Using the idea of code concatenation in classical coding theory, we make the suggestion of constructing general concatenated quantum codes by choosing certain quantum codes as outer code and inner code.

With the development of the quantum cascade technique,it is particularly important to develop short wave quantum cascade lasers.

The preparation and main characteristics of the InGaAs/InAlAs quantum cascade laser were given.

There are obviously different features of quantum cascade microcavity lasers for different formats of waveguide and resonant cavity.

Energy band design for Si/SiGe quantum cascade laser;

Simulation of waveguide of terahertz quantum cascade laser;

Interface phonons in the active core of a quantum cascade laser;

Terahertz quantum cascade lasers;

Progress on the material structure design ofGaAs-based quantum cascade lasers;

Research of the Structural Characteristics of Quantum Cascade Lasers Fundamental Materials;

In order to optimize the Al composition of the barrier in GaN-based quantum cascade laser,a self-consistent calculation to the schrodinger and poisson equations of one periods in QCL has been done.