Photonic-crystal Lasers with Extremely Short Embedded Active-regions

We have fabricated an InP-based lambda-scale embedded active-region photonic-crystal (LEAP) laser with an extremely short active-region length of just the lattice constant (∼430 nm) of the photonic crystal (PhC). We have achieved lasing with a low threshold current of
$8.7\ \mu \mathrm{A}$
at room temperature. Still, this threshold is rather high compared with those with two (
$4.9\ \mu \mathrm{A}$
) or three times (
$6.6\ \mu \mathrm{A}$
) longer active regions. The dependence of the static characteristics on the active-region length is discussed, which infers that improvement in the current injection structure is necessary for further reduction in the operation energy of LEAP lasers with such extremely short active regions.