Michael L. Davenport

Silicon on ultra-low-loss waveguide photonic integration platform.

We demonstrate a novel integrated silicon and ultra-low-loss Si3N4 waveguide platform. Coupling between layers is achieved with (0.4 ± 0.2) dB of loss per transition and a 20 nm 3-dB bandwidth for one tapered coupler design and with (0.8 ± 0.2) dB of loss per transition and a 100 nm 3-dB bandwidth for another. The minimum propagation loss measured in the ultra-low-loss waveguides is 1.2 dB/m in the 1590 nm wavelength regime.

Low threshold and high speed short cavity distributed feedback hybrid silicon lasers.

In this paper we investigate reducing threshold and improving the efficiency and speed of distributed feedback hybrid silicon lasers. A low threshold current of 8.8 mA was achieved for a 200 μm cavity at 20 °C. A 3 dB bandwidth of 9.5 GHz as well as 12.5 Gb/s direct modulation of DFB laser diode was achieved on the hybrid silicon platform for the first time.

Heterogeneous Silicon Photonic Integrated Circuits

We review recent breakthroughs in the silicon photonic technology and components, and describe progress in silicon photonic integrated circuits. Heterogeneous silicon photonics has recently demonstrated performance that significantly outperforms native III/V components. The impact active silicon photonic integrated circuits could have on interconnects, telecommunications, sensors, and silicon electronics is reviewed.

Low-Loss Silicon Nitride AWG Demultiplexer Heterogeneously Integrated With Hybrid III–V/Silicon Photodetectors

A unique and novel platform that combines III-V and silicon photonic components with ultra-low loss silicon nitride waveguides for monolithic integration of novel photonic circuits is presented. Successful (proof-of-principle) integration of eight hybrid III-V/silicon photodetectors and an arrayed waveguide grating is shown. The InGaAs photodiodes in this platform had average fiber-coupled responsivity of 0.36 A/W at 1550 nm, 30 GHz electrical bandwidth, and operated up to 50 Gb/s. The AWG had an insertion loss of 0.85 dB and adjacent-channel cross-talk less than -38 dB.

Widely Tunable Narrow-Linewidth Monolithically Integrated External-Cavity Semiconductor Lasers

We theoretically analyze, design, and measure the performance of a semiconductor laser with a monolithically integrated external cavity. A ~4 cm long on-chip cavity is made possible by a low-loss silicon waveguide platform. We show tuning in excess of 54 nm in the O-band as well as significant reduction in laser linewidth due to controlled feedback from the external cavity. The measured linewidth in full tuning range is below 100 kHz and the best results are around 50 kHz. Approaches to further improve the performance of such laser architectures are described.

Arrayed narrow linewidth erbium-doped waveguide-distributed feedback lasers on an ultra-low-loss silicon-nitride platform

We demonstrate an array of erbium-doped waveguide-distributed feedback lasers on an ultra-low-loss Si(3)N(4) platform. Sidewall gratings providing the lasing feedback are defined in the silicon-nitride layer using 248 nm stepper lithography, while the gain is provided by a reactive co-sputtered erbium-doped aluminum-oxide layer. We observe lasing output over a 12 nm wavelength range (1531-1543 nm) from the array of five separate lasers. Output powers of 8 μW and lasing linewidths of 501 kHz are obtained. Single-mode operation is confirmed, with side-mode suppression ratios over 35 dB for all designs.

Heterogeneous Silicon/III–V Semiconductor Optical Amplifiers

We report high output power and high-gain semiconductor optical amplifiers integrated on a heterogeneous silicon/III-V photonics platform. The devices produce 25 dB of unsaturated gain for the highest gain design, and 14 dBm of saturated output power for the highest output power design. The amplifier structure is also suitable for lasers, and can be readily integrated with a multitude of silicon photonic circuit components. These devices are useful for a wide range of photonic integrated circuits. We show a design method for optimizing the amplifier for the desired characteristics. The amplifier incorporates a low loss and low reflection transition between the heterogeneous active region and a silicon waveguide, and we report transition loss below 1 dB across the entire measurement range and parasitic reflection coefficient from the transition below 1 · 10-3.

Ultra-long cavity hybrid silicon mode-locked laser diode operating at 930 MHz

An integrated 9-cm cavity hybrid silicon laser that is fundamentally mode-locked at 930 MHz is presented. The laser outputs chirped 200-ps pulses at 1.1-ns repetition rate. Harmonic mode-locking up to the 8th harmonic is shown, with 35-ps pulses at the 3rd harmonic.

Narrow linewidth tunable laser using coupled resonator mirrors

A novel fully integrated tunable single mode hybrid silicon laser is demonstrated. We report a linewidth of 260kHz, which is the lowest reported for a monolithically integrated laser. The side-mode suppression ratio is >40dB.

A 400 Gb/s WDM receiver using a low loss silicon nitride AWG integrated with hybrid silicon photodetectors

A heterogeneously integrated WDM receiver based on an AWG demultiplexer and hybrid silicon/InGaAs detectors is presented in a novel platform that combines hybrid silicon components with ultra-low loss silicon nitride waveguides.