Ultra-narrow band Faraday normal dispersion atomic filter and filtering method based on cavity electromagnetic induction transparency

Abstract

The invention relates to an ultra-narrow band Faraday normal dispersion atom filter and filtering method based on cavity electromagnetic induction transparency, which at least comprises a filter partand a gain part; the method comprises the following steps: introducing a gain system to establish quantum coherence between atomic Zeeman energy levels, combining a cavity electromagnetic induction transparency system, amplifying the weak detection light signal intensity by several times to more than a dozen times, further narrowing the passband bandwidth of the detection signal light to about 0.1MHz to 1.0 MHz, simultaneously enhancing the Faraday rotation effect of the system, realizing the mutual vertical of the polarization planes of the light signal in the passband and the stray light ofthe background outside the passband, and completely filtering the stray light of the background outside the passband.

Description

technical field [0001] The invention relates to the field of optoelectronic technology, in particular to an ultra-narrowband Faraday normal dispersion atomic optical filter and a filtering method based on cavity electromagnetically induced transparency. Background technique [0002] In the process of optical information transmission, due to the influence of environmental background stray light, dispersion absorption and other factors, the signal strength is weakened, making it difficult for the receiver to receive the signal. The function of the optical filter is to shield the strong broadband background interference light other than the frequency of the signal light, and extract the signal light. When the optical signal intensity is extremely low, existing absorbing filters and Faraday anomalous dispersion filters (FADOF) are no longer effective. [0003] At the same time, the absorbing atomic filter utilizes the spontaneous emission process of atoms. Although the acceptan...

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Problems solved by technology

FADOF has the advantages of fast response and narrow bandwidth, but it works in the atomic resonance absorption peak, so it is difficult to extract weak optical signals

[0004] Absorptive atomic filters and FADOF can achieve bandwidths in the vicinity of dozens of MHz to 100 MHz, and cannot achieve MHz and sub-MHz bandwidth filtering; whether it is an absorbing atomic filter or FADOF, the light to be extracted The signal has a certain absorption, and there are certain requirements for the light intensity of the detected signal.

[0005] In order to solve the above problems, Chinese patent CN 108539569 A discloses an ultra-narrow-band atomic optical filter and i

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