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What are the disadvantages of using a single mode Fabry-Perot laser diodes in interferometry, as opposed to distributed feedback laser diodes? I'm specifically interested in potential problems that FB laser diodes could cause when used in Michelson or Mach-Zehnder interferometers, due to a wider spectrum of FB lasers as oppsed to DFB lasers. Are any commercial interferometers employing single mode FB laser diodes?

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    $\begingroup$ A good place to start with this kind of question is the RP Photonics Encyclopedia. For example, see the articles on Fabry–Perot Laser Diodes and Distributed Bragg Reflector Lasers. If that doesn't get you what you need, see the Buyer's Guide. Manufacturers often will help you get components suited to your needs. $\endgroup$
    – mmesser314
    Feb 21 at 22:43
  • $\begingroup$ You start out asking about Fabry-Perot lasers, but then you talk about "FB" laser diodes. What's an "FB" laser diode? Second question: Do you even have a source where you can buy a Fabry-Perot laser diode? They're just not that common on the market, at least in the wavelength and power ranges I'm familiar with. $\endgroup$
    – The Photon
    Feb 22 at 0:15

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I'm specifically interested in potential problems that FB laser diodes could cause when used in Michelson or Mach-Zehnder interferometers, due to a wider spectrum of FB lasers as oppsed to DFB lasers.

Wider linewidth will mean lower contrast in the interference fringes, and shorter coherence length. Shorter coherence length will mean smaller optical path differences can be tolerated before the contrast drops substantially.

A bare FP laser (without some kind of feedback stabilization) will also have greater variation of wavelength due to temperature changes than a DFB, making the interferometer less accurate as a measurement tool for displacement or index of a sample.

The FP laser is also going to be less tolerant of back-reflections (although they can also cause problems for DFB's).

Are any commercial interferometers employing single mode FB laser diodes?

I don't even know of any commercially available FP lasers, but my experience is limited to a fairly small range of wavelengths and operating powers.

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