Pulse Train Calculator

About this calculator

This calculator is used to calculate various useful properties of an optical pulse train. Input parameters include pulse duration, repetition rate, average power, and (for intensity calculations) optional spot diameter. First, the calculator gives the duty cycle D, which is the product of the pulse duration T and the repetition rate f, and essentially represents the proportion of time that the optical power is "on."

Duty cycle D = pulse duration T × repetition rate f

The calculator then also calculates the pulse energy, which is the average power divided by the repetition rate:

Pulse energy E_pulse = average power P_avg / repetition rate f

Next, assuming a rectangular pulse shape, the peak power is simply calculated by dividing the pulse energy by the pulse duration:

Peak power P_peak = pulse energy E_pulse / pulse duration T

However, for Gaussian and sech pulses, a correction factor is required to obtain the correct peak power.

The peak power of a Gaussian pulse P_peak,Gaussian ≈ 0.94 × (pulse energy E_pulse / pulse duration T)

The peak power of a sech pulse P_peak,sech² ≈ 0.88 × (pulse energy E_pulse / pulse duration T)

The duration of the pulse interval or repetition period is the inverse of the repetition rate.

The pulse interval ΔT = 1 / repetition rate f

Finally, the intensity is calculated by dividing the power (average power or peak power) by the spot area, which is A = πw², where w = d/2 is the spot radius.

Intensity I = Power P / Spot Area A