ABSTRACT
We present monolithically integrated multi-channel coherent L-band transmitter (Tx) and receiver (Rx) photonic integrated circuits (PICs) on InP substrates. The L-band PICs are able to provide post-forward error correction (FEC), error-free operation for dual-polarization (DP) 16-QAM coherent transmission at 33 Gbaud. These transceivers operate at 200 Gbps per channel and support 1.2 Tbps aggregate capacity per 6 channel PIC. We also demonstrate in this work a C + L band communication system with two C-band superchannels (2 x 6λ) and three L-band superchannels (3 x 6λ) over a 600 km link. The received signals all have Q > 7.7 dB, which is well above the error-free threshold of the FEC used in this work.
ABSTRACT
We present a novel waveguide coupling scheme where a germanium diode grown via rapid melt growth is wrapped around a silicon waveguide. A 4 fF PIN photodiode is demonstrated with 0.95 A/W responsivity at 1550 nm, 6 nA dark current, and nearly 9 GHz bandwidth. Devices with shorter intrinsic region exhibit higher bandwidth (30 GHz) and slightly lower responsivity (0.7 A/W). An NPN phototransistor is also demonstrated using the same design with 14 GHz f(T).
ABSTRACT
We propose a cladding engineering method that flexibly modifies the radiation patterns and rates of metal-clad nanoscale optical cavity. Optimally adjusting the cladding symmetry of the metal-clad nanoscale optical cavity modifies the modal symmetry and produces highly directional radiation that leads to 90% coupling efficiency into an integrated waveguide. In addition, the radiation rate of the cavity mode can be matched to its absorption rate by adjusting the thickness of the bottom-cladding layer. This approach optimizes the energy-flow rate from the waveguide and maximizes the energy confined inside the nanoscale optical cavity.
ABSTRACT
We propose two designs of nanoscale sub-fF germanium photodiodes which are efficiently integrated with silicon waveguides. The metal-optic cavities are simulated with the finite difference time domain method and optimized using critical coupling concepts. One design is for a metal semiconductor metal photodiode with <200 aF capacitance, 39% external quantum efficiency, and 0.588 (λ/n)³ cavity volume at 1.5 µm wavelength. The second design is for a vertical p-i-n photodiode with <100 aF capacitance, 51% external quantum efficiency, and 0.804 (λ/n)³ cavity volume. Both designs make use of CMOS compatible materials germanium and aluminum metal for potential future monolithic integration with silicon photonics.
