All-optical phase modulation system of quantum cascade laser

Abstract

The invention relates to an all-optical phase modulation system of a quantum cascade laser, wherein the system comprises a quantum cascade laser and an externally modulated light source. On the basis of a basic structure of a traditional quantum cascade laser, a quantum cascade laser working area, an all-optical phase modulation area of the quantum cascade laser, and an all-optical phase modulation optical window of the quantum cascade laser are manufactured. Besides, the externally modulated light source is utilized to generate a modulation light by modulating the light intensity; a free electron and a cavity are excited in a laser gain medium of the whole all-optical phase modulation area of the quantum cascade laser through the all-optical phase modulation optical window of the quantumcascade laser; and carrier concentrations of a conduction band (the electron) and a valence band (the cavity) are changed, so that an effective refractive index of an infrared laser in a resonant cavity of the quantum cascade laser is changed; and therefore, phase modulation on a high-speed and high-modulation coefficient of the quantum cascade laser is realized. According to the invention, the provided all-optical phase modulation system of the quantum cascade laser can be applied to a high-sensitive infrared laser spectrum technology and high speed frequency modulation infrared optical communication of free space.

Description

technical field [0001] The invention belongs to the field of infrared laser spectrum technology and free space infrared optical communication technology, and in particular relates to an all-optical phase modulation system based on an infrared quantum cascade laser. Modulation can be applied to high-sensitivity infrared laser spectroscopy technology and free space high-speed frequency modulation infrared optical communication. Background technique [0002] In the prior art, high-speed pure phase modulation of quantum cascade lasers cannot be realized yet. The current phase modulation usually uses a sinusoidal current to change the temperature or carrier (electron) concentration of the quantum cascade laser resonator, and then change the effective cavity length of the quantum cascade laser resonator, so as to realize the phase modulation of the laser output. However, due to the influence of the parasitic capacitance of the quantum cascade laser itself, the modulation speed is...

AI Technical Summary

Problems solved by technology

However, due to the influence of the parasitic capacitance of the quantum cascade laser itself, the modulation speed is greatly limited, so it is difficult to achieve high-speed phase modulation with current modulation

[0003] Although the fast wavelength modulation of quantum cascade lasers has been reported by the method of all-optical modulation, however, the reported modulation method cannot achieve a large phase due to the limitation of the penetration depth of the modulated beam in the quantum cascade laser. Modulation factor

Moreover, this method cannot avoid changing the output light intensity of the quantum cascade laser while generating phase modulation, so it is difficult to achieve simple phase modulation

These make it difficult to obtain a pure phase modulation technology with high speed and high modulation coefficient in the infrared spectrum range, which greatly limits the development of infrared laser spectroscopy technology and free space infrared optical communication technology

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