Optical mirror image interference, self-interference suppression and optical fiber transmission integrated device and method

Abstract

According to the optical-assisted simultaneous mirror image interference and self-interference suppression device under the in-band full-duplex ROF system, a wavelength tunable laser, a polarization controller A, a fixed wavelength laser, a polarization controller B, a polarization beam combiner, an integratable electro-optical modulator K and an electric phase shifter are arranged in a base station A; a single mode fiber; an erbium-doped optical fiber amplifier, an optical detector and an orthogonal demodulation module are arranged in the central station B; wherein the electro-optical modulator K comprises a polarization beam splitter, a first double-parallel Mach-Zehnder modulator, a second double-parallel Mach-Zehnder modulator and a second polarization beam combiner. A corresponding method is also provided. According to the invention, self-interference elimination, frequency conversion, suppression of mirror image interference introduced by frequency conversion and anti-dispersion transmission of useful signals are realized at the same time by using a simple structure; accurate adjustment of time delay is realized by using the dispersion effect of the optical fiber, and the depth of self-interference elimination is ensured; mirror image interference suppression and power-free fading transmission of useful signals are realized at the same time by tuning a bias point of the integratable electro-optical modulator.

Description

technical field [0001] The invention belongs to the technical field of microwave photon signal processing, and in particular relates to an integrated device and method for optical image interference, self-interference suppression and optical fiber transmission under an in-band full-duplex ROF system. Background technique [0002] Microwave signal over optical link transmission (ROF) has the advantages of large bandwidth, strong parallel processing capability, small size, strong anti-electromagnetic interference ability, etc., and has received extensive attention in the past few years. Usually, in order to avoid interference, a base station in a full-duplex ROF system receives uplink signals from mobile users in a certain frequency band, and transmits downlink signals in a different frequency band at the same time. With the research and deployment of the next-generation mobile communication system network, the user's demand for the transmission rate and transmission capacity ...

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Problems solved by technology

[0005]However, the above solution has certain limitations

1) and 2) do not consider the long-distance transmission and frequency conversion capabilities of optical fibers; 3) also do not consider its frequency conversion capabilities, and use a dispersion module, which increases the complexity of the system. At the same time, the PolM modulator is greatly affected by the polarization state. The stability is poor, and the impact of counteracting the multipath effect is realized by increasing the optical hardware in large quantities; 4), 5) use the integrated electro-optical modulator, and the delay and amplitude tuning are carried out in the electrical domain. Self-interference cancellation depth will be affected

In 6), the Hartley structure, as a phase-cancelling structure, has high requirements on the accuracy of the phase, and the imprecise phase shift will greatly reduce the image suppression effect of the system. At the same time, this scheme does not consider the signal distance distance transmission

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