Terahertz Optical Asymmetric Demultiplexer Research Articles

PERFORMANCE ANALYSIS OF OPTICAL PARALLEL FULL ADDER USING ARTIFICIAL NEURAL NETWORK

A verbal exchange today wishes for quick operational progress. This can be accomplished by replacing devices that are primarily concerned with commutation and logic with photon-based systems instead of the usual data service, the electron. The basic building blocks of superior frames are called gates. With the aid of these gates, various logical and mathematical operations can be performed. All-optical arithmetical and logical processes are eagerly expected in high-speed dialogue frameworks. In this chapter, we’ve introduced parallel models for adding two binary digits that are based on Sagnac gates with help from semiconductor optical amplifiers (SOA) and terahertz optical asymmetric demultiplexers (TOAD). We created a Full adder that works in parallel using only two TOADs as total switches. Using artificial neural networks (ANN), we have created a model of this circuit that is equivalent. Utilizing ANN, this circuit design has been validated. This optical circuit is now capable of synthesizing light as an input and successfully structuring the aspiration output in addition to speeding up calculation. This parallel circuit’s biggest advantage is that it doesn’t need synchronization for distinct inputs. An ANN model was used to analyze this circuit’s performance in detail.

OPTICAL 4:1 MULTIPLEXER USING SAGNAC SWITCHES

This paper presents the design and implementation of an Optical 4:1 Multiplexer using Sagnac Switches as Terahertz Optical Asymmetric Demultiplexers (TOADs). Optical multiplexers play a crucial role in modern communication systems by combining multiple signals onto a single optical channel. The proposed multiplexer architecture leverages the benefits of Sagnac Switches, such as low insertion loss, high extinction ratio, and low crosstalk, along with TOADs to achieve efficient signal routing and demultiplexing. The design is evaluated through simulations, demonstrating its performance in terms of insertion loss, extinction ratio, and crosstalk. The experimental validation of the multiplexer verifies its effectiveness in real-world scenarios. The Optical 4:1 Multiplexer using Sagnac Switches as TOADs offers a promising solution for optical communication networks, enabling efficient signal multiplexing and demultiplexing while maintaining high data integrity and low signal degradation.

ALL-OPTICAL CARRY SKIP ADDER WITH THE HELP OF TERAHERTZ OPTICAL ASYMMETRIC DEMULTIPLEXER-BASED SWITCH

The terahertz optical asymmetric demultiplexer (TOAD) or semiconductor optical amplifier (SOA)-assisted Sagnac switches have been used to construct an all-optical 4-bit carry skip adder. This design aims to satisfy the high speed and accuracy requirements of modern ultrafast digital transmission. Using a combination of an all-optical multiplexer and an all-optical full adder, we describe an all-optical carry skip adder. When compared to ripple carry adder and carry look-ahead adder, carry skip adder may be employed to create a fast arithmetical processing unit. Numerical simulation is used to develop and validate this theoretical model.

Optical Multiplexer

In this paper, we present an all-optical multiplexer based on a Terahertz Optical Asymmetric Demultiplexer (TOAD) device. The TOAD is used as a nonlinear optical switch to selectively route optical signals based on their wavelength or frequency, allowing for the multiplexing of multiple optical channels onto a single fiber optic cable. We describe the design and implementation of the TOAD-based multiplexer, including the optical components and signal processing algorithms used to achieve high-speed, low-error-rate operation. We also present experimental results demonstrating the performance of the multiplexer, including its ability to maintain signal quality over long distances and under various noise and interference conditions. Our results show that the TOAD-based multiplexer offers a promising approach to all-optical multiplexing for high-speed, high-capacity optical communications systems.

Simultaneous all-optical 1's complement cum division-by-two schemes

Odd and even number detection is an important mathematical operation. Generally when any number is divisible by 2 then it is called an even number, otherwise, it is an odd number. Division by 2 can be easily obtained by putting a point before the least significant bit of any binary number. As an example a number (27)10 = (11011)2 when divided by 2 its result will be (1101.1)2 = (13.5)10. Hence when we find the fractional bit as logic-1 we can say that the number is odd, otherwise, it is even. This operation can be obtained by using a demultiplexer. Here we have developed an optical circuit that can divide any binary integer number by 2, apart from that its 1’s complement can also be obtained from the circuit. Both of the results can be obtained simultaneously. Terahertz optical asymmetric demultiplexer based switch plays a very important role to design this n-bit circuit. Numerical simulations are done to find the performance of the circuit.

OPTICAL PARALLEL HALF ADDER USING SEMICONDUCTOR OPTICAL AMPLIFIER-ASSISTED SAGNAC GATES

Today communication needs huge operational speed. This will be accomplished in case the conventional carrier of data, i.e. electron is supplanted by a photon for gadgets based on switching and logic. Gates are the basic building pieces of advanced frameworks. Different logic and arithmetic operations can be done using this gate. Optical logic and arithmetic operations are exceptionally much anticipated in high-speed communication frameworks. In this paper, we have presented parallel models to perform the addition of two binary digits based on terahertz optical asymmetric demultiplexer (TOAD)/semiconductor optical amplifier (SOA)-assisted Sagnac gates. Using only two TOAD-based switches we have designed a parallel half adder. This optical circuit increases the speed of calculation and is also capable of synthesizing light as an input to form the output. The most advantage of this parallel circuit is that no synchronization is required for distinctive inputs. The circuit is hypothetically planned and confirmed by numerical simulations.

Micro-ring resonator based all-optical Arithmetic and Logical Unit

Silicon photonics is achieving developments in optical computing and information processing. It necessitates the efficient design of Arithmetic Logic Unit (ALU) to perform optical micro-operations such as adder/subtractor, comparator. The earlier work reported for ALU design used Mach-Zehnder Interferometer (MZI), semiconductor optical amplifiers, terahertz optical asymmetric demultiplexer (TOAD) and beam splitter. These approaches make optical circuit larger in size and difficult to integrate with Very Large Scale Integrated Optics (VLSIO). Here, we propose an all-optical ALU exclusively using Micro-Ring Resonator (MRR) to perform addition and comparison. The use of MRR to design ALU makes the proposed design novel and easy to integrate with VLSIO. The operations performed are one-bit addition and one-bit comparison. Beam splitter is replaced by MRR which has resulted in low intensity losses. The performance of the proposed ALU is discussed with simulation results and calculated losses. The output is verified for different input combinations of the half adder and comparator with electric field intensity distribution using 1550 nm wavelength. More losses are observed in comparator circuit as compared to adder circuit. Low losses and less MRR makes ALU design optimized.

40 Gb/s quantum random number generation based on optically sampled amplified spontaneous emission

We present a photonic approach for fast quantum random number generation based on optically sampled amplified spontaneous emission (ASE). This approach utilizes a terahertz optical asymmetric demultiplexer to sample the ASE and then digitize the sampled optical pulses into random bits using a multi-bit parallel comparator. A proof-of-concept experiment demonstrates that 40 Gb/s random bits with verified randomness can be obtained using our method. The current generation rate is mainly limited by the bandwidth of the available ASE source.

All-optical Frequency Divider using TOAD based D-Flip-Flop

From the last few decades the optical communication has been established as much easier process than electrical communication. Many optical proposed circuits have already been suggested in many fields in support of this. The optical communication circuits demand frequency dividers capable of operating well above 10 GHz. Here, an all-optical frequency divider using terahertz optical asymmetric demultiplexer (TOAD) based D-flip-flop is proposed in the optical domain in a configuration exactly like the standard electronic setup. It presents a high-speed flip-flop-based frequency divider incorporating a new high-speed latch topology with satisfactory performance. The proposed all-optical frequency division scheme has been theoretically demonstrated in this paper. In this scheme the input and output binary digits are expressed as the presence (1) and the absence (0) of the light pulses. The performance of this proposed optical realization is evaluated by numerical simulation that confirms its feasibility in terms of the choice of the critical parameters.

Design and Analysis of X-OR Gate and 4-Bit Binary to 4-Bit Gray and Gray to Binary Code Converter Using Dual Control Dual SOA TOAD (DCDS-TOAD)

Background: In this paper we have design and analyzed 4-bit binary to 4-bit gray code and 4-bit gray to 4-bit gray code converter using dual control dual semiconductor optical amplifier terahertz optical asymmetric demultiplexer (DCDS-TOAD). We used control pulse as a Soliton pulse train. We calculate the extinction ratio, contrast ratio and Q value and found very high values. The high values of E.R., C.R. and Q value distinguishes the high (‘1’) level to the low(‘0’) very clearly also shown the variation of E.R., C.R. and Q value with control pulse energy and amplified spontaneous emission power factor. Methods: The basic equations governing the TOAD performance is simulated using MATLAB. The extinction ratio, contrast ratio and Q value are calculated for analysis of the device. Results: Results of operation for the code converters are performed at a bit rate of 100Gbps. The structure of DCDSTOAD enable us to achieve high values of ER(~ 81dB), CR(~83dB) and Q factor (86dB). A high Q factor shows very low bit error rate (BER). The eye diagram shows a large eye opening (REOP~98.5%). Conclusion: Design and analyzed 4-bit binary to 4-bit gray code and 4-bit gray to 4-bit gray code converter using dual control dual semiconductor optical amplifier terahertz optical asymmetric demultiplexer (DCDS-TOAD) is proposed and analyzed. We used control pulse as a Soliton pulse train. The proposed X-OR gate finds applications in many devices.

Design and performance analysis of all optical 4-bit parity generator and checker using dual-control dual SOA terahertz optical asymmetric demultiplexer (DCDS-TOAD)

Abstract Tera hertz optical asymmetric demultiplexer (TOAD) using two semiconductor optical amplifiers and two control signals has been used to design an all optical parity checker and generator. The same circuit can generate and check both even and odd parity using a control input. The numerical simulation using Matlab 2007b is done for performance analysis of the proposed device in terms of output bit pattern, amplified spontaneous emission (ASE) noise, extinction ratio, contrast ratio, pseudo eye diagram, relative eye opening (98.9% for 20 dB gain and 96.21% for 10 dB gain) and their variation with input control pulse energy, amplified spontaneous emission noise factor for different unsaturated gain. The simulated value of E.R. = 81.39 dB, C.R. = 83.15 dB, REOP = 98.9% and Q value = 86.16 dB are found for this proposal.

An alternative method for implementation of frequency-encoded logic gates using a terahertz optical asymmetric demultiplexer (TOAD)

All-optical frequency-encoded AND, OR, and NOT logic gates are proposed and their performance simulated to confirm their feasibility. Terahertz optical asymmetric demultiplexer (TOAD)-based logic gates with a control pulse energy as low as 50 fJ are used, and real-time simulations of their input and output pulse patterns reveal a rate of 20 Gbps. Such logic gates could be used for future all-optical logic processors for optical computation and communication systems.

All-Optical DFT Using TOAD-Based Cross-Bar Switches

The discovery of ultra-high-speed all-optical switches in the very recent past based on semiconductor optical amplifier (SOA) especially in the interferometric configuration is very pronouncing due to their features like high repetition rate, low power consumption, fast switching time, noise and jitter tolerance, being easily integrable and operationally versatile, thereby bringing a revolution in all-optical information processing systems. In this work, an all-optical computing tool namely SOA-based [Formula: see text] terahertz optical asymmetric demultiplexer (TOAD) is used because it can be employed to design more complex circuits and subsystems of enhanced combinational and sequential functionality. In this paper, (a) a switching network with its two switching actions and (b) an all-optical [Formula: see text] cross-bar network architecture, i.e., a multistage cube network for [Formula: see text] using TOAD-based [Formula: see text] optical cross-bar switch for discrete Fourier transform (DFT), are proposed. Numerical simulation of this work is done with OptiSystem v7.0 to evaluate the performance of the proposed circuit.

Full-Optical TOAD based Walsh-Hadamard code generation

Transmission of information takes place simultaneously over the same available channel bandwidth in Code Division Multiple Access (CDMA) technique. The spread spectrum (SS) technique is used in CDMA systems for transmission of information by employing spreading codes. A unique spreading code, acts as a signature code, is assigned for each individual user. The signal occupies a bandwidth much larger than the minimum necessary to send the information in SS modulation technique. A synchronized reception with the code at the receiver is applied for dispreading the information before the data recovery. From a long-term, Walsh-Hadamard codes have been employed as spread spectrum codes in CDMA communications due to their ease of generation. Walsh-Hadamard codes are absolutely orthogonal binary user codes which have so many favourite applications in synchronous multicarrier communications. However, the optical application of Walsh-Hadamard codes turns important for optical CDMA to solve the above problem. For this, the designs need the use of nonlinear optics capable of controlling multi-valued signals. To achieve this goal all-optical terahertz optical asymmetric Demultiplexer based design of Walsh-Hadamard codes is explored in this paper.

Chaotic laser-based ultrafast multi-bit physical random number generation without post-process

Random numbers have great application value in the fields of secure communications, which are commonly used as secret keys to encrypt the information. To guarantee that the information is absolutely secure in the current high-speed communication, the applied random keys should possess a generation speed not less than the encrypted data rate, according to one-time pad theory found by Shannon (Shannon C E 1949 Bell.Syst.Tech.J. 28 656) Pseudo-random numbers generated by algorithm may easily reach a fast speed, but a certain periodicity makes them difficult to meet the aforementioned demand of information security. Utilizing physical stochastic phenomena can provide reliable random numbers, called physical random number generators (RNGs). However, limited by the bandwidth of the conventional physical sources such as electronic noise, frequency jitter of oscillator and quantum randomness, the traditional physical RNG has a generation speed at a level of Mb/s typically. Therefore, real-time and ultrafast physical random number generation is urgently required from the view of absolute security for high-speed communication today. With the advent of wideband photonic entropy sources, in recent years lots of schemes for high-speed random number generation are proposed. Among them, chaotic laser has received great attention due to its ultra-wide bandwidth and large random fluctuation of intensity. The real-time speed of physical RNG based on chaotic laser is now limited under 5 Gb/s, although the reported RNG claims that an ultrafast speed of Tb/s is possible in theory. The main issues that restrict the real-time speed of RNG based on chaotic laser are from two aspects. The first aspect is electrical jitter bottleneck confronted by the electrical analog-to-digital converter (ADC). Specifically, most of the methods of extracting random numbers are first to convert the chaotic laser into an electrical signal by a photo-detector, then use an electrical ADC driven by radio frequency (RF) clock to sample and quantify the chaotic signal in electronic domain. Unfortunately, the response rate of ADC is below Gb/s restricted by the aperture jitter (several picoseconds) of RF clock in the sample and hold circuit. The second aspect comes from the complex post-processes, which are fundamental in current RNG techniques to realize a good randomness. The strict synchronization among post-processing components (e.g., XOR gates, memory buffers, high-order difference) is controlled by an RF clock. Similarly, it is also an insurmountable obstacle to achieve an accurate synchronization due to the electronic jitter of the RF clock. In this paper, we propose a method of ultrafast multi-bit physical RNG based on chaotic laser without any post-process. In this method, a train of optical pulses generated by a GHz mode-locked laser with low temporal jitter at a level of fs is used as an optical sampling clock. The chaotic laser is sampled in the optical domain through a low switching energy and high-linearity terahertz optical asymmetric demultiplexer (TOAD) sampler, which is a fiber loop with an asymmetrical nonlinear semiconductor optical amplifier. Then, the peak amplitude of each sampled chaotic pulse is digitized by a multi-bit comparator (i.e., a multi-bit ADC without sample and hold circuit) and converted into random numbers directly. Specifically, a proof-of-principle experiment is executed to demonstrate the aforementioned proposed method. In this experiment, an optical feedback chaotic laser is used, which has a bandwidth of 6 GHz. Through setting a sampling rate to be 5 GSa/s and selecting 4 LSBs outputs of the 8-bit comparator, 20 Gb/s (=5 GSa/s4 LSBs) physical random number sequences are obtained. Considering the ultrafast response rate of TOAD sampler, the speed of random numbers generated by this method has the potential to reach several hundreds of Gb/s as long as the used chaotic laser has a sufficient bandwidth.

Fully photonics-based physical random bit generator.

We propose a fully photonics-based approach for ultrafast physical random bit generation. This approach exploits a compact nonlinear loop mirror (called a terahertz optical asymmetric demultiplexer, TOAD) to sample the chaotic optical waveform in an all-optical domain and then generate random bit streams through further comparison with a threshold level. This method can efficiently overcome the electronic jitter bottleneck confronted by existing RBGs in practice. A proof-of-concept experiment demonstrates that this method can continuously extract 5Gb/s random bit streams from the chaotic output of a distributed feedback laser diode (DFB-LD) with optical feedback. This limited generation rate is caused by the bandwidth of the used optical chaos.

Design of optical switching devices using all-optical half adder based on terahertz optical asymmetric de-multiplexer

This paper provides a detailed study to design and simulate all-optical half adder using terahertz optical asymmetric demultiplexer (TOAD). The effect of the semiconductor optical amplifier parameters on the operation of TOAD is studied. Through the use of the designed all-optical half adder unit, design of all-optical full adder, S-R flip flop, 1 bit random access memory (RAM) and 4 × 4 RAM are proposed. The contrast ratio, extinction ratio and amplitude modulation values are analyzed for all-optical half adder. The performance of all the proposed designs is investigated at 10 Gbps by using OptiSystem simulation software.

All-optical TOAD based new binary sequence generator

Spread-spectrum communication, with its inherent interference attenuation capability, has over the years become an increasingly popular technique for use in many different systems. In multiuser environment, Gold sequences are an important class of sequences that allow construction of long sequences. To achieve this goal, a modified Gold code generator in all-optical domain using semiconductor optical amplifier based terahertz optical asymmetric demultiplexer (TOAD) is explored in this paper. All-optical Gold code generator circuit realization is TOAD based D flip-flop and exclusive-OR logic gates in a configuration analogous to the standard electronic setup, with properties similar to that of both Gold and Kasami sequences. It is compatible with a multichannel direct sequence spread spectrum system. Numerical simulation confirmed the circuit’s feasibility and performance in terms of the choice of the critical parameters. However, the proposed sequence generator circuit is more complex than the existing Gold sequence generator, but it is less complex than the Kasami sequence and has performance better than both.

All-optical pseudorandom bit sequences generator based on TOADs

Abstract A scheme for all-optical pseudorandom bit sequences (PRBS) generator is demonstrated with optical logic gate ‘XNOR’ and all-optical wavelength converter based on cascaded Tera-Hertz Optical Asymmetric Demultiplexer (TOADs). Its feasibility is verified by generation of return-to-zero on–off keying (RZ-OOK) 263-1 PRBS at the speed of 1 Gb/s with 10% duty radio. The high randomness of ultra-long cycle PRBS is validated by successfully passing the standard benchmark test.

Optical Arithmetic Operation Using Optical Demultiplexer

Using Terahertz Optical Asymmetric Demultiplexer (TOAD) based switch we have designed all-optical parallel half adder and full adder. The approach to design this all-optical arithmetic circuit not only enhances the computational speed but also is capable of synthesizing light as input to produce desire output. The main advantage of parallel circuit is synchronization of input which is not required. All the circuits are designed theoretically and verified through numerical simulations.