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Optical SSB modulator/frequency shifter with ultralow spurious sidebands
Applied Optics
|September 9, 2020
Summary
This paper introduces a novel optical modulator using Sagnac interferometers for ultralow spurious sidebands. The design offers robust performance and tunable carrier-to-sideband ratios for advanced optical signal processing.
Area of Science:
- Photonics
- Optical Communications
- Signal Processing
Background:
- Optical modulators are crucial for signal processing.
- Existing designs often suffer from spurious sidebands and DC bias drift.
- Achieving suppressed-carrier signals with high purity is essential for advanced applications.
Purpose of the Study:
- To theoretically investigate and report a novel optical single-sideband suppressed-carrier (OSSB-SC) modulator/frequency shifter.
- To achieve ultralow spurious sidebands and robust performance.
- To enable tunable optical carrier-to-sideband ratios (OCSR).
Main Methods:
- The proposed structure utilizes three Sagnac interferometers (SIs) and two bidirectional phase modulators (PMs).
- Four radio frequency (RF) signals with equal powers and controlled phases drive the PMs.
- Analytical investigation and simulations using commercial software were employed.
Main Results:
- An OSSB-SC signal with only (4n+1)th-order sidebands is generated.
- An OSSB with carrier (OSSB+C) modulator with tunable OCSR is achievable.
- The structure demonstrates robustness against environmental perturbations and DC bias-drift due to the SI-based design.
Conclusions:
- The proposed SI-based modulator offers superior performance with ultralow spurious sidebands.
- The design provides flexibility for tunable OCSR, enhancing its applicability.
- The robustness and lack of DC bias requirement make it suitable for practical optical systems.
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