Erik J. Skogen

A quantum-well-intermixing process for wavelength-agile photonic integrated circuits

Wavelength-agile photonic integrated circuits are fabricated using a one-step ion implantation quantum-well intermixing process. In this paper, we discuss, the issues in processing optimized widely tunable multisection lasers using this technique and present the results achieved using this process. This quantum-well intermixing process is general in its application and can be used to monolithically integrate a wide variety of optoelectronic components with widely tunable lasers.

Monolithically integrated active components: a quantum-well intermixing approach

As the demand for bandwidth increases, the communications industry is faced with a paradigm shift. Photonic integration is a key technology that will facilitate this shift. Monolithic integration allows for the realization of highly functional optical components, called photonic integrated circuits. Herein, we discuss the advantages and potential applications of photonic integration, and after a brief overview of various integration techniques, provide a detailed look at our work using a novel quantum well intermixing processing platform.

Widely tunable monolithically integrated all-optical wavelength converters in InP

Design, fabrication, and characterization of monolithically integrated widely tunable all-optical wavelength converters in InP is reported. The devices are based on the SGDBR laser integrated with different MZI-SOA wavelength converters. Error-free wavelength conversion at 2.5 Gbps was demonstrated over 50 nm input and 22 nm output wavelength range. Static operation, extinction ratio enhancement, signal reamplification, dynamic range, and chirp properties were characterized as well.

A widely tunable high-speed transmitter using an integrated SGDBR laser-semiconductor optical amplifier and Mach-Zehnder modulator

The first integrated sampled-grating distributed Bragg reflector (SGDBR) laser-semiconductor optical amplifier-Mach-Zehnder modulator transmitter is presented. Devices have 3 dB bandwidth ranging from 13-18 GHz corresponding to electrodes lengths that range between 200-300 /spl mu/m long. This corresponds to a V/sub pi/ of 4.8-6.2 V.

Monolithically integrated Mach-Zehnder interferometer wavelength converter and widely tunable laser in InP

The first monolithically integrated widely tunable wavelength converter, consisting of a sampled-grating distributed-Bragg-reflector laser (SGDBR) and an SOA-based Mach-Zehnder interferometer, is reported. The integration process requires only a single regrowth step. Static extinction ratios (electrical/optical) better than 18 dB and 13 dB, respectively, were measured over a 22-nm wavelength tuning range. Digital wavelength conversion at bit rate of 2.5 Gb/s was demonstrated to be error free, with 2.6-dB power penalty.

Postgrowth control of the quantum-well band edge for the monolithic integration of widely tunable lasers and electroabsorption modulators

We describe a quantum-well intermixing process for the monolithic integration of various devices, each with a unique band edge. The process involves a single ion implant followed by multiple etch and anneal cycles. We have applied this method to design and fabricate widely tunable sampled-grating distributed Bragg reflector lasers with integrated electroabsorption modulators. The devices employ three unique band edges, and demonstrate exceptional tuning, gain, and absorption characteristics.

Design and performance of a monolithically integrated widely tunable all-optical wavelength converter with independent phase control

We report on a new widely tunable all-optical wavelength converter consisting of a sampled-grating distributed Bragg reflector (SGDBR) laser monolithically integrated with a Mach-Zehnder interferometer semiconductor optical amplifier (MZI-SOA)-based wavelength converter. The new design incorporates independent phase control of the interferometer and SOAs for amplification of the SGDBR output. For the first time, error-free operation for data rates of up to 10 Gb/s is reported for 35-nm output tuning range. The high-speed operation is enabled by high photon density in the SOA due to large power transfer from the on-board tunable laser and amplifiers. We also report on device sensitivity of -10 dBm at 2.5 Gb/s and -5 dBm at 10 Gb/s, with an average output power of 0 dBm.

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

Design and demonstration of novel QW intermixing scheme for the integration of UTC-type photodiodes with QW-based components

We present the design and demonstration of unitraveling carrier (UTC) photodiodes fabricated using a novel quantum-well (QW) intermixing and metal-organic chemical vapor deposition (MOCVD) regrowth fabrication platform. The photodiodes discussed here were realized on the same chip as high gain centered QW active regions, intermixed passive centered well waveguides, and low optical confinement offset QW active regions regrown over intermixed wells. This demonstration lifts previous constraints imposed on high functionality photonic circuits, which forced a common waveguide architecture in the detector, laser, and amplifier by validating a platform suited for the monolithic integration of UTC photodiodes into photonic integrated circuits comprised of widely tunable high gain laser diodes, high efficiency modulators, and low optical confinement high saturation power semiconductor optical amplifiers. In this manuscript we focus on the design and performance of UTC photodiodes fabricated on intermixed QWs using this novel scheme. The photodiodes exhibit /spl sim/90% internal quantum efficiency, excellent photocurrent handling capabilities, and minimal response roll-off over the 20 GHz of our testing capability. The 40 Gb/s operation was achieved with the demonstration of open eye diagrams.