Wavelength monitor based on two single quantum well absorbers in a standing wave

The recent growth in wavelength division multiplexing has increased the need for integrated wavelength monitors and wavelength-sensitive detectors. We demonstrate a novel standing wave device that contains two, thin-absorber photodetectors at different points in the standing wave. Our device can function as either a multiple wavelength detector or wavelength monitor. It is a surface-normal device that could be readily integrated with silicon electronics, for example by solder bonding. The device is an n-i-p-i-n structure grown by MBE. The DBR mirror stack is n-doped with a concentration of 10¹⁸ cm^-3 and consists of 15.5 pairs of Al_0.11Ga_0.89As/AlAs. The absorbers are single 95 Å GaAs/AlGaAs quantum wells. Each quantum well is placed in the intrinsic region of a p-i-n diode in order to collect the photocurrent that is generated from the absorption of light