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Bandwidth enhancement of electro-optic sensing using high-even-order harmonic sidebands.
Dong-Joon Lee1, John F Whitaker
1Center for Electromagnetic Wave, Korea Research Institute of Standards and Science, 1 Doryong-dong, Yusong-gu, Daejeon 305-340, Republic of Korea. dongjoonlee@kriss.re.kr
Optics Express
|August 19, 2009
Summary
High-order harmonic sidebands in electro-optic sensing significantly enhance bandwidth. This method expands sensing frequency range by four times, enabling broadband microwave detection without distortion.
Area of Science:
- Photonics
- Electrical Engineering
- Applied Physics
Background:
- Electro-optic sensing systems are crucial for measuring electromagnetic fields.
- Current systems face limitations in bandwidth and sensing range.
- Enhancing nonlinearity in modulation is key to overcoming these limitations.
Purpose of the Study:
- To demonstrate significant bandwidth enhancement in electro-optic sensing.
- To explore the use of high-order even harmonic sidebands for improved performance.
- To enable broadband detection of microwave fields without nonlinear distortion.
Main Methods:
- Utilizing two cascaded electro-optic modulators to generate even-order harmonic sidebands (order > 2).
- Analytical description of harmonic modulation sidebands up to the sixth order.
- Photonic heterodyne down-conversion of microwave signals using these harmonics.
Main Results:
- Achieved a four-fold expansion of the sensing frequency range compared to fundamental harmonics.
- Successfully generated and utilized up to sixth-order harmonic sidebands.
- Extracted transverse near-field distributions of an 18.5 GHz patch antenna using fourth- and sixth-order harmonics.
Conclusions:
- High-order even harmonic sidebands offer a robust method for significantly enhancing electro-optic sensing bandwidth.
- This technique provides broadband microwave detection capabilities without nonlinear distortion.
- The demonstrated approach opens new possibilities for advanced electromagnetic field measurements.
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