Amplifiers in the Arms of a Mach-Zehnder Interferometer
John C. Cartledge
Department of Electrical and Computer Engineering
Queen's University at Kingston
| Organizer:IEEE Lasers and Electro-Optics Society |
| Title: Wavelength Conversion Based on
Semiconductor Optical Amplifiers in the Arms of a Mach-Zehnder Interferometer |
| Speaker: John C. Cartledge Department of Electrical and Computer Engineering Queen's University at Kingston |
| Abstract: Wavelength conversion will be a key feature of optical networks that incorporate wavelength routing. To provide this network function, wavelength converters based on semiconductor optical amplifiers in the arms of a Mach-Zehnder interferometer (SOA-MZI) have several attractive features including efficient up- and down-conversion, the small chirp of the wavelength-converted signal, and monolithic integration. In this seminar, the results of a detailed experimental characterization of the properties of a three-port, all-active SOA-MZI wavelength converter are presented. The a-parameter, which provides a small-signal characterization of the chirp, is determined along the conversion curve for both co- and counter-propagating signals. Using three optical modulators with quite different chirp properties to generate the modulated input signal to the wavelength converter, it is shown that the chirp of the wavelength-converted signal is essentially independent of the chirp of the input signal. The a-parameter of the wavelength-converted signal is negative for non-inverting operation and positive for inverting operation. For counter-propagating signals, an optical filter is not required at the output, in which case the output signal consists of the wavelength-converted signal and modulated ASE noise. Using time- and frequency-domain measurements, the contribution of the modulated ASE noise is characterized. It is shown that for WDM systems, the modulated ASE noise must be considered in setting the operating point of the wavelength converter. Finally, current activities will be described that are aimed at developing a device model that is suitable for system-level simulations. For system design purposes, the properties of the intensity modulation and phase modulation (chirp) of the wavelength-converted signal are important. The objective is to obtain an accurate and efficient model that is specified based upon an appropriate set of measurements. |
| Biography: From 1979 to 1982, Dr. Cartledge was a Member of the Scientific Staff at Bell-Northern Research, Ottawa, Ontario, Canada, where his work involved fiber-optic systems for the exchange access network and high-capacity digital radio systems. Since 1982 he has been with the Department of Electrical and Computer Engineering, Queen's University. His research interest is in combining theoretical and experimental studies to assess the impact that the properties of active and passive components have on lightwave system performance. He currently leads research projects sponsored by Communication and Information Technology Ontario, Photonics Research Ontario, and the Canadian Institute for Photonic Innovations. He has spent one-year sabbatical leaves with the Lightwave Systems Technology Research Division of Bellcore, Red Bank, NJ, in 1988-89, and with the Optical Communications Department of Tele Danmark Research, Hrrsholm, Denmark in 1995-96. He has served as a consultant in the area of lightwave technology to several companies in Canada, USA, and Europe. |
| Time and Location: Tuesday September 4, 4:00 p.m. - 5:00 p.m. University of Toronto, Galbraith Building, room 248 The Galbraith Building is located at 35 St. George Street. Coffee and cookies will be served For more information contact Emanuel Istrate (e.istrate@ieee.org). |
The Institute of Electrical and Electronics Engineers,
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