Semiconductor optical modulator and driving circuit

摘要

A modulating circuit for a semiconductor optical modulator is composed of a driver (3) DC-coupled to an optical modulator (2), a load resistor (4) connected in parallel to the modulator (2), and a constant current source (5) connected in parallel to the optical modulator (2) for drawing out the photo-current generated in the optical modulator (2) by absorption of light emitted from a semiconductor laser. The modulating circuit can perform light intensity modulation with low wavelength chirping using a driver DC-coupled to the optical modulator (2). The drawing out current is approximately equal to or more than an average of photo-current which is generated in the optical modulator (2) by light absorption at the time of modulation. <IMAGE>