Optical modulation apparatus

An optical modulation apparatus configured to modulate an optical signal in response to a differential input signal, the optical modulation apparatus comprising:

• an electric circuit including:
• an input circuit configured to generate a first differential signal in response to the differential input signal;
• a first amplifier configured to amplify the first differential signal, and output an amplified first differential signal as a second differential signal;
• a first transmission line portion configured to propagate the second differential signal;
• a second amplifier configured to amplify the second differential signal propagated through the first transmission line portion, and output an amplified second differential signal as a third differential signal;
• a second transmission line portion configured to propagate the third differential signal;
• and
• a termination circuit configured to terminate the the third differential signal propagated through the second transmission line portion;
• and
• an optical modulator including:
• a first optical modulation portion configured to modulate a phase of the optical signal in response to the second differential signal propagating through the first transmission line portion;
• an optical delay portion configured to delay the phase of the optical signal modulated by the first optical modulation portion by a first delay time;
• and
• a second optical modulation portion configured to modulate the phase of the optical signal modulated by the first optical modulation portion and delayed by the optical delay portion, in response to the third differential signal propagating through the second transmission line portion,
• wherein the second amplifier has a gain that has a maximum value in a first frequency region of the second differential signal set to be smaller than a minimum value in a second frequency region higher in frequency than the first frequency region.