Vikrant Lal

Current Status of Large-Scale InP Photonic Integrated Circuits

In this paper, the current state of the art for large-scale InP photonic integrated circuits (PICs) is reviewed with a focus on the devices and technologies that are driving the commercial scaling of highly integrated devices. Specifically, the performance, reliability, and manufacturability of commercial 100-Gb/s dense wavelength-division-multiplexed transmitter and receiver PICs are reviewed as well as next- and future-generation devices (500 Gb/s and beyond). The large-scale PIC enables significant reductions in cost, packaging complexity, size, fiber coupling, and power consumption which have enabled benefits at the component and system level.

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.

Monolithic Wavelength Converters for High-Speed Packet-Switched Optical Networks

This paper describes the design and demonstration of advanced 40-Gb/s return-to-zero (RZ) tunable all-optical wavelength converter technologies for use in packet-switched optical networks. The device designs are based on monolithic integration of a delayed interference Mach-Zehnder interferometer (MZI) semiconductor optical amplifier (SOA) wavelength converter with a sampled-grating distributed Bragg reflector tunable laser and an on-chip waveguide delay. Experimental results are presented demonstrating error-free wavelength conversion with 1-dB power penalty at 40-Gb/s data rates. By incorporating label modulation functionality on-chip along with a fast tunable 40-Gb/s wavelength converter, fully monolithic packet-forwarding chips are realized that are capable of simultaneous error-free wavelength conversion of 40-Gb/s payloads, remodulation of 10-Gb/s packet headers, and data routing through fast wavelength switching

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.

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.

10 Channel, 100Gbit/s per channel, dual polarization, coherent QPSK, monolithic InP receiver photonic integrated circuit

A 10 channel, dual polarization, monolithically integrated, coherent QPSK receiver on InP operating at 100Gbit/s per channel is demonstrated.

Multi-channel coherent PM-QPSK InP transmitter photonic integrated circuit (PIC) operating at 112 Gb/s per wavelength

A 10-wavelength, polarization-multiplexed, monolithically integrated InP transmitter PIC is demonstrated for the first time to operate at 112 Gb/s per wavelength with a coherent receiver PIC.

Integrated Photonics for Low-Power Packet Networking

Communications interconnects and networks will continue to play a large role in contributing to the global carbon footprint, especially in data center and cloud-computing applications exponential growth in capacity. Key to maximizing the benefits of photonics technology is highly functional, lower power, and large-scale photonics integration. In this paper, we report on the latest advances in the photonic integration technologies used for asynchronous optical packet switching using an example photonic integrated switched optical router, the label switched optical router architecture. We report measurements of the power consumed by the photonic circuits in performing their intended function, the electronics required to bias the photonics, processing electronics, and required cooling technology. Data is presented to show that there is room (potentially greater than 10 ×) for improvement in the router packet-forwarding plane. The purpose of this exercise is not to provide a comparison of all-optical versus electronic routers, rather to present a data point on actual measurements of the power contributions for various photonic integration technologies of an all-optical packet router that has been demonstrated and conclude, where the technology can move to reduce power consumption for high-capacity packet routing systems.

10 Channel, 45.6 Gb/s per Channel, Polarization-Multiplexed DQPSK, InP Receiver Photonic Integrated Circuit

We demonstrate a 10 wavelength, 200 GHz spaced, monolithically integrated, polarization-multiplexed, InP differential quadrature phase shift keying receiver operating at 45.6 Gb/s per wavelength. The receiver is based on a novel technique for polarization demodulation and phase tracking that does not require any external components.