Extinction Ratio

Exail header intensity modulators

What is Extinction Ratio?

Extinction ratio is a measure of the difference between the maximum and minimum optical power produced by an optical modulator or other photonic device. It is typically expressed in decibels (dB) and indicates how effectively a device can distinguish between its high-power and low-power states.

A high extinction ratio means that the minimum optical power is very low compared with the maximum power, which is important for accurate optical signal modulation and transmission.


HOW Extinction Ratio Works

Extinction ratio quantifies how effectively an optical device switches or modulates between high and low optical power states. In an intensity modulator, it is determined by comparing the optical power in the "on" and "off" states.

Maximum transmission

The modulator is driven to its high-transmission state, producing the maximum output optical power.

Minimum transmission

The modulator is driven to its low-transmission state, where ideally no optical power would be transmitted.

Power comparison

The ratio between these two optical power levels determines the extinction ratio. A higher value indicates better suppression of the unwanted optical signal.