Optically controlled K-band oscillator

PIN photodiodes play an important role in detection of modulated light in fiberoptic links, however, these devices are essentially junction devices, with bias-dependent capacitance very similar to those of varactor diodes. Particularly under proper biasing conditions, junction capacitance of these devices can be changed by light illumination. Results are reported of tuning and frequency modulation experiments of a 24.5-GHz oscillator configured with a PIN photodiode as the tuning element. Both electrical and optical tuning were investigated, resulting in tuning range of few hundred megahertz at K-band.<>