Introductory physics

In this chapter it is attempted to give the reader an easy-to-follow introduction to the operation of single frequency laser diodes and their characteristics and to provide the basic background that is considered necessary to understand the following chapters on modelling and characterisation of DFB laser diodes. To this end, the structure of a laser diode is first described in section 2 and the fundamental physical laws governing the behaviour of the component are explained in section 3. The subsequent sections then introduce briefly the chapters 7 to 9 and deal with common problems encountered in laser modelling and characterisation (section 4) and general approximations used in laser diode modelling (section 5). Section 6, finally, summarises the work that was done on standardisation of laser parameters in the framework of COST 240.