US Patent 11929592 Silicon-photonics-based semiconductor optical amplifier with N-doped active layer

A semiconductor optical amplifier for high-power operation includes a gain medium having a multilayer structure sequentially laid with a P-layer, an active layer, a N-layer from an upper portion to a lower portion in cross-section thereof. The gain medium is extendedly laid with a length L from a front facet to a back facet. The active layer includes multiple well layers formed by undoped semiconductor material and multiple barrier layers formed by n-doped semiconductor materials. Each well layer is sandwiched by a pair of barrier layers. The front facet is characterized by a first reflectance Rf and the back facet is characterized by a second reflectance Rb. The gain medium has a mirror loss α