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On the interrelations between an optical differentiator and an optical Hilbert transformer.
1Photonics Research Centre, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore. eqnngo@ntu.edu.sg
Optics Letters
|March 16, 2011
Summary
A novel optical Hilbert transformer (OHT) acts as both a temporal optical differentiator and a phase shifter. This integrated-optic device offers versatile functionalities for advanced optical signal processing.
Area of Science:
- Photonics and optical engineering
- Signal processing
Background:
- Optical Hilbert transformers (OHTs) are crucial for applications like single-sideband modulation.
- Temporal optical differentiators (ODs) are essential for complex signal analysis and generation.
Purpose of the Study:
- To demonstrate a practically realizable first-order optical Hilbert transformer (OHT).
- To show that the OHT can simultaneously perform temporal optical differentiation and phase shifting.
Main Methods:
- Analytical and numerical simulations were employed.
- A four-tap finite impulse response filter was designed using the Remez iteration algorithm.
- An integrated-optic OHT was numerically verified.
Main Results:
- The OHT functions as a first-order temporal optical differentiator (negative/positive) in the stopband.
- The OHT provides broadband ±90° phase shifting in the passbands.
- The designed integrated-optic OHT was numerically validated.
Conclusions:
- A single first-order OHT design can achieve multiple functionalities.
- This integrated-optic device offers a versatile platform for optical signal processing applications.
- The proposed OHT is practically realizable and numerically verified.
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