Patent ID: 8670639

Claim:
An optical-switch driver circuit comprising: a pulse signal source configured to generate pulse waves that rise from a first voltage to a second voltage; a voltage-applying circuit that includes a high-frequency emphasis filter and a low-frequency emphasis filter, the high-frequency emphasis filter includes a first resistor and a first capacitor with a variable capacitance, the high-frequency emphasis filter being configured to be able to vary, in accordance with the capacitance of the first capacitor, time required to decrease an applied voltage to below the second voltage, and the low-frequency emphasis filter includes a second resistor and a second capacitor with a variable capacitance, the low-frequency emphasis filter being configured to be able to vary, in accordance with the capacitance of the second capacitor, time required to increase the applied voltage to the second voltage, wherein the voltage-applying circuit is configured to, for a pulse wave, output a third voltage higher than the second voltage, then output a fourth voltage lower than the second voltage, and further output the second voltage.