Dear Sanjay,
There is optical and electrical amplitude modulator components in OptiSystem. You may check the examples in the example library for more information on both components.
Typically, we use optical AM modulator to modulate a laser light with a signal and control its amplitude depending where on the LI curve you make the modulation. However, the carrier is the laser frequency which is for example 193.1THz. To create DSB signal there are different tricks that you need to use. Please refer to the example library in OptiSystem for more information on this topic.
Regards,
Ahmad