A technique for tunable microwave/millimeter-wave generation based on a polarization-stable dual-wavelength polarization maintaining fiber Bragg grating laser

Abstract

A technique for tunable microwave/millimeter-wave generation based on a polarization-stable dual-wavelength polarization maintaining fiber Bragg grating (PMFBG) laser is proposed in which the frequency selecting of PMFBG is used to produce two polarization-stable lasing signals, the polarization scrambler is adopted to ensure the consistency of the orthogonal polarization's power, and then the beating frequency in high-speed photodetector is used to generate the microwave/millimeter-wave. Lateral strain loading on the PMFBG allows the frequency of the microwave/millimeter to be controlled. In the experiment, a scheme for tunable microwave/millimeter-wave generation based on a polarization-stable dual-wavelength PMFBG laser is produced, and the microwave signals of 20.407 GHz and 22.050 GHz are generated by different axial pulls loading on PMFBG. In the simulation, the millimeter-wave of 60 GHz is generated and transmission performance of the millimeter-wave in radio-over-fiber downlink is analyzed. The results show that the eye diagrams demodulated in the mobile station are excellent when the optical carrier which is modulated as the millimeter-wave sub-carrier transmits over 80 kilometers from center station to base station. The excellent performance of the system is verified.

Theory study on a photonic-assisted radio frequency phase shifter with direct current voltage control

“…[19] The operation principle of the proposed IMZM is similar to that of traditional optical-electrical modulators in Refs. [20] and [21]. Figure 1(b) is the diagram of 1×2 MMI and 1×4 MMI couplers.…”

Effect of the nonlinearity of the CCD in Fourier transform profilometry on spectrum overlapping and measurement accuracy

“…[1][2][3][4] When it is used to measure object height, under ideal conditions, there may exist a direct proportional relationship between the light intensity output and that of the input in dynamic scope of the charge coupled device (CCD). [5][6][7] However, under the actual conditions, because of the nonlinearity of CCD, when we use a CCD camera to acquire the deformed fringe of the object surface and then to carry, the Fourier transformation, [8][9][10] may include not only the first-order spectra but also the second-order and third-order spectra and so on among spectrum distribution, leading to the spectrum overlapping phenomenon. Therefore, not only the application scope of the method is restricted, but also the measurement accuracy of the object shape is reduced.…”