Patent ID: 7596325

Claim:
An apparatus for pulse-amplitude equalization of rational harmonic mode-locked optical pulses, the apparatus comprising: a rational harmonic mode-locked optical fiber ring laser for producing rational harmonic mode-locked optical pulses, the rational harmonic mode-locked optical fiber ring laser having a Mach-Zehnder modulator including first and second electrodes configured to receive first and second modulation voltages, respectively; and a modulation signal generator for providing the first and second modulation voltages to the first and second electrodes of the Mach-Zehnder modulator, wherein the modulation signal generator includes: a pulse pattern generator to generate first and second RF signals, a first amplifier to receive and amplify the first RF signal, a phase shifter to receive the first RF signal amplified by the first amplifier and phase shift the first RF signal, a first attenuator to receive and attenuate the first RF signal that has been phase shifted by the phase shifter, a first bias circuit to receive the first RF signal that has been attenuated by the first attenuator and generate the first modulation voltage by applying a first bias voltage to the first RF signal, second amplifier to receive and amplify the second RF signal, a second attenuator to receive and attenuate the second RF signal, a second bias circuit to receive the second RF signal that has been attenuated by the second attenuator and generate the second modulation voltage by applying a second bias voltage to the second RF signal, wherein a potential difference between the first and second modulation voltages applied to the first and second electrodes of the Mach-Zehnder modulator is greater than a switching voltage of the Mach-Zehnder modulator, so that the Mach-Zehnder modulator can be operated to apply the same transmission coefficient to the rational harmonic mode-locked optical pulses and provide an amplitude equalized rational harmonic mode-locked optical pulse train.