KR20080099713A - Photonic crystal wavelength demultiplexer - Google Patents

Abstract

A micro type photonic crystal wavelength splitter using an inversed image of wavelength is provided to easily separate many wavelengths by inserting a photonic crystal. A micro type photonic crystal wavelength splitter using an inversed image of wavelength comprises the followings: an input unit(10) of a single-mode waveguide receiving a wavelength mixed in a photonic crystal; a reflection crystal unit(20) which is inserted in order to reflect a specific wave in a multiple mode waveguide separating the mixed wavelength; a reflection output unit(30) of the single-mode waveguide outputting a wavelength reflected from the reflection decision unit; and a passage output unit(40) of a single waveguide outputting the wavelength which is not reflected in the reflection decision unit.

Description

Photonic Crystal Wavelength Demultiplexer

1 shows schematically a photonic crystal wavelength separator according to the invention;

2 schematically illustrates a photonic crystal wavelength separator according to the present invention.

3 schematically illustrates a photonic crystal wavelength separator according to the present invention;

4 schematically illustrates a photonic crystal wavelength separator according to an embodiment of the present invention.

5 schematically illustrates a photonic crystal wavelength separator according to an embodiment of the present invention.

FIG. 6 illustrates a columnar shape of the photonic crystal wavelength separator according to one embodiment of the present invention. FIG.

FIG. 7 illustrates a hole type of a photonic crystal wavelength separator according to an embodiment of the present invention. FIG.

8 illustrates an optical bandgap of a photonic crystal wavelength separator according to the present invention.

9 is an electric field distribution diagram according to the wavelength of the photonic crystal wavelength separator according to the present invention.

      <Brief description of reference numerals for the main parts of the drawings>

1: Photonic Crystal Wavelength Separator 10: Input Section

10a: first input unit 10b: second input unit

20: reflection determination unit 20a: first reflection determination unit

20b: second reflection crystal part 21: second photonic crystal

23: third photonic crystal 25: fourth photonic crystal 30: reflective output section 31: first reflective output section

33: second reflection output section 40: pass output section

41: first pass output unit 43: second pass output unit

50: multi-mode region 50a: first multi-mode region

50b: second multi-mode region 60: first photonic crystal

The present invention relates to a photonic crystal wavelength splitter, and more particularly, a photonic crystal capable of reflecting a specific wavelength at a half point of self-imaging by using an ego phase image of a wavelength inverted in a multi-mode region of a photonic crystal wavelength splitter. By inserting, it is possible to reflect or transmit a specific wavelength, thereby designing without being constrained to the bit length of each incident wavelength, and compacting by reducing the increased length according to the least common multiple of the bit length of each incident wavelength. The present invention relates to a photonic crystal wavelength separator capable of fabricating one ultra-small wavelength separator and that can be easily separated even by inserting a photonic crystal even for a plurality of mixed wavelengths.

In general, a photonic crystal is a structure in which photonic band gaps (PBGs) are formed by periodically arranging materials having different dielectric constants, and a single mode is formed by forming a defect mode that breaks periodicity in the photonic crystal. Multi-Mode Interference (MMI) and Multi-Mode, and Self-Imaging can be used to fabricate Multi-Mode Interference (MMI) based devices.

Here, the multi-mode interference-based device is based on the principle of ego phase imaging, which forms a single image and a multiple image at periodic intervals along a propagation direction, and uses wavelength division multiplexing (WDM). Wavelength separator is required.

In addition, the multi-mode interference-based device is formed with a length of the least common multiple of the bit length of the input wavelength, which is a first wavelength having a bit length of 3, for example, because the lengths of ego imaging are different. The first wavelength and the second wavelength are self-imaged at the point where the second wavelength having the bit length of 4 is commonly self-imaged at the point of 12, which is the least common multiple of 3 and 4.

However, as the signal used increases, the length according to the least common multiple of the beat length of the increased signal wavelength increases, and the length of the wavelength separator increases, thereby increasing the size of the device and increasing the density of the light. In implementing the circuit, it acts as a defect in size, and using Bragg Grating does not allow the error range of the separated wavelength band, and in separating the wavelength, the input wavelength has a slight error range. If it had, there was a problem such as not separating it.

The present invention has been made to solve the above problems, by using a self-image which is the inverted phase of the wavelength in the multi-mode region of the photonic crystal-based wavelength separator, a photonic crystal capable of reflecting a specific wavelength to half of the self-image formation By inserting, it is possible to reflect or transmit a specific wavelength, thereby designing without being constrained to the bit length of each incident wavelength, and compacting by reducing the increased length according to the least common multiple of the bit length of each incident wavelength. It is an object of the present invention to provide a photonic crystal wavelength separator which can manufacture one ultra-small wavelength separator and which can be easily separated even by the insertion of a photonic crystal even for a plurality of mixed wavelengths.

In order to achieve the above object, the present invention provides an input unit which is a single mode waveguide into which a wavelength mixed in a photonic crystal is input; A reflection determiner inserted to reflect a specific wavelength in the multi-mode waveguide in which the mixed wavelengths are separated; A reflection output unit which is a single mode waveguide to which the wavelength reflected from the reflection determination unit is output; A pass output unit which is a single waveguide for outputting a wavelength not reflected by the reflection determination unit; It includes.

The reflection determining unit may be provided in plural to reflect a plurality of wavelengths.

Here, the reflection determining unit is characterized in that the reflected wavelength is inserted into a half point of the length of the self-image.

In addition, the ego imaging is characterized in that the inverted image (Mirrored Image).

In addition, the reflective output is characterized in that formed at the point where the reflected wavelength is self-imaged.

Here, the pass output portion is characterized in that formed at the point where the non-reflected wavelength is self-imaged.

In addition, the ego imaging is characterized in that the mirrored image (Mirrored Image) and a replica (Replica Image).

In addition, the photonic crystal and the reflective crystal portion is formed as a pillar of a rectangular grating, characterized in that the mixed wavelength is input to the TE polarized light.

In addition, the photonic crystal and the reflective crystal is characterized in that the hole formed in the triangular grating in the photonic crystal mixed wavelength is input to TM polarized light.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view schematically showing a photonic crystal wavelength separator according to the present invention. As shown in the figure, the photonic crystal demultiplexer 1 according to the present invention has a defect mode in which the periodicity in the photonic crystal constituting the photonic crystal is locally broken to artificially form a defect. Mode to separate the input wavelength.

The photonic crystal wavelength separator 1 according to the present invention describes forming each photonic crystal in a rod shape to separate the mixed wavelengths incident by TE (Transverse Electric) polarization. Forming a hole (Hole), filling it with air (Air), and separating the mixed wavelength incident to the TM (Transverse Magnetic) polarization will be described.

Here, in the case of transverse electric polarization (TE) polarization, when an optical crystal is formed in a columnar shape, an electric field component of an electric magnetic wave propagating along a transmission system such as a waveguide is parallel to the axis of the photonic crystal pillar. The magnetic field is a magnetic field of electric magnetic wave propagated along a transmission system such as a waveguide when a photonic crystal is formed in a hole type. ) Refers to a wave that is incident so that the component is perpendicular to the axis of the photonic crystal hole.

The wavelengths λ ₁ and λ ₂ mixed in the photonic crystal are input to the input unit 10. An input waveguide is formed in the photonic crystal formed in the column type (empty space), and the mixed wavelength in a single mode. Let (λ ₁ , λ ₂ ) be input.

In this case, a single mode is an optical waveguide capable of transmitting in a wavelength having only the lowest constrained mode of a pair of orthogonal polarizations, and has only one propagation form of light and only one mode of waveguide. The mixed wavelengths λ ₁ and λ ₂ are provided to be input as they are without being dispersed.

In addition, the mixed wavelengths λ ₁ and λ ₂ input to the input unit 10 enter the multi-mode region 50, and the mixed wavelengths λ ₁ and λ ₂ have multiple modes. It is made so that can be waveguided, so that the mixed wavelength (λ ₁ , λ ₂ ) is dispersed.

Here, wavelengths dispersed in the multi-mode region 50 are inserted into the multi-mode region 50, and have different physical properties such as refractive index from the first photonic crystal 60 constituting the photonic crystal wavelength separator 1. The second photonic crystal 21 is selectively reflected by the reflection determining unit 20 which is axially perpendicular to the input direction of the mixed wavelengths λ ₁ and λ ₂ .

In addition, the wavelengths λ ₁ and λ ₂ incident on the multi-mode region 50 exhibit a self-imaging phenomenon through a mode propagation analysis (MPA) on a two-dimensional waveguide structure. This can be explained by Multi-Mode Interference (MMI).

In addition, the index for determining the number of modes in the waveguide is a normalization frequency (V), and as the standardization frequency increases, a plurality of multimodes exist. Occurs when a specific condition is satisfied.

In addition, the self-imaging according to the present invention is divided into a replica-image and a mirror-image, and the replica-image is the same position as the input image, that is, the same. It refers to an image having the same characteristics on the line, and the mirror-image has the same characteristics as mirrored, but does not occur on the same line as the input image.

Here, in the basic photonic crystal wavelength separator 1 according to the present invention, the wavelength separator having the most compact size may be manufactured by using a mirror image on both of the mixed wavelengths λ ₁ and λ ₂ . .

And, the second photonic crystal length 21 is to be self-imaging in a first wavelength (λ ₁₎ is inverted phase (Mirrored-Image) of the reflected determiner 20 inserted so as to reflect a first wavelength (λ ₁₎ It is arranged in the axis of ordinates at half the point.

Therefore, since the first wavelength λ ₁ reflected on the second photonic crystal 21 of the reflection determination unit 20 uses a mirror-image, light reflected on the same line of the input unit 10 is input to the input unit 10. Rather than being reflected by (10), the reflection is output to the reflection output unit 30 to separate the first wavelength λ ₁ .

In addition, the reflection output unit 30 is formed at a point where the first wavelength λ ₁ is self-imaged in an inverted phase, and is formed so that the wavelength reflected by the reflection determination unit 20 is output.

In addition, the second wavelength λ ₂ , which is a wavelength that is not reflected by the reflection determination unit 20, forms a pass output unit 40 at a point where the self-crystallization of the inverted phase is performed. λ ₂ ) to be output in a single mode.

In this case, since the second wavelength λ ₂ is an inverted phase, the pass output unit 40 is not formed on the same line as the input unit 10. A single mode waveguide is formed.

As described above, the reflection determination unit 20 reflects the first wavelength λ ₁ to be output to the reflection output unit 30, and the second wavelength λ ₂ passing through the reflection determination unit 20 is described above. The photonic crystal wavelength separator 1 is formed to be output to the opposite side of the reflective output unit 30.

2 is a view schematically showing a photonic crystal wavelength separator according to the present invention. As shown in the figure, the photonic crystal wavelength separator 1 according to the present invention uses a defect mode that locally breaks the periodicity in the photonic crystal constituting the photonic crystal to artificially form a defect. Separate the incoming wavelength.

The photonic crystal wavelength separator 1 according to the present invention describes forming each photonic crystal in a rod shape to separate the mixed wavelengths incident by TE (Transverse Electric) polarization. Forming a hole in the hole, filling it with air, and separating the mixed wavelength incident by TM (Transverse Magnetic) polarization will be described.

The wavelengths λ ₁ and λ ₂ mixed in the photonic crystal are input to the input unit 10. An input waveguide is formed in the photonic crystal formed in the column type (empty space), and the mixed wavelength in a single mode. Let (λ ₁ , λ ₂ ) be input.

In this case, a single mode is an optical waveguide capable of transmitting in a wavelength having only the lowest constrained mode of a pair of orthogonal polarizations, and has only one propagation form of light and only one mode of waveguide. The mixed wavelengths λ ₁ and λ ₂ are provided to be input as they are without being dispersed.

In addition, the mixed wavelengths λ ₁ and λ ₂ input to the input unit 10 enter the multi-mode region 50, and the mixed wavelengths λ ₁ and λ ₂ have multiple modes. It is made so that can be waveguided, so that the mixed wavelength (λ ₁ , λ ₂ ) is dispersed.

Here, wavelengths dispersed in the multi-mode region 50 are inserted into the multi-mode region 50, and have different physical properties such as refractive index from the first photonic crystal 60 constituting the photonic crystal wavelength separator 1. The second photonic crystal 21 is selectively reflected by the reflection determining unit 20 which is axially perpendicular to the input direction of the mixed wavelengths λ ₁ and λ ₂ .

In addition, the wavelengths λ ₁ and λ ₂ incident on the multi-mode region 50 exhibit a self-imaging phenomenon through a mode propagation analysis (MPA) on a two-dimensional waveguide structure. This can be explained by Multi-Mode Interference (MMI).

In addition, the index for determining the number of modes in the waveguide is a normalization frequency (V), and as the standardization frequency increases, a plurality of multimodes exist. The periodic imaging characteristics due to the multimode interference may include mode coefficients and phase elements. Occurs when certain conditions are met.

In addition, the self-imaging according to the present invention is divided into a replica-image and a mirror-image, and the replica-image is the same position as the input image, that is, the same. It refers to an image having the same characteristics on the line, and the mirror-image has the same characteristics as mirrored, but does not occur on the same line as the input image.

Here, the basic photonic crystal wavelength separator 1 according to the embodiment of the present invention uses the mirror-image as the first wavelength λ ₁ among the mixed wavelengths λ ₁ and λ ₂ , and uses the second wavelength. (λ ₂ ) may manufacture a wavelength separator using a replica-image.

And, the second photonic crystal length 21 is to be self-imaging in a first wavelength (λ ₁₎ is inverted phase (Mirrored-Image) of the reflected determiner 20 inserted so as to reflect a first wavelength (λ ₁₎ It is arranged in the axis of ordinates at half the point.

Therefore, since the first wavelength λ ₁ reflected on the second photonic crystal 21 of the reflection determination unit 20 uses a mirror-image, light reflected on the same line of the input unit 10 is input to the input unit 10. Rather than being reflected by (10), the reflection is output to the reflection output unit 30 to separate the first wavelength λ ₁ .

In addition, the reflection output unit 30 is formed at a point where the first wavelength λ ₁ is self-imaged in an inverted phase, and is formed so that the wavelength reflected by the reflection determination unit 20 is output.

In addition, the second wavelength λ ₂ , which is a wavelength that is not reflected by the reflection determination unit 20, forms a pass output unit 40 at a point where it is self-determined as a replica. λ ₂ ) to be output in a single mode.

In this case, since the second wavelength λ ₂ is a replica, a single pass waveguide, which is a pass output unit 40, is formed at a position at which a replica is formed by forming a pass output unit 40 on the same line as the input unit 10. (Single Mode Waveguide) is formed.

As described above, the reflection determination unit 20 reflects the first wavelength λ ₁ to be output to the reflection output unit 30, and the second wavelength λ ₂ passing through the reflection determination unit 20 is described above. The photonic crystal wavelength separator 1 is formed to be output to the opposite side of the reflective output unit 30.

3 is a view schematically showing a photonic crystal wavelength separator according to the present invention. As shown in the figure, the photonic crystal wavelength separator 1 according to the present invention can design the reflection output portion 30 of the photonic crystal wavelength separator 1 of FIG. 1 as an input portion 10, which is shown in FIG. The photonic crystal wavelength separator 1 is formed in a symmetrical form.

Like the photonic crystal wavelength splitter 1 of FIG. 1, the most compact using an inverted phase for both the first wavelength and the second wavelength among the self-imaging to separate the mixed wavelengths λ ₁ and λ ₂ . Design a compact wavelength separator.

Then, the mixed wavelengths λ ₁ and λ ₂ are input to the input unit 10. An input waveguide is formed in the photonic crystal formed in the column type (empty space), and the mixed wavelengths ( λ ₁ , λ ₂ ) are input.

In this case, a single mode is an optical waveguide capable of transmitting in a wavelength having only the lowest constrained mode of a pair of orthogonal polarizations, and has only one propagation form of light and only one mode of waveguide. The mixed wavelengths λ ₁ and λ ₂ are provided to be input as they are without being dispersed.

In addition, the mixed wavelengths λ ₁ and λ ₂ input to the input unit 10 enter the multi-mode region 50, and the mixed wavelengths λ ₁ and λ ₂ have multiple modes. It is made so that can be waveguided, so that the mixed wavelength (λ ₁ , λ ₂ ) is dispersed.

In this case, the wavelengths dispersed in the multi-mode region 50 are inserted into the multi-mode region 50, and have different physical properties such as refractive index from the first photonic crystal 60 constituting the photonic crystal wavelength separator 1. The second photonic crystal 21 is selectively reflected by the reflection determining unit 20 which is axially perpendicular to the input direction of the mixed wavelengths λ ₁ and λ ₂ .

In addition, the self-imaging according to the present invention is divided into a replica-image and a mirror-image, and the replica-image is the same position as the input image, that is, the same. It refers to an image having the same characteristics on the line, and the mirror-image has the same characteristics as mirrored, but does not occur on the same line as the input image.

Here, in the basic photonic crystal wavelength separator 1 according to the present invention, the wavelength separator having the most compact size may be manufactured by using a mirror image on both of the mixed wavelengths λ ₁ and λ ₂ . .

And, the second photonic crystal length 21 is to be self-imaging in a first wavelength (λ ₁₎ is inverted phase (Mirrored-Image) of the reflected determiner 20 inserted so as to reflect a first wavelength (λ ₁₎ It is arranged in the axis of ordinates at half the point.

Therefore, since the first wavelength λ ₁ reflected on the second photonic crystal 21 of the reflection determination unit 20 uses a mirror-image, light reflected on the same line of the input unit 10 is input to the input unit 10. Rather than being reflected by (10), the reflection is output to the reflection output unit 30 to separate the first wavelength λ ₁ .

In addition, the reflection output unit 30 is formed at a point where the first wavelength λ ₁ is self-imaged in an inverted phase, and is formed so that the wavelength reflected by the reflection determination unit 20 is output.

In addition, the second wavelength λ ₂ , which is a wavelength that is not reflected by the reflection determination unit 20, forms a pass output unit 40 at a point where the self-crystallization of the inverted phase is performed. λ ₂ ) to be output in a single mode.

In this case, since the second wavelength λ ₂ is an inverted phase, the pass output unit 40 is not formed on the same line as the input unit 10. A single mode waveguide is formed.

As described above, the reflection determination unit 20 reflects the first wavelength λ ₁ to be output to the reflection output unit 30, and the second wavelength λ ₂ passing through the reflection determination unit 20 is described above. The photonic crystal wavelength separator 1 is formed to be output to the opposite side of the reflective output unit 30.

4 schematically illustrates a photonic crystal wavelength separator according to an embodiment of the present invention. As shown in the figure, the photonic crystal demultiplexer 1 according to the present invention is configured to separate three mixed wavelengths.

Here, the input wavelength is separated by using a defect mode that locally breaks the periodicity in the photonic crystal constituting the photonic crystal to artificially form a defect. The photonic crystal wavelength separator 1 according to the present invention is used. In the following example, each of the photonic crystals is formed in a pillar shape to separate the mixed wavelengths incident by TE (Transverse Electric) polarization. In the following example, a hole is formed in each of the photonic crystals. Filling with (Air) and separating the mixed wavelength incident with TM (Transverse Magnetic) polarization will be described.

The wavelengths λ ₁ , λ ₂ , and λ ₃ mixed in the photonic crystal are input to the first input unit 10a. An input waveguide is formed in the photonic crystal formed in the column type (empty space), and a single mode is used. The mixed wavelengths λ ₁ , λ ₂ and λ ₃ are input to

In this case, a single mode is an optical waveguide capable of transmitting in a wavelength having only the lowest constrained mode of a pair of orthogonal polarizations, and has only one propagation form of light and only one mode of waveguide. The mixed wavelengths λ ₁ , λ ₂ and λ ₃ are provided so as to be input as they are without being dispersed.

In addition, the mixed wavelengths λ ₁ , λ ₂ , and λ ₃ input to the first input unit 10a enter the first multi-mode region 50a. The mixed wavelengths λ ₁ , Since λ ₂ and λ ₃ can be guided in a plurality of modes, the mixed wavelengths λ ₁ , λ ₂ and λ ₃ are dispersed.

Here, the wavelengths dispersed in the first multi-mode region 50a are inserted into the first multi-mode region 50a, and the first photonic crystal 60 constituting the photonic crystal wavelength separator 1 has properties such as refractive index ( The first reflective crystal portion 20a which is axially oriented so that the second photonic crystal 21 and the third photonic crystal 23 having different physical properties are perpendicular to the input direction of the mixed wavelengths λ ₁ , λ ₂ , and λ ₃ . Is optionally reflected).

In addition, the wavelengths λ ₁ , λ ₂ , and λ ₃ incident on the first multi-mode region 50a exhibit a self-imaging phenomenon, and a mode propagation analysis (MPA) for a two-dimensional waveguide structure This can be explained by Multi-Mode Interference (MMI) through Propagation Analysis.

In addition, the index for determining the number of modes in the waveguide is a normalization frequency (V), and as the standardization frequency increases, a plurality of multimodes exist. The periodic imaging characteristics due to the multimode interference may include mode coefficients and phase elements. Occurs when certain conditions are met.

In addition, the self-imaging according to the present invention is divided into a replica-image and a mirror-image, and the replica-image is the same position as the input image, that is, the same. It refers to an image having the same characteristics on the line, and the mirror-image has the same characteristics as mirrored, but does not occur on the same line as the input image.

Here, the photonic crystal wavelength separator 1 according to the present invention may manufacture a wavelength separator having the most compact size using a mirror-image on all of the mixed wavelengths λ ₁ , λ ₂ , and λ ₃ . Can be.

And, the first wavelength (λ _1), a first reflection determination section (20a) inserted so as to reflect two optical crystal (21) has a first wavelength (λ ₁₎ is to be self-focusing in the reverse phase (Mirrored-Image) It is arranged in the axis of ordinates at half the length.

Further, the fourth optical crystal 25 of the first reflecting determination section (20a) inserted so as to reflect the second wavelength (λ ₂₎ is the second wavelength (λ ₂₎ is to be self-focusing in the reverse phase (Mirrored-Image) It is arranged in the axis of ordinates at half the length.

Thus, the first wavelength λ ₁ and the second wavelength λ ₂ reflected by the second photonic crystal 21 and the third photonic crystal 23 of the first reflection crystal part 20a are inverted images. ) to a first input (10a), instead of being the reflected light on dongilseon reflected by the first input (10a) of the first reflection is outputted to the output unit 31, the first wavelength (λ ₁₎ and a hayeoteumeuro using Two wavelengths λ ₂ are separated from the third wavelength λ ₃ .

Accordingly, the third wavelength λ ₃ is output to the first pass output part 41 so as to be separated from the first wavelength λ ₁ and the second wavelength λ _{2. In the} present embodiment, the third wavelength λ 3 is output. ₃ ) is manufactured to minimize the size of the photonic crystal wavelength separator 1 according to the present invention by using an inverted image, and accordingly outputs the third wavelength λ ₃ , but using the replica image, the first input unit 10a. It is also preferable to output to the opposite side of the same position as.

Here, the first wavelength λ ₁ and the second wavelength λ ₂ are output to the first reflection output unit 31, so that the first wavelength λ ₁ and the second wavelength λ ₂ are not separated. Since it is not in the state, in order to separate it, the photonic crystal wavelength separator 1 is further provided.

Then, the first wavelength λ ₁ and the second wavelength λ ₂ are input to the second input unit 10b. An input waveguide is formed in the photonic crystal formed in the pillar type (empty space), and In this mode, the first wavelength λ ₁ and the second wavelength λ ₂ are input.

In addition, the second input (10b) of the first wavelength (λ ₁₎ and second wavelength (λ ₂₎ inputted to the there is, it goes into a second multi-mode zone (Multi Mode Region, 50b), the first wavelength (λ ₁ ) and the second wavelength λ ₂ can be guided in multiple modes.

Here, wavelengths dispersed in the second multi-mode region 50b are inserted into the second multi-mode region 50b, and have properties such as refractive index and the first photonic crystal 60 constituting the photonic crystal wavelength separator 1. The fourth photonic crystal 25 having different materials is selectively reflected by the reflection crystal part 20 axially aligned in the longitudinal direction so as to be perpendicular to the input direction of the mixed wavelengths λ ₁ and λ ₂ .

And, the fourth optical crystal 25 of the second reflecting determiner (20b) inserted so as to reflect a first wavelength (λ ₁₎ has a first wavelength (λ ₁₎ is to be self-focusing in the reverse phase (Mirrored-Image) It is arranged in the axis of ordinates at half the length.

Therefore, since the first wavelength λ ₁ reflected by the second photonic crystal 21 of the second reflection determination unit 20b uses a mirror-image, reflection is performed on the same line of the second input unit 10b. The reflected light is not reflected to the second input unit 10b but is reflected and output to the second reflective output unit 33 to separate the first wavelength λ ₁ .

In addition, the second reflection output unit 33 is formed at a point where the first wavelength λ ₁ is self-imaged in an inverted phase, and is formed so that the wavelength reflected by the second reflection determination unit 20b is output.

In addition, a second pass output part 43 is formed at a point where the second wavelength λ ₂ , which is a wavelength not reflected by the second reflection determination part 20b, is self-determined in an inverted phase, thereby being dispersed in multiple modes. The second wavelength λ ₂ is output in a single mode.

In this case, since the second wavelength λ ₂ is an inverted phase, the second pass output unit 43 is not formed on the same line as the second input unit 10b, but the second pass output is formed at a position where the inverted image is formed. A single mode waveguide, which is a portion 43, is formed.

As described above, the second reflection determination unit 20b reflects the first wavelength λ ₁ to be output to the second reflection output unit 33, and the second wavelength passing through the second reflection determination unit 20b. λ ₂ forms the photonic crystal wavelength separator 1 so as to be output to the opposite side of the second reflective output portion 33.

5 is a schematic view showing a photonic crystal wavelength separator according to an embodiment of the present invention. As shown in the figure, the photonic crystal demultiplexer 1 according to the present invention is configured to separate three mixed wavelengths.

Here, the input wavelength is separated by using a defect mode that locally breaks the periodicity in the photonic crystal constituting the photonic crystal to artificially form a defect. The photonic crystal wavelength separator 1 according to the present invention is used. In the following example, each of the photonic crystals is formed in a pillar shape to separate the mixed wavelengths incident by TE (Transverse Electric) polarization. In the following example, a hole is formed in each of the photonic crystals. Filling with (Air) and separating the mixed wavelength incident with TM (Transverse Magnetic) polarization will be described.

The wavelengths λ ₁ , λ ₂ , and λ ₃ mixed in the photonic crystal are input to the input unit 10. An input waveguide is formed in the photonic crystal formed in the column type (empty space), and the single mode is used. The mixed wavelengths λ ₁ , λ ₂ and λ ₃ are input.

In this case, a single mode is an optical waveguide capable of transmitting in a wavelength having only the lowest constrained mode of a pair of orthogonal polarizations, and has only one propagation form of light and only one mode of waveguide. The mixed wavelengths λ ₁ and λ ₂ are provided to be input as they are without being dispersed.

In addition, the mixed wavelengths λ ₁ , λ ₂ , and λ ₃ input to the input unit 10 enter the multi mode region 50, and the mixed wavelengths λ ₁ , λ ₂ and λ ₃ ) can be guided in multiple modes, so that the mixed wavelengths λ ₁ , λ ₂ , λ ₃ are dispersed.

Here, wavelengths dispersed in the multi-mode region 50 are inserted into the multi-mode region 50, and have different physical properties such as refractive index from the first photonic crystal 60 constituting the photonic crystal wavelength separator 1. The second photonic crystal 21 is selectively reflected by the reflection determination unit 20 axially perpendicular to the input direction of the mixed wavelengths λ ₁ , λ ₂ , and λ ₃ .

In addition, the wavelengths λ ₁ , λ ₂ , and λ ₃ incident on the multi-mode region 50 exhibit a self-imaging phenomenon. A mode propagation analysis for a two-dimensional waveguide structure is performed. Can be explained by Multi-Mode Interference (MMI).

In addition, the index for determining the number of modes in the waveguide is a normalization frequency (V), and as the standardization frequency increases, a plurality of multimodes exist. The periodic imaging characteristics due to the multimode interference may include mode coefficients and phase elements. Occurs when certain conditions are met.

In addition, the self-imaging according to the present invention is divided into a replica-image and a mirror-image, and the replica-image is the same position as the input image, that is, the same. It refers to an image having the same characteristics on a line. The mirrored image has the same characteristics as mirrored, but does not occur on the same line as the input image.

Here, the basic photonic crystal wavelength separator 1 according to the present invention has an inverted phase with respect to the first wavelength λ ₁ and the third wavelength λ ₃ among the mixed wavelengths λ ₁ , λ ₂ and λ ₃ . Image is used, and the second wavelength λ ₂ is produced using a replica-image.

And, the second photonic crystal length 21 is to be self-imaging in a first wavelength (λ ₁₎ is inverted phase (Mirrored-Image) of the reflected determiner 20 inserted so as to reflect a first wavelength (λ ₁₎ It is arranged in the axis of ordinates at half the point.

Therefore, since the first wavelength λ ₁ reflected on the second photonic crystal 21 of the reflection determination unit 20 uses a mirror-image, light reflected on the same line of the input unit 10 is input to the input unit 10. The first wavelength λ ₁ is separated by being reflected by the reflection output unit 30 instead of being reflected by 10.

In addition, the reflection output unit 30 is formed at a point where the first wavelength λ ₁ is self-imaged in an inverted phase, so that the wavelength reflected by the second photonic crystal 21 of the reflection determination unit 20 is output. Is formed.

In addition, the first pass output unit 41 and the second pass at a point where the second wavelength λ ₂ and the third wavelength λ ₃ , which are wavelengths not reflected by the reflection determination unit 20, are self-determined in common. The output unit 43 is formed so that the second wavelength λ ₂ and the third wavelength λ ₃ , which have been dispersed in the multiple modes, are output in the single mode.

In this case, since the second wavelength λ ₂ is a duplicate image, a single mode waveguide, which is a first pass output unit 41, is formed on the same line as the input unit 10 to form a duplicate image. Since the second wavelength λ ₂ is output and the third wavelength λ ₃ is inverted, the second pass output unit 43 is not formed on the same line as the input unit 10. The single mode waveguide which is the second pass output part 43 is formed at the position where the inverted image is formed.

As described above, the reflection determination unit 20 reflects the first wavelength λ ₁ and outputs it to the reflection output unit 30, and the second wavelength λ ₂ and the second that have passed through the reflection determination unit 20. The three wavelengths λ ₃ form the photonic crystal wavelength separator 1 so as to be output to the first pass output part 41 and the second pass output part 43.

6 is a diagram illustrating a columnar shape of the photonic crystal wavelength separator according to the embodiment of the present invention. As shown in the figure, the photonic crystal wavelength separator 1 according to the present invention may be formed in a pillar shape.

Here, TE (Transverse Electric) polarization is used, and pillars are formed in a rectangular grating shape.

That is, when forming the photonic crystal wavelength separator 1 according to the present invention in the form of a rod (Rod), the TE polarized incident light should be input, it should be formed in a rectangular grid form.

And, as in the above embodiment, it is possible to separate even if the input wavelength is mixed in two or more, by using the ego imaging properties of the mixed wavelength, the inverted phase of the ego phase image in both the reflection wavelength and the pass wavelength In use, the reflection output section 30 and the passage output section 40 are spaced apart from each other by a predetermined distance, and are formed at the point where the self image is formed.

On the other hand, when the replica is used for the pass wavelength, the pass output part 40 can be formed on the same line as the input part 10. When the replica is used for the reflected wavelength, the pass output part 40 is output to the input part 10. Design to use a reversed phase.

In addition, when the input wavelength exceeds two, a plurality of mixed wavelengths are input to the input unit 10, and the photonic crystals capable of reflecting the respective wavelengths to the reflection determination unit 20 are arranged vertically. The wavelength reflected by the photonic crystal is outputted by forming the reflection output unit 30 at the point where the inverted image is formed, and the pass wavelength forms the inverted image so that the pass wavelength is output using the inverted or replica image. The pass output unit 40 is formed at a point where the pass wavelength or a pass wavelength forms a replica.

Here, when two or more wavelengths are output to the reflective output unit 30, the optical crystal wavelength separator 1 according to the present invention is further provided, and the separated wavelengths outputted to the reflective output unit 30 are separated again. In order to input two or more wavelengths to the input unit 10, and output them in the same manner as described above, if two or more wavelengths are output in the re-separation process, and again provided with a photonic crystal wavelength separator 1 according to the present invention It is preferable that the wavelength is separated by the method.

The photonic crystal wavelength separator 1 according to the present invention can be designed by all the methods used in the above embodiments, but when the inverted phase is used, the photonic crystal wavelength separator 1 which is more compact than the replica image is used. It can be formed, and can be modified in all the ways of the embodiment.

7 is a diagram illustrating a hole type of the photonic crystal wavelength separator according to the embodiment of the present invention. As shown in the figure, the photonic crystal wavelength separator 1 according to the present invention can be manufactured as a photonic crystal having a certain physical property by forming holes (Hole) at a predetermined interval on the dielectric substrate.

Here, TM (Transverse Magnetic) polarization is used, and a hole is formed in a triangular grating shape.

That is, in the case of forming the photonic crystal wavelength separator 1 according to the present invention in the form of a hole, the TM polarized incident light should be input and formed in a triangular lattice form.

And, as in the above embodiment, it is possible to separate even if the input wavelength is mixed in two or more, by using the ego imaging properties of the mixed wavelength, the inverted phase of the ego phase image in both the reflection wavelength and the pass wavelength In use, the reflection output section 30 and the passage output section 40 are spaced apart by a predetermined distance, and are formed at a point where an ego image is formed.

On the other hand, when the replica is used for the pass wavelength, the pass output part 40 can be formed on the same line as the input part 10. When the replica is used for the reflected wavelength, the pass output part 40 is output to the input part 10. Design to use a reversed phase.

In addition, when the input wavelength exceeds two, a plurality of mixed wavelengths are input to the input unit 10, and the photonic crystals capable of reflecting the respective wavelengths to the reflection determination unit 20 are arranged vertically. The wavelength reflected by the photonic crystal is outputted by forming the reflection output unit 30 at the point where the inverted image is formed, and the pass wavelength forms the inverted image so that the pass wavelength is output using the inverted or replica image. The pass output unit 40 is formed at a point where the pass wavelength or a pass wavelength forms a replica.

Here, when two or more wavelengths are output to the reflective output unit 30, the optical crystal wavelength separator 1 according to the present invention is further provided, and re-separating the reflected wavelengths output to the reflective output unit 30 In order to input two or more wavelengths to the input unit 10, and output them in the same manner as described above, if two or more wavelengths are output in the re-separation process, and again provided with a photonic crystal wavelength separator 1 according to the present invention It is preferable that the wavelength is separated by the method.

The photonic crystal wavelength separator 1 according to the present invention can be designed by all the methods used in the above embodiments, but when the inverted phase is used, the photonic crystal wavelength separator 1 which is more compact than the replica image is used. It can be formed, and can be modified in all the ways of the embodiment.

8 is a view showing an optical bandgap of the photonic crystal wavelength separator according to the present invention. As shown in the figure, the optical bandgap of the first photonic crystal 60 of the photonic crystal wavelength separator 1 according to the present invention is shown in (a), and the reflection output section 30 and the pass output section 40 are shown. Is shown in (b), the optical bandgap of the multi-mode region 50 is shown in (c), and the optical bandgap of the reflection determining unit 20 is shown in (d).

In this embodiment, when the first wavelength λ ₁ and the second wavelength λ ₂ are represented by a / λ, the first wavelength λ ₁ is 0.417 and the second wavelength λ ₂ is 0.35.

Since a is 542.5 nm, the first wavelength λ ₁ is 1.3 μm, and the second wavelength λ ₂ is 1.55 μm, a / λ ₁ is 0.417 and a / λ ₂ is calculated as 0.35.

At this time, a is a lattice constant, which represents the distance between each photonic crystal. The unit of a is also a distance, and the unit of λ is also a distance, and thus the unit of the vertical axis (y-axis) of each graph is canceled out.

In addition, in (a), since the optical bandgap of the first photonic crystal 60 is about 0.3 to 0.44, the wavelength corresponding to the optical bandgap cannot be guided, and thus, a of the first wavelength λ ₁ 0.417 which is / λ _{1 and} 0.35 which is a / λ ₂ of the second wavelength λ ₂ can not be waveguided.

In addition, (b) shows that only 0.41 (a / λ ₁ ) of the first wavelength (λ ₁ ) and 0.35 (a / λ ₂ ) of the second wavelength (λ ₂ ) can be obtained using only the first photonic crystal 60 structure of (a). Since the waveguide cannot be guided, the waveguide is formed by removing the photonic crystal in a line form to form an empty region in order to form a defect mode in the structure of the first photonic crystal 60.

Accordingly, the reflection output unit 30 and the pass output unit 40 are formed as a single mode waveguide. Referring to (b) illustrating an optical band structure of the reflection output unit 30 and the pass output unit 40, The optical band gap is about 0.3 to 0.31, and there is only one point overlapping with 0.35, which is 0.417 representing a / λ ₁ of the first wavelength λ ₁ and a / λ ₂ of the second wavelength λ ₂ . This means that the device is in a single mode with respect to the first wavelength λ ₁ and the second wavelength λ ₂ .

Then, looking at (c), the multi-mode region 50, illustrates the optical band gap in a multi-mode waveguide of the first of a / λ ₁ of the first wavelength (λ ₁₎ 0.417 and the second wavelength (λ ₂₎ The point overlapping with 0.35, which is a / λ ₂ , is about 4-5, which means that it is a multi-mode having 4 to 5 modes.

In addition, (d) shows an optical bandgap of the reflection determination unit 20, and includes only 0.417, which is a / λ ₁ of the first wavelength λ ₁ , and a / of the second wavelength λ ₂ . It does not include 0.35, which is λ ₂ , which means that it can reflect only the first wavelength λ ₁ and pass without reacting to the second wavelength λ ₂ .

Here, since the optical bandgap of the reflection determination unit 20 has a range of about 0.25-0.28 and 0.38-0.48, the optical bandgap can reflect the wavelength within the above range, and accordingly, the error band has a certain error range. As it is acceptable, it is more comprehensively available.

9 is an electric field distribution diagram according to the wavelength of the photonic crystal wavelength separator according to the present invention. As shown in the figure, the photonic crystal wavelength separator 1 according to the present invention is a diagram showing an electric field distribution based on the basic photonic crystal wavelength separator 1 of FIG.

Here, a / λ ₁ of the first wavelength (λ ₁₎ in the embodiment of Figure 8 is 0.417, and the a / λ ₂ of the second wavelength (λ ₂₎ is 0.35, and when showing the electric field distribution by using this, a Since is 542.5 nm, the first wavelength λ ₁ is 1.3 μm and the second wavelength λ ₂ is 1.55 μm.

Here, (a) is the second photonic crystal 21 of the reflective crystal portion 20 at a half point where the first wavelength λ ₁ having 1.3 μm is reflected by the reflective crystal portion 20 and is self-imaged in an inverted image. ) Is arranged, and the reflection output unit 30 is formed at the point where the self image is formed, and thus only the first wavelength λ ₁ is output to the reflection output unit 30 in an inverted image.

And, (b) is 1.55μm in a second wavelength (λ ₂₎ are reflected through the determining unit 20, the forms pass through the output section 40 to the point at which the self-imaging in a reverse second wavelength (λ ₂ ) Only shows the electric field distribution output to the passage output unit 40.

At this time, the input light is moved in a single mode in the input unit 10 and the output unit (reflective output unit 30 and the pass-through output unit 40) in (a) and (b), in the multi-mode region 50 You can see that you are moving to multiple modes.

In addition, in (a), it can be seen that only the first wavelength λ ₁ reflected by the reflection determination unit 20 is reflected and passed through the second wavelength λ ₂ as it is.

As described above, in the photonic crystal wavelength separator 1 according to the present invention, the first wavelength λ ₁ and the second wavelength λ ₂ are self-imaged simultaneously, that is, the first wavelength λ ₁ and the second wavelength λ _2. Since it is not formed to have a length equal to the minimum common multiple of the length of the ego image, it can have a compact size and length, and has a range as wide as the optical band gap, so that even if an error occurs in the wavelength to be reflected, it can be separated. Is done.

Although the preferred embodiments of the present invention have been described above by way of example, the scope of the present invention is not limited to such specific embodiments, and those skilled in the art are appropriate within the scope described in the claims of the present invention. It will be possible to change.

As described above, the present invention having the configuration as described above uses a self-imaging, which is an inverted phase of the wavelength, in a multi-mode region of the photonic crystal-based wavelength separator to provide a photonic crystal capable of reflecting a specific wavelength at a half point of self-image formation. By inserting, it is possible to reflect or transmit a specific wavelength, thereby designing without being constrained to the bit length of each incident wavelength, and reducing the increased length according to the least common multiple of the bit length of each incident wavelength. It is possible to fabricate a compact and ultra-compact wavelength separator, and to achieve an effect such as being easily separated by only inserting a photonic crystal with respect to a wavelength mixed with a plurality.

Claims (9)

An input unit which is a single mode waveguide into which the wavelength mixed in the photonic crystal is input; A reflection determiner inserted to reflect a specific wavelength in the multi-mode waveguide in which the mixed wavelengths are separated; A reflection output unit which is a single mode waveguide to which the wavelength reflected from the reflection determination unit is output; A pass output unit which is a single waveguide for outputting a wavelength not reflected by the reflection determination unit; Photonic crystal wavelength separator comprising a. The method of claim 1, And a plurality of reflection determining units are provided to reflect a plurality of wavelengths. The method of claim 1, And the reflection crystal part is inserted at a half point of a length at which the reflected wavelength is self-imaged. The method of claim 3, And the ego imaging is a mirrored image. The method according to claim 1 or 2, And the reflective output unit is formed at a point where the reflected wavelength is self-imaged. The method according to claim 1 or 2, And the pass output part is formed at a point where an unreflected wavelength is self imaged. The method of claim 6, Wherein the ego phase image is a mirrored image and a replica image. The method of claim 1, And the photonic crystal and the reflective crystal part are formed as pillars of a square lattice, and the mixed wavelengths are input by TE polarized light. The method of claim 1, And the photonic crystal and the reflective crystal part are formed in a hole of a triangular lattice in the photonic crystal, and the mixed wavelength is input as TM polarized light.

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