Dynamics and its Effects on Saturation Region in Semiconductor Optical Amplifiers

We focus on studying the dynamics of bulk semiconductor optical amplifiers and their effects on the saturation region for short pulse that differ, however there is the same unsaturated gain for both dynamics. Parameters like current injection, fast dynamics present by carrier heating (CH), and spectra hole burning (SHB) are studied for regions that occur a response to certain dynamics. The behavior of the saturation region is found to be responsible for phenomena such as recovery time and chirp for the pulse under study.

Influencing Factors, Energy Consumption, and Carbon Emission of Central Heating in China: A Supply Chain Perspective

The rapid growth of energy demand in China’s central heating sector and the large differences in regions have posed challenges to its energy supply safety, which affected the progress of China’s energy transformation. From a supply chain perspective, this study uses the feasible generalized least squares method to conduct empirical research on the central heating data of 17 provinces in China from 2006 to 2017. The results shows that the main factors of central heating includes energy consumption structure, heat generation method, heat transport carrier, heating degree days and heating area; The main factor that increases the energy consumption of central heating in each province is the same, namely Heating area (HA). However, the main factors that reduce energy consumption in each province are different; using gas instead of coal for clean heating can reduce some greenhouse gas emissions while bringing huge gas supply pressure. According to the results, this study provides some policy suggestions.

Монополярное умножение горячих носителей заряда в полупроводниках A-=SUP=-III-=/SUP=-B-=SUP=-V-=/SUP=- в сильном электрическом поле и бесшумные лавинные фотодиоды (О б з о р)

The results of theoretical and experimental studies of impact ionization processes and charge carrier heating in multi-valley A3B5 semiconductors at high electric field are presented and their relationship with the features of the band structure is discussed. A role of subsidiary L- and X-valleys, complex structure of the valence band and orientation dependence of the ionization coefficients are taken into account. A new approach to the choice of semiconductor materials with a large ratio of the ionization coefficients of holes and electrons to create the noiseless avalanche photodiodes due to monopolarity of hot charge carrier multiplication is proposed.

The effect of doping on the electrons and holes in quantum dot semiconductor optical amplifiers

The doping effect on the reservoir carrier temperature of the electron and hole in quantum dot optical amplifiers (QD SOAs) has been formalized and modeling, taking into account the most of carrier heating (CH) contributions such as; free carrier absorption, carrier heating time relaxation, interdot relaxation time, occupation probability of dot level, injected current and electron-hole interaction. The theoretical simulation shows the carrier temperature increasing straight forward with increasing the surface density of the donor and accepter which had not studied earlier as the best of our knowledge. It clears that, the surface carrier concentration of donor or acceptor atoms supplying more hot carriers for wetting layer (WL) which is leading an increasing the carrier temperature. In other word, the long life time of carriers from WL to Quantum Dot (QD) states is very high. Consequently, the collision of carriers and nonradiative relaxation are increasing the CH effect. Also, the majority of carrier is responsible on the increasing of electron or hole temperature, so the variation electron temperature in N-type is higher than hole in valence band, while the reverse is done with doping with P-type.