Quantum Dot-Semiconductor Optical Amplifiers (QD-SOA): Dynamics and Applications

Quantum dot-semiconductor optical amplifiers (QD-SOA) attracted strong interest for applications in optical communications and in all-optical signal processing due to their high operation rate, strong nonlinearity, small gain recovery time of about few picosec- onds, broadband gain, low injection current and low noise figure (NF). In this chapter, we present the theoretical investigation of the gain recovery time acceleration in DQ SOA; the specific features of the cross gain modulation (XGM) in QD-SOA; the influence of the optical injection on the dynamics of QD-SOA based on the QD in a well (QDWELL) structure. We describe the following applications of QD-SOA: the all-optical ultra-wideband (UWB) pulse generation based on the Mach-Zehnder interferometer (MZI) with a QD-SOA; the ultra-fast all-optical signal processor based on QD-SOA-MZI; the ultra-fast all-optical memory based on QD-SOA. The contents of the chapter are mainly based on the original results. that the proposed memory is characterized by high operation rate up to 100 Gb = s due to the QD-SOA fast dynamics and in particular rapid gain recovery process. Evaluations show that for the 4 PAM modulation format, l ¼ 1 km light velocity in the optical fiber v ≈ 2 (cid:4) 10 8 m = s and typical values of the bit rate of 50 Gb = s and 100 Gb = s the memory storage values are 0 : 25 Mb and 0 : 5 Mb , respectively. The corresponding storage times are 5 μ s and 10 μ s , respectively.