noise eaters (original) (raw)

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

Page views in 12 months: 626

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

Content quality and neutrality are maintained according to our editorial policy.

📦 For purchasing noise eaters, use the RP Photonics Buyer's Guide — an expert-curated directory for finding all relevant suppliers, which also offers advanced purchasing assistance.

What is a Noise Eater?

A noise eater is a device 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 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.

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.

Frequently Asked Questions

What is a noise eater?

A noise eater is a device for reducing the intensity noise of a laser beam. It uses an electrically controlled attenuator to adjust the optical power based on real-time measurements, thereby stabilizing it.

How does a noise eater work?

It measures the laser beam's power, typically with a fast photodiode. This measurement is used in a control loop (either feedback or feedforward) to regulate an attenuator, such as an electro-optic modulator. The attenuation is increased for high power and decreased for low power.

When is it better to use a noise eater instead of direct laser stabilization?

A noise eater is an external device, which is a good solution when the laser itself is not suitable for internal modifications required for direct laser power stabilization.

Suppliers

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.