Tesis doctoral de Antonio Consoli Barone
This thesis describes the research work that has been carried out on the generation of optical pulses, with duration of tens of picoseconds, from semiconductor lasers. The work is focused on 1550 nm vertical cavity surface emitting lasers (vcsel), which are promising optical transmitters due to their advantageous characteristics in the context of fiber optical communications with directly modulated sources. The high bandwidth expected for future optical networks requires the accurate knowledge of the transmitter electrical properties and of the laser generated optical pulses which carry the binary information. This thesis describes the various achievements obtained in the characterization of these devices and the generated pulses, as well as their applications to an optical communication environment. Vcsels emitting at 1550 nm, based on quantum wells and tunnel junction, have been characterized by static and dynamic impedance measurements and modulation response up to 10 ghz. The electrical parasitics and the equivalent circuit of the device have been modeled, taking into account the effects of capture and escape of carriers in quantum wells, and the laser intrinsic parameters have been extracted from the measurements. The vcsels have been used for pulse generation at different repetition rates using the gain switching technique and the duration, peak amplitude, jitter and spectral width of the pulses have been measured as a function of the gain switching conditions. The shortest duration achieved has been 55 ps. The effect of optical injection on the pulses generated by gain switched vcsels has been investigated, obtaining a jitter reduction over a wide range of injection parameters. An optical code division multiple access (ocdma) encoder based on optical delay lines has been designed and implemented, using the optical pulses generated by the gain switched devices. Finally, a novel implementation of the phase reconstruction using optical ultrafast differentiation (proud) technique has been proposed and demonstrated for optical pulse characterization in amplitude and phase. The optical differentiator required in the proud technique has been realized with a birefringent interferometer based on a polarization maintaining fiber and proud has been applied to the measurement of the instantaneous frequency of pulses generated from a gain switched semiconductor laser. The linewidth enhancement factor of the laser has been extracted from the time resolved chirp and intensity measurements. The accuracy of the proposed method has been validated by the comparison between the independently measured and recovered (from temporal amplitude and phase) pulse spectra.
Datos académicos de la tesis doctoral «Short pulse generation from semiconductor lasers: characterization, modeling and applications«
- Título de la tesis: Short pulse generation from semiconductor lasers: characterization, modeling and applications
- Autor: Antonio Consoli Barone
- Universidad: Politécnica de Madrid
- Fecha de lectura de la tesis: 29/07/2011
Dirección y tribunal
- Director de la tesis
- Ignacio Esquivias Moscardo
- Tribunal
- Presidente del tribunal: Miguel angel Muriel fernandez
- beatriz Romero herrero (vocal)
- Juan ignacio Garces gregorio (vocal)
- luís Pesquera gonzález (vocal)