amplitude modulation

By using techniques like cascade configurations, incidence at grazing angles or excitation coupled Bragg modes within the LC film, the device can be configured for high transmission flat-top narrow pass-band filters, steep amplitude modulators or broadband pure phase modulators.

Accomplishing this modulation with an amplitude modulator and a phase modulator is difficult and complex.

"We essentially made an amplitude modulator that changed the light intensity by about 30% at the maximum operating efficiency," says Evans.

The microphotograph of the biphase amplitude modulator chip designed for operation at 30 GHz (which measures 1.1 mm x 0.9 mm) is shown in Figure 4.

The source can be easily modulated using either the source output leveling loop or a broadband amplitude modulator. The demodulators can be the broadband diode detectors commonly used in scalar network analysis.