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The effect of two-photon absorption (TPA) on all-optical logic operation in quantum-dot semiconductor optical amplifier (QD-SOA) has been carried out. We model the rate equation with the TP...

We investigate all-optical logic operation in quantum-dot semiconductor optical amplifier (QD-SOA) based Mach–Zehnder interferometer considering the effects of two-photon absorption (TPA). TPA occu...

A high-performance quantum dot semiconductor optical amplifier directly grown on a CMOS compatible Si substrate is demonstrated to improve the receiver sensitivity in a filterless 60-Gbit/s NRZ transmission system over temperatures from 20°C to 60°C.

We have studied the saturation output power of 1.3-μm wavelength quantum dot semiconductor optical amplifier (QD-SOA) under high temperature by using Fabry-Perot laser diode structure. The saturation output power of 5 dBm has been confirmed under 85°C with a single stripe device (375 μm length).

We report the first demonstration of the O-band quantum dot semiconductor optical amplifier (QD-SOA) that is directly grown on CMOS compatible on-axis silicon substrate. The QD-SOA has a length of 3600 μm, tapered from 4 μm to 5.5 μm, which can offer 29 dB on-chip gain and 22.8 dBm saturation output power with a minimum 7 dB fiber to fiber noise figure.

A wavelength-division multiplexing/time-division multiplexing (WDM/TDM) network exploiting the broad wavelength range of T-band (1000–1260 nm) is proposed. The network is based on different wavebands of downlink and uplink channels, with each transmitter consisting of a wavelength tunable laser utilized for more than one user through wavelength tuning. The downlink section of the network also introduces interconnecting optical lines and semiconductor optical amplifiers (SOAs), pairing up each of the downlink wavebands to provide structural redundancy by allowing transmitters to be shared between the paired wavebands through TDM. Quantum dot (QD)-based wavelength tunable lasers and SOAs were fabricated for a preliminary demonstration experiment. Error-free transmission with less than 1 dB of power penalty was obtained for a wavelength range of 24.2 nm (5.6 THz). The QD-SOAs exhibited a decent rise and fall time, as well as extinction ratios throughout the wavelength range, which enable it to be used as path switches.

We realize a multiple-input all-optical OR gate by cascading logic gates based on quantum-dot semiconductor optical amplifier (QD-SOA). We demonstrate that it can be implemented by three QD-SOAs.

Storage and manipulation of quantum information requires (nearly) perfect timing---or precisely timed pulse sequences, anyhow. In quantum memory based on photon echoes, for example, the appearance time of the echo must be determined with great accuracy. This study shows how to control photon echoes in a quantum-dot optical amplifier operating at room temperature. As the amplifier is a distributed device, propagation effects are dominant in the generation of the echo pulse, and shaping the excitation pulse serves to control the echo's appearance time and strength.

The polarization independent SOA module for T-band communication was fabricated using the quantum dot gain chip and the polarization diversity circuits with photonic crystal waveplates. The polarization dependent gain was successfully reduced to 0.5 dB.

We demonstrate simultaneous four-channel wavelength conversion of 50-Gbit/s non-return-to-zero differential quadrature-shift-keying signals with a channel spacing of 100-GHz using a quantum-dot semiconductor optical amplifier. Error-free operations with low-power penalties are successfully achieved with various channel configurations.

We experimentally investigate the phase-sensitive amplification characteristics in quantum-dot semiconductor optical amplifier. Phase-sensitive dynamic ranges (PSDRs) of ∼3dB and ∼11dB are obtained for degenerate and non-degenerate components, respectively, with 5-dBm total launch power.

Fast gain recovery observed in quantum-dot semiconductor-optical-amplifiers (QDSOAs) is useful for amplifying high-speed optical signals. The small but finite slow recovery component can deteriorate the signal amplification due to the accumulation of gain saturation during 10 Gb/s operation. A study of the gain recoveries and pattern effects in signals amplified using a 1.5 mu m InAs/InGaAsP QDSOA reveals that the gain recovery is always fast, and pattern-effect-free amplification is observed at the ground state. However, at the excited state, the slow component increases with the current, and significant pattern effects are observed. Simulations of the pattern effects agreed with the observed experimental trends. (C) 2012 Optical Society of America

In this paper, we focus on three issues: 1) proposing a novel photonic crystal waveguide based Symmetric-Mach- Zehnder-type ultrafast all-optical switch using Quantum Dot Semiconductor Optical Amplifier (QD-SOA) and the basic parameters of the photonic crystal waveguide, 2) simulating the general features of the QD-SOA, 3)performance analysis of the all-optical switch. We find that the switching contrast ratio of this kind of all-optical switch has been enhanced due to the superior optical confinement of the photonic crystal waveguide.

Error-free booster amplification in a 4-mm QD-SOA has been achieved with 1-dB OSNR-penalty up to +15dBm output power for single-channel 80-Gb/s RZ-OOK signals and up to +8.3dBm for 4-channel multi-wavelength (80-Gb/s RZ-OOK + 3×40-Gb/s NRZ-OOK) signals on a 5-nm grid.

This work presents group delay measurements for a 1.3 μm quantum dot semiconductor optical amplifier at various injection currents. White-light interferometry is used to obtain group delay data spanning both ground state and first excited state transitions, ranging from 1200 nm to 1320 nm. The group delay, group velocity dispersion and existence of higher order dispersion is observed and quantified.

Time-resolved gain and phase dynamics of an InAs/InGaAsP/InP quantum-dot semiconductor optical amplifier are investigated. The recovery is dominated by an ultrafast component (~1 ps), indicating strongly that the gain medium is genuinely dot-like in character.

We have studied gain dynamics of InAs/InGaAsP quantum dot semiconductor optical amplifier. The recovery time at the ground state was ~3 ps, much faster than the previously reported values at 1.5 um.

The performance of optical logic such as XOR is analyzed by solving rate equations of quantum dot SOA. Results show SOA with quantum dots active region can greatly increase the operation frequency limiting regular SOAs.

Ultra linear quantum-dot semiconductor optical amplifiers at 1.3 mum provide high dynamic input power range for single and multiple channels with error-free amplification. Good burst-mode tolerance is observed.

A 1.55-mum polarization-insensitive quantum dot semiconductor optical amplifier was realized for the first time by applying columnar dots surrounded by tensile-strained side-barriers. The polarization dependent gain was only 0.4 dB at 1.55 mum.

We demonstrate the applicability of quantum-dot semiconductor-opticalamplifier based wavelength converters to the implementation of an ultra-high speed optical packet switching buffer. The buffer architecture consists of cascaded programmable delay stages that fully utilize the available wavelengths and thus minimize the number of wavelength converters that are required to implement the buffer. Physical layer simulations demonstrate error-free operation of the buffer with 3 cascaded Time-Slot-Interchager (TSI) stages at 160 Gbps in the 1.55um window.

By utilizing the four-wave mixing effect in a quantum dot semiconductor optical amplifier, we have demonstrated multi-channel wavelength conversion with greater than 100% efficiency and small signal modulation bandwidths in excess of 25 GHz.

Slow light in the absorption regime and fast light in the gain regime are demonstrated in 1.55 μm quantum-dot semiconductor optical amplifiers at room temperature for both ground state and excited state.

We demonstrate for the first time the low penalty cascaded performance of a 1.3mum QD SOA. Eleven passes are feasible for 10Gb/s data while maintaining a Q-factor exceeding 6 for filter-free operation.

A highly efficient non-degenerate four-wave mixing (FWM) process using CW pump and probe signals around the L-band wavelength range in an InAs/InGaAsP quantum dot semiconductor optical amplifier (QD-SOA) is experimentally demonstrated for the first time. The preliminary experimental results indicate that the FWM efficiency using QD-SOA is independent of the sign of the frequency detuning and decreases by less than 20 dB/decade with frequency detuning increasing.

The outstanding features of Quantum Dot Semiconductor Optical Amplifiers (QD-SOA’s) such as all-optical signal processing and signal regeneration are caused them are widely used in the optical communication systems. Due to the nano structure of these amplifiers, accurate design and modelling of them is a complex and challenging problem. This paper addresses design a QD-SOA. We present a novel method based on genetic algorithm to design QD-SOA. Since it is essential to having a model for designing, a numerical model is obtained in the first step. Then, an artificial neural network model is made using training data sampled from numerical model. The experiments show the proposed neural model has high accuracy as well as low computation time. In the next step, we convert the design problem to a genetic algorithm problem. Using neural model, the suitable fitness function is defined. The user can optimize the cost of production by setting the weight for the design parameters. The proposed system finds the best solution that satisfies desired gain regarding the production cost.

Ramsey interference were observed in an inhomogeneously broadened InAs/InP quantum dot semiconductor optical amplifier operating at room temperature. The imprint of the Ramsey fringes on pulse intensity, phase and temporal position were demonstrated.