Flat optical frequency comb generation by using one DPMZM and superposed harmonics

In this work, we propose a novel approach to the generation of flat optical frequency comb (OFC) by using dual-parallel Mach-Zehnder modulator (DPMZM) and superposed harmonics, where the superposed harmonics drive only one child Mach-Zehnder modulator of DPMZM. By adjusting precisely the modulation indices and phases of harmonics as well as the biases for DPMZM, flat OFCs are generated. In the experiment, a 9-line OFC with 0.26-dB flatness is achieved when the superposed fundamental tone and third harmonic drive the DPMZM; a 13-line OFC with 0.58-dB flatness is achieved when the fundamental tone, second harmonic, and third harmonic drive the DPMZM simultaneously.

Automated summary

In this work, a novel approach to generate flat optical frequency comb (OFC) using dual-parallel Mach-Zehnder modulator (DPMZM) and superposed harmonics is proposed. The superposed harmonics only drive one child Mach-Zehnder modulator of the DPMZM, and by precisely adjusting the modulation indices, phases, and biases, flat OFCs are generated. In the experiment, a 9-line OFC with 0.26-dB flatness is achieved using the superposed fundamental tone and third harmonic to drive the DPMZM; a 13-line OFC with 0.58-dB flatness is achieved when the fundamental tone, the second harmonic, and the third harmonic simultaneously drive the DPMZM.