Channel-spacing tunable silicon comb filter using two linearly chirped Bragg gratings

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• Comb filters are crucial optical components in wavelength-division multiplexing (WDM) systems.
• Existing tunable comb filters often face limitations in tuning range or complexity.

Purpose of the Study:

• To propose and numerically analyze a novel silicon-based tunable optical comb filter.
• To demonstrate continuous tuning of channel spacing using the thermo-optic effect.

Main Methods:

• Utilizing a Michelson interferometer configuration.
• Employing a pair of apodized linearly chirped Bragg gratings (ALC-BGs).
• Leveraging the thermo-optic effect to tune the effective refractive index.

Main Results:

• Achieved continuous tuning of channel spacing from 8.21 nm to 0.19 nm.
• Demonstrated an out-of-band rejection ratio exceeding 30 dB.
• Validated the proposed silicon photonic comb filter design through numerical calculations.

Conclusions:

• The proposed silicon-based comb filter offers a wide and continuous tuning range for channel spacing.
• The device exhibits excellent out-of-band rejection, suitable for advanced optical communication systems.
• This tunable comb filter represents a significant advancement in silicon photonics for telecommunications.