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In this paper, we present the design, fabrication, and measurement of an evanescently coupled waveguide photodetector operating at 1.55 μm, which mainly comprises a diluted waveguide, a single-mode rib waveguide and a p—i—n photodiode with an extended optical matching layer. The optical characteristics of this structure are studied by using a three-dimensional finite-difference time-domain (3D FDTD) method. The photodetector exhibits a high 3-dB bandwidth of more than 35 GHz and a responsivity of 0.291 A/W at 1550 nm directly coupled with a cleaved fiber. Moreover, a linear response of more than 72-mW optical power is achieved, where a photocurrent of more than 21 mA is obtained at a reverse bias voltage of 3 V. [ABSTRACT FROM AUTHOR]

Tunable metamorphic InGaAs partially depleted absorber photodiodes with resonant cavity enhanced structure are fabricated on GaAs substrate. Dark-current densities of 7.2 × 10-7 A/cm2 at 0V and 3.6 × 10-4 A/cm2 at -5 V, a high quantum efficiency of 74.4 % at 1546 nm, and a 3-dB bandwidth up to 12 GHz are achieved. The full width at half maximum of the detector is about 16 nm. Furthermore, through thermal tuning, the peak wavelength red shifts from 1527nm to 1544 nm, and a tuning range of 17nm is realized without fabricating extra tuning electrodes. [ABSTRACT FROM AUTHOR]

A separate absorption, grading, charge and multiplication InGaAs/InP avalanche photodiode with ultra low dark current and high responsivity is demonstrated. It has a thin multiplication layer and a planar structure. Through the use of a well and a single floating guard ring to suppress edge breakdown, the device can easily be fabricated by one step epitaxial growth and one step diffusion. The dark current of a 30 μm diameter device is as low as 0.028 nA at punch-through and 0.1 nA at 90% of the breakdown voltage. The responsivity at 1.55 μm is 0.93A/W at unity gain and the multiplication layer is estimated to be less than 300 nm. [ABSTRACT FROM AUTHOR]