Intra-cavity loss modulation for ultrahigh-speed direct modulation lasers based on photon–photon resonance

The characteristics of the intra-cavity loss modulation laser diode (ICLM-LD) proposed in this paper were numerically and experimentally evaluated. A lower modulation sensitivity degradation rate (MSDR) of −0.30 dB/GHz and a wider 3 dB bandwidth of 49 GHz compared to those of direct modulation lasers (−0.49 dB/Hz, 16 GHz) were numerically confirmed. In addition, an MSDR of −0.29 dB/GHz and a 3 dB bandwidth wider than 30 GHz were experimentally confirmed using the fabricated ICLM-LD. The ICLM-LD will thus become a key part of ultrahigh-speed direct modulation lasers with external cavities whose modulation sensitivity is enhanced by the photon–photon resonance effect.