TABLE OF CONTENTS In Chapters 4 6, several characteristics of semiconductor laser amplifiers (SLAs) were studied theoretically. These include: the effective refractive index of the active region and the polarisation dependence on modal gain coefficients (Chapter 4); amplifier gain and output saturation power (Chapter 5); spontaneous emissions from a SLA and their effect on the noise characteristics of the amplifier (Chapter 6). An equivalent circuit consisting of negative resistances and lossless transmission lines has been developed, which can be used as a basis for computer-aided design and analysis of SLAs, even with fairly complex structures. This has been illustrated by using it to analyse the effects of stray reflections from the ends of coupling fibres on the spontaneous emissions generated by SLAs, and on their gain characteristics (see Subsection 6.3.3 in Chapter 6). The investigation so far has been purely theoretical. Before this theory can be used for the design of devices or systems, it is necessary to check the validity of its predictions by experimental studies. These experimental studies are arranged in three parts: (i) characterisation of the recombination mechanism in the SLA by measuring its output spontaneous emission power against injection or bias current; (ii) measurement of the gain characteristics; and (iii) measurement of the noise generated by a SLA in the presence of an input signal. These results will be compared with those predicted by theory. The experimental set-up will also demonstrate some of the practical aspects of operating SLAs.
Experimental work has been...
