Non-inverted Wavelength Conversion Research Articles

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.

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.

Simultaneous Realization of Wavelength Conversion, 2R Regeneration, and All-Optical Multiple Logic Gates with OR, NOR, XOR, and XNOR Functions Based on Self-Polarization Rotation in a Single SOA: An Experimental Approach

We highlight the feasibility of experimental implementation of both inverted and noninverted wavelength conversion, 2R regeneration, and all-optical logic functions, such as OR, NOR, XOR, and XNOR optical gates by exploiting the self-polarization rotation in a semiconductor optical amplifier (SOA) device without changing the setup configuration. Switching between each optical function is done by only adjusting the input optical power level. In order to allow optimum control and preserve the polarization state of the injected and collected signals, the polarimetric measures have been carried out in free space.

Theoretical study on non-inverted wavelength conversion based on semiconductor optical amplifier and optical band-pass filter

A single semiconductor optical amplifier （SOA） assisted by optical filter is exploited to realize high-speed all-optical wavelength conversion, in which, the filter is employed to optimize output spectrum. We propose a spectrum optimizer which contains a band pass filter （BPF） and a delay interferometer （DI）. Based on this configuration, 80 Gbit/s all-optical non-inverted conversion has been numerically simulated. Furthermore, the quality of output signal has been improved greatly using genetic algorithms to optimize the parameters of the spectrum optimizer. Additionally，the effect of ultra-fast carrier dynamics in SOA on the output signal is analyzed theoretically. The dependence of the signal extinction ratio （ER） and pattern effect （PE） on variations of the BPF’s ER and DI’s ER is also studied.

All‐optical 3R regeneration based on the XPM effect of semiconductor optical amplifier

AbstractWe propose a 40 Gb/s all optical 3R regeneration system. A high Finesse Fabry‐Perot (F‐P) filter (FSR = 40 GHz, finesse = 1012) and a gain‐saturated SOA are used to extract 40 GHz clock. Before the clock extraction, 40 Gb/s RZ optical signals are converted into a stable wavelength after noninverted wavelength conversion based on the XPM of a single SOA. In the all optical decision, dual SOAs in series were used to lengthen active region of SOA. The 40 Gb/s degraded RZ signals are regenerated based on the XPM of dual SOAs in series, when a 0.26‐nm OBPF is blue shifted with respect to the wavelength of extracted clock. The experimental results show better eye opening, the decreased timing jitter from 5 to 1.4 ps and the 15 dB improved optical signal to noise ratio (OSNR). © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1807–1810, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23473

Towards 640 Gbit/s wavelength conversion based on nonlinear polarization rotation in a semiconductor optical amplifier

Taking into account ultra-fast carrier dynamics, this paper models 640 Gbit/s wavelength conversion scheme based on nonlinear polarization rotation (NPR) in a single semiconductor optical amplifier (SOA) and investigates the performance of this kind of wavelength conversion scheme in detail. In this model, two carrier temperature equations are introduced to substitute two energy density equations, which reduce the complexity of calculation in comparison with the previous model. The temporary gain and phase shift dynamics induced by ultra-short optical pulses are numerically simulated and the simulated results are qualitatively in good agreement with reported experimental results. Simulated results show that non-inverted and inverted 640 Gbit/s wavelength conversions based on NPR are achieved with clear open eye diagrams. To further investigate the performance of the non-inverted wavelength conversion scheme, the dependence of output extinction ratio (ER) on some key parameters used in simulation is illustrated. Furthermore, simulated analyses show that high performance non-inverted wavelength conversion based on NPR can be achieved by using a red-shifted filtering scheme.

Ultrafast All-Optical Signal Processing Based on Single Semiconductor Optical Amplifier and Optical Filtering

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> We propose and demonstrate several all-optical signal-processing technologies, including wavelength conversion (WC), leading/trailing edge detection, and logic gates based on a semiconductor optical amplifier (SOA) and a detuning optical bandpass filter (OBF). The system is based on pump-probe scheme. When the pump signal is return-to-zero (RZ) format, both inverted WC and noninverted WC at 40 Gb/s are obtained, and the polarity variation is highly dependent on the OBF detuning. When the pump signal is nonreturn-to-zero (NRZ) format, both the inverted WC and leading/trailing edge detection are obtained. In the inverted WC, the OBF detuning is small, and it helps to accelerate the amplitude recovery. However, in the noninverted WC and pulse edge detection, the OBF detuning is relatively large, and it acts as frequency–amplitude conversion. Finally, we present all-optical reconfigurable logic gates based on various nonlinearities in an SOA. The logic gates including <emphasis emphasistype="smcaps">and</emphasis>, <emphasis emphasistype="smcaps">nor</emphasis>/<emphasis emphasistype="smcaps">not</emphasis>, and <emphasis emphasistype="smcaps">or</emphasis> are obtained by four-wave mixing, cross-gain modulation, and transient cross-phase modulation in the SOA, respectively. The <emphasis emphasistype="smcaps">nor</emphasis> and <emphasis emphasistype="smcaps">or</emphasis> gates are capable of operating at 40 Gb/s with the help of the OBF detuning. The <emphasis emphasistype="smcaps">xnor</emphasis> gate is implemented by combining the <emphasis emphasistype="smcaps">and</emphasis> output and <emphasis emphasistype="smcaps">nor</emphasis> output. </para>

Simultaneously All-Optical Inverted and Noninverted Wavelength Conversion Employing Ultra-Small Silicon-on-Insulator Waveguide

We propose single-to-dual all-optical wavelength conversion based on stimulated Raman effect on silicon waveguides. Simulation results of non-return-to-zero (NRZ) pseudorandom bit sequence (27–1 code) at 10, 50, and 200-Gbit/s rates of conversion in an ultra-small silicon-on-insulator waveguide are presented. The main goal in the proposed scheme is that the converted signal can be obtained simultaneously inverted, at the 1550 nm channel (down-conversion) and non-inverted, at the 1846 nm channel (up-conversion), for original signal fixed at 1686 nm.

Semiconductor-Optical-Amplifier-Based Inverted and Non-Inverted Wavelength Conversion at 40 Gb/s Using a Detuning Optical Bandpass Filter

We experimentally demonstrate 40 Gb/s semiconductor-optical-amplifier-based tunable wavelength conversion (WC) using a detuning optical bandpass filter. Both inverted and non-inverted WCs are obtained by shifting the filter central wavelength with respect to the probe wavelength. When the filter is red shifted by 0.4 nm or blue shifted by 0.3 nm, the WC is non-inverted. However, when the filter is blue shifted by 0.1 nm, the WC is inverted. It is experimentally demonstrated that the WC has a tunable range covering the C-band.

Theoretical Study of SOA-Based Wavelength Conversion with NRZand RZ Format at 40 Gb/s

We theoretically discuss 40 Gb/s semiconductor opticalamplifier (SOA)-based wavelength conversion (WC) using a detuningoptical bandpass filter based on ultrafast dynamic characteristics ofSOA. Both the inverted and non-inverted WCs are obtained by shiftingthe filter central wavelength with respect to the probe wavelength wheninput data signal is in return-to-zero (RZ) format. However, we can obtainformat conversion from nonreturn-to-zero (NRZ) to pseudo-return-to-zero(PRZ) and inverted WC when the input signal is in NRZ format.

Investigation of optimum wavelength converter based on nonlinear polarisation rotation in a bulk SOA

This work is focused on understanding and optimising the physical mechanisms responsible for wavelength conversion based on cross-polarisation modulation (XPolM) in a bulk semiconductor optical amplifier. A comparison is made between the conversion performance that can be achieved with cross-gain modulation (XGM) and XPolM in co- and counter-propagation configurations. Wavelength independent conversion can be achieved when nonlinear polarisation rotation and XGM effects are balanced in the case of non-inverted wavelength conversion.

Simultaneously all‐optical inverted and noninverted wavelength conversion employing SOA‐based Sagnac interferometer

AbstractThis paper have successfully demonstrated an all‐optical wavelength conversion scheme for all‐speed return‐to‐zero (RZ) format data at 10 Gbit/s rate by using a Sagnac interferometer based on semiconductor optical amplifier (SOA). The attractive issue of the proposed method is that the converted signal can be obtained simultaneously with inverted and noninverted wavelength conversion signals. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 547–551, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22192

Investigation on inverted and non-inverted wavelength conversion based on transient cross phase modulation of semiconductor optical amplifier

All-optical wavelength conversion based on transient cross phase modulation of semiconductor optical amplifier (SOA) is a promising approach to achieve high-speed all-optical signal processing. We experimentally demonstrate inverted and non-inverted wavelength conversion (WC) based on single SOA and an optical bandpass filter with 0.4 nm bandwidth. When the central wavelength of the following filter is blue shifted by 0.25 nm or red shifted by 0.05 nm with respect to the wavelength of probe signal, the WC is inverted. When the filter detuning is blue shifted 0.29 nm or red shifted 0.25 nm, the WC is non-inverted. The polarity evolution from inverted WC to non-inverted WC is also presented with numerical simulation. The obtained results are in good agreement with the experiment.

Optimization of Optical Band-Pass Filters for All-Optical Wavelength Conversion Using Genetic Algorithms

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> We propose using genetic algorithms to numerically optimize optical band-pass filters (OBFs) for inverted and noninverted wavelength conversion based on semiconductor optical amplifiers. A fourth order Hermite–Gaussian sum series is used to describe the filter transfer function. Signal eye openings greater than 30 dB are obtained for both inverted and noninverted output signals. The dependence of the eye opening, overshoot and pulse amplitude fluctuation on variations in the filter center frequency and bandwidth is explored. We find that for an optimized eye opening in the noninverted signal the filter should be detuned towards lower frequency with respect to the probe frequency. Finally, we show that the optimum filter transfer function obtained with the genetic algorithm can be approximated with good agreement using an asymmetric Mach–Zehnder interferometer combined with a Gaussian OBF. </para>

Simultaneous observation of inverted and noninverted wavelength conversion of picosecond pulses in LiNbO3 waveguides

AbstractWe propose and demonstrate simultaneously inverted and noninverted wavelength conversion of picosecond pulses in periodically poled LiNbO3 waveguides. By only use of sum‐frequency generation, inverted wavelength conversion from the signal wavelength to pump wavelength both within the 1.5‐μm band is experimentally verified. By exploiting cascaded sum‐ and difference‐frequency generation (SFG + DFG), both inverted and noninverted wavelength conversion are observed in the experiments. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 295–298, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22119

Analytical Solution for SOA-Based All-Optical Wavelength Conversion Using Transient Cross-Phase Modulation

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> All-optical wavelength conversion (WC) based on transient cross-phase modulation (T-XPM) of semiconductor optical amplifier (SOAs) is a promising approach to accelerate the gain recovery of SOAs. An analytical solution is deduced to explain the polarity variation of WC based on T-XPM of SOAs from the viewpoint of the impulse response functions. We conclude that both inverted and noninverted WCs can be realized when the central wavelength of the optical bandpass filter is either blue-shifted or red-shifted with respect to the wavelength of the probe signal. We are able to validate the formula against our experimental results recently published. </para>

Simultaneous all-optical inverted and noninverted wavelength conversion using a single-stage fiber-optical parametric amplifier

We have demonstrated, for the first time to our knowledge, simultaneous all-optical inverted and noninverted wavelength conversion by using a single-stage two-pump fiber-optical parametric amplifier with an extinction ratio between 7 and 14 dB over 24 nm.

Experimental demonstration of both inverted and non-inverted wavelength conversion based on transient cross phase modulation of SOA

We demonstrate experimentally ultrafast inverted and noninverted wavelength conversion (WC) based on a semiconductor optical amplifier (SOA) and an optical bandpass filter (OBF). In the case of small detuning, the WC is inverted regardless if the OBF is blue- or red-shifted with respect to the central wavelength of the converted signal. However the WC is non-inverted when the filter detuning is relatively large. An analytical formula for the transient cross phase modulation is applied to reveal the polarity variation of WC with respect to the OBF detuning. The theoretical detuning values are in good agreement with our experimental results.

All-optical inverted and noninverted wavelength conversion using two-cascaded semiconductor optical amplifiers

A two-cascaded semiconductor optical amplifier configuration in a counterpropagating topology is proposed for an all-optical wavelength conversion operation. The attractive issue of the proposed method is that the converted signal can be obtained simultaneously with an inverted and noninverted signal. The all-optical noninverted wavelength conversion feasibility is also demonstrated delivering an extinction ratio higher than 7 dB over a wide range of wavelengths.

Wavelength conversion using nonlinear polarization rotation in a single semiconductor optical amplifier

We discuss an all-optical wavelength converter based on nonlinear polarization rotation in a single semiconductor optical amplifier. We show that inverted and noninverted wavelength conversion can be realized. We also demonstrate this wavelength-conversion concept can operate over a large wavelength range. Experiments show that error-free wavelength conversion can be obtained at a bit rate of 10 Gb/s.