KR100845272B1 - Encoder and Decoder of Optical Code Devision Multiple Access Using Ring Resonator - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical CDMA encoder and decoder using a ring resonator, wherein a ring resonator is formed to be spaced apart from an optical waveguide for changing a propagation constant by using an optical speed that is changed according to a propagation constant in an optical CDMA. It is possible to delay the advancing speed and time of the incident optical signal of the encoder and decoder which encrypts and decrypts the data and the received data, and by increasing the number of the ring resonators, the digital time delay is proportional to the time delay of the single ring resonator. It is possible to obtain a time delay proportional to the radius of the ring resonator, so that various time delays can be easily generated and components required for the time delay of the encoder and decoder system can be removed. Ring resonator for easy downsizing and integration An optical CDMA encoder and decoder comprising: an optical CDMA encoder for delaying and forming and encrypting transmission data converted into an optical signal in an optical waveguide according to a predetermined time code and a wavelength code; An optical CDMA decoder configured to correspond to the encoder to decrypt the encrypted optical signal; A ring resonator including a ring-shaped optical waveguide spaced apart from the optical waveguide by a predetermined distance so as to resonate and couple with the optical signal for generation of a speed and a time delay of the optical signal in the optical waveguides of the encoder and the decoder; Characterized in that formed.

OCDMA, time delay, encoder, decoder, ring resonator, optical coupling

Description

Optical CDMA encoder and decoder using ring resonator {Encoder and Decoder of Optical Code Devision Multiple Access Using Ring Resonator}

1 is a block diagram schematically showing an optical CDMA system using a ring resonator in accordance with the present invention.

2 is a conceptual diagram schematically showing an operation of an optical CDMA encoder using a time division ring resonator according to the present invention;

3 is a partially enlarged view for showing a time delay of an optical waveguide encoder using a ring resonator according to the present invention, which is part A of FIG.

4 is a conceptual diagram schematically showing the operation of an optical CDMA decoder using a time division ring resonator according to the present invention;

5 is a partially enlarged view for illustrating a time delay of an optical waveguide decoder using a ring resonator according to the present invention, which is a portion B of FIG.

          <Description of reference numerals for the main parts of the drawings>

1: optical CDMA system 20: optical transmitter

20a: light source 20b: encoder

20b ': ring resonator 40: optical receiver

40a: decoder 40a ': ring resonator

The present invention relates to an optical CDMA encoder and a decoder using a ring resonator, and more particularly, by forming a ring resonator to be spaced apart from an optical waveguide for changing a propagation constant by using an optical speed that is changed according to a propagation constant in an optical CDMA. And a digital signal proportional to the time delay of the single ring resonator by delaying the advancing speed and time of the incident optical signal of the encoder and decoder for encrypting and decrypting the transmission data and the reception data of the receiver and increasing the number of the ring resonators. It is possible to obtain a time delay, and to obtain a time delay that is proportional to the radius of the ring resonator, so that various time delays can be easily generated, and components required for the time delay of the encoder and decoder system can be eliminated. As a result, ring balls are easy to miniaturize and integrate encoders and decoders. An optical CDMA encoder and decoder using a true mechanism.

In general, Optical Code Division Multiple Access (hereinafter referred to as optical CDMA) allows for multiple access by code or asynchronous connection between users, so that optical LAN, optical exchange, subscriber network and station transmission, and infrared It is available in the field of wireless communication and the like, and provides a switching function different from the wireless communication in the entire system including a transmitter and a receiver by random access and self-routing by code in a spread spectrum region.

In addition, the optical CDMA spreads a band by a time or a wavelength, encrypts a signal, and receives and restores the signal. In the case of encrypting a signal by temporally dividing the signal, the optical CDMA has a separate optical path difference for each signal for time division and delay. Create a time delay.

However, when optical CDMA divides and encrypts an optical signal in time, separate optical path differences are generated in a transmitter and a receiver of the optical CDMA system for temporal division and delay, so that an encoder of a transmitter and a decoder of a receiver are used. (Decoder) has increased in size, and thus, integration and miniaturization are not easy, and additional costs are increased by generating a separate optical path difference.

The present invention has been made to solve the above problems, by forming a ring resonator to be spaced apart from the optical waveguide for changing the propagation constant by using the optical speed that is changed according to the propagation constant in the optical CDMA, the transmission data of the transmitter and the receiver and It is possible to delay the traveling speed and time of the incident optical signal of the encoder and decoder which encrypts and decrypts the received data, and by increasing the number of the ring resonators, a digital time delay proportional to the time delay of the single ring resonator can be obtained. Since a time delay proportional to the radius of the ring resonator can be obtained, various time delays can be easily generated, and components required for the time delay of the encoder and decoder system can be removed, thereby miniaturizing the encoder and the decoder. And CDMA Encoder Using Ring Resonators for Easy Integration And an object thereof is to provide a decoder.

In order to achieve the above object, the present invention provides an optical CDMA encoder for delaying and forming a transmission data converted into an optical signal in an optical waveguide according to a predetermined time code and a wavelength code; An optical CDMA decoder configured to correspond to the encoder to decrypt the encrypted optical signal; A ring resonator including a ring-shaped optical waveguide spaced apart from the optical waveguide by a predetermined distance so as to resonate and couple with the optical signal for generation of a speed and a time delay of the optical signal in the optical waveguides of the encoder and the decoder; Is formed.

The optical waveguide and the ring resonator may have the same width.

In addition, the ring resonator is characterized in that spaced apart from several micro to several tens of micro.

Here, the optical waveguide and the ring resonator may be spaced apart from several micros to several tens of micros.

In addition, the speed and time delay of the optical signal is characterized in proportion to the radius of the ring resonator.

Here, the speed and time delay of the optical signal is characterized in proportion to the number of the ring resonator.

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

1 is a block diagram schematically showing an optical CDMA system using a ring resonator according to the present invention. As shown in the figure, the optical network composed of the optical CDMA system 1 converts the data to be transmitted to the light source 20a, and encodes and transmits the encoder 20b for encoding and transmitting the light output from the light source 20a. And a combiner (not shown) for distributing the encoded optical signals received from the plurality of optical transmitters 20, a decoder 40a for decoding the received optical signals, and the optical transmitter ( And an optical receiver 40 including a determiner (not shown) for determining whether or not the data has been transmitted at 20).

Each subscriber of the optical network is connected to one optical transmitter 20 and an optical receiver 40, and each optical transmitter 20 or each optical receiver 40 is identified by a specific code. The optical transmitter 20 has a variable encoder 20b capable of producing optical signals that conform to this particular code, and the optical receiver 40 includes a fixed decoder 40a to receive only optical signals that conform to this code. Equipped.

In addition, the optical transmitter 20 includes optical signals that are encoded according to the type of the bits of the destination optical receiver 40 in the data bits to be sent through the encoder 20b, and combines at the center of the optical network ( Transmits to all optical receivers 40 through a not shown.

At this time, the optical signal is decoded by the decoder 40a in each of the optical receivers 40. In the optical receiver 40 as a destination, an optical signal having an intensity greater than or equal to a threshold value is detected, and other optical signals are detected. The receiver 40 receives the data bits in such a manner that an optical signal having an intensity less than or equal to a threshold value is detected.

FIG. 2 is a conceptual diagram schematically illustrating an operation of an optical CDMA encoder using a time division type ring resonator according to the present invention, and will be described with reference to FIG. 1. As shown in the figure, the data to be transmitted is changed to the light source 20a, and the light source 20a is incident on the encoder 20b of the transmitter, which is called an optical signal.

A method of dividing the incident optical signal into N pieces, delaying each power at regular time intervals, distributing them at regular time intervals, and encrypting time is illustrated.

Here, the incident optical signal is divided into N through 1 XN splitters, and each divided optical signal has a time delay of a predetermined time interval with respect to time, which is the first optical signal divided into N. (A) of part A will proceed without any time delay.

In addition, the (I) of the A portion, which is the second optical signal divided into N, after the 1 XN splitter, has a time delay Δτ shown in a circle, and the circle generally has a time delay ( time delay).

In addition, the optical signal having a time delay of the singular circle proceeds with a time delay Δτ than the optical signal of (a).

In addition, (C) of the A portion, which is the third optical signal divided into N, after passing through the 1 XN splitter, has two time delays (2 · Δτ) shown in two circles, and ( It has a time delay of Δτ over the optical signal of b) and a time delay of 2 · Δτ over the optical signal of (a).

In addition, (D) of the A portion, which is the N-th optical signal divided into N, after passing through the 1 XN splitter, is represented by N-1 circles, N-1 time delay (N-1 ) And have a time delay of (N-3) .Δτ than the optical signal of (C), and have a time delay of (N-2). In addition, the optical signal of (a) has a time delay of (N−1) · Δτ.

FIG. 3 is a partially enlarged view for illustrating the time delay of the optical waveguide encoder 20b using the ring resonator according to the present invention, which is part A of FIG. 2, and will be described with reference to FIG. As shown in the figure, in order to time-delay the incident optical signals separated into N, the optical waveguides are formed to be spaced apart from the optical waveguide in the encoder 20b by a predetermined interval, and formed in a ring shape using an optical coupling phenomenon. An in-ring resonator 20b may change the speed and time of the optical signal.

In addition, an optical signal having a wavelength satisfying a resonator condition is coupled to the ring resonator 20b, which is an optical waveguide, in the optical waveguide, and generates a delay for a predetermined time when proceeding to the ring resonator 20b. The optical signal generated by the delay of time is combined with the optical waveguide again and output.

And, the optical signal coupled to the ring resonator 20b has a delay of a certain time compared to the optical signal not coupled to the ring resonator 20b, and when the plurality of ring resonators 20b are arranged, Therefore, the proportional time delay can be digitally increased.

At this time, the non-linear proportional to the radius and radius of the ring resonator 20b.

Here, the incident optical signal is divided into N through 1 XN splitters, and each divided optical signal has a time delay of a predetermined time interval with respect to time, which is the first optical signal divided into N ( A) proceeds without any time delay, and thus does not cause any change in the optical waveguide, and the width of the optical waveguide is Wa.

In addition, the second optical signal divided by N after (1 XN) splitter (N) has a time delay (Δτ) shown in a circular shape, and thus changes the propagation constant that can change the speed of light. In order to achieve this, a ring resonator 20b ₁ ′ is formed such that a ring resonator having a width of Wa and a radius of R is spaced apart from the optical waveguide.

Here, the ring resonator 20b ₁ ′ and the optical waveguide are installed to be spaced apart from several μm to several tens of μm so as to exclude interference between the respective ring resonators 20b ₁ ′, and each ring resonator 20b. The interference is also provided so as to exclude the interference.

The optical signal having the time delay of the single ring resonator 20b ₁ ′ has a time delay of Δτ compared to the optical signal of (a).

In addition, the third optical signal (C), which is divided into N and passes through the 1 XN splitter, has two time delays (2 · Δτ) shown in two circles. It has a time delay of Δτ than the optical signal, and a time delay of 2 · Δτ than the optical signal of (a).

Here, two ring resonators 20b ₁ ′ and 20b ₂ ′ are formed so as to be spaced apart from the optical waveguide so as to generate a physical length of the optical waveguide through which the optical signal passes so as to cause a time delay of 2 · Δτ. Generate increasing optical coupling.

In addition, the N th optical signal divided by N through (1) is divided into N -1 circular and ring resonators 20b ₁ ′, 20b ₂ ′, 20b ₃ ′, ‥‥ 20b _{N −1} '), which is represented by _{N −1} ′), and has a time delay of (N−3) · Δτ than the optical signal of (C). The optical signal of (b) has a time delay of (N−2) · Δτ, and the optical delay of (a) has a time delay of (N −1) · Δτ.

At this time, the ring resonators 20b ₁ ′, 20b ₂ ′, 20b ₃ ′, ... 20b _{N − 1} ′ are formed with N − 1 spaced apart from the optical waveguide at a predetermined interval so that the optical signal is N − 1. The optical coupling causes an increase in the physical length of the optical waveguide through which the optical signal passes so as to cause a time delay of Δτ.

4 is a conceptual diagram schematically illustrating an operation of an optical CDMA decoder using a time division ring resonator according to the present invention, and will be described with reference to FIG. 1. As shown in the figure, an optical signal according to a time delay, which is received data, is incident to the decoder 40a of the optical receiver 40.

In the encoding of the encoder 20b, which is the encryption process of the optical transmitter 20, each power is delayed at predetermined time intervals, and distributed and passed through the 1 XN splitter. .

Then, a part A of the first optical signal divided into N parts of the optical transmitter 20 through 1 XN splitter is smaller than (D) of part A of the Nth optical signal. 1) Since it has a time delay of △ τ, it has a time delay of (N-1) · △ τ of B to compensate for the time delay of (N-1) · △ τ All.

In addition, the (I) of the A part, which is the second signal divided into N parts of the optical transmitter 20 through 1 XN splitter, is equal to (N-2) than the (D) of the A part which is the Nth optical signal. Since there is a time delay of Δτ, a time delay of (N-2) · Δτ is given to (b) of B to compensate for the time delay of (N−2) · Δτ.

After passing through a 1 XN splitter, (C) of the A portion, which is the third signal divided into N of the optical transmitter 20, (C) is smaller than (D) of the A portion, which is the Nth optical signal. Since there is a time delay of Δτ, a time delay of (N-3) · Δτ is given to (C) of B to compensate for the time delay of (N-3) · Δτ.

Finally, (D) of the A part, which is the Nth signal divided into N of the optical transmitter 20 after passing through a 1 XN splitter, is an Nth optical signal, so that it is decoded without any time delay. do.

As described above, the optical transmitter 20 compensates for the optical signal given a time delay, and compensates the optical signal for which the time delay is not applied. In the process of combining and decoding signals into one, noise according to decoding may be inserted.

FIG. 5 is a partially enlarged view for illustrating a time delay of an optical waveguide decoder using a ring resonator according to the present invention, which is part B of FIG. 4. It demonstrates with reference to FIG. As shown in the figure, an optical signal that is data that has been separated at a predetermined interval (Δτ) with respect to the incident time to the optical receiver 40 passes through a splitter of 1 XN, respectively divided optical signal Since the (A) part A has no time delay with respect to the time delay of the predetermined time interval, the ring resonator 40a ₁ 'by (N-1). , 40a ₂ ', 40a ₃ ', ..., 40a _{N -1} ', the ring resonator (40a ₁ ', 40a ₂ ', 40a ₃ ', ..., 40a _{N -1} ') is N- The width of the ring resonators 40a ₁ ′, 40a ₂ ′, 40a ₃ ′,..., 40a _N-1 ′ may be changed.

At this time, the radius of the ring resonators 40a ₁ ′, 40a ₂ ′, 40a ₃ ′, ..., 40a _{N −1} ′ may also be changed, and the time delay may be flexibly changed according to the circumference distance as the radius increases or decreases. Can be.

In addition, part (A) of part A, which is the second optical signal divided into N parts, is processed with a time delay of Δτ, passing through the 1 XN splitter, and thus, (N-2) ) Δτ as much as ring resonators 40a ₁ ′, 40a ₂ ′, 40a ₃ ′,..., 40a _{N − 2} ′, whereby the ring resonators are formed N − 2, the width of which is Wa, which is the same as the waveguide, has a radius of R and is compensated by Δτ than the (a) optical signal of the portion B so as to be spaced apart from the optical waveguide.

In this case, the width of the ring resonators 40a ₁ ', 40a ₂ ', 40a ₃ ', ..., 40a _{N- 2} ' is formed to be equal to the width Wa of the existing optical waveguide, the ring resonator 40a ₁ ', 40a ₂ ', 40a ₃ ', ‥‥, 40a _{N- 2} ' width can be changed, the ring resonator (40a ₁ ', 40a ₂ ', 40a ₃ ', ..., 40a _N-2 ' The radius of) can also be changed, and the time delay can be flexibly changed according to the distance of the circumference as the radius increases or decreases.

After the 1 XN splitter, (C) of the A portion, which is the second optical signal divided into N, has two ring resonators 20b ₁ ′ and 20b ₂ ′, Since there is a time delay, the ring resonators 40a ₁ ′, 40a ₂ ′, 40a ₃ ′, ‥‥, 40a _{N − 3} ′ as much as (N − 3). Here, the ring resonators (40a ₁ ', 40a ₂ ', 40a ₃ ', ..., 40a _{N- 3} ') is formed N-3, the width is increased Wb than Wa, the length is formed by △ L To compensate for the optical signal of part (b) of the B part by Δτ.

At this time, the width of the ring resonators 40a ₁ ', 40a ₂ ', 40a ₃ ', ..., 40a _{N- 3} ' is formed to be the same as the width (Wa) of the existing optical waveguide, the ring resonator (40a ₁₎ ', 40a ₂ ', 40a ₃ ', ‥‥, 40a _{N -3} ' width can be changed, the ring resonator (40a ₁ ', 40a ₂ ', 40a ₃ ', ..., 40a _N-2 ' The radius of) can also be changed, and the time delay can be flexibly changed according to the distance of the circumference as the radius increases or decreases.

In addition, (D) of the A portion, which is the second optical signal divided into N, is divided into N-1 ring resonators 20b ₁ ', 20b ₂ ', 20b ₃ ', ... 20b _{N -1} ') and has a time delay of (N-1) · Δτ, so that the ring resonator 40a is not formed so as not to have any time delay in (D) of the B portion, and the optical waveguide The width of the existing optical waveguide is formed as it is.

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 forms a ring resonator to be spaced apart from an optical waveguide for changing the propagation constant by using an optical speed that is changed according to the propagation constant in the optical CDMA, thereby transmitting data of the transmitter and the receiver and It is possible to delay the traveling speed and time of the incident optical signal of the encoder and decoder which encrypts and decrypts the received data, and by increasing the number of the ring resonators, a digital time delay proportional to the time delay of the single ring resonator can be obtained. Since a time delay proportional to the radius of the ring resonator can be obtained, various time delays can be easily generated, and components required for the time delay of the encoder and decoder system can be removed, thereby miniaturizing the encoder and the decoder. And easy to integrate.

Claims (6)

An optical CDMA encoder for delaying and forming and encrypting transmission data converted into an optical signal in an optical waveguide according to a predetermined time code and a wavelength code; An optical CDMA decoder configured to correspond to the encoder to decrypt the encrypted optical signal; Including but not limited to: The encoder and the decoder may include: a separator for dividing an input signal into N optical signals; And A ring resonator formed spaced apart from the optical waveguide at a predetermined interval and formed in at least one direction parallel to the optical waveguide for delaying the divided optical signal; Optical CDMA encoder and decoder using a ring resonator comprising a. The method of claim 1, And a width of the optical waveguide and the ring resonator is the same. The method of claim 1, And an optical CDMA encoder and decoder using a ring resonator, wherein the ring resonators are spaced apart from several micros to several tens of micros. The method of claim 1, An optical CDMA encoder and decoder using a ring resonator, wherein the optical waveguide and the ring resonator are spaced apart from several micros to several tens of micros. The method of claim 1, And a time delay of the optical signal is proportional to a radius of the ring resonator. The method of claim 1, And a time delay of the optical signal is proportional to the number of the ring resonators.

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