Quantum-well optoelectronic modulators in high magnetic field: A technological issue for the operation in particle accelerators

We have investigated the effect of a high magnetic field on the operation of an infrared electro-optic modulator constituted of In0.10Ga0.90As/GaAs quantum wells grown by metal-organic chemical vapor deposition. The magnetic field changes the working wavelength and the switching threshold of the device due to the diamagnetic blue-shift of the exciton ground-level energy and to the enhancement of the exciton oscillator strength, respectively. This is a consequence of the compression of the exciton wave function induced by the magnetic field.