SBS reduction in nanosecond fiber amplifiers by frequency chirping.

We demonstrate a technique for SBS reduction in a nanosecond Yb-fiber amplifier by imposing 1.19 GHz/ns frequency chirp on the seed pulses with a pulse-driven phase modulator. A nearly 9-fold increase in the SBS threshold was observed for 8.

Narrowband Er:YAG nonplanar ring oscillator at 1645 nm.

We report 1645 nm narrowband operation of a monolithic Er:YAG nonplanar ring oscillator resonantly pumped at 1532 nm. Unidirectional cw power up to 0.5 W was obtained with a measured linewidth of 21 kHz.

Multiwatt continuous-wave and Q-switched Er:YAG lasers at 1645 nm: performance issues.

The cw and Q-switched performance of Er:YAG lasers operating at 1645 nm were measured. Guided by previous work in the literature, we sought to improve efficiency at low pulse repetition frequencies by decreasing the doping level from 0.5 to 0.

Time-gated filter for sideband suppression.

A time-gated filter is demonstrated that converts a double-sideband radio-frequency (rf) waveform on a pulsed optically chirped carrier into a single sideband (SSB) waveform. Electrical technology to produce SSB modulation is currently limited to rfs less than 20 GHz, while our filter operates up to the maximum frequency available from optical modulators. Application of the filter in photonic time-stretch analog-to-digital converters (TS-ADCs) mitigates severe frequency fading owing to the dispersion penalty that limits the rf input signal bandwidth and time aperture.