A novel approach to generate the flattened optical frequency comb (OFC) with tunable frequency spacing is proposed. The proposed generator consists of two cascaded polarization modulators driven by two radio frequency signals with different frequencies. By adjusting the parameters, 9, 12, and 16 comb lines can be generated with tunable frequency spacing. The scheme requires no DC bias voltage of the modulators and no optical filter, which makes our method simple and stable. A concept proof simulation is conducted to confirm the feasibility of the generation schemes of the 9-, 12-, and 16-line OFCs.
['Yang Yang', 'Jianxin Ma', 'Xiangjun Xin', 'Qi Zhang', 'Yi Zhang', 'Xiaoli Yin', 'Ruijiao Zhang', 'Wen Liu']
Optical frequency comb generation using two cascaded polarization modulators