Semiconductor Optical Amplifier Mach-Zehnder Interferometer Research Articles

Broadband Operation of High-Speed All-Optical Gated Wavelength Shifter

We report an extensive experimental wavelength characterization of a scheme for all-optical gated wavelength shifting operation. This scheme is suitable for dynamic wavelength routing and add or drop operation in wavelength-division multiplexing systems and optical packet switched networks. A single semiconductor-optical amplifier Mach–Zehnder interferometer with a multi-inputs configuration is exploited. We demonstrate an error-free operation in the case of 10 Gb/s NRZ-OOK data with moderate power penalties $({ over the entire C-band.

All‐optical OOK‐to‐QAM modulation format conversion utilizing parallel SOA‐MZI wavelength converters

AbstractA novel all‐optical modulation format conversion scheme from on‐off keying to quadrature amplitude modulation (QAM) utilizing wavelength conversion in the semiconductor optical amplifier Mach–Zehnder Interferometers is proposed. The numerical simulations show generation of the 16‐QAM signal proofing the principle of the proposed concept and its utility in future telecommunication systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2429–2433, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27084

Ultrahigh Speed Optical Signal Processing Logic Based on an SOA-MZI

This paper presents the simulation and design of all-optical logic gates OR, AND, XNOR, and XOR at ultrahigh speed by proposing the semiconductor optical amplifier-Mach-Zehnder interferometer (SOA-MZI) configuration. The simulations of all logic gates are obtained by SOA-MZI structure parameters at 40 and 120 Gb/s. The OR, AND, and XOR logics are implemented first time at 120 Gb/s by using single wavelength and an SOA-MZI. The XNOR logic is realized directly by the proposed SOA-MZI without any implementation with existing logics. Thus, realization of these logics at 40 and 120 Gb/s will enhance the future optical signal processing applications for super-high speed operation.

40-Gb/s NRZ-to-RZ and OOK-to-BPSK Format and Wavelength Conversion on a Single SOA-MZI for Gridless Networking Operations

We propose and experimentally demonstrate simultaneous format and wavelength conversion at 40 Gb/s exploiting a single commercial semiconductor optical amplifier Mach-Zehnder interferometer. Conversion from nonreturn-to-zero (NRZ) to a 2-ps return-to-zero (RZ) on-off keying (OOK) format suitable for grooming onto a 160-Gb/s optical time-division-multiplexing frame is achieved. Furthermore, for the first time to the best of our knowledge, 40-Gb/s conversion from RZ OOK to RZ binary phase-shift keying (BPSK) is achieved. The effectiveness of the proposed scheme is demonstrated by means of bit-error-rate measurements. Error-free operations are reported, with a power penalty of 0.5 dB for the case of NRZ-to-RZ OOK conversion and of 3 dB (comprehensive of the degradation due to the wavelength conversion used to generate the probe signal) for the case of OOK-to-BPSK conversion.

Theoretical analysis of all-optical clocked D flip-flop using a single SOA assisted symmetric MZI

A novel scheme for an all-optical clocked D flip-flop, with very low complexity, is proposed and numerically demonstrated. This new flip-flop configuration is based on a semiconductor optical amplifier — Mach–Zehnder interferometer (SOA-MZI), with a feedback loop, and presents two stable states determined by the phase shift between the two MZI arms.

All-Optical Gated Wavelength Converter-Eraser Using a Single SOA-MZI

We propose and experimentally demonstrate an original scheme for simultaneous all-optical wavelength conversion and data erasing under an optical gate signal, suitable for on-off keying (OOK) signals. This function is obtained in a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) exploiting nonlinear interaction between a continuous data stream and an optical gate signal at a different wavelength. In correspondence of the gate signal, a burst of data from the optical stream is converted at the optical gate wavelength and, at the same time, cancelled at the input stream wavelength. Fast switching time enabling selective wavelength shifting on a data stream at 10 Gb/s without any bit loss is demonstrated. Error-free operation with 0.2-dB power penalty for the wavelength-preserved output data and 1.8 dB for the shifted data is reported.

Demonstration of All-Optical Divider Circuit Using SOA-MZI-Type xor Gate and Feedback Loop for Forward Error Detection

We investigated the feasibility of using an optical divider circuit with a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI)-based exclusive or (XOR) gate for an all-optical forward error detection and correction scheme with a cyclic code. We employed a conventional cyclic code scheme: the same divider circuit acts as both encoder and decoder with a given generator polynomial. The divider circuit consists of cascaded XOR circuits and feedback lines. Therefore, the performance of the XOR circuit is one of the key factors for realizing an all-optical scheme. We numerically investigated the operation performance of the SOA-MZI-based all-optical XOR gate. Dynamic operation was simulated using rate equations via the transfer matrix method. The XOR function was also investigated experimentally. The eye diagram obtained from the simulation at a bit rate of 10 Gb/s showed good qualitative agreement with experimental results. Additionally, we confirmed that the optimal condition for a high quality factor (Q-factor) is obtained with equal power for each signal. Next, we demonstrated all-optical divider processing with the SOA-MZI-based XOR circuit and a feedback line that forms the generator polynomial x + 1. The preliminary results for division operation could be verified.

Analytical Investigation of an All-Optical T-Type Flip-Flop Using a Semiconductor Optical Amplifier Mach–Zehnder Interferometer with Push–Pull Configuration

To achieve an optical regenerator for a differential phase-shift keying signal based on a semiconductor optical amplifier Mach–Zehnder interferometer (SOA-MZI), we need an all-optical T-type flip-flop (T-FF) for encoding. We propose an all-optical T-FF consisting of an SOA-MZI with push–pull configuration and a feedback mirror to overcome the speed limitation of the previously proposed counter-faced configuration. Numerical simulation reveals its possibility of stable operation in 10 Gbps with a 27 - 1 pseudo random binary sequence (PRBS) signal even by using a conventional SOA with a slow carrier recovery of 100 ps, and the possibility of 40 Gbps operation is also investigated.

Performance Investigation of All-Optical NRZ-to-Manchester Format Conversion with SOA-MZI Based XOR Logic Gate

All-optical format conversion between non-return-to-zero (NRZ) and the Manchester code is implemented by using an optical exclusive-OR (XOR) logic gate based on a semiconductor optical amplifier Mach-Zehnder Interferometer (SOA-MZI). There is 10 Gbit/s all-optical NRZ-to-Manchester conversion implemented in our simulation system and BER performance of the format conversion is investigated. Transmission performances of the converted Manchester coded signal are discussed in terms of transmission length and received optical power.

A Proposal and Analytical Investigation of an All-Optical T-type Flip-Flop Using Semiconductor Optical Amplifier Mach–Zehnder Interferometer Configuration for Differential Phase-Shift Keying Encoding Operation

An all-optical differential phase-shift keying (DPSK) regenerator with a DPSK demodulator and a conventional on–off keying (OOK) regenerator requires a DPSK encoding process that is realized by T-type flip-flop (T-FF) operation. To solve this problem, we propose an all-optical T-FF circuit consisting of counter-faced semiconductor optical amplifier (SOA)-based exclusive OR (XOR) gates for the first time. Numerical investigation with rate equation reveals the possibility of its stable operation in 10 Gbps with 27-1 pseudorandom binary sequence (PRBS) signal. It also reveals that it is necessary to decrease the equivalent turn-off time for high bit-rate operation using push–pull configuration.

Improved all-optical modified signed-digit adders using semiconductor optical amplifier and Mach–Zehnder interferometer

In this paper, we present improved all-optical circuits that implement ultra-fast adders based on the carry-free property of the modified signed-digit (MSD) number representation. The all-optical realizations are based on semiconductor optical amplifier (SOA) and Mach–Zehnder interferometer (MZI) switches, which represent one of the most promising solutions due to their compact size, thermal stability and low power operation. Several all-optical circuit designs are proposed with the objective to minimize the number of the SOA–MZI switches, the time delay in the adders and some other optical elements. The proposed circuits are more efficient comparing to previously published ones in terms of the number of optical components (less by 50%) as well as the operational speed (faster by 50%).

Dynamic Analysis of All-Optical Wavelength Conversion of Differential Phase-Shift Keyed Signals Based on Semiconductor Optical Amplifier Mach–Zehnder Interferometer

All-optical wavelength conversion of differential phase-shift keyed (DPSK) signals based on semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) is simulated and analyzed. The results show that, to obtain both good quality of the converted signal and high conversion efficiency, phase difference between the upper and lower arms of MZI should be near ¿, which suggests strong cross-phase-modulation (XPM) and cross-gain-modulation (XGM) for optimized operation of this wavelength converter, while weak XPM and XGM will lead to sacrifice of conversion efficiency. The results also show larger wavelength up-conversion range, and suggest non-return-to-zero (NRZ) format for 10 Gb/s operation while return-to-zero (RZ) format for 40 Gb/s operation. Besides, short carrier lifetime is preferred for high-speed applications and appropriate linewidth enhancement factor can be utilized to mitigate amplitude fluctuation of the converted signal if the carrier lifetime is not short enough.

All-optical XOR and XNOR operations at 864 Gb/s using a pair of semiconductor optical amplifier Mach-Zehnder interferometers

We propose a method for increased-speed all-optical XOR operation using semiconductor optical amplifiers. We demonstrate XOR and XNOR operations at 86.4 Gb/s using a pair of photonic-integrated semiconductor optical amplifier Mach-Zehnder interferometers.

An SOA-MZI NRZ Wavelength Conversion Scheme With Enhanced 2R Regeneration Characteristics

We present a novel scheme for all-optical nonreturn-to-zero (NRZ) wavelength conversion with enhanced 2R regenerative characteristics. It employs a hybridly integrated semiconductor optical amplifier Mach-Zehnder interferometer using bidirectional data injection and an additional external continuous-wave signal for differentially biasing the interferometer arms, optimizing gain and phase conditions during the switching functionality. Experimental verification of its superior 2R regenerative capabilities are demonstrated for 10-Gb/s NRZ data signals.

Optical Static RAM Cell

We demonstrate an optical static random access memory cell that provides read and write functionality at 5 Gb/s. The circuit comprises a hybridly integrated semiconductor optical amplifier-Mach-Zehnder interferometer (SOA-MZI) flip-flop serving as the memory unit and two additional SOA-based cross-gain modulation switches for controlling access to the memory cell.

Contention Resolution for Burst-Mode Traffic Using Integrated SOA-MZI Gate Arrays and Self-Resetting Optical Flip-Flops

We demonstrate a photonic routing system that resolves the contention between bursty optical packets. The circuit is realized exclusively with integrated photonic components through the interconnection of semiconductor optical amplifier Mach-Zehnder interferometers gate arrays and optical flip-flops. The system resolves the contention - without burst segmentation - in the wavelength domain with a low power penalty ( < 1 dB).

Simultaneous Data Regeneration and Digital Label Swapping in an SOA-MZI Device

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> We demonstrate all-optical regeneration of a 10-Gb/s data stream, with bit-error-rate improvement, simultaneously with digital label swapping, in a monolithically integrated semiconductor optical amplifier Mach–Zehnder interferometer device. </para>

Continuously Tunable Microwave Photonic Filter With Negative Coefficients Using Cross-Phase Modulation in an SOA-MZ Interferometer

A notch filter with negative tap is proposed based on exploiting cross-phase modulation in a semiconductor optical amplifier Mach-Zehnder interferometer. This configuration shows a high operation bandwidth and reduces the chirp of the modulated signal compared to prior proposed configurations based on cross-gain modulation. We compare the operation of the structure when optic delay lines or dispersive fibers are used to generate the optical taps. Moreover, a continuous free-spectral range tuning is shown.

Efficient performance optimization of SOA-MZI devices

We present a novel characterization method for semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) switches which combines a pump-probe measurement with an interferometer bias scan. In addition to a wealth of information on the switching dynamics for all operating points of the switch, we can create an extinction map to pinpoint regions of highest extinction for optimizing all-optical ultrafast switching. We experimentally verify the accuracy of this characterization method by performing a wavelength characterization at the optimal bias point and a nearby, non-optimal point. A 1-dB penalty was observed.

Implementation of an All-Optical Time-Slot-Interchanger Architecture

We demonstrate a wavelength-converter-based optical time-slot-interchanger. It consists of three cascaded programmable delay stages and employs the first hybrid integrated, on a chip, quadruple array of semiconductor optical amplifier Mach-Zehnder interferometer switches. It exhibits error-free operation with 10-Gb/s nonreturn-to-zero packets and a power penalty of 1.8 dB.