Compact on-chip spectrometer with high spectral channel density using cascaded filters

Area of Science:

• Photonics
• Spectroscopy
• Integrated Optics

Background:

• Chip-scale spectrometers are crucial for spectroscopy but face challenges in miniaturization and channel density.
• Existing on-chip spectrometers struggle with balancing compact size and a large number of spectral channels.

Purpose of the Study:

• To propose and demonstrate an ultra-compact computational spectrometer.
• To overcome the limitations of existing on-chip spectral analysis devices.

Main Methods:

• Utilized a silicon-on-insulator platform for device fabrication.
• Cascaded eight micro-ring resonators and a waveguide Bragg grating for spectral filtering.
• Employed a single heater for thermo-tuning the device.

Main Results:

• Achieved a spectral resolution of 0.17 nm.
• Demonstrated an operating bandwidth of 60 nm.
• Obtained a high spectral-channel-to-footprint ratio of 88,000 channels/mm².

Conclusions:

• The developed spectrometer offers an ultra-compact solution for integrated spectroscopy.
• The high spectral-channel-to-footprint ratio addresses the need for miniaturized spectrometers with numerous channels.
• This technology presents a viable path towards highly integrated spectroscopic systems.