RP Photonics logo
RP Photonics
Modeling & Design Software
Technical consulting services on lasers, nonlinear optics, fiber optics etc.
Profit from the knowledge and experience of a top expert!
Powerful simulation and design software.
Make computer models in order to get a comprehensive understanding of your devices!
Success comes from understanding – be it in science or in industrial development.
The famous Encyclopedia of Laser Physics and Technology – available online for free!
The ideal place for finding suppliers for many photonics products.
Advertisers: Make sure to have your products displayed here!
powerful tools for efficient laser development and laser science
This page gives you an overview on our software products.
RP Fiber Calculator is a convenient tool for calculations on optical fibers.
RP Fiber Power is an extremely flexible tool for designing and optimizing fiber devices.
RP Resonator is a particularly flexible tool for laser resonator design.
RP ProPulse can simulate the pulse evolution e.g. in mode-locked lasers and sync-pumped OPOs.
RP Coating is a particularly flexible design tool for dielectric multilayer systems.
RP Q-switch can simulate the power evolution in Q-switched lasers.
Most of our software products support a powerful script language, which gives you an extraordinary degree of flexibility.
Here you learn about software license conditions, updates and upgrades, etc.
Competent technical support is a key quality associated with software from RP Photonics.
RP Photonics has distributors in various countries.
The RP Photonics Software News keep you updated on our developments and give the users additional interesting hints.
Here you can make inquiries e.g. concerning technical details, prices and quotations.
en | de

RP ProPulse – Numerical Simulation of Pulse Propagation

Example Case: Active Mode Locking

In this simple example, we consider an actively mode-locked laser. The laser resonator is described in the script as follows:

resonator: ring
* Crystal: gain(l) = g(l) [P_sat_av = P_sat_g, KK = 0]
* Modulator: mod(t) = t_mod(t)
* OC: T_out = T_OC
resonator end

This refers to some variable values, the definitions of which are not shown here. The gain function g(l) has a limited bandwidth of 0.2 nm, and the modulator modulates the resonator round-trip losses with 100 MHz and peak losses of 10%.

The initial pulse duration was chosen to be somewhat longer than in the steady state. It is found that the steady-state value of the pulse duration agrees with the result of Kuizenga–Siegman theory (see the diagram below).

evolution of pulse duration

The script code required for that diagram is pretty simple:

; ---------------------------
diagram 1:
 
"Evolution of Pulse Parameters"
 
x: 0, 20000
"number of round trips", @x
y: 0, 300
"pulse duration (ps)", @y
frame
legpos 200, 160
hx
hy
 
tau_th := 0.45 * ((0.5 * T_OC) / (0.25 * A_mod))^0.25 / sqrt(f_mod * df_g)
 { theoretical value for steady-state pulse duration
   according to Kuizenga-Siegman theory }
 
f: tau_th / ps,
  "steady-state value from theory",
  style = dashed, width = 3
 
f: (getpulse(x / rt_per_step,0); tau()) / ps,
  "numerical simulation", color = blue, width = 3

Also, we can see the temporal pulse profile after 2000 resonator round trips (which are calculated within a few seconds on an ordinary PC):

profile of output pulse

(back to the list of example cases)

arrow