KR100523871B1 - Emboding Equipment and Its Method for an all-optical NOR gate using gain saturation of a semiconductor optical amplifier - Google Patents

Abstract

The present invention relates to an all-optical NOR logic device realization apparatus and method using the gain saturation characteristics of a semiconductor optical amplifier, and more particularly, to an optical signal transmitted from any point of the optical circuit, such as optical computing, pump signal and irradiation signal The present invention relates to a device for implementing a 10Gbit / s all-optical NOR logic device among logic devices and a method of implementing the same.

In the method of implementing the all-optical NOR logic device of the present invention, the A + B signal, which is the sum of the input signal pattern A of 1100 and the input signal pattern B of 0110, is used as the pump signal 1110 and is clocked into the input signal pattern A of 1100. A signal is generated and used as the irradiation signal 1111, and the irradiation signal and the pump signal are incident on the semiconductor optical amplifier (SOA) at the same time in the opposite direction to Boolean logic expression. It is characterized by obtaining.

The all-optical NOR logic device according to the present invention has a simple structure because it is implemented by the cross gain modulation (XGM) method using the gain saturation characteristics of the semiconductor optical amplifier, and the all-optical logic devices having different functions can be configured in the same way. And it is expected to play an important role in the implementation of the light system.

Description

Embodiment of an all-optical NOR logic device using gain saturation of semiconductor optical amplifier and its method {Emboding Equipment and Its Method for an all-optical NOR gate using gain saturation of a semiconductor optical amplifier}

The present invention relates to an all-optical NOR logic device realization apparatus and method using the gain saturation characteristics of a semiconductor optical amplifier, and more particularly, to an optical signal transmitted from any point of the optical circuit, such as optical computing, pump signal and irradiation signal The present invention relates to a device for implementing a 10Gbit / s all-optical NOR logic device, and a method of implementing the same, among logic devices that perform all-optical logic operations.

Recent trends show that the demand for higher speed and higher capacity of systems is growing exponentially.

Many systems today are mostly based on silicon materials, or electrical signals, and the future dependence is uncertain because of the large barriers to speed and information processing limitations.

On the other hand, indium phosphide (InP) -based optical devices are expected to solve the above problems in all aspects of speed and information processing capacity.

In general, when a system is constructed, a method of integrating based on a single logic element (AND, OR, XOR, NAND, NOR, NXOR) is used, even in a system using light.

Logic elements with two stable states, called logic zeros and ones, are the basic building blocks of a digital computer.

Computers symbolize all information by these two bits.

Therefore, all-optical logic devices will certainly play an important role in the development of all-optical systems and photo-electric systems for future information technology.

To date, all-optical logic devices for ultra-fast optical information processing have been made using nonlinearity of light or wavelength conversion.

In particular, all-optical NOR logic devices utilizing the nonlinear gain of a semiconductor optical amplifier (SOA),

(One). NOR using a single-arm ultrafast nonlinear interferometer (UN) [N. S. Patel, K. L. Hall, and K. A. Rauschenbach, Opt. Lett., 21, 1466 (1996)],

(2). All-optical NOR [A. Sharaiha, H. W. Li, F. Matchese and J, Le Bihan, Electron. Lett., 33, 323 (1997)],

(3). All-optical NOR using Pump Signals with Two Different Wavelengths [Byun Young-tae, Kim Sang-hyuk, Kim Dong-hwan, Woo Deok-ha, Kim Sun-ho, Saephyl, 40, 560 (2000); Young Tae Byun, Sang Hyuck Kim, Deok Ha Woo, Seok Lee, Dong Hwan Kim, Sun Ho Kim, "Apparatus ane Method for Realizing All-Optical NOR Logic Device", Patent No. (US 6,424,438 B1), Date of Patent (Jul. 23, 2002)],

(4). And all-optical NOR (Ali Hamie, Ammar Sharaiha, Mikael Guegan, and Benoit Pucel, IEEE Photon. Technol. Lett., 14, 1439 (2002)) implemented by connecting two semiconductor optical amplifiers.

As shown in (1), the all-optical NOR logic device using UNI has the advantage of high operating speed, but its core components are complicated as optical fiber devices and difficult to integrate with other devices, making it difficult to apply to optical operation systems requiring high integration. it's difficult.

On the other hand, all-optical logic devices using a single SOA have the advantages of being stable, small in size, easy to combine with other optical devices, and not dependent on polarization and wavelength [T. Fjelde, D. Wolfson, A. Kloch, B. Dagens, A. Coquelin, I. Guillemot, F, Gaborit, F. Poingt, and M. Renaud, Electron. Lett., 36, 1863 (2000)].

However, if only non-linear characteristics of a single SOA are used without an optical fiber interferometer, the structure of an all-optical NOR device is simple and can be integrated with other devices, but its operation speed is less than 100 MHz.

Also, as shown in (4), the all-optical NOR device implemented by connecting two SOAs has the characteristic of improving ON / OFF ratio at a wider wavelength than using a single SOA, but has a disadvantage of low operation speed of 62.5 MHz. have.

That is, in the conventional all-optical NOR logic elements (2)-(4) that do not use an optical fiber interferometer, the pump signal is a non-return to zero (NRZ) using a square wave. Pattern), and the probe signal is a continuous wave (CW) laser light is used.

In this case, the operating speed of the all-optical NOR logic device is limited to less than 100 MHz because of the NRZ pattern and continuous wave (CW) type.

Therefore, there is an urgent need for the development of an all-optical NOR logic device having a simple structure, integration with other optical devices, and an operation speed of several GHz to several tens of GHz.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described necessity, and an object of the present invention is to provide a technique for implementing a 10 Gbit / s all-optical NOR logic device using gain saturation characteristics of a semiconductor optical amplifier.

In order to achieve the above object, the present invention uses the A + B signal, which is the sum of the input signal pattern A of 1100 and the input signal pattern B of 0110, as the pump signal 1110 and clocks the input signal pattern A of 1100. A signal is generated and used as the irradiation signal 1111, and the irradiation signal and the pump signal are incident on the semiconductor optical amplifier (SOA) at the same time in the opposite direction to Boolean logic expression. An object of the present invention is to provide a method for implementing an all-optical NOR logic device using gain saturation of a semiconductor optical amplifier.

In order to achieve the above object, the present invention provides a pump signal realization means that uses the input signal pattern A of 1100 and the input signal pattern B of 0110 to generate an A + B signal that is the sum of input signals and uses the pump signal 1110 as the pump signal 1110;

Irradiation signal realization means for generating a clock signal from the input signal pattern A of 1100 and using it as an irradiation signal 1111;

The irradiation signal and the pump signal are simultaneously incident to the semiconductor optical amplifier (SOA) in the opposite direction by a Boolean logic formula An object of the present invention is to provide an all-optical NOR logic device using a gain saturation of a semiconductor optical amplifier including a NOR implementation means.

Hereinafter, the configuration and operation of the present invention will be described with reference to the accompanying drawings.

1 conceptually illustrates the operation principle of a new all-optical NOR logic device.

In the present invention, both the probe signal and the pump signal are made of a return to zero (RZ) pattern signal to improve the operation speed.

When a pump signal having a high light intensity enters the SOA, carrier depletion occurs in the SOA.

Therefore, the output signal has a logic opposite to that of the pump signal since the irradiation signal in the form of a pulse of a certain period is modulated and output in the SOA in the same manner as gain modulation due to carrier depletion.

However, when the pulse signal is used, the on-off difference of the pulse is so large that the output signal is very small in the absence of the pulse signal and can be regarded as 0.

Therefore, when there is no pulse signal of the irradiation signal, the output signal becomes 0 regardless of the pump signal.

2A and 2B are basic configuration diagrams and NOR logic tables of an all-optical NOR logic element.

In FIG. 2A, it is assumed that the signal is turned ON when there is a pulse and OFF when there is no pulse. When the pump signal is turned OFF, the clock signal passes through the SOA and the output signal turns ON.

Therefore, as shown in FIG. 2A, when the A and B signals are combined and then injected into the SOA in the opposite direction together with the clock signal, a Boolean logic expression that is the NOR value of the A and B signals. Is obtained.

This coincides with the Boolean value of the NOR logic element truth table shown in FIG. 2B, meaning that the all-optical NOR logic element can be implemented using a single SOA.

3 is an implementation diagram of an all-optical NOR logic device.

The input signal patterns A and B of the all-optical NOR logic element are made of a mode-locked fiber laser (MLFL) with a wavelength of 1550 nm.

The mode locked fiber laser (MLFL) is driven at 2.5 GHz with a period of 400 ps by a pulse generator (PG).

The width of the generated pulse is about 38 ps.

The output of the mode locked fiber laser (MLFL) is controlled by a variable delay (VD1), which is a delay means to obtain a time delay of 100 ps after being separated by the first 50:50 fiber coupler (FC1). Input signal pattern A (1100) operated at 10 Gbit / s by passing through an attenuator (ATTN1) and a polarization controller (PC1), which are then means, and then combined with a second 50:50 fiber optic coupler (FC2) Is generated.

The upper fiber at the output of the second 50:50 fiber coupler FC2 is separated from the fourth 50:50 fiber coupler FC4.

The incident light 1100 of the upper optical fiber passes through the variable delay unit VD2, which is a delaying means, to obtain a time delay of 100 ps, thereby making an input signal pattern B 0110, and the incident light 1100 of the lower optical fiber is adjusting means. It passes through the phosphor polarization controller PC2 and the optical attenuator ATTN2.

The output light B of the upper optical fiber and the output light A of the lower optical fiber are combined in the fifth 50:50 optical fiber combiner FC5 to generate the sum of the input signal patterns A and B and A + B 1110. do.

On the other hand, after the input signal pattern A 1100 coupled to the lower optical fiber of the second 50:50 optical fiber coupler FC2 is separated from the sixth 50:50 optical fiber coupler FC6, the incident light 1100 of the upper optical fiber is 200 ps. Passing through the variable retarder (VD3) is a delay means to obtain a time delay of the incident light, the incident light 1100 of the lower optical fiber through the polarization controller PC3 and the optical attenuator (ATTN3) control means the seventh optical fiber coupler (FC7) By adding together, the clock signal pattern 1111 is made.

The pump signal pattern A + B 1110 of the upper optical fiber of the fifth 50:50 optical fiber coupler (FC5) output stage is amplified by an erbium-doped optical fiber amplifier (EDFA) and passed through the optical circulator (C). 50 The optical fiber coupler FC7 is incident on the semiconductor optical amplifier SOA in a direction opposite to the irradiation signal pattern of the optical fiber above the output terminal.

An optical filter is required to separate the irradiation signal when the irradiation signal and the pump signal having different wavelengths are incident on the SOA in the same direction [Young Tae Byun, Jae Hun Kim, Young Min Jeon, Seok, Deok Ha Woo, and Sun Ho Kim, "An All-Optical OR Gate by using casacaded SOAs," 2002 International Topical meeting on Photonics in Switching, Hyatt Regency (Cheju Island, KOREA), 187 (2002).].

However, when the two signals are incident on the semiconductor optical amplifier (SOA) in the opposite direction, not only an optical filter is required but also the wavelength of the irradiation signal and the pump signal may be the same.

In this case, a Boolean logic expression having a 0001 pattern in which the gain of the A + B signal is modulated by the gain saturation characteristic of the semiconductor optical amplifier S0A. Signal is obtained.

In the present invention, the case where the wavelengths of the irradiation signal and the pump signal are the same is exemplified. However, even when the wavelengths are different, the operation of the all-optical NOR logic element can be obtained by the above method.

Unmarked Symbol ISO is an optical deflector, PD is a photodetector, and OSC is an oscilloscope.

4 is a diagram showing characteristics of an all-optical NOR logic device operated at 10 Gbit / s.

4A is an input signal pattern A having a pattern of 1100 measured at the third 50:50 fiber coupler FC3, and FIG. 4B is an input signal having a pattern of 0110 measured at the front end of the fifth 50:50 fiber coupler FC5. Pattern B, FIG. 4C is the sum of input signal patterns A and B measured at the lower optical fiber of the fifth 50:50 optical fiber coupler FC5, A + B, and FIG. 4D is a seventh 50:50 optical fiber coupler (FIG. FC7) This is the pattern of the clock signal measured on the optical fiber below the output.

4E is an output waveform generated when the A + B pattern 1110, which is the sum of two input signal patterns, passes through the semiconductor optical amplifier SOA in a direction opposite to the clock signal pattern 1111 as the irradiation signal. 0), (1,1) and (0,1) do not have output light, and only (0.0) output light exists.

Therefore, it is confirmed that the operating characteristics of the all-optical NOR logic element are realized when the light intensity of the irradiation signal and the pump signal is 0.3 dBm and 10.8 dBm, respectively.

Each of the above mentioned optical signals was measured using a 45 GHz photodetector and sampling oscilloscope.

As described above, according to the present invention, four logic signals [(1,0), (1,1), (0,1), by two input signal patterns A (1100) and B (0110) of the same wavelength Pump signal pattern A + B signal having (0,0)] is obtained, and after the input signal pattern A (1100) is separated, one signal is delayed by 200 ps and summed with the other signal (A). The in clock signal 1111 is obtained.

In addition, a 10 Gbit / s all-optical NOR logic device has been successfully implemented due to gain saturation characteristics of the SOA when the pump signal and the irradiation signal pass through the semiconductor optical amplifier (SOA) in opposite directions.

That is, the output signal is logic 1 only when both the A signal having the 1100 pattern and the B signal having the 0110 pattern are logic 0, and all of the output signals have logic 0 except for the other.

This result is consistent with the truth table of the Boolean NOR in FIG. 2B, so the invention of the all-optical NOR logic device is experimentally demonstrated.

Therefore, according to the present invention, an all-optical logic operation can be easily implemented on a complicated optical circuit of the optical computing and all-optical signal processing system.

All-optical NOR logic devices, along with other single all-optical logic elements (OR, NAND, AND, XOR, and NXOR), are essential logic components in optical computing or all-optical signal processing systems.

NOR is a key element of the full adder, the basis of all logic calculations, and applies to almost all logic systems.

In particular, since the all-optical NOR logic device according to the present invention is implemented by the cross gain modulation (XGM) method using the gain saturation characteristics of the semiconductor optical amplifier, the structure is simple, and the all-optical logic devices of other functions may be configured in the same way. It is expected to play an important role in the implementation of all-optical circuits and all-optical systems.

Therefore, if the integrated technology of efficient all-optical logic devices is developed, it is possible to control all systems using only optical signals without relying on electrical signals.

1 is a characteristic diagram showing an operation principle of an all-optical NOR logic element.

2A and 2B are a basic diagram and a truth table of an all-optical NOR logic element.

3 is a block diagram of a device for implementing an all-optical NOR logic device according to the present invention.

4 is a characteristic diagram of an all-optical NOR logic device operating at 10 Gbit / s in accordance with the present invention.

<Description of the symbols for the main parts of the drawings>

ATTN1, ATTN2, ATTN3: Optical Attenuator C: Optical Circulator

EDFA: Erbium-doped fiber amplifier FC1,... , FC7: Fiber Optic Coupler

ISO: optically deflective tube MLFL: mode locked fiber laser

OTDM MUX: Optical Time Division Multiplexer

OSC: Oscilloscope PC1, PC2, PC3: Polarization Controller

PD: Photodetector PG: Pulse Generator

SOA: Semiconductor Optical Amplifier VD1, VD2, VD3: Variable Delay

Claims (14)

A first step of dividing the presence or absence of an optical pulse into 1 and 0 and using the A + B signal, which is the sum of the input signals of the input signal pattern A of 1100 and the input signal pattern B of 0110, as the pump signal 1110; A second step of generating a clock signal using the input signal pattern A of 1100 and using it as an irradiation signal 1111; A third step of simultaneously injecting the irradiation signal and the pump signal into a semiconductor optical amplifier (SOA) in opposite directions; And Boolean logical expression that is a logical value of NOR by the incident signal A method for implementing an all-optical NOR logic device using gain saturation of a semiconductor optical amplifier comprising a fourth step of obtaining a. The method of claim 1, wherein the pump signal, The modulation waveform of the mode-locked fiber laser is multiplexed to form an input signal pattern A of 1100, and the input signal of 1100 is time-delayed to form an input signal pattern B of 0110, and the sum of the two input signals obtained using the fiber coupler is A. A method for implementing an all-optical NOR logic device using gain saturation of a semiconductor optical amplifier, characterized in that the + B signal. The method of claim 2, wherein the mode-locked fiber laser operates at 2.5 GHz, has a wavelength of 1550 nm, and multiplexes at 10 Gbit / s. The method according to claim 2, wherein the delay time of the 1100 input signal is 100 ps. The method according to claim 1, wherein the irradiation signal, And a clock signal obtained by multiplexing the 1100 input signal pattern A and multiplexing the non-delayed input signal pattern A. The method of claim 1, wherein the gain saturation of the semiconductor optical amplifier is performed. The method of claim 5, wherein the delay time of the 1100 input signal is 200 ps. The all-optical NOR logic device using gain saturation of a semiconductor optical amplifier according to claim 1, wherein both the irradiation signal and the pump signal are incident on the SOA in the form of a pulse so that a NOR logic device is implemented by a cross gain modulation (XGM) method. Way. The method according to any one of claims 1, 2, and 5, wherein wavelengths of the irradiation signal and the pump signal are different from each other. A pump signal realization means for dividing the presence or absence of an optical pulse by 1 and 0, using the input signal pattern A of 1100 and the input signal pattern B of 0110 to make an A + B signal, which is a sum of input signals, to use as a pump signal 1110; Irradiation signal realization means for generating a clock signal from the input signal pattern A of 1100 and using it as an irradiation signal 1111; The irradiation signal and the pump signal are simultaneously incident to the semiconductor optical amplifier (SOA) in the opposite direction by a Boolean logic formula An all-optical NOR logic device implementation using gain saturation of a semiconductor optical amplifier comprising a NOR implementation means to obtain. The method of claim 9, wherein the pump signal implementing means, Pattern A implementation means for multiplexing the modulated waveform of the mode locked fiber laser (MLFL) to form an input signal pattern A of 1100, Pattern B implementation means for delaying the input signal of 1100 to form an input signal pattern B of 0110; An apparatus for implementing an all-optical NOR logic element using gain saturation of a semiconductor optical amplifier, comprising: A + B implementation means for generating an A + B signal which is a sum of two input signals obtained by using a fifth optical fiber coupler. The method according to claim 10, wherein the pattern A implementation means, A mode locked fiber laser driven by a pulse generator to output light of a predetermined wavelength; A first optical fiber combiner for separating output light of the mode locked fiber laser; A first variable retarder for delaying output light of one side separated by the first optical fiber coupler, A first optical attenuator and a first polarization controller for controlling the output light of the other side separated by the first optical fiber coupler; And an optical fiber coupler configured to combine the delayed output light and the adjusted output light. The method according to claim 11, wherein the pattern B implementation means, A fourth optical fiber combiner for separating the output of the third optical fiber combiner connected to the output of the second optical fiber combiner; A second variable retarder delaying output light of one side separated from the fourth optical fiber coupler; And a second optical attenuator for controlling the output light of the other side separated from the fourth optical fiber coupler, and a second polarization controller. The method according to claim 9, The irradiation signal implementing means, A sixth optical fiber coupler separating the output of the input signal pattern A of 1100; A third variable retarder for delaying output light of one side separated by a sixth optical fiber coupler, A third optical attenuator and a third polarization controller for controlling the output light of the other side separated by the sixth optical fiber coupler; And a seventh optical fiber combiner for combining the delayed output light and the adjusted output light. The method according to claim 9, The NOR implementation means, Erbium-doped fiber amplifier (EDFA) for amplifying the pump signal, An optical circulator for incident the amplified pump signal to one side of a semiconductor optical amplifier; When the pump signal is incident on one side and the irradiation signal is incident on the other side, a Boolean logic expression having a 0001 pattern in which the gain of the pump signal is modulated by gain saturation characteristics. An all-optical NOR logic device implementation using gain saturation of a semiconductor optical amplifier, characterized in that consisting of a semiconductor optical amplifier.