We used two‐step molecular beam epitaxial (MBE) growth to integrate monolithically single and double vertical‐cavity structures on a wafer. This technique is useful for making a single vertical‐cavity surface‐emitting laser–thyristor with a low threshold and a double vertical‐cavity heterojunction phototransistor with both a high responsivity and a large spectral bandwidth. Regrowth on a patterned distributed Bragg reflector after thermal desorption of a passivating GaAs layer resulted in the laser in the single‐cavity section having a threshold current density of 1.0 kA/cm2, which is comparable to that of one grown by conventional one‐step MBE. Controlling thickness to within ±0.3% resulted in the regrown double‐cavity section having a bandwidth of 5 nm.