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Published on: August 30, 2012
Long-period-grating in a trench assisted planar optical waveguide
Nandam Ashok1, Vipul Rastogi, Ajeet Kumar
1Department of Physics, Indian Institute of Technology Roorkee, Roorkee, India. nandam.ashok@gmail.com
Applied Optics
|March 23, 2013
Summary
We developed a novel long-period grating in a planar optical waveguide with a low-index trench. This structure achieves ultrawide band rejection, enabling applications in filters and sensors.
Area of Science:
- Photonics and Waveguide Optics
- Nanophotonics
- Optical Engineering
Background:
- Long-period gratings (LPGs) are crucial components in optical signal processing.
- Controlling the transmission spectrum of LPGs is essential for advanced photonic devices.
- Introducing perturbations like trenches can modify LPG characteristics.
Purpose of the Study:
- To investigate the impact of a low-index trench in the cladding of a planar optical waveguide on LPG transmission spectra.
- To explore the potential of this structure for applications in optical filtering, sensing, and amplification.
Main Methods:
- Analysis of the waveguide structure using the transfer matrix method.
- Calculation of the grating's output spectrum via coupled mode theory.
- Numerical simulations to study the effects of trench parameters.
Main Results:
- The position, strength, and width of the trench significantly influence the grating's transmission spectrum.
- Observed triple resonance between coupled modes.
- Achieved ultrawide band rejection in the output spectrum.
Conclusions:
- The proposed planar optical waveguide with a low-index trench offers a versatile platform for optical device design.
- Demonstrated potential for wideband rejection filters, refractive index sensors, and gain equalization in amplifiers.
