Relative intensity noise

Relative intensity noise (RIN), describes the instability in the power level of a laser. The noise term is important to describe lasers used in fiber-optic communication and LIDAR remote sensing.

Additional recommended knowledge

What is the Correct Way to Check Repeatability in Balances?

How to ensure accurate weighing results every day?

Better weighing performance in 6 easy steps

Relative intensity noise can be generated from cavity vibration, fluctuations in the laser gain medium or simply from transferred intensity noise from a pump source. Since intensity noise typically is proportional to the intensity, the relative intensity noise is typically independent of laser power. RIN typically falls off with frequency and is a kind of pink noise.

Relative intensity noise is measured by sampling the output current of a photodetector over time and transforming this data set into frequency with a fast Fourier transform. RIN is usually presented as relative noise power in decibels per hertz at one or several intensities.

See also

• Shot noise

External reference

• Intensity noise in Encyclopedia of Laser Physics and Technology