Simulator of Optical Pulse Propagation in Optical Fiber
Copyright(c) 1999 by Takahashi. All rights reserved.



-- Introduction --
In 1998, we developed a new simulator of optical pulse propagation in optical fiber.
In this simulator, we employed the most common technology called "Split Step Fourier Transform Method". We take only the terms of beta2, beta3, alpha and gamma into consideration, so if the pulse's width is too small(less than 100 fs), the higher order dispersion effects and other nonlinear effects become innegligible. In such case, slight modification of simulation program is necessary. If you need this verification, please contact to us.

This simulator is made by using Java, so you can take a look at the propagating pulse's pulse shape.
...isn't it cool??

-- How to use? --
It is just simple. First, please proceed to the simulator's location by just clicking the underlined part which is linked from underneath.
Simulator's panel is devided into 2 parts. Left part is for parameter input, right side is for display of the result.
Please input parameter values in the left side, units will be shown on the footer if you click the parameter's name.
After completing filling the form, please push "Start" button, which is located at the bottom part of input parameter's panel.
...Then the result will appear on the right side, in the display panel.
If you have ever tried to do this kind of simulation, you don't need the explanation of parameters, right? But for those who is now thinking "What the heck is this simulation?...", I will present some explanation about parameters.

Name Meaning Unit
alpha Fiber's Loss 1/m
beta2 second order Fiber dispersion s*s/m
beta3 third order Fiber dispersion s*s*s/m
gamma Nonlinearity of the Fiber rad/W/m
span fiber length m
step Calculation step m
power Pulse energy W
chirp Pulse chirp parameter rad/s
To Pulse width s
duration Window s

Please, please make sure those units. Slight mistake may lead to a serious mistake...
You may think "I have no idea what you are talking about?" ...I understand how you feel. I DO understand, because I used to be in the same situation that you are facing right now...so for those people, I will give you a simple, but powerful explanation about this simulator.

"When we make a phonecall to other country, do you know how the information of your voice trasported? Generally optical fiber is used as a propagation guide of transporting information, and optical pulse is used as a medium. This transmission is not perfect, and some additional noise(or loss) will occur during the propagation, just like we can talk to a person who is sitting around us, but cannot talk to a person who is at the opposite side of the cliff of Grand Canyon, in Arizona State, US. This is because our voice will be decreased during the propagation in the air. The same thing happens to optical pulse which is propagating in optical fiber.
And...we can simulate such effect with this simulator.
Generally, the smaller the width of the optical pulse is, the more information the pulse can transport. But if the width is smaller, the effect of unwelcomed phenomenon becomes greater, which lead to the state of unable to send information. So we can get to know with this simulator how narrow the width of pulse can become.
...this is an overall explanation about this simulator. Did you figure it out?? If you didn't, please send email to me.

Lastly, I hope many people are interested in optics by playing with this simulator!!

-- Simulation --


Two dimensional Simulator

Two dimensional Simulator with Time and Frequency domain

Three dimensional Simulator


-- Recommended CPU ability --
This simulator is made possible by using Java, but generally many computer which is currently existing cannot execute Java program quickly. The computer I am now using accompanies "Pentium II" processor. The java applet works very smoothly with this computer. So your computer's CPU ability may equal to or higher than Pentium II processor.

--- Related Links ---
Transform Limited Pulses (by Takushima Sensei)
Waveform and autocorrelation function (by Takushima Sensei)