CN209690558U - Photon crystal filter with tangent bend L shape microcavity - Google Patents

Abstract

The utility model provides a kind of photon crystal filter with tangent bend L shape microcavity, the 2 D photon crystal formed including multiple dielectric posts periodic arrangements, the dielectric posts for removing a row of horizontal in the 2 D photon crystal form output waveguide, the certain media column for removing another row of horizontal in the 2 D photon crystal forms input waveguide, the remaining dielectric posts form the reflection cavity adjacent with the input waveguide, remove the certain media column of several rows between the input waveguide and the output waveguide in the 2 D photon crystal to form two L-type defects being centrosymmetric, two L-type defects and its internal dielectric posts surrounded constitute resonant cavity, two very wide forbidden bands can be generated, make it possible to achieve the filter action of two wavelength periods, filter effect is fine, with very high transmissivity and compared with low-loss.

Description

Photonic crystal filter with double curved L-shaped microcavity

technical field

The utility model relates to a photonic crystal, in particular to a photonic crystal filter with a double-curved L-shaped microcavity.

Background technique

Photonic crystal is a new type of artificial structure whose dielectric constant changes periodically. It is divided into one-dimensional, two-dimensional and three-dimensional. Its characteristic is that it has a photonic band gap. Light waves of frequencies corresponding to the forbidden band cannot propagate in it, so a photonic crystal can form a natural band-stop filter. When a certain defect is introduced into the photonic crystal or the dielectric constant is changed somewhere, the original periodicity of the photonic crystal will be destroyed, thereby forming a defect state. When the frequency of the light wave matches the frequency of the defect state, the light wave will be confined. So as to achieve a good filtering function. Photonic crystals also have the characteristics of miniaturization and easy integration, and will have more research value in the future

The microcavity structure introduces point defects into the photonic crystal to achieve the purpose of coupling filtering. Theoretically, the transmission coefficient of the microcavity can reach a very high value, and the resonant frequency and mode of the microcavity can be changed by adjusting the size and dielectric constant of the microcavity dielectric column, which is a very ideal filter device.

As a semiconductor material, silicon has very important applications in the fields of photovoltaic technology and micro-semiconductor inverter technology. And its dispersion is very small, which can effectively reduce the dispersion loss of waves. In addition, the various characteristics of silicon have been studied very thoroughly, the processing technology is pure, and the price is low, so it is the first choice for making filter materials. However, how to overcome the deficiencies of existing technologies to fabricate photonic crystal filters with double-curved L-shaped microcavities that are easy to integrate and highly tunable is one of the key points that researchers need to solve urgently.

Utility model content

The purpose of the utility model is to provide a photonic crystal filter with a double-curved L-shaped microcavity to solve the problems that the existing photonic crystal filter with a double-curved L-shaped microcavity is not easy to integrate and has low controllability .

In order to achieve the above object, the utility model provides a photonic crystal filter with a double-curved L-shaped microcavity, which includes a two-dimensional photonic crystal formed by a plurality of dielectric columns periodically arranged, characterized in that: the two-dimensional photonic One row of horizontal dielectric columns is removed from the crystal to form an output waveguide, another row of horizontal dielectric columns is removed from the two-dimensional photonic crystal to form an input waveguide, and the remaining dielectric columns form a reflection cavity adjacent to the input waveguide In the two-dimensional photonic crystal, some rows of dielectric columns between the input waveguide and the output waveguide are removed to form two centrally symmetrical L-shaped defects, and the two L-shaped defects and their inner surroundings The dielectric pillars form a resonant cavity.

Optionally, the two-dimensional photonic crystal is a hexagonal lattice photonic crystal, and the dielectric column radius of the hexagonal lattice photonic crystal is 0.21a, a is a lattice constant, and the dielectric column of the hexagonal lattice photonic crystal is Silica glass matrix with air in the background.

Optionally, the lattice constant of the hexagonal lattice photonic crystal is a=540nm.

Optionally, the dielectric columns of the two-dimensional photonic crystal are distributed in a 19*17 array.

Optionally, the reflection cavity includes six dielectric columns, and the six dielectric columns are located in the same row.

Optionally, five rows of medium columns are enclosed within the two L-shaped defects.

Optionally, after the waveguide signals with a Gaussian distribution are input through the input waveguide, the waveguide signals outside the two set wavelength ranges are filtered out, and the output waveguide outputs the waveguide signals within the two set wavelength ranges. waveguide signal,

Optionally, the two set wavelength ranges are 548nm-798nm and 1071nm-1345nm respectively.

Optionally, both the input end of the input waveguide and the two output ends of the output waveguide are provided with observation points.

In the photonic crystal filter with a double curved L-shaped microcavity provided by the utility model, it includes a two-dimensional photonic crystal formed by periodic arrangement of a plurality of dielectric pillars, and a row of horizontal dielectric pillars is removed from the two-dimensional photonic crystal An output waveguide is formed, another row of horizontal dielectric columns is removed from the two-dimensional photonic crystal to form an input waveguide, and the remaining dielectric columns form a reflective cavity adjacent to the input waveguide, and the two-dimensional photonic crystal removes Several rows of partial dielectric columns between the input waveguide and the output waveguide form two centrally symmetrical L-shaped defects, and the two L-shaped defects and the dielectric columns surrounded by them form a resonant cavity, which can generate Two very wide forbidden bands make it possible to achieve filtering in two wavelength bands. The filtering effect is very good, with high transmittance and low loss. In addition, the photonic crystal filter with double curved L-shaped microcavity Belonging to the nanometer level, small volume, easy to integrate, and high controllability, it provides help for the application of photonic crystal filters with double-curved L-shaped microcavities in communication systems.

Description of drawings

Fig. 1 is the structural representation of the two-dimensional photonic crystal with the photonic crystal filter of the double curved L-shaped microcavity that the utility model embodiment provides;

Fig. 2 is the bandgap distribution diagram under the TE polarization mode of the photonic crystal filter with double curved L-shaped microcavity that the utility model embodiment provides;

Fig. 3 is the electric field distribution diagram when the waveguide signal provided by the embodiment of the present invention is 681nm;

Fig. 4 is the transmittance diagram when the waveguide signal provided by the embodiment of the present invention is 681nm;

Fig. 5 is the electric field distribution diagram when the waveguide signal provided by the embodiment of the present invention is 1203nm;

Fig. 6 is a transmittance diagram when the waveguide signal is 1203nm provided by the embodiment of the present invention.

Detailed ways

The specific implementation manner of the present utility model will be described in more detail below in combination with schematic diagrams. According to the following description and claims, the advantages and features of the utility model will be more clear. It should be noted that all the drawings are in very simplified form and use inaccurate scales, which are only used to facilitate and clearly illustrate the purpose of the embodiment of the present utility model.

As shown in Figure 1, the present embodiment provides a photonic crystal filter with a double curved L-shaped microcavity, including a two-dimensional photonic crystal formed by a plurality of dielectric pillars periodically arranged, the two-dimensional photonic crystal is removed A row of horizontal dielectric columns forms the output waveguide 2, another row of horizontal dielectric columns is removed from the two-dimensional photonic crystal to form the input waveguide 1, and the remaining dielectric columns form a reflection cavity adjacent to the input waveguide 1 3. In the two-dimensional photonic crystal, some rows of dielectric columns between the input waveguide 1 and the output waveguide 2 are removed to form two centrally symmetrical L-shaped defects, the two L-shaped defects and The dielectric column surrounded by it constitutes the resonant cavity 4 .

Further, the two-dimensional photonic crystal is a hexagonal lattice photonic crystal, and the dielectric column radius of the hexagonal lattice photonic crystal is 0.21a, a is a lattice constant, and a=540nm, the hexagonal lattice photonic crystal has a The dielectric column is a silica glass matrix with air as the background. The hexagonal lattice structure is more likely to produce a wider forbidden band than the tetragonal lattice structure, so the hexagonal lattice structure is selected.

Optionally, the dielectric pillars of the two-dimensional photonic crystal are distributed in a 19*17 array and arranged along the X-Z plane, wherein the input waveguide 1 and the reflective cavity 3 are located in the same row, that is, a row of dielectric pillars is removed Part of the dielectric columns form the input waveguide 1 , and the remaining six dielectric columns form the reflection cavity 3 . The reflective cavity 3 is at the tail of the input waveguide 1 to reflect the waveguide signal output by the input waveguide 1 to reduce scattering loss and improve transmission efficiency.

Further, the resonant cavity 4 includes two L-shaped defects and five rows of dielectric columns surrounded by the two L-shaped defects, and each row of the dielectric columns only includes a part of the dielectric columns. The resonant cavity 4 is located between the input waveguide 1 and the output waveguide 2. When the waveguide signal with a Gaussian distribution is input through the input waveguide 1, only the waveguides within the set wavelength range falling within the forbidden band The signal can pass and be coupled out to realize the function of specific frequency (wavelength) filtering, that is, to filter out the waveguide signals outside the two set wavelength ranges, and the waveguide signals within the two set wavelength ranges pass through the output waveguide 2 outputs. In this embodiment, the two set wavelength ranges are 548nm-798nm and 1071nm-1345nm respectively.

Optionally, the input end of the input waveguide 1 and the two output ends of the output waveguide 2 are provided with observation points (K1, K2, K3) for observing the waveguide signals in the input waveguide 1 and the output waveguide 2 To analyze the transmission situation.

Fig. 2 is the bandgap distribution under the TE polarization mode of the photonic crystal filter with double curved L-shaped microcavity of the present embodiment, wherein abscissa is K vector, and ordinate is normalized frequency, as shown in Fig. 2 , the photonic crystal filter with double curved L-shaped microcavity has two obvious band gaps, the corresponding band gap wavelength ranges are 548nm-798nm and 1071nm-1345nm respectively, and its central resonance frequency is 681nm and 1203nm respectively.

Figure 3 and Figure 4 are the electric field distribution diagram and transmittance diagram when the waveguide signal is 681nm, respectively, Figure 5 and Figure 6 are the electric field distribution diagram and transmittance diagram when the waveguide signal is 1203nm, respectively, as shown in Figure 3 and Figure 4, Figure 5 and 6, the waveguide signal is confined in the photonic crystal filter with a double-curved L-shaped microcavity for transmission, the transmittance is very high, the peak value can almost reach 100% transmission, and the loss is very low, and there is a relatively high Good filtering performance.

To sum up, in the photonic crystal filter with a double curved L-shaped microcavity provided by the embodiment of the present invention, it includes a two-dimensional photonic crystal formed by a plurality of dielectric pillars periodically arranged, and one of the two-dimensional photonic crystals is removed. A row of horizontal dielectric columns forms an output waveguide, and another row of horizontal dielectric columns is removed from the two-dimensional photonic crystal to form an input waveguide, and the remaining dielectric columns form a reflection cavity adjacent to the input waveguide, and the two In the three-dimensional photonic crystal, some rows of dielectric pillars between the input waveguide and the output waveguide are removed to form two centrally symmetrical L-shaped defects, and the two L-shaped defects and the dielectric pillars surrounded by them constitute The resonant cavity can generate two very wide forbidden bands, so that the filtering effect of two wavelength bands can be realized. The filtering effect is very good, with high transmittance and low loss. In addition, it has a double-bent L-shaped microcavity The photonic crystal filter belongs to the nanometer level, small in size, easy to integrate, and high in controllability, which provides assistance for the application of photonic crystal filters with double-curved L-shaped microcavities in communication systems.

The above are only preferred embodiments of the utility model, and do not limit the utility model in any way. Any person skilled in the technical field, without departing from the scope of the technical solution of the utility model, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the utility model, all of which are within the scope of the utility model. The content of the technical solution still belongs to the protection scope of the present utility model.

Claims (9)

1. a kind of photon crystal filter with tangent bend L shape microcavity, which is characterized in that periodically arranged including multiple dielectric posts The 2 D photon crystal formed is arranged, the dielectric posts for removing a row of horizontal in the 2 D photon crystal form output waveguide, described The certain media column for removing another row of horizontal in 2 D photon crystal forms input waveguide, and the remaining dielectric posts are formed and institute The adjacent reflection cavity of input waveguide is stated, is removed between the input waveguide and the output waveguide in the 2 D photon crystal The certain media column of several rows two L-type defects and its internal is surrounded with forming two L-type defects being centrosymmetric Dielectric posts constitute resonant cavity.

2. having the photon crystal filter of tangent bend L shape microcavity as described in claim 1, which is characterized in that the two dimension Photonic crystal is hexagonal lattice photonic crystal, and the medium column radius of the hexagonal lattice photonic crystal is 0.21a, and a is crystalline substance The dielectric posts of lattice constant, the hexagonal lattice photonic crystal are silica glass matrix, and background is air.

3. having the photon crystal filter of tangent bend L shape microcavity as claimed in claim 2, which is characterized in that the hexagonal The lattice constant a=540nm of lattice photonic crystal.

4. having the photon crystal filter of tangent bend L shape microcavity as claimed in claim 2, which is characterized in that the two dimension The dielectric posts of photonic crystal are in 19*17 array distribution.

5. having the photon crystal filter of tangent bend L shape microcavity as claimed in claim 4, which is characterized in that the reflection Chamber includes six dielectric posts, and six dielectric posts are located at same row.

6. having the photon crystal filter of tangent bend L shape microcavity as claimed in claim 5, which is characterized in that two L 5 row's dielectric posts are surrounded in type defect.

7. having the photon crystal filter of tangent bend L shape microcavity as claimed in claim 6, which is characterized in that by described After input waveguide input is in the waveguide signal of Gaussian Profile, the waveguide signal set except wave-length coverage at two is filtered out, it is described Waveguide signal of the output waveguide output within two setting wave-length coverages.

8. having the photon crystal filter of tangent bend L shape microcavity as claimed in claim 7, which is characterized in that described in two Setting wave-length coverage is respectively 548nm-798nm and 1071nm-1345nm.

9. having the photon crystal filter of tangent bend L shape microcavity as described in claim 1, which is characterized in that the input The input terminal of waveguide and two output ends of the output waveguide are provided with point of observation.