Jon Peters

Compact Polarization Beam Splitter Using an Asymmetrical Mach–Zehnder Interferometer Based on Silicon-on-Insulator Waveguides

A compact polarization beam splitter based on an asymmetrical Mach-Zehnder interferometer (MZI) on a sub-micron silicon-on-insulator platform is demonstrated experimentally. The present MZI polarization beam splitter (PBS) is fabricated with a double-etching process and the deeply-etched region includes the MZI arms and the multimode- interference (MMI) couplers. In this way, the birefringence of the MZI arms and the power splitting ratio of the MMI coupler become insensitive to the etching depth, which makes the fabrication easier. The 2×2 MMI couplers are optimized to be polarization-insensitive and have a balanced ratio (50:50) for both polarizations. The measured extinction ratio of the fabricated MZI PBS is higher than 10 dB in the wavelength range from 1.54 to 1.58 μm.

Fully integrated hybrid silicon two dimensional beam scanner

In this work we present the first fully-integrated free-space beam-steering chip using the hybrid silicon platform. The photonic integrated circuit (PIC) consists of 164 optical components including lasers, amplifiers, photodiodes, phase tuners, grating couplers, splitters, and a photonic crystal lens. The PIC exhibited steering over 23° x 3.6° with beam widths of 1° x 0.6°.

8 × 8 × 40 Gbps fully integrated silicon photonic network on chip

We demonstrate a fully integrated photonic network-on-chip circuit with wavelength division multiplexing transceivers on silicon. The total transmission capacity is up to 8×8×40 Gbps for intra- and inter-chip interconnections.

Electrically pumped continuous-wave 1.3 μm quantum-dot lasers epitaxially grown on on-axis (001) GaP/Si.

We demonstrate 1.3 µm quantum dot lasers grown directly on (001) silicon substrates without offcut or germanium layers, with thresholds down to 30 mA and lasing up to 90°C. Measurements of relative intensity noise versus feedback show 20 dB higher tolerance to reflections compared to quantum well lasers on silicon.

InP-based waveguide photodiodes heterogeneously integrated on silicon-on-insulator for photonic microwave generation

High-linearity modified uni-traveling carrier photodiodes on silicon-on-insulator with low AM-to-PM conversion factor are demonstrated. The devices deliver more than 2.5 dBm RF output power up to 40 GHz and have an output third order intercept point of 30 dBm at 20 GHz. Photodiode arrays exceed a saturation current-bandwidth-product of 630 mA · GHz and reach unsaturated RF output power levels of 10 dBm at 20 GHz.

Fully integrated hybrid silicon free-space beam steering source with 32 channel phased array

Free-space beam steering using optical phased arrays is a promising method for implementing free-space communication links and Light Detection and Ranging (LIDAR) without the sensitivity to inertial forces and long latencies which characterize moving parts. Implementing this approach on a silicon-based photonic integrated circuit adds the additional advantage of working with highly developed CMOS processing techniques. In this work we discuss our progress in the development of a fully integrated 32 channel PIC with a widely tunable diode laser, a waveguide phased array, an array of fast phase modulators, an array of hybrid III-V/silicon amplifiers, surface gratings, and a graded index lens (GRIN) feeding an array of photodiodes for feedback control. The PIC has been designed to provide beam steering across a 15°x5° field of view with 0.6°x0.6° beam width and background peaks suppressed 15 dB relative to the main lobe within the field of view for arbitrarily chosen beam directions. Fabrication follows the hybrid silicon process developed at UCSB with modifications to incorporate silicon diodes and a GRIN lens.

Heterogeneously integrated III-V-on-silicon multibandgap superluminescent light-emitting diode with 290 nm optical bandwidth.

A broadband superluminescent III-V-on-silicon light-emitting diode (LED) was realized. To achieve the large bandwidth, quantum well intermixing and multiple die bonding of InP on a silicon photonic waveguide circuit were combined for the first time, to the best of our knowledge. The device consists of four sections with different bandgaps, centered around 1300, 1380, 1460, and 1540 nm. The fabricated LEDs were connected on-chip in a serial way, where the light generated in the smaller bandgap sections travels through the larger bandgap sections. By balancing the pump current in the four LEDs, we achieved 292 nm of 3 dB bandwidth and an on-chip power of -8  dBm.

Heterogeneous integration of lithium niobate and silicon nitride waveguides for wafer-scale photonic integrated circuits on silicon

An ideal photonic integrated circuit for nonlinear photonic applications requires high optical nonlinearities and low loss. This work demonstrates a heterogeneous platform by bonding lithium niobate (LN) thin films onto a silicon nitride (Si3N4) waveguide layer on silicon. It not only provides large second- and third-order nonlinear coefficients, but also shows low propagation loss in both the Si3N4 and the LN-Si3N4 waveguides. The tapers enable low-loss-mode transitions between these two waveguides. This platform is essential for various on-chip applications, e.g., modulators, frequency conversions, and quantum communications.

Reliability of Hybrid Silicon Distributed Feedback Lasers

We present results from reliability studies on hybrid silicon distributed feedback lasers. The devices show no degradation at 70 °C for 5000 h. We investigate the influence on reliability of a superlattice between the active region and the bonded interface. Transmission electron microscopy images from a failed device show no defects in the active region along a 15-μm-long longitudinal cross section at the center of the laser cavity.

Highly linear heterogeneous-integrated Mach-Zehnder interferometer modulators on Si

In this paper we demonstrate highly linear Mach-Zehnder interferometer modulators utilizing heterogeneous integration on a Si substrate (HS-MZM). A record high dynamic range was achieved for silicon devices, obtained using hybrid III-V/Si phase modulation sections and single drive push-pull operation, demonstrating a spurious free dynamic range (SFDR) of 112 dB∙Hz2/3 at 10 GHz, comparable to commercial Lithium Niobate MZMs.