Generation of a frequency sextupled optical millimeter wave with a suppressed central carrier using one single-electrode modulator

We have theoretically and experimentally investigated the generation of optical millimeter wave (mm-wave) generation based on a quadrupling and sextupling technique using one single-electrode intensity modulator (IM) with a simultaneously suppressed optical central carrier. By adjusting the bias voltage and utilizing proper peak-to-peak voltage of the RF signal drive on the IM, undesired sidebands can be suppressed. Based on this rule, an experiment was performed to generate 48 and 72-GHz optical mm-waves using a sinusoidal clock source running at only 12 GHz.     

8mm GaAs Gunn稳态功率放大器

报导了以商用ＧａＡｓＧｕｎｎ氏振荡管（超临界掺杂Ｇｕｎｎ二极管）研制稳态型功率放大器的设计方法和研制结果。提出了放大器宽温不稳定的解决方法。单管单级放大器，增益大于１０ｄＢ，带宽大于２ＧＨｚ（３３～３５ＧＨｚ），最大输出功率２００ｍｗ，能在－４０～＋５５℃内稳定工作，全温增益变化小于０．５ｄＢ，带内波纹小于０．５ｄＢ。可靠性高。     

Ka波段数字通信技术

该文简要阐述了用于无线接入的Ka波段数字通信系统的设计要点,具体介绍了Ka波段42048kb/s数字通信系统的方案、关键技术及性能,该系统通信距离大于30km。     

A novel optical mm-wave generation scheme based on three parallel Mach-Zehnder modulators

We propose a novel optical mm-wave generation scheme based on three parallel Mach-Zehnder modulators (MZMs) for the first time. First, the scheme is investigated theoretically, which suggests that it can be used for sextupling, 12-tupling, and 18-tupling mm-wave generation. Then simulation results are given, 60 GHz mm-wave is generated from 5 GHz, or 10 GHz RF oscillator based on frequency 12-tupling or sextupling, and 90 GHz mm-wave is generated from 5 GHz RF oscillator based on frequency 18-tupling. The optical sideband suppression ratio (OSSR) and the radio frequency spurious suppression ratio (RFSSR) are analyzed by simulation, in which several non-ideal factors are taken into consideration. Results indicate that all the three mm-wave generation methods are practical and very good performance can be obtained when the extinction ratio of the MZM is 30 dB, even if the extinction ratio of the MZM is 20 dB, the performance is still good, especially for the sextupling mm-wave generation method, whose performance is excellent and insensitive to the extinction ratio of MZM, the non-ideal RF driving voltage and the non-ideal DC bias. At last, we set up a RoF system by simulation to verify the transmission performance of the scheme. The BER performance and eye diagrams are given.     

The forbidden rotational Q branch of CH3SiF3: A study in internal rotation

The pure rotational spectrum driven by the small dipole moment produced perpendicular to the symmetry axis by centrifugal distortion has been investigated for CH₃SiF₃ in the ground vibrational state using a Fourier transform waveguide spectrometer. Between 10.9 and 17.0 GHz, four (k + 3 ← k) series in the Q branch have been measured in the lowest torsional state v₆ = 0 for k = 4, 5, 6, and 7 with 54 ? J ? 65. In each transition, the quantum number σ = 0, +1, −1 labelling the different torsional sub-levels is conserved. For given (J,k), splittings from ∼10 to ∼45 MHz have been observed between lines with different values of σ. The global data set includes the anticrossing molecular beam energy differences of [W.L. Meerts, I. Ozier, Chem. Phys. 71 (1982) 401-415] as well as the mm-wave R branch frequencies and (A₁ − A₂) splittings of [P. Dréan, J.-M. Colmont, J. Demaison, L. Dore, C. Degli Esposti, J. Mol. Spectrosc. 176 (1996) 23-27]). A good fit was obtained by varying 15 molecular parameters characterizing the torsion-rotation Hamiltonian H_TR for the vibrational ground state. Because of the strong correlation between two of the quartic torsion-distortion parameters (F_0,3K and D_0,Km) and a redundancy connecting the centrifugal distortion constants, four models were obtained yielding comparable fits. In each case, effective values were determined for the A-rotational constant and the height of the potential hindering the internal rotation. A high precision determination of the structural parameter ρ was made that is the same in all four models. For the off-diagonal quartic centrifugal distortion constant ε₀ and the sextic constants H_0,J, H_0,JK, H_0,KJ, and h_0,3, the differences in the values obtained in the two different reductions used have been explained in terms of the redundancy connecting these parameters. For σ = 0, +1, −1, the energy level pattern for (|k| = 3) is discussed for the case where the pure torsional energy splitting and the matrix elements off-diagonal in k are of comparable magnitude. A method is described of using an R branch study of the resulting σ-splittings for (|k| = 3) to probe the zeroth-order torsional Hamiltonian.