Analysis of all-optical demultiplexing from 160/320 Gbit/s to 40 Gbit/s using quantum-dot semiconductor optical amplifiers assisted Mach-Zehnder interferometer

Abstract

ABSTRACT:The performance of ultrafast all-optical demultiplexer using quantum-dot semiconductor optical amplifiers (QD-SOAs) assisted Mach-Zehnder interferometer (MZI) is analyzed. Through numerical simulations, a set of key parameters are optimized and all-optical demultiplexing from 160/320 Gbit/s to 40 Gbit/s can be realized with fairly high performance. The results are useful for the system performance studies and practical application.

On the Feasibility of 320 Gb/S All-Optical and Gate Using Quantum-Dot Semiconductor Optical Amplifier-Based Mach-Zehnder Interferometer

“…This happens because a lower current density facilitates the saturation of a QD-SOA [57]. As a result the gain of QD-SOA1 is dropped to a greater extent and it becomes more difficult for it to recover closer to its unsaturated value, which is additionally verified by Fig.…”

“…7(c) shows that if J is adjusted to be over 0.9 kA/cm 2 then the Q-factor is made acceptable. The corresponding bias current is 108 mA, which lies within reasonable limits [57] and can be practically supplied by commercial current sources. Therefore a moderate current density is fine for allowing the proposed AND gate to be realized at least with an adequate performance.…”

“…Finally, regarding the QD-SOA saturation properties, in [72] the steady-state static gain has been obtained as a function of the input power for different values of J, which shows that the gain begins to saturate as the input power is increased and that the saturation power is increased with J. This dependence on J can also be noticed in [57], where the 3 dB input saturation power, P in,sat , is calculated as a function of J for different values of QD-SOA length. This unveils that if the current density is kept constant the QD-SOA saturation power is decreased as its length is increased.…”

“…The feasibility of the scheme is thoroughly investigated by applying a numerical model that takes into account the dynamical behaviour of QD-SOAs in order to simulate the operation of the standard MZI configured as AND gate when it receives a pair of fully-loaded pseudorandom binary sequences (PRBS) as inputs. This is done at 320 Gb/s, where so far efforts with the QD-SOA-based MZI in single rail switching mode have included only demultiplexing [57]. However in this application many data pulses travel intact through the interferometer without being transmitted at the output.…”

Ultrafast All-Optical Full Adder Using Quantum-Dot Semiconductor Optical Amplifier-Based Mach-Zehnder Interferometer

“…The maximum value changes and shifts to the right as the current density becomes larger. From a physical perspective this happens because the current density determines the power required to alter the optical properties of a QD-SOA and properly saturate its gain, and the higher it is, the more power is necessary for this purpose [37]. This fact also explains that as we move well enough into the falling slope of the curves, a larger current density is necessary to enhance the ER and hence improve performance for a given power.…”