Linearized optical digital-to-analog modulator

摘要

A modulator device for converting digital data into modulation of an optical signal includes an electronic input for receiving an input data word of N bits and an electrically controllable modulator for modulating the intensity of an optical signal, the modulator including M actuating electrodes where M≧N. An electrode actuating device, most preferably a digital-to-digital converter, operates actuating electrodes so that at least one electrode is actuated as a function of values of more than one bit of the input data word. According to an alternative, or supplementary, aspect of the invention, the set of electrodes includes at least one electrode having an effective area which is not interrelated to others of the set by factors of two. In one preferred implementation, a Mach-Zehnder modulator also provides phase modulation to give QAM functionality. Another implementation employs a semiconductor laser.

主权项

1. A system for converting digital data into a modulated signal, comprising:
(a) an electrically controllable device having M actuating electrodes for actuating said device, the device providing an optical signal that is modulated in response to binary voltages applied to the actuating electrodes; and (b) an electrode actuating device having an electronic input for receiving digital input data words of N bits, and at least one digital-to-digital converter configured for providing a mapping of the input data words to binary actuation vectors of M bits and supplying the binary actuation vectors to the M actuating electrodes, where M>N; wherein the at least one digital to digital converter is configured to map each digital input data word to a binary actuation vector by selecting said actuation vector from a plurality of actuation vectors of M bits to represent the input data word of N bits; and wherein said electrode actuating device actuates at least one of said actuating electrodes in a manner differing from any one-to-one correspondence of the bits of the digital input data word to the actuating electrodes.