Quantum cascade laser-based full-optical and pure-frequency modulation system

Abstract

The invention discloses a quantum cascade laser-based full-optical and pure-frequency modulation system. The system comprises a quantum cascade laser, a high-precision current source, a constant-temperature control device, a double-light-beam modulation system, a light beam collimator, a beam splitter, a Fourier infrared spectrometer, a beam focusing device, a high-frequency infrared detector and a high-precision oscilloscope. According to the technical scheme of the invention, a frequency-modulated light source is adopted to irradiate the emergent end surface of the quantum cascade laser, so that the high-speed amplitude and frequency modulation is realized, wherein the amplitude modulation is positive modulation. An amplitude-modulated inhibited light source is adopted to irradiate the emergent end surface of the quantum cascade laser, so that the high-speed amplitude and frequency modulation is realized, wherein the amplitude modulation is negative modulation. Based on the synchronization of the frequency-modulated light source and the amplitude-modulated inhibited light source, the sync suppression of the amplitude modulation and the pure frequency modulation are realized.

Description

technical field [0001] The invention relates to the fields of free space infrared optical communication technology and infrared laser spectrum technology, in particular to an all-optical pure frequency modulation system based on quantum cascade lasers. Background technique [0002] In the prior art, as a widely used infrared coherent light source, the quantum cascade laser has the advantages of narrow line width, high power, and can work at room temperature. Due to the low transmission loss of the mid-infrared laser in the atmosphere, it has the application advantage of free space optical communication; since the mid-infrared band covers the fingerprint spectral region of most gas molecules, it has great potential for trace gas detection. Advantage. Frequency modulation technology can increase the transmission bandwidth of quantum cascade lasers and the signal-to-noise ratio of spectral signals, but frequency modulation must be accompanied by amplitude modulation, which aff...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide an all-optical pure frequency modulation system based on quantum cascade lasers, which solves the problem that the electrical modulation is affected by parasitic capacitance, the modulation speed is limited, and the combination of light and electricity is affected by the thermal effect of the laser current, so that The output wavelength of the quantum cascade laser is red-shifted, which reduces the problem of laser frequency variation caused by light modulation

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