Device for generating photo-induced microwave carrier signal through single sideband modulation

Abstract

The invention discloses a device for generating a photo-induced microwave carrier signal through single sideband modulation. The device comprises a first distributed feedback type single mode laser, a lithium niobate external modulator, a local oscillator electric signal source, an erbium-doped optical fiber amplifier, a polarization controller, a three-port optical circulator, a second distributed feedback type single mode laser and a photoelectric detector, wherein the first distributed feedback type single mode laser is used for generating optical carrier; the lithium niobate external modulator is used for externally modulating the optical carrier input by the first distributed feedback type single mode laser; the local oscillator electric signal source is used as a driving signal source of the lithium niobate external modulator; the erbium-doped optical fiber amplifier is used for amplifying an optical signal input by the lithium niobate external modulator; the polarization controller is used for controlling a polarization state of the optical signal input by the lithium niobate external modulator; the three-port optical circulator is used for performing unidirectional transmission on the optical signal input by the polarization controller; the second distributed feedback type single mode laser is used as an injected slave laser; and the photoelectric detector is used for performing photoelectric conversion on the optical signal input by the three-port optical circulator to generate a microwave carrier signal. By using the device, the microwave carrier signal with frequency which is several times the frequency of a local oscillator electric signal can be generated without being limited to an optical filter.

Description

Technical field [0001] The invention relates to the field of optical communication technology, and more specifically to a single-sideband modulated light-generated microwave carrier signal generator. Background technique [0002] The optical microwave carrier technology is the core technology of the RoF system. The microwave carrier signal generated by the traditional double-sideband modulation method is affected by the fiber dispersion, so that the amplitude of the generated microwave carrier signal fluctuates periodically with the transmission distance, while the amplitude of the microwave carrier signal generated by the single-sideband modulation method will not Periodic fluctuations occur with the transmission distance. Using an optical filter to filter out one of the sidebands of the double-sideband modulated optical signal is the most direct way to obtain a single-sideband modulation method. This method has the following shortcomings: First, the optical filter itself will...

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Problems solved by technology

This method has the following disadvantages: First, the optical filter itself will be affected by the external environment to cause its working wavelength to drift, thereby affecting the filtering effect, thereby affecting the performance of the system; second, the 3-dB bandwidth of the filter limits the generated The frequency of the microwave carrier signal so that the frequency of the generated microwave carrier signal cannot exceed the 3-dB bandwidth of the filter

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