On-chip low-loss all-optical MoSe\(_2\) modulator

Monolayer transition metal dichalcogenides (TMDCs), like MoS\(_2\), MoSe\(_2\), WS\(_2\), and WSe\(_2\), feature direct bandgaps, strong spin-orbit coupling, and exciton-polariton interactions at the atomic scale, which could be harnessed for efficient light emission, valleytronics, and polaritonic lasing, respectively. Nevertheless, to build next-generation photonic devices that make use of these features, it is first essential to model the all-optical control mechanisms in TMDCs. Herein, a simple model is proposed to quantify the performance of a 35\(\,\)\textmu m long Si\(_3\)N\(_4\) waveguide-integrated all-optical MoSe\(_2\) modulator. Using this model, a switching energy of 14.6\(\,\)pJ is obtained for a transverse-magnetic (TM) and transverse-electric (TE) polarised pump signals at \(\lambda =\,\)480\(\,\)nm. Moreover, maximal extinction ratios of 20.6\(\,\)dB and 20.1\(\,\)dB are achieved for a TM and TE polarised probe signal at \(\lambda =\,\)500\(\,\)nm, respectively, with an ultra-low insertion loss of \(