All-fiber high-resolution incoherent broadband spectrometer

Area of Science:

• Spectroscopy and Photonics
• Optical Engineering
• Biochemical Sensing

Background:

• Miniaturized spectrometers often compromise between wavelength range and spectral resolution.
• There is a need for robust, compact, and cost-effective spectroscopic devices for various applications.

Purpose of the Study:

• To develop and demonstrate an all-fiber optical spectrometer with simultaneously broad wavelength operation and high spectral resolution.
• To overcome the limitations of existing miniaturized spectroscopic instruments.

Main Methods:

• Utilized two cascaded Bragg gratings with synchronous control of grating lengths.
• Employed mechanical stretching of internal fiber for fast wavelength tuning.
• Demonstrated Doppler-limited spectroscopy using a near-infrared LED source.

Main Results:

• Achieved a record spectral resolution of 1 pm and a high wavelength span-to-resolution ratio.
• Demonstrated fast, millisecond-timescale wavelength tuning over several nanometers.
• Obtained gas absorption spectra comparable to laser-based setups, with accurate retrieved gas-line parameters.

Conclusions:

• The developed all-fiber spectrometer offers superior performance for miniaturized spectroscopic devices.
• It is suitable for high-resolution interrogation of fiber-optic sensors and broadband imaging.
• This technology advances portable biochemical sensing and spectroscopic applications.