Duty Cycle is a term most often used for pulsed lasers. It defines the fraction of time for which the laser output is available. In other words, it is the maximum amount of time that the laser can remain in the ‘ON State’ before it goes into an OFF state.

Duty cycle is the ratio of pulse width which is the time duration between the rising and falling edges of a pulse, to the total period of the signal which is the time taken for it to complete one on-and-off cycle.

Duty cycle is sometimes called duty factor and is expressed as the percentage of ON time. For example, a 75% duty cycle refers to a signal that is ON 75% of the time and remains in the OFF state for 25% of the time. The absence of a signal is referred to as 0% duty cycle and a 100% duty cycle signifies a wave which is always in the ON state, i.e. a continuous wave.