An Electronic System for the Tuning of Masers

The automatic tuning of frequency standards gives a method of removing drifts due to cavity pulling. The paper describes an apparatus designed primarily for tuning the hydrogen maser. The apparatus can also be used for tuning other masers such as the rubidium maser. The system incorporates several of the best features of similar devices previously described in the literature. It includes a digital averager which makes possible the use of a reference oscillator less stable than the maser to be tuned. It includes also a digital integrator, solving the usual problem of offsets in standard integrators. Frequency corrections are made either proportionally or by unit steps through a varactor coupled to the maser cavity. The electronics are made almost entirely with TTL digital integrated circuits (type 7400) for low cost, reliability, and availability. Results on the tuning of rubidium and hydrogen masers are given.     

XUV Lasers

Abstract

Recent dramatic progress worldwide in the development of XUV lasers using laser-produced plasmas as the active media is reviewed, with particular reference to XUV lasers in recombining plasmas being developed by University groups in the U.K. using the SERC's Central Laser Facility.     

Dynamic-single-mode Lasers

Recent progress in the dynamic-single-mode (DSM) semiconductor laser for long wavelength optical fibre communications is reviewed, and applications to wide-band optical fibre communication in the lowest loss wavelength region of 1·5–1·65 μm are studied. A DSM laser consists of a mode selective resonator and a transverse-mode-controlled waveguide, such as the narrow-striped distributed Bragg reflector (DBR) laser, to maintain a fixed axial mode under rapid direct modulation. The technology of monolithic integration for optical circuits is applied to realize some DSM lasers. The structures and properties of DSM lasers are reviewed.     

双光抽运^87Rb激射器的理论分析

应用密度矩阵理论,给出了适合不同偏振状态的双光抽运~(87)Rb激射器的密度矩阵方程及其解,分析了双光抽运~(87)Rb激射器的振荡性能,特别是激射器的振荡功率与光抽运率、振荡参数的关系,并将结果与传统的单光(谱灯)抽运的情况作了比较。