Four-wave Mixing Effect Research Articles

All optical multi‐functional signal processing scheme for D8PSK and DQPSK format using four‐wave mixing in semiconductor optical amplifiers

AbstractIn this article, a multifunctional optical processing unit for differential eight phase‐shift‐keying (D8PSK) and differential quadrature phase‐shift‐keying (DQPSK) based on four‐wave mixing (FWM) effects in semiconductor optical amplifier (SOA) is proposed. All‐optical wavelength conversion, D8PSK‐to‐DQPSK format conversion and signal encryption of 10‐Gbaud DQPSK and D8PSK optical signals are achieved simultaneously by simulation. Detailed theoretical analysis and simulation results are conducted to verify the feasibility of the scheme. The Q factor of the electrical signals and the bit error rate recovered from wavelength and format converted components are approximated to be around 6, and 10−9, which indicates the feasibility of the scheme. For the encrypted signal, the FWM effect of another SOA is utilized to decrypt the encrypted signal, and the encryption function of 10‐Gbaud DQPSK and D8PSK optical signals is also verified.

All-Optical Aggregation and De-Aggregation Between 8QAM and BPSK Signal Based on Nonlinear Effects in HNLF

An all-optical aggregation and de-aggregation scheme between one 8-ary quadrature amplitude modulation (8QAM) signal and three binary phase shift keying (BPSK) signals is proposed and theory simulated based on nonlinear effects in high nonlinear fiber (HNLF). In this scheme, the input 8QAM signal is de-aggregated into three BPSK signals by deploying self-phase modulation (SPM), cross-phase modulation (XPM), four wave mixing (FWM) and parameter amplification (PA) effect. Firstly, an improved amplitude compression loop (ACL) is designed based on SPM effect to convert 8QAM signal into quadrature phase shift keying (QPSK) signal. A degenerate phase sensitive amplifier (PSA) based on FWM effect is used to decompose QPSK signal into the first two BPSK signals (BPSK-1 and BPSK-2). The third BPSK signal (BPSK-3) can be extracted from the probe light modulated in its phase by the input 8QAM signal thanks to XPM and PA effect. Secondly, BPSK-3 is converted into an atypical on-off keying (OOK) signal through a 1-bit delay interference (DI). BPSK-1 and BPSK-2 are recombined into one QPSK signal through a coupler. Finally, the recombined QPSK signal and the atypical OOK signal are aggregated into one 8QAM signal by using XPM and PA effect. The error vector magnitude (EVM) and bit error ratio (BER) of the 8QAM and BPSK signal before and after de-aggregation and aggregation are calculated to analyse the performance of the scheme. The scheme can be applied in the network node to connect different networks which explore to use 8QAM and BPSK signal respectively.

Generation of four-wave mixing with nonlinear Vanadium-carbide (V2C)-deposited side-polished fiber (SPF) in 1.5- and 2.0-µm wavelength operation

In this work, we report the use of V2C-deposited SPF as a nonlinear device for the generation of four-wave mixing (FWM) effect in 1.5- and 2.0-µm wavelength operation. The FWM-based system was able to generate idlers at 1.5- and 2.0-µm with a peak conversion efficiency of –44 dB and –41 dB and had a maximum tuning range of 5.5 nm and 12 nm respectively. The nonlinear optical properties of V2C MXene were studied by Z-scan analysis, where V2C had a nonlinear absorption coefficient, β and nonlinear refractive index, n2 of (5.95 ± 5.18)×10-8 m/W and (-2.43 ± 4.93)×10-20 m2/W. The experimental results demonstrated that V2C-deposited SPF was effectively employed as a nonlinear device to induce the FWM effect.

Utilization of slow light enhancement of four-wave mixing within a silicon photonic crystal for microwave frequency measurement purposes

We report the demonstration of an instantaneous frequency measurement system based on the four-wave mixing (FWM) effect in short dispersion engineered slow-light silicon photonic crystal waveguides for RF frequency measurement purposes within a range of 10 MHz to 80 GHz. Three nonlinear media were investigated including 3 mm ridge waveguide, 80 µm nanowire, and 80 µm photonic crystal (PhC). The system size could thus be decreased, and as a result system integration would become possible. We have shown that the optical power required to excite FWM is low enough to remove any need for optical amplification, and hence the system noise floor will be kept low. Issues due to the amplifier saturation will also be resolved this way. As a result, no noise reduction system, like lock-in amplification, would be required. A better system latency will also be achieved accordingly. The system dynamic range would also be improved in two ways. First, due to the low noise floor, and second, because of removing any optical amplifier that possibly could become saturated at higher power levels. All three media behaviors were simulated by the split step Fourier method, and the results showed that the best medium to be used is PhC.

A New Suppression approach of FWM Crosstalk Effect in Optical Communication Link based on Polarization combiner Method

To meet the growing needs of internet data, optical communication systems have become the backbone of modern communications networks. At the present time, the dense wavelength division multiplexing (DWDM) technique has been used to increase the number of channels, but the nonlinear effects have a great impact that limits the performance of doubling the DWDM system. The four wave mixing (FWM) is the most harmful and dangerous as the effect of FWM increases on the system the greater the optical connection distances. The new approach of pairing groups of different optical signals was investigated to suppress the FWM effect. The simulation was conducted for an 8-channel system with a total data rate (80Gb/s). A comparative study was conducted on the suppression of FWM by the difference in the power inputs (-0.5 to 20) dBm. The robustness of the proposed technique was examined using two forms of modulation (Carrier Suppressed Return to Zero (CSRZ) and Duo Binary Modulation class -1(DBM-1)) techniques, with optical fiber system of (1,2,5) spans, each of length 60 Km, with spacing between the channels 50GHz. The power of FWM was significantly reduced with the CSRZ & DBM-1 techniques to less than (47.97%, 41.38 %) respectively, at an input power of 12.5 dBm. The performance of the proposed system with the polarization technique was improved by the rate of the quality factor (Q-factor of (91.59%, 78.67%) for the same sequence of modulation.

Robust Optical Frequency Comb Generation by Using a Three-Stage Optical Nonlinear Dynamic

In this article, we propose and investigate a novel scheme to generate optical frequency combs (OFCs) by using a three-stage generator, which is based on optical injection–induced dynamics cascaded by subharmonic electro-optic modulation and the four-wave mixing (FWM) effect. A primary seed OFC is rooted from the nonlinear dynamics in the optically injected semiconductor laser, and its performance is improved using a two-stage booster based on subharmonic electro-optic modulation and the FWM effect. The comb spacing can be easily tuned by adjusting that of the primary seed OFC or through electro-optic modulation by the use of subharmonics with different orders. Moreover, it becomes stabilized because the phase relationship between the comb teeth can be fixed in the process of subharmonic electro-optic modulation. Its optical spectrum continues to be broadened in the following FWM process. Finally, robust OFCs with a comb spacing of 4 GHz and a comb teeth number of 23 and a comb spacing of 5 GHz and a comb teeth number of 21 are experimentally demonstrated.

Multiuser 4×10 Gb/s bidirectional transmission with wavelength conversion using a single SOA

We investigate a transparent wavelength conversion based on four-wave-mixing (FWM) in semiconductor optical amplifier. We verify the effectiveness of the proposed scheme by analyzing the spectra and bit error rate. Then, we set up a 10-Gb / s single-user and 4 × 10 Gb / s multiuser transmission by Optisystem and discuss their performance. The simulation results show that the FWM effect between the two waves achieves a 2.4-nm wavelength conversion. At BER = 10 − 3 level, for single-user transmission the sensitivities of downstream (DS) and upstream (US) reach −23.6 and −23.4 dBm, and for multiuser transmission the sensitivities of DS and US reach −23.9 and −23.8 dBm, respectively.

Optical chaotic communication using correlation demodulation between two synchronized chaos lasers

This paper theoretically investigates the scheme of optical chaotic communication based on correlation demodulation between two synchronized semiconductor lasers. In the scheme, a semiconductor laser (SL) system, which is subject to phase conjugation and electro-optical phase modulation feedback, generates optical chaos with high-complexity, simultaneously, the time-delay (TD) signature can be well concealed. We use the digital signal “0” and “1” to control the chaotic signal’s switching between two arms of electro-optical (E-O) switch to indirectly achieve spreading spectrum. Concretely, for the “0” bit, at the cross arm the waveform of the optical chaotic signal is reversed by utilizing the cross gain modulation (XGM) effect of semiconductor optical amplifier (SOA); for the “1” bit, the chaotic signal is exchanged from the cross arm into the through arm. Based on the four-wave mixing (FWM) effect of optical parameter amplifier (OPA), the optical chaotic signal is converted to the same center wavelength as SOA’s output, and then two chaotic sequences are coupled into a channel in turn, as a results, the power of the signal of 5 Gbit/s is uniformly distributed and expanded to about 23.45 GHz bandwidth, thus its power spectrum density (PSD) becomes very low. We numerically demonstrate that this chaotic dynamics between the transmitter and the receiver can be identically synchronized due to coupling. The results indicate that the novel correlation-demodulation-based optical chaotic communication scheme can tolerate a higher noise level, and it can achieve a high-quality communication under lower signal-to-noise ratio (SNR). Compared with the scheme of synchronized error monitor, the correlation demodulation way has better ability for anti-noise interference.

Mid-infrared broadband all-optical wavelength converter in Ge20Sb15Se65 photonic crystal fiber with flattened dispersion

A chalcogenide photonic crystal fiber (PCF) with flattened dispersion and high nonlinearity in mid-infrared (mid-IR) based on a triangular and circular lattice hybrid cladding structure is proposed. The structural parameters of the PCF are optimized by the full-vectorial finite-difference method. The numerical simulation results show: when d1 = 0.4 µm, d2 = 0.16 µm, d3 = 0.04 µm, Ʌ1 = 0.88 µm, Ʌ2 = 0.8 µm, Ʌ3 = 0.5 µm, the flatten and low dispersion is obtained in the wavelength range of 3.8–5 µm. The dispersion value is between ± 1.2 (ps/nm/km), and the maximum nonlinear coefficient is as high as 2464.2 km-1 W-1 at 2.5 µm. Based on the four-wave mixing (FWM) effect in the proposed PCF, the all-optical wavelength conversion performance is numerically analyzed. When the pumping wavelength is 4.02 µm, the 3 dB conversion bandwidth can reach 4833 nm (from 2.737 µm to 7.57 µm), and the maximum wavelength conversion efficiency is 12.12 dB. The proposed all optical wavelength converter is having large bandwidth and high conversion efficiency in mid-IR band due to the flat dispersion and high nonlinearity of the PCF, which has potential application in future space optical communication network and mid-IR photonic.

Generation of four-wave mixing in molybdenum ditelluride (MoTe2)-deposited side-polished fibre

In this work, we report the effect of four-wave mixing (FWM) in MoTe2 deposited on a side-polished fibre (SPF). The MoTe2 layer has a nonlinear coefficient of 17.368 W−1 km−1 at 1550 nm, while the coated SPF has a conversion efficiency of – 38 dB and output tuning range of 5 nm. The generated idlers from the induced FWM effect were observed to be highly stable with minimal peak fluctuations and only minor changes in their measured conversion efficiency. The proposed MoTe2 based SPF is thus a suitable device for inducing the FWM effect in an optical fibre laser cavity and could also serve to induce other non-linear optical effects for use in optical communications networks.

Palliation of Four-Wave Mixing in Optical Fibers Using Improved DSP Receiver

A long haul optical communication system (LHOCS) is one of the key resources to fulfill the higher capacity requirements in future communication networks. To launch LHOCS, the system mainly faces high order nonlinear effects. The four-wave mixing (FWM) is one of the major nonlinear effects, which limits the transmission distance. Therefore, in this paper, an advanced duo-binary (DB) modulation scheme-based system is evaluated by employing an improved digital signal processing (IDSP) approach at the receiver side to suppress the FWM effect. In addition, an analytical analysis is also performed for the proposed system. To observe the difference between the IDSP and conventional digital signal processing (DSP), the various performance metrics such as bit error rate (BER), Q-factor, and optical signal-to-noise ratio (OSNR) parameters are evaluated. Variable channel spacing along with polarization mode dispersion (PMD) are analyzed at several ranges of input powers and fiber lengths. The analytical and simulation-based calculations exhibit the effectiveness of the proposed model and hence, FWM effect are compensated to achieve 500 km optical fiber propagation range with a BER below 10−6.

All-Optical Non-Inverted Parity Generator and Checker Based on Semiconductor Optical Amplifiers

An all-optical non-inverted parity generator and checker based on semiconductor optical amplifiers (SOAs) are proposed with four-wave mixing (FWM) and cross-gain modulation (XGM) non-linear effects. A 2-bit parity generator and checker using by exclusive NOR (XNOR) and exclusive OR (XOR) gates are implemented by first SOA and second SOA with 10 Gb/s return-to-zero (RZ) code, respectively. The parity and check bits are provided by adjusting the center wavelength of the tunable optical bandpass filter (TOBPF). A saturable absorber (SA) is used to reduce the negative effect of small signal clock (Clk) probe light to improve extinction ratio (ER) and optical signal-to-noise ratio (OSNR). For Pe and Ce (even parity bit and even check bit) without Clk probe light, ER and OSNR still maintain good performance because of the amplified effect of SOA. For Po (odd parity bit), ER and OSNR are improved to 1 dB difference for the original value. For Co (odd check bit), ER is deteriorated by 4 dB without SA, while OSNR is deteriorated by 12 dB. ER and OSNR are improved by about 2 dB for the original value with the SA. This design has the advantages of simple structure and great integration capability and low cost.

Four-Wave Mixing Effect and Its Security Implications on a WDM System

The data yearning of the world is expanding massively with time and it is convincing media transmission organizations tomount up procedures to satisfy the high information need just as giving a proficient support. During the exponentialdevelopment of data hungry clients, media transmission organizations fantasize about giving nature of administrations ata lower cost to their clients to endure the challenge in the market. Transmitting products of signs through a solitary directin perspective on serving a huge number of clients all the while by wavelength division multiplexing (WDM) is theappropriate response. Four-wave multiplexing (FWM) is the optical sign float from one channel to the next. This impacthas the inclination of forcing a danger on the fiber correspondence organize consequently undermining the security andsecrecy of the data sent by the clients. In this work, FWM impact and its security issues are broken down. The differentTangle lab reenactment consequences of this FPM is contemplated utilizing optical.
 Citation: Anita Antwiwaa, Seth Okyere-Dankwa, Mensah Sitti and Anil Kumar, Four-Wave Mixing Effect and Its SecurityImplications on a WDM System, 2020; 5(4): 1－11.
 Received: October 3, 2020Accepted: December 31, 2020

Effect of four-wave mixing on the loss budget of four-channel multiplexing NG-PON systems

In this study, the loss budget for adopting non-return-to-zero (NRZ) and four-level pulse amplitude modulation (PAM4) in next-generation passive optical networks (NG-PONs) was investigated by simulation and experiment. Through simulation, the signals are distorted by four-wave mixing (FWM) when the zero-dispersion wavelength locates in the middle of the channels. For 25-Gb/s NRZ, a maximal loss budget of approximately 32.5 dB is obtained. For 50-Gb/s PAM4, the bit error rate cannot reach 1 × 10−3. While, the impact becomes negligible whens the zero-dispersion wavelength stays away from the middle of the channels, and the loss budget is 36 and 25.7 dB for NRZ and PAM4 systems. Therefore, at least a 32.5-dB loss budget ise obtained in a 4 × 25G NRZ system. While, the loss budget cannot reach the basic requirement of 29 dB in the 4×50G PAM4 system. The experimental resultso verify this conclusion.

Supervised regression modelling for mitigation of four-wave mixing in dense wavelength-division multiplexing systems

A recent global crisis associated with COVID-19 has encouraged millions of people to work from home, thus causing a drastic increase in overall network traffic, data-rate requirements and end network capabilities. This has also produced more noise, cross-talk and undesirable optical-fibre nonlinearities, especially a four-wave mixing (FWM) effect that deteriorates performance of dense wavelength-division multiplexing (DWDM) systems. A presence of FWM in the DWDM systems imposes increasing complexity and latency of networks, and decreases their spectral efficiency. In its turn, this degrades efficient utilization of optical bandwidth. To mitigate the above problems, we suggest a supervised regression modelling (SRM). A relevant SRM-DWDM approach performs self-parametric optimization of the DWDM systems with machine-learning techniques and finds real trade-offs among various factors that affect the FWM. Our model reduces complexity of modelling and computational time, resulting in accurate and reliable prediction of parameter values. We also evaluate the performance of our SRM-DWDM technique by comparing its data with the iterative results obtained for different parameters (e.g., output signal-to-noise ratio, Q-factor, signal power and noise power). Finally, we specify the procedures necessary for global optimization of DWDM systems

Suppression of four wave mixing effect in DWDM system

Abstract This article discusses the nonlinear effect, four-wave mixing (FWM), which lowers the performance of optical communication systems. The concept of orthogonal polarization was introduced to reduce the effects of FWM. Here, orthogonal polarization is used with various modulation techniques such as NRZ, RZ, GAUSSIAN and RAISED COSINE. Orthogonal polarization was found to reduce the effect of FWM more than round polarization. Weaknesses of the four wavelength mixes were analyzed for various levels of input power. The capacity of a four-wave mixing product (FWM) is assessed by an optical spectrum analyzer. System performance is analyzed in terms of quality factors and BER.

Au coated ZnO/MWCNTs nanocomposites film-induced four-wave-mixing effect for multi-wavelength generation in erbium-doped fiber laser

High optical nonlinearity of nanostructured materials has been attested as a reliable technique for the generation of a multi-wavelength fiber laser. Herein, we experimentally demonstrate a simple and efficient method for generating continuous-wave (CW) multi-wavelength erbium-doped laser (EDFL) using a nonlinear effect of four-wave mixing (FWM) in a highly nonlinear nanocomposite film. A nanocomposite film containing gold nanostars coated zinc-oxide nanorods/multi-walled carbon nanotubes (ZnO-NRs@Au NSs/MWCNTs) embedded in polyvinyl alcohol (PVA) polymer was prepared, characterized, and then incorporated into the laser cavity to induce the FWM effect. Benefiting from the FWM processes, the induced intensity-dependent gain alleviates the intense gain-competition in the EDFL and increases the number of lasing wavelengths. A five-lasing line with a side mode suppression ratio (SMSR) of 36.3 dBm has been observed by appropriately adjusting the pump strength to 300 mW. Repeated measurements verified the high stability of the laser operating at room temperature with less than 3 dBm fluctuations on output power and 0.21 nm lasing wavelength drifts for all wavelengths cases. To the best of the author’s knowledge, this is the first demonstration of multi-wavelength fiber laser utilizing ZnO-NRs@Au NSs/MWCNTs nanocomposite. The results reveal the excellent nonlinear optical properties of the prepared nanocomposite and lay a foundation for its application in the generation of a multi-wavelength fiber laser.

Generalized Darboux transformation and the higher-order semirational solutions for a non-linear Schrödinger system in a birefringent fiber

Temporal birefringent effects in the fibers change the crosstalk behaviors inside and between the fiber cores in the linear and non-linear optical power areas. This paper studies a non-linear Schrödinger system with the four-wave mixing term, which describes the optical solitons in a birefringent fiber. We construct the generalized Darboux transformation, and acquire the higher-order semirational solutions consisting of the second- and third-order semirational solutions, which represent the complex amplitudes of the electric fields in the two orthogonal polarizations. We acquire the interactions between/among the two/three solitons. Such interactions are elastic and generate the rogue waves around the interacting regions. We obtain the interactions among the second-/third-order rogue waves and two/three solitons, respectively. When [Formula: see text] decreases, amplitude of the second-order rogue wave increases, with [Formula: see text] and [Formula: see text] accounting for the self-phase modulation and cross-phase modulation, respectively, while [Formula: see text] representing the four-wave mixing effect. With [Formula: see text] kept invariant, when [Formula: see text] increases and [Formula: see text], amplitudes of the second-order rogue wave and two bright solitons increase, while when [Formula: see text] increases and [Formula: see text], amplitudes of the second-order rogue wave and two dark solitons increase, with [Formula: see text] and [Formula: see text] being the constants.

Modulation instability analysis and optical solitons in birefringent fibers to RKL equation without four wave mixing

In this present work, we retrieve the optical solitons in birefringent fibers modeled by Radhakrishnan-Kundu-Lakshmanan (RKL) equation in coupled vector form. The system is composed of self-phase, cross-phase modulation terms, self-steepening terms and the effect of four-wave mixing is discarded. In this article, by employing innovative integration norms known as the extended rational sine-cosine/sinh-cosh techniques different forms of optical solitons like dark, singular, combined and complex soliton solutions are recovered. Furthermore, singular periodic wave solutions are also observed. The constraint conditions which ensure the formation of soliton solutions are also specified. By using the suitable values of the parameters involved, the 2-, 3-dimensional and the contour graphs of some of the reported solutions are plotted. The stability of the given model is studied by exercising the modulation instability analysis which confirms that the model is stable and guarantees that all extracted solutions are stable and exact.

Verification of All-Optical Regeneration with Hybrid Modulation and with On-Off Keying Modulation with Return to Zero and Non-Return to Zero Coding

In this work we study the non-linear effects through the analysis of the operating results of three alloptical 3R regeneration (re-amplifying, re-shaping and re-timing) under the effects of cross-phase modulation (XPM) and four-wave mixing (FWM), being a system with hybrid modulation and two other communication systems with modulation on-off keying (OOK) with return to zero (RZ) and non-return to zero (NRZ) coding. The main part of the 3R regeneration system proposed here is a Mach-Zehnder interferometer (MZI) composed of an acousto optical filter (AOF) and a highly nonlinear photonic crystal fiber (HNL-PCF), so the system proposed here was named 3R-MZIAOF regenerator. The comparison of the system results occurred through the variation of the input power variation from -10 dBm to 10 dBm for the link length of 121.3 km and transmission rate 10 Gbps. The results showed that the regeneration 3R scheme OOK-NRZ with AOF presented excellent values of bit error rate (BER) equal to 10-21 and quality factor (Q-Factor) equal to 9.4, when compared to a system with OOK-NRZ 3R regeneration and hybrid modulation.