Calculating Photodetector sensitivity

Hello Domail Singh. Greetings.

Why do you need to calculate the receiver sensitivity when you can set it in the global parameters itself. What for you need to calculate it?

With Regards
Atul Sharma

Hi Domail Singh,
Through Responsivity, we measures the input–output gain of a detector system. In the specific case of a photodetector, responsivity measures the electrical output per optical input.
It is the ratio of output current or voltage to the radiation energy.
The responsivity of a photodetector is usually expressed in units of either amperes or volts per watt of incident radiant power.

R = Eta* lambda (in micrometer)/1.24
eta is the quantum efficiency

The responsivity is generally defined for the steady state.

The term responsivity sensitivity are not same, the latter is the lowest detectable light level, which is typically determined by detection noise and significantly influenced by the required detection bandwidth.

A photodetector should ideally be operated in a spectral region where its responsivity is not far below the highest possible value.

Seeking your response.

Thanks and regards
Rajguru

Hi Domail Singh,

What kind of mathematical model ? Can you please specify I don’t understand what you mean to ask ?

Regards
Ankita

Hi all,

If Domail was looking for mathematical expression then i think Rajguru has just posted it for you. I hope your query is solved.

Thank you

Hello Domail

The formula for reciever sensitivity is given as:
Sensitivity=10×log10(kTB)+NF+C⁄N
You can refer to this link for more info
http://www.highfrequencyelectronics.com/index.php?option=com_content&view=article&id=553:receiver-sensitivity-and-equivalent-noise-bandwidth&catid=94:2014-06-june-articles&Itemid=189

I hope it will be useful.
Regards
Shafeen

Hi Shafeen,

I think you are correct about the formula for receiver sensitivity…
Thanks

Regards

Hi Shafeen,

Thanks for the link.. It is indeed very useful…

Regards

Thank you shafeen al yasin,
For sharing such important information.
Are you sure this formula is valid for photodiode as you have use formula for sensitivity of a receiver by using following performance parameters: the noise figure (NF), the ENBW, and the carrier to noise ratio (C/N) required to achieve the desired quality signal.

I think this formula is used for photodetector as: The responsivity of a photodetector is usually expressed in units of either amperes or volts per watt of incident radiant power.

R = Eta* lambda (in micrometer)/1.24
eta is the quantum efficiency.

Seeking your response.

Hello Domail.

You have already the value for receiver sensitivity available in the global layout parameters. What is the purpose of recalculating it. You may check the dialog box for receiver sensitivity. I hope it is helpful.

Regards
Remo

Hi Domail,

Well I hope you got the desired information..

Regards
Ankita

Hello Domail.

I agree with Domail that you have already have the value for receiver sensitivity available in the global layout parameters…. You may check the dialog box for receiver sensitivity. I hope it is helpful.

Regards

Hi all,

Thanks for the information..

Indeed a very nice discussion…

Hi Jyoti,
As we know a system’s sensitivity is the inverse of the stimulus level required to produce a threshold response, with the threshold typically chosen just above the noise level.
I think in case of photodetector, we only calculate responsivity not sensitivity.

As Responsivity measures the amount of output swing produced by a specified input swing while how “sensitive” a detector is, because you can always take an electrical signal and boost it with an low-noise amplifier. If you did this, your responsivity would go up, but the noise intrinsic to the detector would also be boosted (i.e., your signal-to-noise ratio would remain the same). There are multiple definitions for sensitivity; one common one is the noise-equivalent power, which is the amount of power required on the photodetector to produce a signal-to-noise ratio of 1.

So, it is confusion between them.

Hi Domail
Responsivity R of a photodiode is a measure of the sensitivity
to light, and it is defined as the ratio of the photocurrent IP to the
incident light power P at a given wavelength:
R = Ip/P

With Regards
Syed

HI Domail,

I agree that in case of photodetector, we only calculate responsivity not sensitivity… The formula for calculating responsivity is mentioned by fareed.. Hope this helps

Hi Domail,

You are welcome..

Thanks and regards

Hi All,
It was an informative discussion. Thank you All.

Regards
Shafeen

Hi Shafeen,

Yes I agree it was an informative discussion..

Regards
Rahul Tiwari

Hi All,
This has been a good discussion indeed. Keep it up. This way one gets a booster i appreciate you all.

Regards
Kanwarjeet

The receiver sensitivity can be defined as the minimum average
optical power at given BER. There is a lot of parameters which contribute to the optical receiver sensitivity by following equation:
Optical sensitivity is given by:
Sen (dBm) = 10log[(OMA*(re+1))/((re-1)*2000)]
– re is the extinction ratio of the received optical signal
– OMA is the optical modulation amplitude:
OMA = Ipp/ρ (in μW)
– ρ is the photodetector responsivity (A/W)
Hope it can be useful for you

Ref: Accurately Estimating Optical Receiver Sensitivity – MAXIM intergrated