Matthew N. Sysak

A hybrid AlGaInAs-silicon evanescent waveguide photodetector.

We report a waveguide photodetector utilizing a hybrid waveguide structure consisting of AlGaInAs quantum wells bonded to a silicon waveguide. The light in the hybrid waveguide is absorbed by the AlGaInAs quantum wells under reverse bias. The photodetector has a fiber coupled responsivity of 0.31 A/W with an internal quantum efficiency of 90 % over the 1.5 mum wavelength range. This photodetector structure can be integrated with silicon evanescent lasers for power monitors or integrated with silicon evanescent amplifiers for preamplified receivers.

Hybrid silicon evanescent devices

Si photonics as an integration platform has recently been a focus of optoelectronics research because of the promise of low-cost manufacturing based on the ubiquitous electronics fabrication infrastructure. The key challenge for Si photonic systems is the realization of compact, electrically driven optical gain elements. We review our recent developments in hybrid Si evanescent devices. We have demonstrated electrically pumped lasers, amplifiers, and photodetectors that can provide a low-cost, scalable solution for hybrid integration on a Si platform by using a novel hybrid waveguide architecture, consisting of III-V quantum wells bonded to Si waveguides.

1310nm silicon evanescent laser.

An electrically pumped 1310 nm silicon evanescent laser (SEL) is demonstrated utilizing the hybrid silicon evanescent waveguide platform. The SEL operates continuous wave (C.W.) up to 105degC with a threshold current of 30 mA and a maximum output power of 5.5 mW.

High Output Saturation and High-Linearity Uni-Traveling-Carrier Waveguide Photodiodes

Waveguide uni-traveling-carrier photodiodes (UTC-PDs) have been fabricated and tested. Output saturation currents greater than 40 mA at 1 GHz are demonstrated for a 10 mumtimes150mum photodiode (PD). The third-order intermodulation distortion is also measured and exhibits a third-order output intercept point of 43 dBm at 20 mA and 34 dBm at 40 mA for this same PD. UTC-PDs with geometries of 5 mumtimes100 mum and 10 mumtimes100 mum are also compared and it is shown that a wider waveguide PD has improved saturation characteristics due to the lower optical power density which reduces the saturation at the front end of the device

High saturation power and high gain integrated photoreceivers

A novel monolithically integrated semiconductor optical amplifier (SOA) receiver is presented. This receiver implements a flared SOA and tapered quantum-well detector. SOAs exhibited 22-dB unsaturated gain and 15.7-dBm output power at the 1-dB gain compression point while the receiver demonstrated 15-GHz bandwidth and -10.5-dBm sensitivity.

Advanced integration schemes for high-functionality/high-performance photonic integrated circuits

The evolution of optical communication systems has facilitated the required bandwidth to meet the increasing data rate demands. However, as the peripheral technologies have progressed to meet the requirements of advanced systems, an abundance of viable solutions and products have emerged. The finite market for these products will inevitably force a paradigm shift upon the communications industry. Monolithic integration is a key technology that will facilitate this shift as it will provide solutions at low cost with reduced power dissipation and foot-print in the form of highly functional optical components based on photonic integrated circuits (PICs). In this manuscript, we discuss the advantages, potential applications, and challenges of photonic integration. After a brief overview of various integration techniques, we present our novel approaches to increase the performance of the individual components comprising highly functional PICs.

40-Gb/s Widely Tunable Low-Drive-Voltage Electroabsorption-Modulated Transmitters

We present the first 40-Gb/s widely tunable electroabsorption modulator (EAM)-based transmitters. The sampled-grating Distributed Bragg Reflector (SG-DBR) laser/EAM devices were fabricated using a multiple-band-edge-quantum-well-intermixing (QWI) technique, which requires only simple blanket regrowth and avoids disruption of the axial waveguide. Devices were fabricated from two different multiple quantum well (MQW) active-region designs for direct comparison. The SG-DBR lasers demonstrated 30 nm of tuning with output powers up to 35 mW. The integrated QW EAMs provided 3-dB optical modulation bandwidths in the 35-39 GHz range, low-drive voltage (1.0-1.5 VPtoP), and low/negative-chirp operation. Bit-error-rate measurements at 40 Gb/s demonstrated 0.2-1.1 dB of power penalty for transmission through 2.3 km of standard fiber

A single regrowth integration platform for photonic circuits incorporating tunable SGDBR lasers and quantum-well EAMs

A monolithic integration platform is demonstrated for high functionality photonic circuits that include quantum-well electroabsorption modulators, semiconductor optical amplifiers, and widely tunable lasers. The platform is based on the selective removal of a set of active quantum wells located above an optical waveguide layer. The waveguide layer contains a second set of quantum wells to be used in modulator regions. Fabrication requires only a single blanket InP regrowth

Single-chip wavelength conversion using a photocurrent-driven EAM integrated with a widely tunable sampled-grating DBR laser

Tunable photocurrent-driven wavelength converters using widely tunable sampled grating distributed Bragg reflector lasers, electroabsorption modulators, semiconductor optical amplifiers, and an optically preamplified receiver have been fabricated and tested. Dynamic wavelength conversion has been achieved over 40 nm with optical bandwidths up to 10 GHz.

Monolithically Integrated Balanced Uni-Traveling-Carrier Photodiode with Tunable MMI Coupler for Microwave Photonic Circuits

A monolithically integrated balanced uni-traveling-carrier photodiode (UTC-PD) with a tunable 2times2 multimode interference (MMI) coupler has been fabricated and tested. Two waveguide UTC-PDs are electrically isolated using high-energy Helium implantation, and then connected in series using a monolithic metal interconnect. On chip metal-insulator-semiconductor (MIS) capacitors provide some DC decoupling. The tunable MMI coupler allows for tuning of the power balance in the PDs. Output saturation currents greater than 40 mA at 1 GHz are demonstrated for a single 10 mum times 150 mum UTC-PD. The third order intermodulation distortion (IMD3) is also measured and exhibits an output intercept point (OIP3) of 43 dBm at 20 mA and 34 dBm at 40 mA for this same UTC-PD. In the balanced configuration, the OIP3 values are therefore 49 dBm and 40 dBm. The balanced UTC-PD is also highly symmetric; the common mode rejection ratio (CMRR) was measured to be around 40 dB.