Fast amplitude modulation of the blue 429-nm output from a frequency-doubled GaAlAs diode laser

Abstract

We report on a new method for fast amplitude modulation of blue 429-nm radiation that is produced by frequency doubling of a GaAlAs diode laser in a monolithic KNbO3 resonator. The diode-laser frequency was locked to the resonator by use of the Pound–Drever technique and FM sidebands that were generated by superimposition of an rf current on the diode-laser injection current. We modulated the blue power output by controlling the amplitude of this rf current, which controls the FM spectrum of the diode laser and thus the fraction of the diode-laser power that is coupled to the frequency-doubling resonator. Using this technique, we have produced blue pulses of 40-mW peak power with rise and fall times of 5 ns and pulse durations as short as 10 ns. Nonperiodic pulse sequences produced with this technique were used to write data on magneto-optical disks. © 1994 Optical Society of America.