Sweep frequency laser light source based on hyperfine tuned filter

Abstract

The invention discloses a sweep frequency laser light source based on a hyperfine tuned filter. An annular laser oscillation cavity is formed by a semiconductor light amplifier, two polarization controllers, a dispersion control delay line, a circulator, the hyperfine tuned filter and an optical fiber coupler. The hyperfine tuned filter mainly consists of a double-grating combined dispersion system of expanded beam grating-auto-collimation beam grating based on a Littman-Littrow structure and a rotary polygonalmirror. The double-grating layout based on the Littman-Littrow structure utilizes the dispersion and beam expanding ability of the expanded beam grating to improve the caliber of the incident light of the auto-collimation beam grating, form different deviations to the auto-collimation condition of the auto-collimation grating by different coloured lights and improve the angle dispersion ability of the double-grating combined dispersion system. In addition, reasonable matching of grating parameters, incident angles and diffraction efficiency can be easily realized. The tuned filter based on the double-grating and the rotary polygonalmirror can simultaneously ensure the hyperfiness of tuning and high transmissivity of the whole tuning range.

Description

technical field [0001] The invention relates to frequency-sweeping optical coherence tomography technology, in particular to a frequency-sweeping laser light source based on an ultra-fine tuned filter. Background technique [0002] Optical coherence tomography (OCT) can non-invasively and non-invasively perform high-resolution three-dimensional imaging of the internal structure and physiological functions of living tissues, and is widely used in biomedical optical imaging. Optical frequency domain imaging (swept frequency OCT) is a new generation of OCT technology, which has only been developed for more than ten years so far. It uses a broadband and fast-tuned frequency-swept laser source and a point detector to detect interference signals. Frequency-swept OCT has the characteristics of tomography, high-resolution, and multi-information. It is expected to become an "optical microbiopsy technology" in clinical medicine to implement clinical functions such as screening of high...

AI Technical Summary

Problems solved by technology

The second form of light irradiates the grating three times successively, which improves the instantaneous line width, but is highly sensitive to the incident angle, and it is difficult to match the high diffraction efficiency

The final limiting factor of the frequency sweep speed of this technology is the frequency sweep speed of the tuned filter, while the frequency sweep speed of the short-cavity frequency-swept laser source is not only limited by the filter tuning speed but also by the intracavity laser settling time

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