Photonic crystal waveguide structure and polarized light transmission equipment

Abstract

The utility model discloses a photonic crystal waveguide structure, which comprises two dielectric cylinder arrays and a waveguide channel, the two dielectric cylinder arrays are arranged at intervals, each dielectric cylinder array comprises a plurality of dielectric cylinders arranged at intervals, and the waveguide channel is formed in the interval space between the two dielectric cylinder arrays. According to the utility model, a photonic forbidden band is formed through the dielectric cylinder arrays, THz light in a certain frequency band cannot be transmitted in the dielectric cylinder arrays, and a waveguide channel is formed in the interval space between the two dielectric cylinder arrays, so that the THz light in the frequency band is transmitted in the waveguide channel, and the transmission loss of the light is reduced. In addition, the utility model also discloses polarized light transmission equipment.

Description

Technical Field

[0001] The utility model relates to the field of polarized light, in particular to a photonic crystal waveguide structure and polarized light transmission equipment. Background Art

[0002] Polarization beam splitter is an important device in optical system, which can separate optical signal into two mutually orthogonal polarization lights and transmit them along different paths. The traditional polarization beam splitter in optical frequency band uses the different refractive index of light in crystal to cause different vibration directions of electric vector of light to split the light. There are three common traditional polarization beam splitters: calcite (Rochon) prism, Wollaston prism and thin film interference polarization beam splitter.

[0003] The related technology provides a photonic crystal THz (terahertz) adjustable polarization control device based on ferrite magneto-optical material. Adjusting the size of the external magnetic field can change the magnetic permeability of the material, thereby changing the photonic band gap of the TE mode (transverse electric mode) while the band gap of the TM mode (transverse magnetic mode) is not affected by the external magnetic field, achieving polarization separation with a frequency of 1THz. Another related technology provides a photonic crystal THz polarization beam splitter based on silicon medium, so that the TE mode and TM mode emerge from different line defects. The device can achieve polarization separation in the frequency range of 0.9998 to 1.0007THz and has a size of 1.02×0.99mm 2 .

[0004] The operating frequency range of THz waveguide devices based on photonic crystals in current technology is relatively narrow. Utility Model Content

[0005] The main purpose of the utility model is to provide a photonic crystal waveguide structure and polarized light transmission equipment, aiming to solve the problem that the operating frequency range of the THz waveguide device of the photonic crystal is narrow.

[0006] To achieve the above object, the utility model proposes a photonic crystal waveguide structure, which includes:

[0007] Two dielectric column arrays, the two dielectric column arrays are arranged at intervals, and each of the dielectric column arrays includes a plurality of dielectric columns arranged at intervals;

[0008] A waveguide channel is formed in the interval space between the two dielectric column arrays.

[0009] Preferably, the two dielectric column arrays are spaced apart along the first direction, each of the dielectric column arrays comprises a dielectric column group, and the dielectric column group comprises a plurality of dielectric columns spaced apart along the second direction;

[0010] The first direction is perpendicular to the second direction.

[0011] Preferably, the dielectric column is a tellurium photonic crystal dielectric column.

[0012] Preferably, the interval between the two dielectric column arrays is greater than the interval between any two adjacent dielectric columns in the same dielectric column array.

[0013] Preferably, the width of the waveguide channel is greater than the size of the outer contour of the dielectric column.

[0014] Preferably, the width of the waveguide channel is the sum of twice the size of the outer contour of the dielectric column and three times the interval between any two adjacent dielectric columns in the same dielectric column array.

[0015] Preferably, the dielectric column is cylindrical.

[0016] Preferably, the radius of the dielectric column is greater than or equal to 13 μm and less than or equal to 19 μm.

[0017] Preferably, the distance between the centers of any two adjacent dielectric pillars in the same dielectric pillar array is 40 μm.

[0018] The utility model further provides a polarized light transmission device, comprising the photonic crystal waveguide structure described in any one of the above technical solutions.

[0019] The beneficial effect of the technical solution of the utility model is that a photon bandgap is formed by a dielectric column array, so that THz light in a certain frequency band cannot be transmitted in the dielectric column array, and a waveguide channel is formed in the interval space between two dielectric column arrays, so that THz light in this frequency band is transmitted in the waveguide channel, thereby reducing the transmission loss of light. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the top view of the structure of an embodiment of the utility model;

[0021] Figure 2 It is a three-dimensional structural schematic diagram of an embodiment of the utility model;

[0022] Figure 3 The energy band diagram of the dielectric column array of the embodiment of the utility model;

[0023] Figure 4 This is a simulation diagram of an embodiment of the utility model in TE mode;

[0024] Figure 5 It is a simulation diagram of an embodiment of the present utility model in TM mode.

[0025] Description of Figure Numbers:

[0026]

[0027] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the scheme in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, top, bottom, side...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0030] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0031] In addition, the descriptions involving "first", "second", etc. in the embodiments of the present invention are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features.

[0032] In view of the technical defects existing in the related art, the utility model proposes a photonic crystal waveguide structure and a polarized light transmission device, aiming to solve the problems in the prior art.

[0033] As an implementation method, Figure 1 and Figure 2As shown, the photonic crystal waveguide structure includes: two dielectric column arrays 1 and a waveguide channel 3. Specifically, the two dielectric column arrays 1 are arranged at intervals, and the waveguide channel 3 is formed in the interval space between the two dielectric column arrays 1. Each dielectric column array 1 includes a plurality of dielectric columns 2 arranged at intervals, and the dielectric columns 2 are arranged in a square lattice so that the light is confined in the waveguide channel 3. Preferably, the dielectric column 2 is a tellurium photonic crystal dielectric column 2. Tellurium photonic crystal is a periodic structure composed of tellurium material. The periodic structure of tellurium photonic crystal optically exhibits the characteristics of photonic crystal. The scale of the periodic structure of photonic crystal is equivalent to or smaller than the wavelength of light. The periodic structure of photonic crystal can affect the propagation mode of light in the crystal. In this embodiment, the dielectric column array 1 is formed by arranging the tellurium photonic crystal dielectric columns 2 in a square lattice, and a photonic bandgap is formed by the dielectric column array 1, so that light of a certain frequency band cannot be transmitted in the dielectric column array 1. In this embodiment, the frequency band of the light is 2.895 THz to 3.03 THz, and a gap is set between the two dielectric column arrays 1 so that the light of 2.895 THz to 3.03 THz is confined in the waveguide channel 3, thereby reducing the propagation loss of the light.

[0034] Furthermore, the spacing between the two dielectric column arrays 1 can be obtained by a variety of methods such as precision processing, colloidal crystal method and inverse opal structure method. Among them, the precision processing method uses precision mechanical processing equipment, such as a laser cutter, to remove the dielectric columns 2 in the specified rows and columns in the dielectric column array 1. This method has high precision, but high cost and is difficult to apply to complex structures. The colloidal crystal method uses colloidal particles to self-assemble to form photonic crystals. By controlling the size and arrangement of the colloidal particles, the particles in specific rows and columns can be accurately removed to achieve the desired spacing between the two dielectric column arrays 1. The inverse opal structure method fixes silica particles on a polymer substrate to form a square lattice structure, and then removes silica particles in specific rows and columns by etching or peeling. According to the principle of this method, the desired spacing between the two dielectric column arrays 1 can be achieved. This method is low in cost and suitable for large-scale preparation.

[0035] Preferably, the dielectric column 2 is cylindrical. Specifically, the cylindrical dielectric column 2 can affect the photon bandgap structure, so that the dielectric column array 1 forms a photon bandgap.

[0036] As an implementation mode, two dielectric column arrays 1 are arranged at intervals along a first direction X, and each dielectric column array 1 includes a dielectric column group, and the dielectric column group includes a plurality of dielectric columns 2 arranged at intervals along a second direction Y. The first direction X is perpendicular to the second direction Y. Further, the number of dielectric columns 2 arranged at intervals along the second direction Y is at least 3 to avoid failure of the waveguide structure.

[0037] As an implementation manner, the interval between two dielectric column arrays 1 is greater than the interval between any two adjacent dielectric columns 2 in the same dielectric column array 1. Specifically, when the interval between two dielectric column arrays 1 is less than or equal to the interval between any two adjacent dielectric columns 2 in the same dielectric column array 1, light of 2.895THz to 3.03THz cannot be transmitted between the two dielectric column arrays 1. Therefore, the interval between two dielectric column arrays 1 is greater than the interval between any two adjacent dielectric columns 2 in the same dielectric column array 1.

[0038] As an implementation mode, the width of the waveguide channel 3 is greater than the size of the outer contour of the dielectric column 2. Specifically, the size of the outer contour of the dielectric column 2 is the diameter of the cylindrical dielectric column 2, that is, at least the width of the diameter of the dielectric column 2 is spaced between two dielectric column arrays 1, so that the transmission loss of the light of 2.895THz to 3.03THz in the waveguide channel 3 is reduced.

[0039] Preferably, the width of the waveguide channel 3 is the sum of twice the size of the outer contour of the dielectric column 2 and three times the interval between any two adjacent dielectric columns 2 in the same dielectric column array 1. At this time, the transmission loss of light from 2.895THz to 3.03THz in the waveguide channel 3 is minimal. It should be noted that when the width of the waveguide channel 3 is the sum of twice the size of the outer contour of the dielectric column 2 and three times the interval between any two adjacent dielectric columns 2 in the same dielectric column array 1, it is equivalent to removing two groups of dielectric column groups 6 from the middle of the dielectric column array 1 including at least four groups of dielectric column groups 6. In other embodiments, when the dielectric column groups 6 removed in the dielectric column array 1 can be more than two groups, the size of the overall structure will be too large, and the more dielectric column groups 6 removed in the dielectric column array 1, the greater the cost.

[0040] As an implementation, the radius R of the dielectric column 2 is greater than or equal to 13 μm and less than or equal to 19 μm. Preferably, the radius R of the dielectric column 2 is 16 μm, in which case the dielectric column array 1 has the best isolation effect on light of 2.895 THz to 3.03 THz.

[0041] As an embodiment, the distance between the centers of any two adjacent dielectric pillars 2 in the same dielectric pillar array 1 is 40 μm. Specifically, the dielectric pillars 2 are arranged according to a square lattice, that is, the distance between the centers of any two adjacent dielectric pillars 2 in the same dielectric pillar array 1 is equal. In this embodiment, the distance between the centers of any two adjacent dielectric pillars 2 in the same dielectric pillar array 1 is the lattice constant a of the square lattice, and a=40 μm. At this time, the dielectric pillar array 1 has the best isolation effect on light from 2.895 THz to 3.03 THz.

[0042] As an embodiment, the width of the waveguide channel 3 is the waveguide width D. In this embodiment, the radius R of the dielectric column 2 is 16 μm, and the distance between the centers of any two adjacent dielectric columns 2 in the same dielectric column array 1 is 40 μm. The interval between any two adjacent dielectric columns 2 in the same dielectric column array 1 is the length between the centers of any two adjacent dielectric columns 2 in the same dielectric column array 1 minus the length of the radius R of the two dielectric columns 2, that is, the interval between any two adjacent dielectric columns 2 in the same dielectric column array 1 = 40-16×2 = 8 μm. Further, the waveguide width D is the sum of twice the size of the outer contour of the dielectric column 2 and three times the interval between any two adjacent dielectric columns 2 in the same dielectric column array 1. Since the interval between any two adjacent dielectric columns 2 in the same dielectric column array 1 is 8 μm, the size of the outer contour of the dielectric column 2 is the diameter of the dielectric column 2 = 16×2 = 32 μm. Therefore, the waveguide width D is 32×2+8×3 = 88 μm. Preferably, the dielectric pillars 2 in the two dielectric pillar arrays 1 are located in the same plane, and the heights of the dielectric pillars 2 in the two dielectric pillar arrays 1 are equal, and the heights of the dielectric pillars 2 are half of the waveguide width D, that is, the heights of the dielectric pillars 2 are 44 μm. In this case, the dielectric pillar array 1 has the best isolation effect on the light of 2.895 THz to 3.03 THz.

[0043] Further, such as Figure 3 As shown, Figure 3 The photon band diagram is obtained by simulating the dielectric column array 1 through RSoft. RSoft is an optical waveguide simulation software that contains a variety of algorithms, making it applicable to various occasions with different requirements. Figure 3 In the equation, Frequency represents the normalized frequency, which can be expressed as: Indicates, where ω represents angular frequency, c represents the speed of light, λ represents wavelength, and a represents the lattice constant of the square lattice, a = 40μm. When the light is 2.895THz, the wavelength λ of the light is about 0.136mm. Figure 3 The normalized frequency in is When the light is 3.03THz, the wavelength λ of the light is about 0.099mm. Figure 3 The normalized frequency in is ≈0.404. Similarly, the normalized frequencies of light from 2.895THz to 3.03THz are 0.386 to 0.404. Figure 3 In the figure, the light with normalized frequency between 0.386 and 0.404, which has TE (Transverse electric) photon band gap 4 and TM (Transverse magnetic) photon band gap 5, that is, 2.895 THz to 3.03 THz, cannot be transmitted in the dielectric column array 1. Figure 3where Γ, X and M represent the directions of the wave vectors.

[0044] like Figure 4 and Figure 5 As shown, Figure 4 and Figure 5 This is a simulation diagram of COMSOL Multiphysics, which is a multi-physics simulation software that can be used to simulate multiple optical physical phenomena. Figure 4 , in TM mode Figure 5 .like Figure 4 As shown, the height of the wave peak in the figure represents the intensity of the wave, in the TE mode, that is, the light injected into the waveguide channel 3 is a TE wave of 2.895 THz to 3.03 THz. Figure 4 The peak height in the waveguide channel 3 indicates that TE waves from 2.895 THz to 3.03 THz are transmitted in the waveguide channel 3. Figure 5 As shown, the height of the wave peak in the figure represents the intensity of the wave, in the TM mode, that is, the light injected into the waveguide channel 3 is a TM wave of 2.895 THz to 3.03 THz. Figure 5 In the graph, the wave crest height in the waveguide channel 3 is low and relatively uniform, which indicates that the TM wave injected into the waveguide channel 3 is waveguided in the waveguide channel 3.

[0045] The utility model forms a photon bandgap through a dielectric column array, so that THz light of a certain frequency band cannot be transmitted in the dielectric column array, and forms a waveguide channel in the interval space between two dielectric column arrays, so that the THz light of the frequency band is transmitted in the waveguide channel, thereby reducing the transmission loss of light.

[0046] The utility model further provides a polarized light transmission device, comprising the photonic crystal waveguide structure described in any one of the above embodiments.

[0047] The above description is only a partial or preferred embodiment of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.

Claims

1. A photonic crystal waveguide structure, characterized in that: include: Two dielectric column arrays, the two dielectric column arrays are arranged at intervals, and each of the dielectric column arrays includes a plurality of dielectric columns arranged at intervals; A waveguide channel is formed in the interval space between the two dielectric column arrays.

2. The photonic crystal waveguide structure according to claim 1, characterized in that: The two dielectric column arrays are arranged at intervals along the first direction, each of the dielectric column arrays includes a dielectric column group, and the dielectric column group includes a plurality of dielectric columns arranged at intervals along the second direction; The first direction is perpendicular to the second direction.

3. The photonic crystal waveguide structure according to claim 1, characterized in that: The dielectric column is a tellurium photonic crystal dielectric column.

4. The photonic crystal waveguide structure according to claim 2, characterized in that: The interval between the two dielectric column arrays is greater than the interval between any two adjacent dielectric columns in the same dielectric column array.

5. The photonic crystal waveguide structure according to any one of claims 1 to 4, characterized in that: The width of the waveguide channel is greater than the size of the outer contour of the dielectric column.

6. The photonic crystal waveguide structure according to any one of claims 1 to 4, characterized in that: The width of the waveguide channel is the sum of twice the size of the outer contour of the dielectric column and three times the interval between any two adjacent dielectric columns in the same dielectric column array.

7. The photonic crystal waveguide structure according to any one of claims 1 to 4, characterized in that: The medium column is cylindrical.

8. The photonic crystal waveguide structure according to claim 7, characterized in that: The radius of the dielectric column is greater than or equal to 13 μm and less than or equal to 19 μm.

9. The photonic crystal waveguide structure according to any one of claims 1 to 4, characterized in that: The distance between the centers of any two adjacent dielectric pillars in the same dielectric pillar array is 40 μm.

10. A polarized light transmission device, characterized in that: It comprises the photonic crystal waveguide structure as claimed in any one of claims 1 to 9.

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