Device and method for analog optical link linear optimization based on dual wavelength and phase modulation to intensity modulation conversion

Abstract

The invention discloses a device and a method for simulating optical link linear optimization based on dual wavelength and phase modulation to intensity modulation conversion, and relates to the technical field of optical communication and microwaves. As shown in an attached figure, the device comprises a laser source, a radio frequency signal source, a polarization controller, a polarization beamcombiner, a phase modulator, a single-mode optical fiber, a wavelength division multiplexer, an optical coupler and a photoelectric detector. According to the method, a polarization multiplexing optical phase modulation signal can be obtained by utilizing double light sources and a phase modulator, and conversion from phase modulation to intensity modulation can be realized through a wavelength division multiplexer. The third-order intermodulation power value can be suppressed by adjusting the ratio of the power values of the two light sources. According to the method, an intensity modulatoris not needed, a complex bias control circuit is avoided, the complexity of the system is reduced, and in addition, the inhibition operation of the third-order intermodulation item is simple, so thatthe method is easy to apply to an actual system.

Description

technical field [0001] The invention relates to the technical field of optical communication and microwave technology, in particular to the linear optimization of analog optical links. Background technique [0002] Due to the advantages of large bandwidth, low loss, and immunity to electromagnetic interference, microwave photonic links have been widely used in systems such as phased array antennas, signal processing, radar, and optical radio frequency. Using optical link instead of traditional microwave link can make it have a series of advantages such as low noise and high gain. [0003] The most basic analog optical link system generally adopts an intensity modulation-direct detection structure. Due to the sin-type transfer function of the intensity modulator, when the input RF power is high, the link will generate high-power third-order intermodulation items. Seriously affected the dynamic range of the system. Therefore, it is of great significance to suppress the third...

AI Technical Summary

Problems solved by technology

[0004] There are roughly two ideas for existing linear optimization schemes for microwave photonic links: one is pre-distortion technology, that is, pre-distortion processing is performed on the signal before it is modulated into the optical carrier, and this method is limited by the performance of external electronic devices. Applied to broadband scenarios

The second is dual-parallel modulation technology. This method makes the power of the two third-order intermodulation items at the receiving end equal and the phase difference is 180 degrees by adjusting the optical power, radio frequency power ratio and bias voltage injected into the intensity modulator of the dual-parallel structure. Coherent synthesis suppresses the third-order term. In this method, dual parallel intensity modulators are mostly used, so an additional modulator bias control circuit is required, which increases the complexity of the system.

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