This chapter presents the basic theory and characteristics of stimulated
emission and optical amplification gain in semiconductors. The former is the
mostimportant principlethat enablessemiconductorlaserstobeimplemented,
and the latter is the most important parameter for analysis of the laser
performances. First, stimulated emission in semiconductors is explained, and
then quantum theory analysis and statistic analysis using the density matrix
of the optical amplification gain are given.
Semiconductor lasers are among the most important optoelectronics
devices. Remarkable development has been accomplished in the three
decades since the first achievement in room-temperature continuous
oscillation, which opened the possibility of practical applications of
semiconductor lasers. Today, various types of semiconductor lasers are
mass-produced and widely used as coherent light sources for a variety of
applications, including optical fiber communication systems and optical
disk memory systems....
In Chapter 3, eigenvalue equations were derived by matching boundary conditions inside DFB laser cavities. From the eigenvalue problem, the lasing threshold characteristic of DFB lasers is determined. The single %/2-phase-shifted (PS) DFB laser is fabricated with a phase discontinuity of %/2 at or near the centre of the laser cavity. It is characterised by Bragg oscillation and a high gain margin value. On the other hand, the SLM deteriorates quickly when the optical power of the laser diode increases.
The introduction of semiconductor lasers has boosted the development of coherent optical communication systems. With the built-in wavelength selection mechanism, distributed feedback semiconductor laser diodes with a higher gain margin are superior to the Fabry– Perot laser in that a single longitudinal mode of lasing can be achieved. In this chapter, results obtained from the threshold analysis of conventional and singlephase-shifted DFB lasers will be investigated. In particular, structural impacts on the threshold characteristic will be discussed in a systematic way. ...
Since its first demonstration in 1960, the laser has found widespread application in diverse
areas including medicine, materials processing, optical communications and information
technology. The number of engineers and scientists working on lasers or in laser related
fields is continuously increasing as new applications for this exciting technology are being
discovered. This also means that more and more people need to gain a detailed knowledge
of lasers and their characteristics.
As fiber-to-the-x (FTTX) architectures gain momentum as a means for delivering
high-speed broadband services to homes and small businesses, many questions
have surfaced regarding the best way to connect the large number of drop
cables feeding into the network. Drop cables typically connect each optical
network terminal (ONT) at the subscriber premise to a fiber access terminal
where they are then connected to a main fiber distribution cable.
In the latest decade we have witnessed a tremendous advance in telecommunications
technology. With the rapid growth and sophistication of digital
technology and computers, communication systems have become more
versatile and powerful. This has given a modern communication engineer
two key problems to solve: (i) how to handle the ever-increasing demand for
capacity and speed in communication systems, and (ii) how to tackle the need
to integrate a wide range of computers and data sources so as to form a highly
integrated communication network with a global coverage....
The dissemination of micro-electronics during the 1980s led to innovation. On the leading
edge of these technologies was the machine tool subsector. However, the Japanese were
the first to apply advanced controls and gained shares in global markets propelled by their
lead. Since then Europe has caught up and ME competes at eye level with Japan.
detailed assessment of the technological position in this area and other fields of relevance
for ME, such as nanotechnology, optics, new materials and composites, is performed in