Patent ID: 8705981
Filing Date: 2014-04-22
Classification: G02F,H04B

Abstract:
1. A driver circuit for driving a phase modulator to generate a phase modulated optical signal by combining a first optical signal obtained by a first phase modulation element and a second optical signal obtained by a second phase modulation element, using a first drive signal for driving the first phase modulation element and a second drive signal for driving the second phase modulation element, the driver circuit comprising: a drive signal generator to generate the first drive signal, the second drive signal, and a clock signal; a first regeneration circuit to regenerate the first drive signal using the clock signal; an attenuator to attenuate the first drive signal regenerated by the first regeneration circuit; a delay element to delay the clock signal; and a second regeneration circuit to regenerate the second drive signal using the clock signal delayed by the delay element, wherein a propagation time of the first drive signal from the drive signal generator to the first regeneration circuit is substantially the same as a propagation time of the second drive signal from the drive signal generator to the second regeneration circuit, a propagation time of the first drive signal from the first regeneration circuit to the first phase modulation element is longer by a delay time caused by the attenuator than a propagation time of the second drive signal from the second regeneration circuit to the second phase modulation element, a propagation time of the clock signal from the drive signal generator to the second regeneration circuit is longer by a delay time of the delay element than a propagation time of the clock signal from the drive signal generator to the first regeneration circuit, the delay time caused by the attenuator is substantially the same as the delay time of the delay element.