We report on an improvement of idler beam quality in a singly resonant optical parametric oscillator (OPO), where the resonant signal is converted to the idler via an additional difference frequency generation (DFG) process. The two processes are phase matched simultaneously by a quasi-periodically poled nonlinear crystal. Whereas back-conversion of the signal and idler to the pump frequency di...

The isolated bidirectional ac–dc converter is for the 380-V dc power distribution system to control the bidirectional power flow and to improve its power conversion efficiency. Here the high-side switches of the ac– dc rectifier employ IGBTs without anti-parallel diodes and SiC diodes. In addition, the low-side switches are consisting of two MOSFETs to reduce the conduction loss in the rectific...

This paper presents the numerical design algorithm for the class-DE amplifier, taking into account optimized resonant inductor designs. The proposed design algorithm provides the element values for satisfying the class-E switching conditions. Simultaneously, the optimal inductors, which have a minimum volume for achieving the permissible power conversion efficiency, can be obtained. By carrying...

Multi-port DC-DC converter has attracted special interest in applications where multiple energy sources are used. In this project, a three-port converter with three active full bridges, two LCC resonant tanks, and a three-winding transformer is proposed. It uses a single power conversion stage with high-frequency link to control power flow between batteries, load, and a renewable source such as...

We developed a robust 252 nm single-mode coherent continuous-wave light source through two-stage highly efficient frequency conversion systems using external cavities. In the first stage, we obtained the second harmonics (SH) power of 630 mW from the LBO-installed external cavity by frequency doubling of a 746 nm Ti: sapphire laser with an efficiency of almost 50% [Y. Asakawa, H. Kumagai, K. Mi...

With increasing offshore wind generation, there is a strong argument for implementing a multi-terminal DC grid offshore by the interconnection of individual HVDC links. The point of intersection of three or more lines can be used to interconnect projects with different voltage levels and to control power distribution. It is being proposed that these points, or nodes, be implemented using DC dev...

A monolithic doubly resonant optical parametric oscillator (OPO) fabricated from MgO:LiNbO(3) was pumped by a cw, frequency-doubled, diode-laser-pumped Nd:YAG laser. The threshold for cw operation was 12 mW, and pump depletions of up to 78% were observed two times above threshold. The total OPO output power was 8.15 mW, with a conversion efficiency for the incident pump of 34% and combined conv...

We show that the rate at which light tunnels between neighboring multimode waveguides can be drastically increased or reduced by the presence of small longitudinal periodic modulations of the waveguide properties that stimulate resonant conversion between the eigenmodes of each waveguide. Such a conversion, available only in multimode guiding structures, leads to periodic power transfer into hi...