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Serial-parallel connection modulation optical frequency multiplication millimeter-wave RoF (Radio Over Fiber) system and QPSK (Quadrature Phase Shift Keying) /16QAM (Quadrature Amplitude Modulation) modulation method thereof

An optical frequency doubling and millimeter wave technology, which can be used in phase modulation carrier systems, multi-carrier systems, electromagnetic wave transmission systems, etc., and can solve problems such as modulation signal interference.

Inactive Publication Date: 2011-02-02
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method can realize 16-QAM or higher PSK modulation, two optical fiber links need two sets of independent electro-optic modulation equipment, which is not good from the perspective of system cost and complexity, and different The optical phase interference noise caused by the optical delay difference of the optical path will interfere with the modulated signal

Method used

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  • Serial-parallel connection modulation optical frequency multiplication millimeter-wave RoF (Radio Over Fiber) system and QPSK (Quadrature Phase Shift Keying) /16QAM (Quadrature Amplitude Modulation) modulation method thereof
  • Serial-parallel connection modulation optical frequency multiplication millimeter-wave RoF (Radio Over Fiber) system and QPSK (Quadrature Phase Shift Keying) /16QAM (Quadrature Amplitude Modulation) modulation method thereof
  • Serial-parallel connection modulation optical frequency multiplication millimeter-wave RoF (Radio Over Fiber) system and QPSK (Quadrature Phase Shift Keying) /16QAM (Quadrature Amplitude Modulation) modulation method thereof

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Embodiment 1

[0086] see figure 1 , the serial-parallel modulation optical frequency-multiplied millimeter wave RoF system of the present invention includes a central station 1 , a base station 2 and a downlink optical fiber 3 . The central station 1 and the base station 2 are connected by a downlink optical fiber 3, which is characterized in that the structure of the central station 1: a laser 1-1 is connected to a dual-electrode Mach-Zehnder optical modulator 1-4 through a polarization-maintaining pigtail The input end is connected; The RF electrode on an arm of the two-electrode Mach-Zehnder optical modulator 1-4 adds a cosine microwave signal output by a first microwave signal source 1-3, and the bias electrode is grounded; the other arm The RF electrode on the top is added with the cosine microwave signal generated by the first microwave signal source 1-3 and then phase-shifted by a π phase shifter 1-2, and the bias electrode is grounded; the two-electrode Mach-Zehnder optical modulato...

Embodiment 2

[0088] This series-parallel modulation optical frequency doubling millimeter wave RoF system QPSK / 16QAM modulation method adopts the above-mentioned system to operate, and is characterized in that: two RF electrodes of a two-electrode Mach-Zehnder optical modulator 1-4 input cosine and inverse respectively phase cosine microwave signal, the DC electrode bias electrode is grounded, and the phase modulation of the input light wave of the light source is performed with a large index, and a series of high-order side modes of light waves around the central wavelength are generated at the output port of the optical modulator 1-4. The frequency difference of adjacent modes is equal to the driving microwave frequency; the four RF electrodes of IQ optical modulator 1-5 input the random baseband digital signal and two phase-orthogonal intermediate frequency signals of I and Q branches respectively, and the two direct currents The poles 1-7, 1-10 are grounded, and at the same time, the DC...

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Abstract

The invention relates to a serial-parallel connection modulation optical frequency multiplication millimeter-wave RoF (Radio Over Fiber) system and a QPSK (Quadrature Phase Shift Keying) / 16QAM (Quadrature Amplitude Modulation) modulation method thereof. The system comprises a central station, a base station and fiber connection thereof, wherein the central station comprises a single longitudinal mode laser, a double-electrode Mach-Zehnder optical modulator, an IQ optical modulator, two microwave signal sources, a pi phase shifter, a pi / 2 phase shifter and an erbium doped fiber amplifier; and the base station comprises an optical detector, a front low-noise amplifier, two millimeter-wave bandpass filters, two millimeter-wave amplifiers, a millimeter-wave duplexer and a millimeter-wave antenna. In the method, the cascading of the double-electrode Mach-Zehnder optical modulator and the IQ optical modulator is adopted, and a balanced optical waveguide structure formed by integrating the two optical modulators avoids the influence of optical source phase interference noise caused by support arm optical delay inequality on modulation signals.

Description

Technical field: [0001] The invention relates to a Radio over Fiber (RoF, Radio over Fiber) system and QPSK and 16QAM modulation methods. The purpose of adopting QPSK and 16QAM signal format is to compress the occupied bandwidth of the signal. A RoF system structure based on the principle of optical frequency doubling and a new series-parallel optical modulation method are proposed. While generating millimeter waves from light waves, it is possible to transfer the modulation of the signal to the light waves to the modulation of the millimeter waves. technical background: [0002] Regarding how to apply the optical QPSK modulation mode to the millimeter-wave RoF system, in the prior art, two independent optical fiber links are used to transmit the I-channel and Q-channel information of the QPSK signal respectively. Although this method can realize 16-QAM or higher PSK modulation, the two optical fiber links require two sets of independent electro-optic modulation equipment, ...

Claims

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Application Information

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IPC IPC(8): H04B10/12H04L27/36H04L27/20H04B10/2575H04B10/556
Inventor 魏林林如俭李迎春邹是桓蔡尤美叶家骏
Owner SHANGHAI UNIV
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