ABSTRACT
Optical modulators accept as input the continuous wave (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 analog format. Insertion loss is the optical power loss in the on state. Polarization dependence quantifies the performance of a modulator for different polarizations. Since any incoming polarization can be thought of as the superposition of two mutually orthogonal polarizations, the performance of the modulator is specified with respect to two mutually orthogonal polarizations. The bandwidth specifies the range of modulation frequencies over which the device can be operated. For some modulators, the bias voltage required to keep the modulator operating properly may change over time. Therefore, constant monitoring of the bias point and its continuous adjustment using a feedback circuitry may be required.
