  A series of simple and low-cost devices for switching, amplifying, and
chirping diode lasers based on current modulation are presented. Direct
modulation of diode laser currents is rarely sufficient to establish precise
amplitude and phase control over light, as its effects on these parameters are
not independent. These devices overcome this limitation by exploiting amplifier
saturation and dramatically outperform commonly used external modulators in key
figures of merit for quantum technological applications. Semiconductor optical
amplifiers operated on either rubidium D line are recast as intensity switches
and shown to achieve ON:OFF ratios $>10^6$ in as little as 50 ns. Current is
switched to a 795 nm wavelength (Rb D1) tapered amplifier to produce optical
pulses of few nanosecond duration and peak powers of 3 W at a similar
extinction ratio. Fast rf pulses are applied directly to a laser diode to shift
its emission frequency by up to 300 MHz in either direction and at a maximum
chirp rate of 150 MHz/ns. Finally, the latter components are combined, yielding
a system that produces watt-level optical pulses with arbitrary frequency
chirps in the given range and <2% residual intensity variation, all within 65
ns upon asynchronous demand. Such systems have broad application in atomic,
molecular, and optical physics, and are of particular interest to fast
experiments simultaneously requiring high power and low noise, for example
quantum memory experiments with atomic vapors.
