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Measuring the coherence function of continuous-wave lasers by a photorefractive grating method
P Pogany1, H J Eichler, J Dziambor
1Optisches Institut, Technische Universität Berlin, Strasse des 17, Juni 135, 10623 Berlin, Germany. pogany@physik.tu-berlin.de
Applied Optics
|February 29, 2008
Summary
We developed a simple method to measure the temporal coherence of semiconductor lasers using photorefractive crystals. This technique is adjustment-insensitive and validated by spectral measurements, offering accurate coherence function determination.
Area of Science:
- Optics and Photonics
- Semiconductor Laser Technology
- Materials Science
Background:
- Characterizing the temporal coherence of semiconductor lasers is crucial for applications like optical communications and sensing.
- Existing methods for measuring temporal coherence can be complex and sensitive to experimental adjustments.
Purpose of the Study:
- To demonstrate a simple, adjustment-insensitive technique for measuring the temporal coherence function of continuous-wave (cw) multimode and monomode semiconductor lasers.
- To validate the technique by comparing results with independent spectral measurements.
Main Methods:
- Utilized two-beam coupling in photorefractive Indium Phosphide (InP) and Cadmium Telluride (CdTe) crystals.
- Independently measured the emission spectra of the semiconductor diodes.
- Calculated coherence functions from the measured spectra for comparison.
Main Results:
- Successfully measured the temporal coherence function of semiconductor lasers using the photorefractive two-beam coupling technique.
- The coherence functions obtained from photorefractive measurements showed excellent agreement with those calculated from the emission spectra.
- Theoretical description of wave coupling in photorefractive media was provided.
Conclusions:
- The demonstrated technique offers a simple and robust method for determining the temporal coherence of semiconductor lasers.
- The agreement between photorefractive measurements and spectral calculations validates the proposed technique.
- The study provides the operational parameter range for the accurate application of this coherence measurement method.
