A low-cost shutter driver and arbitrary waveform generator for optical switching using a programmable system-on-chip (PSoC) device.

We have developed a low-cost mechanical shutter driver with integrated arbitrary waveform generation for optical switching and control using a programmable system-on-chip device. This microcontroller-based device with configurable digital and analog blocks is readily programmed using free software, allowing for easy customization for a variety of applications. Additional digital and analog outputs with arbitrary timings can be used to control a variety of devices, such as additional shutters, acousto-optical modulators, or camera trigger pulses, for complete control and imaging of laser light. Utilizing logic-level control signals, this device can be readily integrated into existing computer control and data acquisition systems for expanded hardware capabilities.

Creation of arbitrary time-sequenced line spectra with an electro-optic phase modulator.

We use a waveguide-based electro-optic phase modulator, driven by a nanosecond-timescale arbitrary waveform generator, to produce an optical spectrum with an arbitrary pattern of peaks. A programmed sequence of linear voltage ramps, with various slopes, is applied to the modulator. The resulting phase ramps give rise to peaks whose frequency offsets relative to the carrier are equal to the slopes of the corresponding linear phase ramps. This simple extension of the serrodyne technique provides multi-line spectra with peak spacings in the 100 MHz range.

Characterization and compensation of the residual chirp in a Mach-Zehnder-type electro-optical intensity modulator.

We utilize various techniques to characterize the residual phase modulation of a waveguide-based Mach-Zehnder electro-optical intensity modulator. A heterodyne technique is used to directly measure the phase change due to a given change in intensity, thereby determining the chirp parameter of the device. This chirp parameter is also measured by examining the ratio of sidebands for sinusoidal amplitude modulation. Finally, the frequency chirp caused by an intensity pulse on the nanosecond time scale is measured via the heterodyne signal. We show that this chirp can be largely compensated with a separate phase modulator. The various measurements of the chirp parameter are in reasonable agreement.