ABSTRACT
Optical modulators accept as input the CW or pulsed output of the laser diode and generate as output a
modulated optical waveform. The modulating signal is an electrical input voltage either in digital or
analogue format. Using an external modulator allows the laser to operate independently. Hence its
output power and frequency is controlled very accurately. There are many different applications that
require modulators. One very important application is the digital fibre optic communication systems.
The advent and widespread use of the Internet increased the data transmission rates drastically. The
demand for more bandwidth continues on an ongoing basis. Fibre optic communication networks have
the capability to deliver such demand. At present, 40Gbit s
