Search

We present a butt-coupled Germanium (Ge) metal-semiconductor-metal photodetectors on silicon (Si) waveguides. This device is implemented by a novel process using self-aligned microbonding technique and rapid-melt-growth method for monolithically integrating single-crystal Ge and Si devices on the same plane. Through inserting a thin amorphous Si (a-Si) layer between the Ge and metal contact, the Schottky barrier height is modulated, which effectively reduces the dark current and increases the operation speed. The fabricated device shows a low dark current of 0.24 μA, a 3 dB bandwidth of 15 GHz and a responsivity of 0.25 A/W, at a bias voltage of -2.6 V for wavelength 1310 nm.

A new technology using hydrogen annealing and thermal oxidation is proposed to fabricate a very compact 2-D multimode interference coupler monolithically integrated with two-layer silicon photonic wires. Two devices, a 1 × 1 cross-power coupler and a 1 × 22 power splitter, are presented and characterized. The experimental result shows that a 3-dB transmission bandwidth of 1.1 nm, and the on-chip coupler losses of 8.6 dB and 2.84 dB were accomplished for the 1 × 1 cross-power coupler and the 1 × 22 power splitter. This paper demonstrates the possibility of realizing 3-D photonic integration for silicon-on-insulator lightwave circuits.

A single crystalline silicon microtoroidal resonator with integrated MEMS-actuated tunable optical coupler is demonstrated for the first time. It is fabricated by combining hydrogen annealing and wafer bonding processes. The device operates in all three coupling regimes: under-, critical, and over-coupling. We have also developed a comprehensive model based on time-domain coupling theory. The experimental and theoretical results agree very well. The quality factor (Q) is extracted by fitting the experimental curve with the model. The unloaded Q is as high as 110 000, and the loaded Q is continuously tunable from 110 000 to 5400. The extinction ratio of the transmittance is 22.4 dB. This device can be used as a building block of resonator-based reconfigurable photonic integrated circuits