Noise Eaters

Author: the photonics expert Dr. Rüdiger Paschotta (RP)

Definition: devices for reducing the intensity noise of an optical beam by automatically adjusting the degree of power attenuation

Categories: article belongs to category photonic devices photonic devices, article belongs to category fluctuations and noise fluctuations and noise

DOI: 10.61835/mgh Cite the article: BibTex plain text HTML Link to this page LinkedIn

A noise eater is a device made for reducing the intensity noise in a laser beam. The principle of operation is that the optical power is reduced with an electrically controllable attenuator, and the control signal is derived from the input power (feedforward scheme) or the output power (feedback scheme) as measured with, e.g., a fast photodiode. Essentially, the attenuation is increased when the power is measured to be too high, and vice versa. This makes it possible to stabilize the laser power, i.e., to decrease intensity noise.

The most common approach is that based on an electronic feedback loop, e.g. of a PID type. An electro-optic modulator can be used to control the power throughput with a high servo bandwidth. Proper design of the feedback electronics is vital for achieving effective noise suppression over a large bandwidth. Alternatively, it is possible to use a feedforward method.

An alternative method is to directly influence the laser output power with some technique of laser stabilization. However, a noise eater can be a good solution if the laser is not suitable for such an intervention.

More to Learn

Encyclopedia articles:

Suppliers

The RP Photonics Buyer's Guide contains two suppliers for noise eaters.

Questions and Comments from Users

Here you can submit questions and comments. As far as they get accepted by the author, they will appear above this paragraph together with the author’s answer. The author will decide on acceptance based on certain criteria. Essentially, the issue must be of sufficiently broad interest.

Please do not enter personal data here. (See also our privacy declaration.) If you wish to receive personal feedback or consultancy from the author, please contact him, e.g. via e-mail.

By submitting the information, you give your consent to the potential publication of your inputs on our website according to our rules. (If you later retract your consent, we will delete those inputs.) As your inputs are first reviewed by the author, they may be published with some delay.