An InGaAsP/InAlAs/InP asymmetric quantum well structure was proposed and fabricated, where a large change in the wave function overlap of electrons and holes can be expected with the application of a low voltage. It was demonstrated by using photocurrent measurements that a large absorption change can be realized by applying a bias within ±1 V. The observed absorption change was caused by a large change in the wave function overlap of electrons and holes with the application of an opposite electric field.