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Reducing residual amplitude modulation in electro-optic phase modulators by erasing photorefractive scatter
1Applied Optics and Nanotechnology, Science and Engineering Faculty, Queensland University of Technology, QLD 4001, Australia. juna.sathian@qut.edu.au
Optics Express
|June 6, 2013
Summary
Residual amplitude modulation (RAM) noise in electro-optic phase modulators increases with intensity. Introducing an intense optical beam can reduce this unwanted noise to below 10(-5).
Area of Science:
- Optoelectronics
- Materials Science
- Photonics
Background:
- Residual amplitude modulation (RAM) is a significant noise source in electro-optic phase modulators.
- Understanding the behavior of RAM is crucial for improving modulator performance.
Purpose of the Study:
- To analyze the intensity-dependent behavior of RAM in MgO:LiNbO(3) modulators.
- To develop a model explaining RAM fluctuations.
- To demonstrate a method for reducing RAM.
Main Methods:
- Analysis of RAM magnitude and phase in MgO:LiNbO(3) modulators.
- Development of a phenomenological model based on photorefractive scattering.
- Experimental demonstration of RAM reduction using an intense optical beam.
Main Results:
- RAM magnitude increases with optical intensity.
- RAM phase becomes less defined at higher intensities, leading to temporal fluctuations.
- A phenomenological model accurately describes the observed RAM behavior.
- RAM was successfully reduced to below 10(-5) by erasing photorefractive scatterers.
Conclusions:
- The intensity-dependent behavior of RAM is linked to evolving photorefractive scattering centers.
- Photorefractive scattering is a key mechanism contributing to RAM in MgO:LiNbO(3) modulators.
- Intense optical beams offer an effective method for mitigating RAM noise in electro-optic modulators.
