Traveling-wave Semiconductor Optical Amplifier Research Articles

An approach to generate cross-polarization modulation-enabled optical frequency comb with enhanced spectral flatness in traveling-wave semiconductor optical amplifiers

Abstract This paper proposes a method for generating an optical frequency comb (OFC) using the cross-polarization modulation (XPolM) effect in a traveling-wave semiconductor optical amplifier (TW-SOA). The TW-SOA acted as a lumped amplifier, enabling pulse generation within the comb. The proposed method of OFC generation achieved a comb spectrum with 51 lines and a maximum power deviation of 1.8 dB, indicating excellent spectral flatness. The proposed approach effectively utilized XPolM in a TW-SOA to create broad flat OFCs. The effectiveness of XPolM depends on various SOA parameters, such as pump and signal powers, and the confinement factor. To understand the XPolM-enabled OFC behavior, various parameters, such as input polarization, bias current, SOA confinement factor, and carrier density, have been optimized. These parameters significantly influenced the generated comb spectrum. This study also provides valuable insights into optimizing comb characteristics through theoretical analysis. The proposed OFC generation was simulated using an OptiSystem simulator. This has paved the way for the potential use of the comb as a multichannel source in various optical devices.

Analytical modeling and bit sequence impact investigation of XPM-SMZI-induced nonlinear crosstalk in 4 × 4 interconnect

This paper presents an analytical model of the origin of nonlinear crosstalk induced by the XPM-SMZI (Cross-Phase Modulation-Symmetric Mach–Zehnder Interferometric) phenomenon occurring in the TWSOA (Traveling Wave Semiconductor Optical Amplifier). We analyze the variation of nonlinear crosstalk with increasing logic levels and length of the input bit sequence. The investigation shows that alteration in high and low logic of bit sequence engenders changes in cross-phase modulation occurring in TWSOA and hence brings nonlinear crosstalk into the picture. The performance is evaluated on 4×4 switching interconnect with a TWSOA cavity length of 500[Formula: see text][Formula: see text]m, a width of 3[Formula: see text][Formula: see text]m, and a height of 0.8[Formula: see text]nm with 0.15[Formula: see text]A injection current in SMZI configuration operating at 10[Formula: see text]Gbps. The performance of the switch is also tested by comparing various combinations of bit logic inputs. The degradation is observed in the quality of service with an increase in the number of ‘1’s in bit sequence. The Extinction Ratio (ER) also deteriorates when a logic ‘1’s appears at consecutive places. This impairment in ER can be controlled by bias conditions of TWSOA. The promising crosstalk of [Formula: see text][Formula: see text]dB has been achieved and is further validated by comparing with previously reported techniques.

Unidirectional hybrid diode laser through the integration of a hook-shaped traveling-wave semiconductor optical amplifier and Taiji ring resonator.

We demonstrate a unidirectional ring diode laser based on hybrid integration of a hook-shaped traveling-wave semiconductor optical amplifier (SOA) and a Taiji ring resonator. The additional crossover bending waveguide inside the silicon nitride Taiji ring introduces a non-reciprocal loss in the laser cavity while the gain is provided by a multiple depth etched hook-shaped SOA. We present the detailed design flow for both active and passive components of the unidirectional hybrid diode laser. This work paves the way to use a hook-shaped SOA-based hybrid platform for various applications including optical sensing, all-optical switching, photonic memories, and topological optics.

Enhancement of traveling wave semiconductor optical amplifier approach for DWDM communication system

In this study, the high performance of dense wavelength division multiplexing (DWDM) by using a traveling wave semiconductor optical amplifier (TW-SOA) at a channel spacing of 100 GHz is investigated, in terms of (Q-factor, injected current, transmitted power, gain). The Optisystem software is employed to send the different range of input power over the different ranges of the TW-SOA injected current with optimized TW-SOA parameters. The data rate of trans- mission optical signal up to 300 Gb/s at -35 dB input signal power have been investigated. The better results have been measured of the information signal with high quality and gain, when the range of input power is corresponding to the optimized range of injected current for the signal to be transmitted effec- tively. The present communication also supports various numbers of users with the same data rate of 5 Gb/s which is used to check the high quality of the signal in the receiver.

Optical transceiver communication systems performance evaluation based on nonlinear cross gain modulation effects

Abstract The aim of study is to simulate the impact of nonlinear cross gain modulation effects on optical transceiver communication systems with wide band traveling wave semiconductor optical amplifiers (WBTWSOAs). The max Q and electrical power against active amplifier length variations are simulated without/with nonlinear cross phase modulation (XPM) effect. We have been simulated the optimum Q Factor and BER at various data rate up to 160 Gbps with nonlinear cross phase modulation effect at the optimum active amplifier length of 300 μm. Also the optimum sig. power versus time and spectral wavelength is clarified with nonlinear CPM effect at the optimum active amplifier length. The total electrical power (TEP) and total optical power (TOP) are reported with nonlinear CPM effect at the optimum active amplifier length.

Conventional/linear/Lorentzian material gain semiconductor optical amplifiers performance signature with four wave mixing (FWM) nonlinearity in optical fiber communication systems

Abstract This study demonstrates the FWM nonlinearity effects on fiber systems based on conventional/linear/Lorentzian material gain wide band traveling wave semiconductor optical amplifiers (WBTWSOAs) at data rates of 10 Gbps. Max signal power (MSP) and noise power (NP) levels are illustrated versus time and SW after WDM multiplexer. The MSP and min NP are clarified against time and SW based conventional, linear, Lorentzian material gain WBTWSOAs. The total optical power after WDM multiplexer, and the total optical power based conventional, linear, Lorentzian material gain WBTWSOAs are measured. Max Q versus time after receiver based WDM multiplexer, and max Q versus time after receiver based conventional, linear, Lorentzian material gain WBTWSOAs are reported clearly in this study. Besides the max Q against CS is studied with/without FWM effects. Nonlinear coefficient, conversion efficiency is analyzed clearly against fiber length without/with FWM effects.

Hybrid NRZ/RZ line coding scheme based hybrid FSO/FO dual channel communication systems

<p><span id="docs-internal-guid-52ae510c-7fff-0f9d-c23b-ec77d8fd1141" style="font-size: 9pt; font-family: 'Times New Roman'; color: #000000; background-color: transparent; font-weight: 400; font-style: normal; font-variant: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">This </span><span id="docs-internal-guid-22aadf85-7fff-c447-0533-2748148ff46b" style="font-size: 9pt; font-family: 'Times New Roman'; color: #000000; background-color: transparent; font-weight: 400; font-style: normal; font-variant: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">study simulates the hybrid non return to zero (NRZ)/return to zero (RZ) line coding scheme based hybrid free space optics (FSO)/fiber optics (FO) dual channel communication systems. The max Q factor/Min BER are simulated after APD receiver based both erbium doped fiber amplifiers (EDFAs) and wide band traveling wave semiconductor optical amplifiers (WBTWSOAs) with 50 km fiber channel and 4 km FSO channel. Max SPAL/min noise SPAL, max signal power amplitude/min noise signal power variations with spectral frequency, and the total electrical power are demonstrated and clarified in this proposed study. This work emphasized that the fiber channel is reached up to 100 km reach and FSO channel can be also extended to 4 km reach with 40 Gbps.</span></p>

Simulative study on the cascaded stages of traveling wave semiconductor optical amplifiers based multiplexing schemes for fiber optic systems improvement

Abstract This study has outlined the performance analysis of the cascade traveling-wave optical amplifier (Semiconductor optical amplifier [SOA]) with multiplexing techniques based on fiber communication transceiver systems. The maximum Quality factor is measured against signal power. Signal input power level is enhanced by using the suggested model with previous model. The low pass Bessel filter removes the unwanted ripples from the original signal. The suggested model has clarified better performance efficiency than the previous model.

All Optical Bidirectional Wavelength Conversion Using Single Wide Band Traveling Wave Semiconductor Optical Amplifiers

Wavelength division multiplexing (WDM) is a very important technique to utilize the bandwidth of optical fiber. At different network nodes, it's requires to add or drop wavelength. The wavelength converter, responsible for converting the wavelength of signal, to another wavelength up or down from the original value. This paper presents a proposed model to generate inverted and non-inverted wavelength conversion by using single wide band traveling wave semiconductor optical amplifier (WBSOA), based on cross gain modulation (XGM). The investigation of conversion efficiency (η) and quality factor (Q) , versus pump power ranging from -30 dBm to 0 dBm, and input signal power of 0 dBm with data rate 25 Gb/s, studies for up and down wavelength conversion co-propagation and counter-propagation respectively, along c-band. All simulations in this study are performed by optisystem ver. 7.

Bandwidth characteristics of TWSOA based inline detector configurations for near infrared communications

Travelling Wave-Semiconductor Optical Amplifier (TWSOA) based 1.55 µm inline detectors are analyzed for their bandwidth characteristics under simultaneous amplification mode. Four different configurations of inline detector are considered for this study and they are full length, short length, multisection and optimum differential electrode based detector configurations. From the numerical solutions of rate equation, it is found that the short length configuration provides a bandwidth of 3 GHz and responsivity of 1650 V/W at − 20 dBm input power, compared to full length and multisection configurations. Optimum differential configuration has the best responsivity characteristics of 3600 V/W at 100 mA at − 20 dBm input power and provides two fold improvement in detection voltage than the best scheme reported earlier. However the bandwidth saturates for higher powers. For applications which demands greater responsivity with considerable bandwidth, the optimum differential configuration could be used. Applications those require higher dynamic bandwidth characteristics, the short length configuration and multi electrode configuration could be useful.

Single Wide Band Traveling Wave Semiconductor Optical Amplifiers for All Optical Bidirectional Wavelength Conversion

Abstract Wavelength division multiplexing (WDM) is a very important technique to utilize the bandwidth of optical fiber; multiple channels can be transmitted in the same fiber cable at the same time, and each channel has individual wavelength. At different network node, it’s required to add or drop wavelength, wavelength converter process is a technique responsible for converting the wavelength of signal to other wavelength up or down from the original value. This paper has presented a proposed model to generate inverted and non-inverted wavelength conversion by using single wide band traveling wave semiconductor optical amplifier (WBSOA), based on cross-gain modulation. The investigation of conversion efficiency (η) and quality factor (Q), versus pump power ranged value from −30 to 0 dB m, and input signal power is 0 dB m with data rate 25 Gb/s, are studied for up and down-wavelength conversion, “co-propagation” and “counter-propagation”, respectively. The simulation results indicate that, to get maximum conversion efficiency and maximum quality factor by using single WBSOA, the pump power should be located between −30 to −20 dB m for maximum conversion efficiency and equal to −10 dB m for maximum quality factor, that for up- and down-wavelength conversion, co-propagation and counter-propagation.

Design of high-speed 10-Gb/s wired/FSO systems for local area communication networks for maximum reach

This paper presents the numerical simulation studies of upgraded system for single-mode fiber (SMF wired)/free space optics (FSO wireless) under high-speed operation of 10 Gb/s. Further, the maximum reach of the system is analyzed based on various advanced modulation techniques, namely phase frequency shift keying (CPFSK), quadrature amplitude modulation, differential phase-shift keying, frequency shift keying, pulse amplitude modulation and different optical amplifiers, namely erbium-doped fiber amplifier, traveling wave semiconductor optical amplifier and parametric optical amplifier, respectively. The overall system studies are done by optiwave system software through which bit error rate and Q-factor are studied. The trade-off between different all-optical amplifiers and modulation techniques is studied to show the enhancement of upgrading system. The simulation results show that the maximum reach of distance belongs to CPFSK modulation scheme.

Lossless WDM PON Photonic Integrated Receivers Including SOAs

The role of a semiconductor optical amplifier (SOA) for amplifying downstream traffic at optical network terminals (ONT) within a silicon-photonics integrated receiver in a high capacity passive optical network (PON) is investigated. The nearly traveling wave SOA effects are evaluated by considering fabrication and link loss constraints through numerical analysis and experimental validation. The impact of hybrid integration of a SOA chip on a silicon on insulator (SOI) photonic chip using the flip chip bonding technique on SOA design is evaluated through numerical analysis of a multi section cavity model. The performance of the proposed ONT receiver design employing twin parallel SOAs is evaluated experimentally on a 32 × 25 Gb/s OOK WDM transmission system considering cross gain modulation (XGM) and amplified spontaneous emission (ASE) constraints. The XGM impact is evaluated through 32 channel wavelength division multiplexing (WDM) transmission and a likely PON worst case scenario of high channel power difference (~10 dB) between adjacent channels. The impact of ASE is evaluated through the worst-case polarization condition, i.e., when all of the signal is coupled to only one. Successful transmission was achieved in both worst-case conditions with limited impact on performance. SOA results indicate that a maximum residual facet reflectivity of 4 × 10−4 for the chip-bonded device can lead to a power penalty below 2 dB in a polarization-diversity twin SOAs receiver.

Tunable laser based on a semiconductor optical amplifier of red spectral region

A tunable laser containing a recently developed travelling wave semiconductor optical amplifier (SOA) of the red spectral region as an active element and an acousto-optic tunable filter in an external fibre ring cavity is studied. Continuous wavelength tuning was achieved within a spectra band up to 20 nm wide with a rate up to 104 nm s−1 at a spectral linewidth below 0.04 nm and a cw output power up to 2 mW. The use of one more similar SOA as an output power amplifier made it possible to increase the output power to 15 mW.

Comparative Analysis of Various Wavelength Division Multiplexed PON Standards

Abstract In this investigation comparison of various Passive optical networks (PON) standards has been done. Bidirectional fiber to home architecture is projected which simultaneously transmits the video and audio signals. The system uses travelling wave semiconductor optical amplifier with injection current of 0.45 A for both upstream and downstream channels. This architecture is investigated for a distance of 40 km and it accommodates 96 users. Further the effect of varied distance and power on Q-factor of system is investigated.

Suitable Optical Fiber Communication Channel for Optical Nonlinearity Signal Processing in High Optical Data Rate Systems

Our research presents best candidate different commercial optical fiber communication channel for optical nonlinearity signal processing in high optical transmission bit rate systems in the presence of traveling wave semiconductor optical amplifier (TW-OSA). These optical fibers that are namely dispersion flattened fiber (DFF), reverse dispersion fiber (RDF), non zero dispersion shifted fiber, dispersion compensated fiber, single mode fiber, and hybrid RDF + DFF. Wavelength division multiplexing (WDM) system is employed to benefit 80 users with the high transmission bit rates up to 160 Gb/s over optical fiber communication channel length up to 200 km with trying to reduce nonlinearity effects by choosing suitable channel spacing and first or second order Bessel, Gaussian WDM Mux./Demux filter. Maximum peak power, optical signal to noise ratio, and signal quality factor can be measured to test the system performance. It is evident that RDF and hybrid RDF + DFF has presented the highest signal quality factor and optical nonlinearity signal processing in compared with other optical fibers communication channel. The obtained results were done using optiwave system software simulation version 7.

Photonic processing of all‐optical Johnson counter using semiconductor optical amplifiers

This study presents a novel design of Johnson counter using D flip-flops. The performance of D flip-flop is carried out by exploiting the cross-gain modulation effect in semiconductor optical amplifier (SOA), purging the use of components like polarisation controllers, switches and so on. Performance is evaluated in terms of various variants like operational speed, cost effectiveness of design, rise time/fall time, quality of signal received and the system is found to give better results in terms of extinction ratio even without any feedback path. The Johnson counter or twisted ring counter is implemented using three all-optical D flip-flops producing six states. The D flip-flop incorporates travelling wave SOA and all-optical NOT gate. The proposed counter is reasonably valuable as it desires half of the flip-flops in association to other ring counters which directly reduce the cost of the system.

Design and optimization of novel two inputs optical logic gates (NOT, AND, OR and NOR) based on single commercial TW-SOA operating at 40 Gbit/s

This work demonstrates and optimizes novel simple design of two inputs all optical logic gates (NOT, AND, OR and NOR) using cross gain modulation technique at 40 Gbit/s. The proposed scheme differs from the previous conventional systems as utilizing only one commercial traveling wave-semiconductor optical amplifier (TW-SOA) and detuning optical band pass filter in order to select the appropriate output rather than using more than one SOA in addition to erbium-doped fiber amplifiers. This scheme overcomes the main problem appeared in the conventional schemes that suffer from the amplified spontaneous emission which considered as an additional noise that degrades output optical signal to noise ratio. Optimization process was done to achieve remarkable BER, Q-factor and acceptable extinction ratio at relatively low pumping powers while maintaining the simple design setup. A clear eye diagram for the all proposed optical logic gates is displayed. No obvious power penalty is observed for overall system.

Numerical Study of the Small-Signal Modulation Bandwidth of Reflective and Traveling-Wave SOAs

We present a comprehensive numerical model for intrinsic small-signal modulation response of both reflective, and traveling-wave semiconductor optical amplifiers. We investigate the small-signal photon and carrier density spatial distribution, modulation response, and $-3\text{dB}$ bandwidth for uniform and lossless traveling-wave modulation current model. The analysis shows that the current model does not significantly affect the modulation response as long as the modulation frequency is within the bandwidth. One of the most important results of our analysis is the discovery of the bandwidth maximum in case of a reflective semiconductor optical amplifier operating with low to moderate input optical powers and high current densities. The bandwidth can be further improved by choosing the optimal amplifier length.

A Self-Consistent Numerical Method for Calculation of Steady-State Characteristics of Traveling-Wave and Reflective SOAs

This paper presents a detailed numerical model of reflective and traveling-wave semiconductor optical amplifiers (SOAs), based on a self-consistent iteration method. The method is fully transparent to the input parameters and provides stable and efficient convergence of all relevant SOA variables as long as the sufficient number of previous iterations is taken into account. The model accounts for the detailed spectral and carrier density dependence of the radiative recombination rate, material gain, refractive index, and confinement factor. The analysis of unstrained bulk and strained multi-quantum well polarization insensitive SOAs based on this model provides a deep and detailed insight into the device internal state, confirming that spectral and carrier density material dependencies critically influence the modeling results.