Four-wave mixing in quantum dot semiconductor optical amplifiers

Abstract

The theory of four-wave mixing (FWM) in the quantum dot (QD) semiconductor optical amplifiers (SOAs) is discussed by combining the QD rate equations system, the quantum-mechanical density-matrix theory, and the pulse propagation in QD SOAs including the three region of QD structure ground state (GS), excited state (ES), and wetting layer. Also, relations for differential gain, gain integral, and nonlinear susceptibility of both pump, probe, and signal pulses were discussed. Gain and differential gain have been calculated for QD structure. FWM efficiency and its components [spectral hole burning (SHB), carrier heating, and carrier density pulsation] are calculated. It is found that inclusion of ES in the formulas and in the calculations is essential since it works as a carrier reservoir for GS. It is found that QD SOA with enough capture time from ES to GS will reduce the SHB component, and so it is suitable for telecommunication applications that require symmetric conversion and independent detuning.

Nondegenerate Four-Wave Mixing in a Dual-Mode Injection-Locked InAs/InP(100) Nanostructure Laser

“…As for the nonlinear gain medium, in contrast to the quantum well (QW) material, quantum dots (QDs) offer various advantages such as a wider gain spectrum [10], ultrafast carrier dynamics [11], higher nonlinear gain effect and thus a larger three-order nonlinear susceptibility [9], [12], [13]. In addition, due to the reduced linewidth enhancement factor (LEF), QDs have the possibility of eliminating destructive interference among the nonlinear processes and also offer an enhanced efficiency in the wavelength up-conversion [14], [15]. In order to improve the dynamical performance of semiconductor lasers, the optical injection-locking technique has been widely used to reduce the spectral linewidth, frequency chirp as well as to suppress relative intensity noise and nonlinear distortion [16]- [18].…”

Materials and Structures for Nonlinear Photonics

“…In the latter case all the recovery processes & timescales discussed above clearly apply and this scenario has also been analysed by several authors for interactions between pulses, e.g. [88,114,115]. In the former case, the recovery processes are strongly suppressed due to the strong CW pump leading to the question of how fast a signal can be accurately phase conjugated or wavelength translated by this process?…”

Octave-Spanning Dispersive Slot Waveguide Based Chip-Level Ultrashort Pulse Stretcher

“…In this work, to better investigate on the properties of pulse stretcher based on the designed dispersive Si3N4 slot waveguides, and to further understand the impacts of the dispersion and the nonlinearity, the amplification process is not included. Otherwise, the bandwidth constraints in the on-chip CPA system could be from the integrated amplifier, of which the best bandwidth could only cover slightly above 100 nm [49][50][51]. Moreover, the gain of integrated amplifiers, including semiconductor optical amplifiers (SOA) [49], Er-doped waveguide amplifiers [50], and quantum dot amplifiers [51], are not flat over the bandwidth.…”

“…Otherwise, the bandwidth constraints in the on-chip CPA system could be from the integrated amplifier, of which the best bandwidth could only cover slightly above 100 nm [49][50][51]. Moreover, the gain of integrated amplifiers, including semiconductor optical amplifiers (SOA) [49], Er-doped waveguide amplifiers [50], and quantum dot amplifiers [51], are not flat over the bandwidth. Octave-spanning optical parametric amplifier based on silicon-rich nitride waveguide has been proposed, which has the potential to serve as the amplifying element in the on-chip CPA system [52].…”