Narrow Linewidth Lasers

Single frequency lasers with a narrow optical emission spectrum.

A number of laser applications require lasers with a very small optical linewidth, with a narrow optical spectrum. Narrow-linewidth lasers usually applies to single-frequency lasers, such lasers also exhibit low intensity noise.

In order to produce a narrow emission bandwidth (linewidth) for a laser, firstly it need to be a single-frequency laser, secondly external noise influences must be minimized.


A particularly important field is the sensors, fiber-optic sensors for strain and/or temperature, various types of interferometric sensing, trace gas detection with differential absorption LIDAR (DIAL), or wind speed measurements with Doppler LIDAR. Linewidths of only a few kilohertz are required for some fiber-optic sensors, whereas 100 kHz can be sufficient for.

Optical frequency metrology requires sources with very narrow linewidth, often achieved with stabilization techniques.

Normally less demanding in terms of linewidth are applications in optical fiber communications, in transmitters or for test and measurement purposes.