Method and device for reducing noise coefficient of analog optical fiber link

Abstract

The invention discloses a method and device for reducing a noise coefficient of an analog optical fiber link. The method comprises the steps that after same modulation is carried out on at least two lasers of different wavelengths, the lasers are received and demodulated into electric signals by corresponding optical detectors; analog signals are converted into digital signals, and the digital signals enter a cross-correlation processing system for cross-correlation processing; correlated parts in the electric signals are reinforced, uncorrelated parts in the electric signals are weakened, and the noise coefficient of the analog optical fiber link is reduced; and the electric signals are converted into the analog signals and then are output. According to the method and the device, through introduction of a double-laser-double-optical detector structure, the cross-correlation processing is carried out on the received signals by employing a cross-correlation technology; the correlated useful signals are reinforced; the uncorrelated parasitic noise is weakened; and finally the noise coefficient of the analog optical fiber link is reduced. The method and the device also can be applied to the input digital signals, and the cross-correlation processing can be directly carried out without carrying out analog to digital and digital to analog conversion.

Description

technical field [0001] The invention belongs to the technical field of optoelectronics, and in particular relates to a method and a device for reducing the noise factor of an analog optical fiber link. Background technique [0002] Glossary: [0003] In the field of signal processing, cross-correlation (sometimes also called "cross-covariance") is a measure used to express the similarity between two signals, and is usually used to find properties in unknown signals by comparing them with known signals. It is a function of time between two signals, sometimes called a sliding dot product, and is a commonly used digital signal processing method in the fields of communication, pattern recognition, and cryptanalysis. [0004] Traditional microwave links are an important part of many commercial and military communication systems, and can be widely used in aerospace, radar, electronic warfare, high-frequency communication, remote sensing and telemetry, and precision measurement. ...

AI Technical Summary

Problems solved by technology

However, as the transmission distance increases, the insertion loss of traditional transmission media such as cables and waveguides increases rapidly, especially in the microwave and millimeter wave frequency bands. The bottleneck of large insertion loss limits the microwave link more and more obviously. Typical coaxial cables The loss in the X-band is higher than 1.8dB / m (1.8×10 3 dB / Km), while the loss of commercial SMF-28 communication fiber at 1.5um wavelength is only close to 0.2dB / Km

Images