Fiber Optics and Wavelength Division Multiplexing Technologies

1- Organic Materials for Communications

Start and End Dates:
May 1, 2000 – April 30, 2003

Principal Investigators:

• Dr. Wayne Wang, Professor and CRC Chair in Emerging Organic Materials, Department of Chemistry, Carleton University
• Dr. Marie D’Iorio, Director General, NRC-IMS

Co-Investigators

• Andrew H. Yu, Postdoctoral Fellow, Carleton University
• Ye Tao, Research Officer, Organic Materials and Devices, NRC-IMS
• Christophe Py, Research Officer, Organic Materials and Devices, NRC-IMS
• Karim Faid, Research Officer, Organic Materials and Devices, NRC-IMS
• Xianyuan Liu, Postdoctoral Fellow, NRC-IMS

Summary:
Work on this project started in January 2001 to address the important innovation of synthesis and application of organic materials for development of hybrid optoelectronic integrated circuits with on-board optical as well as electronic components and devices and eventually photonic ICs. This project was a collaborative effort between the Department of Chemistry at Carleton University with expertise of synthesis and testing of organic materials and the Institute of Microstructural Sciences at the National Research Council with expertise in the development and testing of optoelectronic and microelectronic components and devices. This project was co-led by Dr. Wayne Wang from Carleton University and Dr. Marie D’Iorio from the NRC. The main objectives of this project were:

• Design, synthesis and characterization of organic materials for communications applications at Carleton University. The challenge was to synthesize organic materials that are stable, easy and cheap to process, but still possess the characteristics required to design useful optoelectronic components
• Development of organic optical attenuators at Carleton University. Optical attenuators are employed for equalization of power levels at different wavelengths before combining for transmission over an optical fiber. NIR materials promised realizations with very low power consumption, small packaging and multichannel performance with independent channel control. The challenge was to obtain these characteristics along with fast response, low insertion loss and large dynamic range.
• Screening of organic materials for use in organic lasers at NRC and Carleton University. One of the big challenges to realize electrically pumped organic lasers, was to synthesize materials with high electroluminescence under high current densities and high carrier mobility.
• Development of soft-lithography at NRC. Soft-lithography describes a number techniques that can be used to pattern soft-material thin films with a very high-resolution and at substantially lower cost than conventional lithography. Since organic materials cannot compete for performance with their inorganic counterparts, and are incompatible with conventional UV lithography, this alternative method of creating patterns is seen as a critical part of the viability of organic photonic devices. NRC has demonstrated sub-micron resolution with printing and molding techniques and is working towards the demonstration of printed organic optically-pumped microdisk lasers.
• Design, fabrication and characterization of organic laser structures at NRC. Organic laser diodes require structures to provide population inversion and feedback mechanisms. Thin film deposition techniques have to be optimized to maximize mobility, minimize losses, and achieve gain through master doping. Feedback structures studied at NRC include microcavities, Bragg gratings, deep submicron distributed feedback structures in polymers as well as the formation of organic microdisks.

Organic Light Emitting Diodes (OLEDs) received a lot of attention for their application to flat-panel displays because of the relative easiness of synthesizing efficient compounds in all colors of the spectrum and for potentially drastically reduced fabrication costs. Spectacular progress in efficiency, the result of intense material research, made it possible to envisage the realization of organic laser diodes. Organic lasers could be used for example in local area networks or any photonic application where cost is more important than performance. To achieve electrically-pumped lasing in an OLED, materials have to be found that combine high luminous efficiency and high mobility, structures incorporating the very thin OLEDs have to be designed to provide the feedback necessary for lasing action, and fabrication methods have to be developed that are specific to this class of materials.

2- Millimeter Wave Optoelectronics

Start and End Dates
January 1, 2001 – April 30, 2003

Principal Investigator

• Dr. Jianping Yao, Assistant Professor, SITE, University of Ottawa

Co-Investigators

• Dr. Langis Roy, Professor, Department of Electronics, Carleton University
• Dr. Tet Yeap, Professor, SITE, University of Ottawa
• Dr. Julian Noad, Manager, Optoelectronic Materials and Components, CRC
• Mr. Bob Kuley, VP, Broadband Network Technologies, CRC

Industry Partners
Spectalis, Agilent and Tektronix

Summary:
This research project focused on the development of optoelectronic components operating at mm-waves frequencies for use in the next generation high-speed optical communications systems with information capacity of up to 80 Gbit/s per wavelength. The components under study in this project were:

• Traveling Wave External laser modulators (GaAs)
• Space switches for optical packet switching and wavelength routing (LiNbO3)
• Traveling Wave Optical detectors (InP)
• Broadband mm-wave low noise and medium power amplifiers.
• Hybrid integration of amplifiers with optical detectors and external modulators, and packaging issues (butterfly packaging).

This project started with Dr. Pierre Berini (Ottawa U) as the project leader with expertise in optical components, Dr. Langis Roy (Carleton U) as the project co-leader with expertise in mm microwave components and Dr. Julian Noad from the Communications Research Centre. After almost one year of work, Dr. Berini took a leave of absence from the University of Ottawa and Dr. Langis Roy took over as interim research leader. Dr. Jianping Yao and Dr. Tet Yeap from the University of Ottawa joined the project research team in May 2002. Dr. Yao assumed project Leadership in September 2002 and refocused the research on optical microwave signal generation. Dr. Yao developed and demonstrated a novel wavelength tunable single-frequency erbium-doped fiber ring laser. The single-frequency operation was realized by using a coupler loop mirror with an Er3+-doped fiber saturable absorber, which acted as a narrow-band optical filter. The fiber laser applications are in microwave photonics systems.

3- High-Speed Reconfigurable Optical Router

Start and End Dates
January 1, 2001 – August 30, 2003

Principal Investigator

• Dr. Barry Syrett, Professor, Department of Electronics, Carleton University

Co-Investigators

• Pedro Barrios, Research Officer, NRC-IMS (InP/InGaAsP processing)
• Philip Poole, Research Officer, NRC-IMS (InP/InGaAsP processing)
• Ilya Golub, Research Officer, NRC-IMS (Optoelectronic Measurements)
• Ross McKinnon, Research Officer, NRC-IMS (Electrical Device Modelling)

Industry Partners
Agilent and Asset-Relay

Summary:
This project started in January 2001 to carry out research into the design, performance simulation and realization of a high-speed optical switch building block. The basic technology of choice was carrier injection and depletion to change the refractive index in the waveguide region of an InP rib y-branch structure in order to alter the state of the switch between two output waveguides and hence perform an optical high-speed switch function. Target specifications developed with assistance of researchers at Nortel Networks at the onset of the project were:

• Bandwidth of 30 nm centered at 1550 nm
• Polarization and wavelength independent
• Insertion loss < 6 dB w/g input to w/g output for 8x8 switch
• Switching speeds < 500 ps
• Compatibility with high speed GaAs and InP drivers
• Scalable to 8x8 switch

The use of a switch with 10-100 ns switching speed in a reconfigurable router would have a significant impact on tag-switched IP network design. Optical performance simulation software was considered a very important tool required for the success of this project. Optical simulation software was not yet a mature field when compared with software simulation used for the design of semiconductor components. The commercial optical simulation software LASTIP has been used extensively. Other optical simulation software under investigation included MEDICI from Technology Modeling Associates and APSS from Apollo Photonics.

4- Intelligent Control of Optical Add/Drop Multiplexers

Start and End Dates
      July 1, 2003 – November 30, 2004

Principal Investigator

• Dr. Trevor Hall, Professor and CRC Chair in Photonic Network Technology, SITE, University of Ottawa

Co-Investigators

• Stewart Clark, NCIT Post Doctoral Fellow
• Dr. Paul Jay, CTO, IPC: Intelligent Photonics Controls
• Alex Vukovic, Research Scientist, Communications Research Centre Canada
• Damien Flannery, NCIT Post Doctoral Fellow

Industry Partners
Intelligent Photonics Control (IPC), Peleton and Metro Photonics

Summary:
Intelligent control and agility in optical networks represented the next evolutionary leap forward. Current networks had psuedo-static provisioning of circuit switched channels requiring many man-hours of configuration. The ability to route optical packet traffic in an efficient manner represented a significant step on the path towards both providing agility and cost-effective traffic management.

• Many problems associated with optical transport. EDFAs (Erbium Doped Fibre Amplifiers) have a long emission lifetime and hence suffer from adverse transient conditions when power loading is dynamically changing on timescales similar to that of the erbium lifetime. This makes error-free reception of the signal difficult. Intelligent control of optical network elements offers the promise of a solution.
• This NCIT research team worked to develop a ROADM (Reconfigurable Optical Add/Drop Multiplexor) test bed and to upgrade NCIT*net to access other networks via the ROADM and/or splitters and combiners and enable access to selected wavelengths. This was expected to facilitate connection to a multi-channel environment configured as a star, and to allow realistic traffic conditions to be replicated in a transient management test bed. Intelligent Photonics Control provided the controls for the transient management experiments.

5- Radio-over-Fiber Enhanced Networks

Start and End Dates
      November 01, 2002 – December 30, 2004

Principal Investigator

• Dr. Samy Mahmoud, Dean of Engineering and Design, Carleton University

Co-Investigators

• Dr. Rafik Goubran, Professor and Head, Department of Systems and Computer Engineering, Carleton University
• Dr. Leonard MacEathern, Assistant Professor, Department of Electronics, Carleton University

Industry Partners
Sun Microsystems, Agilent and Skyworks

Summary:
This project started in November 2002 to focus on research that was expected to facilitate a paradigm shift in wireless network design to reduce complexity and cost and increase flexibility and utility. Central to implementation of this paradigm shift was the focus on seamless integration of optical fiber for radio signal transmission within existing and forthcoming communication network infrastructures. This approach of integrating the wireless and optical networks was called radio-over-fiber.

A foremost contribution of this research was expected to be novel network configurations, radio signal processing elements, and frequency plans that fully exploit the concept of simplified remote antenna units and base stations coupled with centralized radio processing units. The research incorporated development of laser and optical link models compatible with existing circuit and system simulation tools. These models were expected to enable the determination of appropriate coding, modulation, and processing techniques for centralized optically-fed radio signal processors. The models included a wider variety of non-linear effects than existing models. The enhanced laser diode models to be produced during the course of the research will be generally usable in a variety of circuit level and system level design tools, such as SPW, Matlab, SpectreRF, System view and HP ADS. Other possible uses of the laser models include improved bit error rate predictions of digital optical links, design and optimization of higher throughput data links, and medical applications requiring precise control of laser power output.

Project investigations also focused on resolving dynamic range, noise, and linearity problems encountered in previous attempts at implementing radio-over-fiber communications links. Improvements in system performance have been achieved due to the novel large-signal laser diode models developed at Carleton University. A combination of electro-optic pre-distortion circuitry controlled by adaptive algorithms and based on an inverse model of laser distortion will be investigated and implemented.

6- Integrated Optoelectronic Oscillators for Wireless Communications

Start and End Dates
      July 1, 2003 – November 30, 2004

Principal Investigators

• Dr. Michael Cada, CRC Chair in Integrated Active Photonics, Professor, SITE, University of Ottawa
• Dr. Len MacEachern, Principal Investigator, Assistant Professor, Department of Electronics, Carleton University

Co-Investigators

• Joe Seregelyi, Project Leader, Advanced Technologies, Communications Research Centre
• Edmond Zauner, Agilent
• Dr. Samy Mahmoud, Dean, Faculty of Engineering and Design Engineering, Carleton University

Industry Partners
Agilent, Skyworks and Lightip

Summary:
Optoelectronic devices are widely regarded as having great potential in many wireless applications, notably for the generation of low-noise microwave carrier wave and local oscillator signals. Given the demanding specifications of emerging wireless systems, it is evident that significant improvements are required in oscillator signal generation. From a research perspective, areas of prime interest are oscillator phase noise and oscillator agility and tunability. This project addressed the demanding requirements of next-generation oscillator generators via an economically attractive mechanism – optoelectronic microwave oscillators. The primary project objectives were:

• To advance the state of the art in optoelectronic microwave frequency oscillator integration
• To advance the state of the art in optoelectronic microwave frequency oscillator performance
• o leverage and extend on-going NCIT research as part of the proposed research
• To produce technology ripe for commercial applications that will be sought after in the wireless communications industry

Contributions of the proposed research included modeling of correlated laser mode interactions and the resulting phase noise at the microwave beat frequency, design and modeling of integrated optoelectronic structures suitable for generation of microwave signals, and implementation of integrated ultra-low-phase-noise oscillators suitable for deployment in base stations of cellular mobile networks. The research team planned to extend the laser models developed over the course of the NCIT-funded Radio-Over-Fiber project at Carleton University where advanced time and frequency domain models including single mode noise sources were developed. These models have been further extended and enhanced to include study of mode interactions and the resulting laser noise. The implementation of an integrated optoelectronic oscillator employing a novel dual laser approach using a shared cavity to promote mode interactions has also been investigated. The performance limits of available implementation technologies have been explored. As part of the prototype implementation, the NCIT team investigated control circuitry for integrated optoelectronic devices for noise reduction and precision tuning of opto-electronically generated microwave signals.