A novel non-isolated bidirectional soft-switching SEPIC/ZETA converter with reduced ripple currents is proposed and characterized in this study. Two auxiliary switches and an inductor are added to the original bidirectional SEPIC/ZETA components to form a new direct power delivery path between input and output. The proposed converter can be operated in the forward SEPIC and reverse ZETA modes with reduced ripple currents and increased voltage gains attributed to the optimized selection of duty ratios. All switches in the proposed converter can be operated at zero-current-switching turn-on and/or turn-off through soft current commutation. Therefore, the switching and conduction losses of the proposed converter are considerably reduced compared with those of conventional bidirectional SEPIC/ZETA converters. The operation principles and characteristics of the proposed converter are analyzed in detail and verified by the simulation and experimental results.

Abstract-We demonstrate a new configuration for an optoelectronic self-injection-locked (SIL) oscillator, where a part of the electrical output signal is self-injected after passing through a long optical delay line for output phase-noise reduction. The SIL oscillator consists of an electrical free-running oscillator and a long optical feedback loop. For the compact and low cost configuration, the free-running oscillator is realized with an InP HPT-based monolithic oscillator and electrical-to-optical conversion is carried out by two low-speed and low-cost laser diodes. With this new configuration, we achieve more than 55-dB phase-noise reduction at 10-kHz frequency offset from the center frequency of about 10.8 GHz by injecting 8-dBm optical signals without using any high-speed optoelectronic components.Index Terms-InP monolithic oscillator, optoelectronic oscillator (OEO), phase-noise reduction, self-injection locking (SIL).

Abstract-We demonstrate a millimeter-wave self-injectionlocked (SIL) oscillator having a long optical delay line as a feedback route. In the SIL oscillator, a part of output signal is self-injected into the oscillator after passing through a long optical delay line, resulting in locked oscillation and phase-noise reduction. By controlling the self-injection power, we achieve 30-GHz oscillation with a sidemode suppression ratio larger than 50 dB and about 18-dB phase-noise reduction at 10-kHz frequency offset.

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