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E-Photon One Curriculum. 2B- Optical Technologies. Coordinator: António Teixeira, Co-Coordinator: K. Heggarty. António Teixeira, Paulo André, Rogério Nogueira, Tiago Silveira, Ana Ferreira, Mário Lima, Ferreira da Rocha, J. Prat, J. A. Lazaro, C. Bock, J. Andrade. Basic Photonic Measurements
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E-Photon One Curriculum 2B- Optical Technologies Coordinator: António Teixeira, Co-Coordinator: K. Heggarty António Teixeira, Paulo André, Rogério Nogueira, Tiago Silveira, Ana Ferreira, Mário Lima, Ferreira da Rocha, J. Prat, J. A. Lazaro, C. Bock, J. Andrade
Basic Photonic Measurements Material growth and processing Semiconductor materials Transmission systems performance assessment tools Optical Amplifiers Semiconductor Optical Amplifiers (SOAs) Erbium Doped Fiber Amplifiers (EDFAs) Fiber Amplifiers- Raman Other Amplifiers Emitters Semiconductor Fiber Receivers PIN APD Modulators Mach Zehnder Electro-absorption Acoust-optic Filters Fiber Bragg gratings Fabry Perot Mach-Zehnder Isolators Couplers Switches Mechanical Wavelength converters Multiplexers/ Demultiplexers Program E1- 2b Optical technologies
António Teixeira, Tiago Silveira Switches
12. Switches 1. Mechanical Switches • 1.1. Optical Network Nodes (1) • 1.2. Modulators and switches - Used effects (1) • 1.3. Optical Switching Elements (1) • 1.4. Optical Cross Connects (1) • 1.5. Optically controlled Switches (2) • 1.6. ADMs (1) 2. Wavelength converters • 2.1. Wavelength converters (2) • 2.2. Crossed Gain Modulation (4) • 2.3. Four Wave Mixing (1) • 2.4. Crossed Phase Modulation (1) • 2.5. Frequency Difference Generation (1) • 2.6. Table of wavelength characteristic types converter (1) E1- 2b Optical technologies
12. Switches • 3. Multiplexers/ Demultiplexers • 3.1. Multiplexers/ Demultiplexers- Characterization (1) • 3.2. Multiplexers/ Demultiplexers- Working Principles (3) E1- 2b Optical technologies
António Teixeira, Tiago Silveira 1) Mechanical Switches E1- 2b Optical technologies
Optical Network Nodes This, can route light from the input fiber to one of two output fibers. E1- 2b Optical technologies
Modulators and switches - Used effects Used effects Electro-optical and magneto-optical effects • some materials (calcite, quartz, lithium niobate) significatively modify their index when in the presence of an electrical and/or magnetic field Electro-absorption effects • some materials (e.g. GaAs) vary their absorption according to the electrical field Acoustic Modulators • Through acoustic waves added to the signal, the frequency /direction of a given signal can be changed ... E1- 2b Optical technologies
Optical Switching Elements By applying a field to only one of the electrodes, the refraction index of the material can be changed in only one of its arms The light will then follow the arm that presents the bigger refraction index E1- 2b Optical technologies IBM White Book, pag.239
Optical X-connects Devices that allow wave switching between the two arms Resonant Coupling • Tampering with an electrical field in one of the arms, the resonant coupling conditions are destroyed Mach-Zehnder • By altering the index in one of the paths, or at two opposite ways, the phase can be altered in order to build constructive or destructive interference in on of the ports E1- 2b Optical technologies IBM White Book, pags.240,241
Optically controlled Switches NOLM- non-Linear Optical Loop Mirror • Used in: Noise cleaning, time demultiplexing based on a non-linear effect (Kerr effect or using another device such as a SOA placed on the loop in an asymmetrical position) Using the Kerr effect, the coupler can’t be 50%-50%, since what is intended is getting interference, therefore different optical paths shoul be used More power – more non linear effect– more phase rotation E1- 2b Optical technologies IBM White Book, pags.242,243
Optically controlled Switches noise filtering NOLM- exemplos logical gate E1- 2b Optical technologies IBM White Book, pags.243,245,246
ADM’s Add-Drop Multiplexer for TDM based on the Mach Zehnder structure E1- 2b Optical technologies IBM White Book, pags.246,247
Wavelength Convertors E1- 2b Optical technologies
Wavelength Convertion O / E / O Optical Dominion Wave Mixing Crossed Modulation Four Wave Mixing Crossed Phase Modulation Frequency difference Generation / second harmonic Crossed Gain Modulation E1- 2b Optical technologies
SOA TOBPF Converted lc Signal ls Pump lc cw Crossed Gain Modulation Gain Modulation due to carrier depletion Disadvantages: • Extinction ratio degradation • SNR degradation • Sequence Invertion • Phase Modulation E1- 2b Optical technologies
pump signal 1540 nm 1550 nm STM-16 Optical Power (dBm) Optical Power (dBm) Wavelength (nm) Wavelength (nm) E1- 2b Optical technologies
1000011100010010011011 Optical Power (ua) Time (ns) E1- 2b Optical technologies
Pump Converted 2fp-fs Signal Satelite 2fs-fp Pump cw fp SOA TOBPF Converted 2fp- fs PC Signal fs Four Wave Mixing E1- 2b Optical technologies
SOA Signal ls Converted lc SOA TOBPF Pump cw lc Crossed Phase Modulation Mach-Zehnder Interferometer. Phase Modulation Intensity Modulation E1- 2b Optical technologies
L Frequency Difference Generation Pumped cw fp TOBPF Converted fp - fc PC Signal fs E1- 2b Optical technologies
Multiplexers/Demultiplexers Function: Mixing and/or removing optical wavelengths • Basic component on WDM (wavelength division multiplexing) systems • Passive, bidirectional components E1- 2b Optical technologies
Multiplexers/Demultiplexers - Characterization • Insertion loss: signal attenuation between input and output ports • Crosstalk: attenuation of other wavelengths not corresponding to the output port • Typical Channel spacing: • CWDM: 20 nm • DWDM: 100GHz or 0,8 nm • Channel bandwidth E1- 2b Optical technologies
Multiplexers/Demultiplexers – Working Principles • Angular dispersion (+lens): • Prism • Diffraction Grating E1- 2b Optical technologies
Multiplexers/Demultiplexers – Working Principles • Based on couplers (as Mach-Zhender) • Based on Thin Film Filters, Multilayer Interference Filters E1- 2b Optical technologies
Multiplexers/Demultiplexers – Working Principles • Arrayed Waveguide Grating (AWG) • Planar integrated optic technology • MxM • Routing capabilities Ivan Kamaninov, T. Li, “Optical Fiber Telecommunications, IVA – Components”, Academic Press, 2002. E1- 2b Optical technologies