How do you calculate the noise-equivalent power of a photodetector?

Measurement of Noise-equivalent Power That result has to be divided by the responsivity. For example, if a photodiode produces a photocurrent with a PSD of 1 nA / Hz1/2, and its responsivity is 0.5 A/W, the NEP is 1 nA / Hz1/2 / 0.5 A/W = 2 nW / Hz1/2.

How is NEP measured?

The NEP defines the incident optical power required to obtain a signal-to-noise ratio (SNR) of 1. For example, when detecting a signal in a Δf = 10 kHz bandwidth with a detector of NEP = 1 pW/√Hz, the optical power required for a SNR of 1 is NEP x (Δf)1/2 = 100 pW. Usually, the NEP is obtained by measuring G and vn.

What is photodetector noise?

Photo detector noise is that undesired disturbance masks the signal in communication system. Read more. Gec bharuch. Photo detector noise is that undesired disturbance masks the signal in communication system. Read more.

What are the noise sources in photodetector?

1 Sources of photodetection noise. Major noise sources in a photodiode can be categorized as thermal noise, shot noise, and dark current noise. Because of the random nature of the noises, the best way to specify them is to use their statistical values, such as spectral density, power, and bandwidth.

How is photodetector bandwidth measured?

“Voltage” Bandwidth = “Optical” Bandwidth In analog, microwave applications the frequency response of a photodetector is often measured by using a microwave power meter, which gives a reading proportional to the square of the output voltage and therefore results in a power spectrum (see Figure 3).

What is NEP in photodiode?

Noise-equivalent power (NEP) is a measure of the sensitivity of a photodetector or detector system. It is defined as the signal power that gives a signal-to-noise ratio of one in a one hertz output bandwidth.

What is a photodetector used for?

Photodetectors are sensors that can convert the photon energy of light into electrical signal. They are absolutely necessary for various scientific implementations like fiber optic communication systems, process control, environmental sensing, safety and security, and also in defense-related applications.

How do you reduce shot noise?

This is accomplished by adding low pass filters after the signal is amplified. Here, q is the charge on an electron (in Coloumbs) and Δf is the bandwidth of the detector. This quadratic relationship to DC current suggests that using small currents in the circuit can significantly reduce the shot noise contribution.

Why is it called pink noise?

Pink noise is one of the most common signals in biological systems. The name arises from the pink appearance of visible light with this power spectrum. This is in contrast with white noise which has equal intensity per frequency interval.

Why is it called white noise?

The noise types are named for a loose analogy to the colors of light: White noise, for example, contains all the audible frequencies, just like white light contains all the frequencies in the visible range.