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Silicon-on-insulator free-carrier injection modulators for the mid-infrared
Optics Letters
|February 16, 2019
Summary
Silicon-on-insulator waveguide modulators operating at 3.8 μm demonstrate the free-carrier effect for optical attenuation and phase shifting. These devices achieve significant modulation depths and operate at high data rates.
Area of Science:
- Photonics and Optical Engineering
- Semiconductor Device Physics
Background:
- Free-carrier effects in silicon waveguides are crucial for optical modulation.
- Existing modulators face challenges in efficiency and operating wavelength.
Purpose of the Study:
- To demonstrate silicon-on-insulator (SOI) waveguide modulators operating at 3.8 μm.
- To leverage the free-carrier effect for both optical attenuation and phase shifting.
Main Methods:
- Utilized PIN diodes for carrier injection into SOI waveguides.
- Configured devices for free-carrier electroabsorption (variable optical attenuator) and electrorefraction (Mach-Zehnder interferometer phase shifter).
Main Results:
- Achieved 34 dB modulation depth for optical attenuation.
- Demonstrated a VπLπ of 0.052 V·mm and 22 dB DC modulation depth for phase shifting.
- Successfully modulated signals at data rates up to 125 Mbit/s.
Conclusions:
- SOI waveguides are effective for mid-infrared (3.8 μm) free-carrier modulation.
- The demonstrated devices offer high performance for optical attenuation and phase shifting applications.
- These modulators show promise for integrated photonic circuits operating at longer wavelengths.
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