Large gain-bandwidth product and low-noise avalanche photodiodes (APDs) in the long-wavelength region are required in long-haul gigabit-rate lightwave systems. We have reported a practical device structure for planar GaInAs APDs with a successful guard ring effect in buried structure APDs.1 To obtain a large gain-bandwidth product, a higher carrier concentration n-InP multiplication layer must be employed to reduce avalanche buildup time. However, this results in deterioration of the excess noise factor for GaInAs APDs. We describe a design condition for achieving a large gain-bandwidth product and low-noise performance at the same time for GaInAs buried structure APDs grown by liquid phase epitaxy (LPE).
© 1987 Optical Society of AmericaPDF Article