed mode separation, has the characteristics that the size is little, switching rate is fast.

Drawings

Fig. 1 is a schematic structural diagram of a 2 × 2 optical waveguide switch based on a phase change material according to an embodiment of the present invention;

fig. 2 is a top view of a phase change material based 2 x 2 optical waveguide switch structure according to an embodiment of the present invention;

fig. 3 is a diagram illustrating an electric field distribution of a phase change material-based 2 × 2 optical waveguide switch structure when a TE-based film is input from an input port of a waveguide according to an embodiment of the present invention;

fig. 4 is a diagram illustrating a magnetic field distribution of a phase change material based 2 × 2 optical waveguide switch structure when a TM-based film is input from an input port of a waveguide according to an embodiment of the present invention;

fig. 5 is a diagram illustrating an electric field distribution of a phase change material based 2 × 2 optical waveguide switch structure when a TE-based film is input from an input port of another waveguide according to an embodiment of the present invention;

fig. 6 is a magnetic field distribution diagram of a phase change material-based 2 × 2 optical waveguide switch structure when a TM-based film is input from an input port of another waveguide according to an embodiment of the present invention.

In the figures, 1, 2. input port of waveguide; 3. 4. a phase change material; 5. 6 output port of the waveguide; 7. a substrate; 8. a switching region; 9. a coupling region.

Detailed Description

The technical solution of the present invention will be further explained with reference to the accompanying drawings and examples.

Example 1

Referring to fig. 1, a schematic structural diagram of a 2 × 2 optical waveguide switch based on a phase change material according to this embodiment is shown. The silicon waveguide comprises two waveguides which are distributed in axial symmetry, two ends of each waveguide are bent, one end of each waveguide is an input port, the other end of each waveguide is an output port, a middle coupling area of each silicon waveguide is linear, and each coupling area is covered with a phase-change film material; in this embodiment, the input ports 1 and 2, the

corresponding output ports

5 and 6, and the

phase change materials

3 and 4 of the waveguide may be binary, ternary, or quaternary compounds of Ge, Sb, Te, or Se, such as GeTe ₂ 、Ge ₂ Sb ₂ Te ₅ Or Ge ₂ Sb ₂ Se ₄ Te ₁ Etc.; the present embodiment is Ge ₂ Sb ₂ Se ₄ Te ₁ The substrate 7 of the device is made of silicon dioxide and the waveguide material is silicon. The overall device length was 29 microns and the width was 8.5 microns.

The cross section of the waveguide is rectangular, the width of the waveguide is 0.25-0.4 micrometer, and the height of the waveguide is 0.25-0.4 micrometer; the length of the coupling region is 15-20 micrometers; the covering width of the phase change film is equal to the width of the silicon waveguide, and the thickness of the phase change film is 10-300 nanometers. The distance between the straight line sections of the two silicon waveguides is 100-500 nanometers.

In this example, the width and height of the waveguides are 0.38 microns, the coupling length is 18.5 microns, and the distance between the straight line segments of the two waveguides is 300 nanometers.

Referring to fig. 2, it is a top view of the 2 × 2 optical waveguide switch structure based on phase change material provided in this embodiment. 8 is a switch area, 9 is a coupling area covering the phase change material; the change of the output port of the optical signal can be realized by changing the phase of the

phase change materials

3 and 4 in fig. 1 according to the difference of the input port.

Referring to fig. 3, it is the electric field distribution diagram of the 2 × 2 optical waveguide switch structure based on phase change material provided in this embodiment when the TE-based film is input from the input port 2 of the waveguide. In the diagram a, when the

phase change materials

3 and 4 are both in a low-loss amorphous state, because the coupling region meets the matching condition, the TE-based film is coupled to another composite waveguide and output from the output port 6 of the waveguide; in the diagram b, when the phase change material 3 is in an amorphous state and the phase change material 4 is in a crystalline state, the TE-based film input at the input port 2 of the waveguide is mismatched due to the mode generated by the higher refractive index of the crystalline phase change material, and the TE-based mode is directly output from the output port 5 of the waveguide.

Referring to fig. 4, it is a magnetic field distribution diagram of the phase change material-based 2 × 2 optical waveguide switch structure provided in this embodiment when the TM base film is input from the input port 2 of the waveguide. In the diagram a, when the

phase change materials

3 and 4 are both in a low-loss amorphous state, because the coupling region meets a specific matching condition, the TM base film is coupled to another composite waveguide and is coupled back to the original composite waveguide again and is directly output from the output port 5 of the waveguide; in the diagram b, when the phase change material 3 is in an amorphous state and the phase change material 4 is in a crystalline state, the TM base film input by the input port 2 of the waveguide cannot generate coupling and is directly output from the output port 5 of the waveguide due to mode mismatch and large absorption caused by the high refractive index of the crystalline phase change material.

Referring to fig. 5, it is a diagram of an electric field distribution of the present embodiment to provide a 2 × 2 optical waveguide switching structure based on a phase change material when a TE-based film is input from an input port 1 of a waveguide. In the diagram a, when the

phase change materials

3 and 4 are both in a low-loss amorphous state, because the coupling region meets the matching condition, the TE-based film is coupled to another composite waveguide and output from the output port 5 of the waveguide; in the diagram b, when the phase change material 4 is in an amorphous state and the phase change material 3 is in a crystalline state, the TE-based film input from the input port 1 of the waveguide is directly output from the output port 6 of the waveguide due to mode mismatch caused by the higher refractive index of the crystalline phase change material.

Referring to fig. 6, it is a magnetic field distribution diagram of the 2 × 2 optical waveguide switch structure based on phase change material provided in this embodiment when the TM base film is input from the input port 1 of the waveguide. In the diagram a, when the

phase change materials

3 and 4 are both in a low-loss amorphous state, because the coupling region meets a specific matching condition, the TM base film is coupled to another composite waveguide and is coupled back to the original composite waveguide again and is output from the output port 6 of the waveguide; in the diagram b, when the phase change material 4 is in an amorphous state and the phase change material 3 is in a crystalline state, the TM base film input by the input port 1 of the waveguide cannot generate coupling and is directly output from the output port 6 of the waveguide due to mode mismatch and large absorption caused by the high refractive index of the crystalline phase change material.

Claims

1. A phase change material based 2 x 2 optical waveguide switch, comprising: on a silicon dioxide substrate, two silicon waveguides are axially symmetrically distributed, two ends of each silicon waveguide are bent, one end of each silicon waveguide is an input port, the other end of each silicon waveguide is an output port, a middle coupling area of each silicon waveguide is linear, and a phase-change film material covers the coupling area; the cross section of the silicon waveguide is rectangular, the width of the silicon waveguide is 0.25-0.4 micrometer, and the height of the silicon waveguide is 0.25-0.4 micrometer; the length of the coupling region is 15-20 micrometers; the covering width of the phase change film is equal to the width of the silicon waveguide, and the thickness of the phase change film is 10-300 nanometers.

2. The phase change material based 2 x 2 optical waveguide switch of claim 1, wherein: the distance between the straight line sections of the two silicon waveguides is 100-500 nanometers.