Coherent detection system and method for homologous common beam of laser

Abstract

The invention discloses a coherent detection system and a coherent detection method for a homologous common beam of a laser, wherein the laser beam generated continuously by the laser is homogenized in a spot homogenizer, so that size and shape of the spot meet effective aperture and uniformity of power distribution of an acoustic optical modulator; the homogenized laser beam is interacted with a radio frequency electric signal input externally in the acoustic optical modulator to realize Bragg diffraction and ensure that the incident light and the diffraction light of the acoustic optical modulator are consistent in state of polarization; a 0-level spot and a 1-level spot formed after optical modulation respectively form reference light and signal light of coherent optical communication; the reference light and the signal light focused by an optical lens and processed by a beam aligner combine and transmit the two beams of spots in parallel to a photoelectric detector to realize conversion of a photoelectric signal. Due to the coherent detection system and the coherent detection method, the optical path structure of the system can be simplified, the laser utilization is improved and the optical matching performance is enhanced.

Description

technical field [0001] The invention relates to the field of coherent optical communication, in particular to a laser homogenous co-beam coherent detection system and method. Background technique [0002] The advent of laser and the development of acousto-optic technology have led to the rapid development of coherent optical communication. Coherent optical communication is widely used in civil and military fields such as transoceanic communication, desert communication, and inter-satellite communication because of its advantages such as high sensitivity, long relay distance, good selectivity, and multiple modulation methods. In current coherent optical detection systems, heterogeneous sources are generally used (see figure 1 ) or homologous spectroscopic (see figure 2 ) method, and then integrate the two laser beams through the combination of optical lenses, and make the two laser beams overlap and then transmit in the same direction, and finally the photoelectric signal ...

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Problems solved by technology

figure 1 The heterogeneous coherent detection method shown requires that the light source at the receiving end (local end) and the light source at the transmitting end (remote end) must be strictly matched in frequency and phase; therefore, the frequency stability of the laser is extremely high, thus limiting coherent optical communication and detection application; figure 2 Although the homologous optical splitting coherent detection method shown is a laser, the power involved in optical modulation is significantly reduced by using optical splitting, and the structure of the optical path is complex, making coaxial adjustment more difficult, and multiple optical interface reflections will lead to loss of optical power

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