| Resonant-cavity-enhanced photodiodes are investigated primarily for use in high-bit-rate data telecommunication applications. The design considerations of resonant-cavities and quarter-wave stacks which act as mirrors in the cavity structure are discussed, as well as the advantages and drawbacks to using a resonant cavity. Several resonant-cavity-enhanced photodiodes are presented. The devices include a high-efficiency, narrow-spectral-linewidth photodiode with a linewidth less than 2 nm, and a tunable, very narrow-spectral-linewidth photodetector with a full width at half maximum of 2 A. The ability to fabricate these devices is considered as an important aspect in the design, and particular attention is paid to the growth of the structures by molecular beam epitaxy. For improved sensitivity, a resonant-cavity-enhanced, separate absorption and multiplication avalanche photodiode structure is examined. As a proof of principle, such a structure based on the AlGaAs material system shows high-gain, peak quantum efficiencies near 80%, low multiplication noise, low dark current, a unity gain bandwidth of 23 GHz and a gain-bandwidth product greater than 130 GHz. A similar design using InGaAlAs on InP, which is capable of detecting light at 1.55 {dollar}mu{dollar}m, demonstrates similar quantum efficiency, gains up to 8, and low dark currents. |
