Highly flat optical comb generation based on dual-parallel Mach-Zehnder and phase modulators

What is it about?

We propose a novel scheme for the generation of an optical frequency comb with exceptionally high flatness for a large number of spectral lines. The scheme consists of a dual-parallel Mach Zehnder modulator (DP-MZM) with which to carve the narrow intensity pulse and phase modulators for the application of high chirp. The experimental results show perfect spectral profiles with 35 lines with less than 1 dB flatness and 54 lines at 1.6 dB flatness when a DP-MZM is combined with two and three phase modulators, respectively.

Featured Image

Why is it important?

By shaping narrow and flat-topped intensity pulses through the proper operation of the DP-MZM, the proposed method can relax the requirement of a quasi-quadratic signal for phase modulations, allowing a simple sinusoidal signal is enough for the phase modulators. Therefore, the proposed method can generate a flexible number of comb lines with highly flatness simply by changing the amplitude of the driving sinusoidal signals for the phase modulators and is easily expandable with additional phase modulators.

Perspectives