Optical modulator module and modulation method for optical signal

摘要

An optical modulator module includes an optical modulator including an optical waveguide which conducts an inputted optical signal, and m modulator regions on the optical waveguide; and m discrete driving circuits serially connected to one another. The discrete driving circuits include a driving circuit which outputs a signal obtained from a digital input signal with a synchronization signal to one of the modulator regions, and a phase shifting circuit which outputs a signal resulting from giving a delay to a signal branched from the synchronization signal. A discrete driving circuit receives the signal outputted from the phase shifting circuit. Each of the modulator regions includes modulation electrodes, an electric field caused by a modulation electric signal applied to each of the modulation electrodes penetrates by a penetration length d, and every two adjacent modulation electrodes has a distance Lgap given by Lgap=2d.

主权项

1. An optical modulator module comprising:
an optical modulation unit including an optical waveguide which conducts an inputted optical signal, and m modulator regions (m being an integer satisfying 2≦m) which are arranged so as to align on the optical waveguide and which modulate the optical signal; and m discrete driving unit that are connected in line, wherein an i-th one of the m discrete driving unit (i being an integer satisfying 1≦i≦m) includes: a driving unit that outputs a signal obtained by amplifying a signal resulting from synchronizing a digital input signal with a synchronization signal to an i-th one of the modulator regions; and a phase shift unit that outputs a signal resulting from giving a delay to a signal branched from the synchronization signal, a j-th one of the discrete driving unit (j being an integer satisfying 1≦j≦m) receives, as the synchronization signal, the signal outputted from the phase shift unit included in a (j−1)th one of the discrete driving unit, and the modulator regions includes a plurality of modulation electrodes, supposing that a penetration length denoted by d is the penetration length of an electric field caused by a modulation electric signal applied to each of the modulation electrodes in a transmission direction of the optical signal, the distance between every two adjacent ones of the modulation electrodes Lgap is given by Lgap =2d.