What is the maximum Bandwidth? - Sixty Symbols
Why Physics Stack Exchange recommends it
Physics Stack Exchange users link it when explaining or questioning why pulsed or switched light contains multiple frequencies and how that relates to bandwidth and the energy-time uncertainty principle.
Recommended by 1 people across 1 different months, 2013 to 2019.
What it is
A Sixty Symbols video in which Professor Mike Merrifield of the University of Nottingham explains the limit on how much data a fibre optic cable can carry. He shows that switching a light source on and off spreads it over a range of frequencies, which sets a bandwidth limit tied to the energy-time uncertainty relation. It is a short conversation-style explainer made by Brady Haran.
What people said
Recommends Wouter · 2013-12 · Physics Stack Exchange · on “Light pulses and energy-time uncertainty principle”
I suggest this YouTube video [this video] as well. It basically talks about the energy-time uncertainty principle in very understandable terms and also deals with the situation where you periodically interrupt a light wave.
Cites luckyseven · 2017-05 · Physics Stack Exchange · on “What is the relationship between bitrate and bandwidth for optical channels?”
I would like to know what the relationship between bitrate and the width of spectrum that needs to be assigned to an optical channel is; assuming the channel uses an OOK modulation format such as RZ or NRZ. Context - First of all I would like to start with, I am not a physicist, and so I don't necessarily understand everything involved with this. I am a computer scientist currently studying routing algorithms over fibre optics in the presence of impairments, specifically in flexi-grid networks; and as part of that I need to build a somewhat realistic simulator. I know that the higher the bitrate of a signal the higher the optical bandwidth required to transmit that signal, and that different
Cites Doddy · 2017-05 · Physics Stack Exchange · on “Does switching a laser on create multiple frequencies?”
I have been fascinated by a Sixty Symbols YouTube video [this video] on the topic of the maximum bandwidth that can be sent down an optical cable. In summary, we are informed of how a laser, which emits red light of one frequency, only does so when it is permanently on. Turning it on or off causes nature to create new frequencies which somehow facilitate the wave being there when it's on, and not when it isn't. Since I'm a musician, I can place a loudspeaker in a medium such as air, and connect it to a sine wave generator in series with a switch. When the switch is open, no sound is generated, but close the switch and the loudspeaker outputs a sine wave. If I were to close the switch precisely wh
Cites user220778 · 2019-02 · Physics Stack Exchange · on “Wavelength of Intermittent Laser vs Prism”
The following YouTube video from Sixty Symbols ( What is the maximum Bandwidth? - Sixty Symbols [this video] )states that only a laser which always shines truly shines as a single frequency (df = (or ~=) 0). A laser which is active only long enough to send a good pulse of coherent light must contain all of the frequencies necessary to shorten that pulse, where df * dt =1. No need to mess with the frequencies present -- the nature of the thing will ensure that sufficient distribution of frequencies are present. If I shine a laser pulse through a prism, intuition says that I still only get a single spectral line coming out. Is this consistent? Is my intuition wrong, and the pulse of coherent light