Tunable quantum emitters on large-scale foundry silicon photonics.

Controlling large-scale many-body quantum systems at the level of single photons and single atomic systems is a central goal in quantum information science and technology. Intensive research and development has propelled foundry-based silicon-on-insulator photonic integrated circuits to a leading platform for large-scale optical control with individual mode programmability. However, integrating atomic quantum systems with single-emitter tunability remains an open challenge.

Electrically pumped quantum-dot lasers grown on 300 mm patterned Si photonic wafers.

Monolithic integration of quantum dot (QD) gain materials onto Si photonic platforms via direct epitaxial growth is a promising solution for on-chip light sources. Recent developments have demonstrated superior device reliability in blanket hetero-epitaxy of III-V devices on Si at elevated temperatures. Yet, thick, defect management epi designs prevent vertical light coupling from the gain region to the Si-on-Insulator waveguides.

High-Q-factor AlO micro-trench cavities integrated with silicon nitride waveguides on silicon.

We report on the design and performance of high-Q integrated optical micro-trench cavities on silicon. The microcavities are co-integrated with silicon nitride bus waveguides and fabricated using wafer-scale silicon-photonics-compatible processing steps. The amorphous aluminum oxide resonator material is deposited via sputtering in a single straightforward post-processing step.

Whispering gallery germanium-on-silicon photodetector.

We design and demonstrate, to the best of our knowledge, the first whispering gallery germanium-on-silicon photodetector with evanescent coupling from a silicon bus waveguide in a CMOS-compatible process. The small footprint (63.6  μm), high responsivity (∼1.

Monolithically-integrated distributed feedback laser compatible with CMOS processing.

An optically-pumped, integrated distributed feedback laser is demonstrated using a CMOS compatible process, where a record-low-temperature deposited gain medium enables integration with active devices such as modulators and detectors. A pump threshold of 24.9 mW and a slope efficiency of 1.

Athermal synchronization of laser source with WDM filter in a silicon photonics platform.

In an optical interconnect circuit, microring resonators (MRRs) are commonly used in wavelength division multiplexing systems. To make the MRR and laser synchronized, the resonance wavelength of the MRR needs to be thermally controlled, and the power consumption becomes significant with a high-channel count. Here, we demonstrate an athermally synchronized rare-earth-doped laser and MRR.

Mode-evolution-based coupler for high saturation power Ge-on-Si photodetectors.

We propose a mode-evolution-based coupler for high saturation power germanium-on-silicon photodetectors. This coupler uniformly illuminates the intrinsic germanium region of the detector, decreasing saturation effects, such as carrier screening, observed at high input powers. We demonstrate 70% more photocurrent generation (9.

Ultra-compact and low-threshold thulium microcavity laser monolithically integrated on silicon.

We demonstrate an ultra-compact and low-threshold thulium microcavity laser that is monolithically integrated on a silicon chip. The integrated microlaser consists of an active thulium-doped aluminum oxide microcavity beside a passive silicon nitride bus waveguide, which enables on-chip pump-input and laser-output coupling. We observe lasing in the wavelength range of 1.

C-band swept wavelength erbium-doped fiber laser with a high-Q tunable interior-ridge silicon microring cavity.

We demonstrate swept-wavelength operation of an erbium-doped fiber laser using a tunable silicon microring cavity. The microring cavity is designed to have 35 nm free spectral range, a high Q of 1.5 × 10, and low insertion loss of <0.

Silicon wavelength-selective partial-drop broadcast filter bank.

We propose an approach to a wavelength-selective 1×N port optical broadcast network demonstrating the approach in a 1×8 port parallel optical drop filter bank utilizing adiabatic micro-ring tunable filters. The micro-ring filters exhibit first-order 92.7±3.

Integrated heterodyne interferometer with on-chip modulators and detectors.

We demonstrate, to our knowledge, the first on-chip heterodyne interferometer fabricated on a 300-mm CMOS compatible process that exhibits root-mean-square (RMS) position noise on the order of 2 nm. Measuring 1 mm by 6 mm, the interferometer is also, to our knowledge, the smallest heterodyne interferometer demonstrated to date and will surely impact numerous interferometric and metrology applications, including displacement measurement, laser Doppler velocimetry and vibrometry, Fourier transform spectroscopy, imaging, and light detection and ranging (LIDAR). Here we present preliminary results that demonstrate the displacement mode.

Generating and identifying optical orbital angular momentum with silicon photonic circuits.

Here, we propose and demonstrate a silicon nanophotonic phased array that is capable of generating light carrying optical orbital angular momentum (OAM). Optical beams carrying different orbital angular momenta have been generated. In addition, the generated OAM wavefronts are experimentally identified by interfering with another on-chip generated Gaussian beam, opening up opportunities of integrating conventional optical systems and functionalities on to a silicon chip.

Integrated phased array for wide-angle beam steering.

We demonstrate an on-chip optical phased array fabricated in a CMOS compatible process with continuous, fast (100 kHz), wide-angle (51°) beam-steering suitable for applications such as low-cost LIDAR systems. The device demonstrates the largest (51°) beam-steering and beam-spacing to date while providing the ability to steer continuously over the entire range. Continuous steering is enabled by a cascaded phase shifting architecture utilizing, low power and small footprint, thermo-optic phase shifters.

Monolithic erbium- and ytterbium-doped microring lasers on silicon chips.

We demonstrate monolithic 160-µm-diameter rare-earth-doped microring lasers using silicon-compatible methods. Pump light injection and laser output coupling are achieved via an integrated silicon nitride waveguide. We measure internal quality factors of up to 3.

CMOS-compatible 75 mW erbium-doped distributed feedback laser.

On-chip, high-power, erbium-doped distributed feedback lasers are demonstrated in a CMOS-compatible fabrication flow. The laser cavities consist of silicon nitride waveguide and grating features, defined by wafer-scale immersion lithography and an erbium-doped aluminum oxide layer deposited as the final step in the fabrication process. The large mode size lasers demonstrate single-mode continuous wave operation with a maximum output power of 75 mW without any thermal damage.

Four-port integrated polarizing beam splitter.

In this Letter, we report on the first integrated four-port polarizing beam splitter. The device operates on the principle of mode evolution and was implemented in a silicon-on-insulator silicon photonics platform and fabricated on a 300 mm CMOS line using 193 nm optical immersion lithography. The adiabatic transition forming of the structure enabled over a 150 nm bandwidth from λ~1350 to λ~1500  nm, achieving a cross-talk level below -10  dB over the entire band.

Two-dimensional apodized silicon photonic phased arrays.

In this Letter, we demonstrate an 8×8 apodized silicon photonic phased array where the emission from each of 64 nanoantennas was tailored to exhibit Gaussian-shaped intensity distributions in the near field so that the sidelobes of the generated far-field optical beam were suppressed compared to that of a uniform phased array. With the aid of the 72 thermo-optic phase tuners directly integrated within the phased array, we dynamically shaped the generated optical beam in the far field in a variety of ways.

Uniformly spaced λ/4-shifted Bragg grating array with wafer-scale CMOS-compatible process.

We report on an integrated λ/4-shifted Bragg grating array using a wafer-scale complementary metal-oxide semiconductor (CMOS) compatible process with silicon-nitride waveguides. A sidewall grating was used to simplify the fabrication process, and a sampled Bragg grating with equivalent phase-shift structure was employed to achieve an accurate λ/4 phase shift. A four-channel λ/4-shifted Bragg grating array with highly uniform channel spacing was demonstrated with a measured channel spacing variation below 10 pm (1.