Unit of Thermal Noise

[Zulia Nurul Karimah]

Please help me give an explanation about the unit of thermal noise formula for ohmic in APD photodetector.
1. for W/H
2. for A/Hz
Like how we get those units since the formula is 4KTB/R then J/K.K.Hz/ohm then we got J.Hz/ohm.

Thank you in advance 🙂

[Hamza Ali Abbas Khan]

You may refer to these papers for the same
http://www.svphotonics.com/pub/pub029.pdf
https://books.google.co.in/books?id=ok0XX-3MgMoC&pg=PA528&lpg=PA528&dq=unit+of+thermal+noise+in+optical+fiber+communication&source=bl&ots=LfVayyUrq-&sig=LUfb6CxrJnLv0Kq1AyjPZJM9nEc&hl=en&sa=X&ved=0ahUKEwiQ6K66suXMAhXn5KYKHRAMCZAQ6AEIJDAB#v=onepage&q=unit%20of%20thermal%20noise%20in%20optical%20fiber%20communication&f=false
http://www.optics.rochester.edu/users/gpa/opt428c.pdf

I hope this clears your doubts.
Thanks

[Hamza Ali Abbas Khan]

you can also refer to this book

https://books.google.co.in/books?id=5JeN4QhYo8kC&pg=PA332&lpg=PA332&dq=unit+of+thermal+noise+in+optical+fiber+communication&source=bl&ots=Z_Y_mWs-2x&sig=p6oc0P_UJUwxry6rJ_UqQkYqjy4&hl=en&sa=X&ved=0ahUKEwiQ6K66suXMAhXn5KYKHRAMCZAQ6AEIKjAD#v=onepage&q=unit%20of%20thermal%20noise%20in%20optical%20fiber%20communication&f=false

[Karan Ahuja]

Hi.

I want to mention that thermal noise or Nyquist noise is the electronic noise generated by the thermal agitation of the charge carriers (usually the electrons) inside an electrical conductor at equilibrium, which happens regardless of any applied voltage. The generic, statistical physical derivation of this noise is called the fluctuation-dissipation theorem, where generalized impedance or generalized susceptibility is used to characterize the medium.

Thermal noise in an ideal resistor is approximately white, meaning that the power spectral density is nearly constant throughout the frequency spectrum (however see the section below on extremely high frequencies). When limited to a finite bandwidth, thermal noise has a nearly Gaussian amplitude distribution

You may refer to http://prola.aps.org/pdf/PR/v29/i2/p350_1

[Karan Ahuja]

I am attaching few more links of papers regarding the units.

http://www.physics.utoronto.ca/~phy225h/experiments/thermal-noise/Thermal-Noise.pdf
http://rfic.eecs.berkeley.edu/~niknejad/ee142_fa05lects/pdf/lect11.pdf
http://www.fis.unipr.it/~gigi/dida/strumentazione/harvard_noise.pdf

[Aabid Baba]

Hello Zulia Nurul,

You may go through this link
https://books.google.co.in/books?id=ok0XX-3MgMoC&pg=PA528&lpg=PA528&dq=unit+of+thermal+noise+in+optical+fiber+communication&source=bl&ots=LfVayyUrq-&sig=LUfb6CxrJnLv0Kq1AyjPZJM9nEc&hl=en&sa=X&ved=0ahUKEwiQ6K66suXMAhXn5KYKHRAMCZAQ6AEIJDAB#v=onepage&q=unit%20of%20thermal%20noise%20in%20optical%20fiber%20communication&f=false

Hope this will clear your doubts about the units.
Regards

[burhan num mina llah]

Hello Zulia,

I did not get your exact problem. As far as i remember you can the properties of the avalanche photodiode in optisystem and there you will find the units for the thermal noise.
By properties i mean the simulation parameters of the avalanche photodiode. I hope this will be be helpful.

Regards

Burhan

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