Electro-optic intensity modulator with improved linearity

摘要

The improved intensity modulator comprises a directional coupler with a single active coupling section with a fixed amount of coupling along with a single pair of electrodes for supplying a voltage-controlled mismatch in propagation constants. Two passively-biased coupling sections are connected in series with the active section, with the two passive sections combined being at least one coupling length long. The bias voltage of the two passive sections are independently varied to compensate for non-linearities by providing additional coupling. In addition to a DC bias voltage, the active coupling section is supplied with an RF signal which may propagate from its input end to its output, along with the optical signal, if a traveling wave electrode is used. Alternate embodiments provide temperature-induced drift compensation and reduction of chirping.