Optical transmitter and optical transmission system
First Claim
1. An optical transmitter utilizing a Mach-Zehnder type optical modulator, said Mach-Zehnder type optical modulator including:
- a light input end for receiving light;
a first arm and a second arm for branching the light from said light input end to propagate the branched light, respectively;
a light output end for synthesizing the branched light propagated through said first and second arms to output the resultant light;
a first electrode for applying a first drive signal to the first arm to thereby drive the first arm; and
a second electrode for applying a second drive signal to the second arm to thereby drive the second arm, comprising;
amplitude adjusting parts for adjusting the respective amplitudes of the first and second drive signals;
phase adjusting parts for adjusting the respective phases of the first and second drive signals;
an amplitude controlling part for detecting the respective amplitudes of the first and second drive signals, to thereby feedback control the amplitude adjusting parts; and
a phase controlling part for detecting the respective phases of the first and second drive signals, to thereby feedback control the phase adjusting parts.
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Accused Products
Abstract
The present invention aims at providing an optical transmitter utilizing a Mach-Zehnder type optical modulator, in which the optical modulator is capable of readily optimizing an optical wavelength chirp to be added to a transmission optical signal. To this end, the optical transmitter of the present invention includes a Mach-Zehnder type optical modulator having two arms driven by two drive signals, respectively, and is constituted to comprise: amplitude adjusting parts for adjusting the amplitudes of the drive signals, respectively; phase adjusting parts for adjusting the phases of the drive signals, respectively; an amplitude controlling part for feedback controlling the amplitude adjusting parts so that an amplitude ratio between the drive signals becomes a value corresponding to an optimum optical wavelength chirp amount; and a phase controlling part for feedback controlling the phase adjusting parts so that the phases of the drive signals are brought into an antiphase relation.
50 Citations
9 Claims
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1. An optical transmitter utilizing a Mach-Zehnder type optical modulator, said Mach-Zehnder type optical modulator including:
- a light input end for receiving light;
a first arm and a second arm for branching the light from said light input end to propagate the branched light, respectively;
a light output end for synthesizing the branched light propagated through said first and second arms to output the resultant light;
a first electrode for applying a first drive signal to the first arm to thereby drive the first arm; and
a second electrode for applying a second drive signal to the second arm to thereby drive the second arm, comprising;
amplitude adjusting parts for adjusting the respective amplitudes of the first and second drive signals;
phase adjusting parts for adjusting the respective phases of the first and second drive signals;
an amplitude controlling part for detecting the respective amplitudes of the first and second drive signals, to thereby feedback control the amplitude adjusting parts; and
a phase controlling part for detecting the respective phases of the first and second drive signals, to thereby feedback control the phase adjusting parts. - View Dependent Claims (2, 3, 4, 5, 6, 9)
- a light input end for receiving light;
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7. An optical transmitter utilizing an external modulator made up by serially connecting a Mach-Zehnder type optical modulator and an optical phase modulator, comprising:
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an amplitude adjusting part for adjusting an amplitude of a drive signal for driving said optical phase modulator;
a phase adjusting part for adjusting a phase of said drive signal;
an amplitude controlling part for detecting the amplitude of said drive signal and for feedback controlling said amplitude adjusting part so that said amplitude of the drive signal becomes a value corresponding to an optical wavelength chirp amount set to reduce transmittal degradation of an optical signal; and
a phase controlling part for detecting the phase of said drive signal and for feedback controlling said phase adjusting part so that said phase is matched with a phase of a signal for driving the Mach-Zehnder type optical modulator. - View Dependent Claims (8)
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Specification