| In this thesis a technique for optical pattern recognition using a segmented semiconductor optical amplifier (SSOA) is presented. An SSOA is an optical amplifier that is fabricated from semiconductor gain material and has electrically isolated gold contacts along its length. As a result, each segment is driven by a separate current source producing a spatial gain-loss pattern along the length of the device. The cross-correlation of a binary optical pattern and the spatial gain-loss pattern is transcribed onto a probe beam by counter-propagating the optical pattern and the probe through the SSOA. Pattern recognition is performed by sampling the peak power of the cross-correlation, which is highest for the match pattern, and comparing the probe power to a threshold level.; The transcription of the cross-correlation onto the probe is caused by the saturation of the gain and loss of the SSOA by the test pattern. Saturation occurs when the carrier population of the SSOA is changed by the test pattern, through absorption or stimulated emission, causing the gain or loss to change. When the test pattern is removed the carriers recover to their steady state population. The saturation and recovery dynamics of the SSOA are experimentally measured using a co-propagating pump-probe setup. These measurements are used in a rate equation model to simulate the output probe power from the SSOA.; Cross-correlations of 4-bit patterns at 85 Gbit/s are experimentally demonstrated and show good agreement with simulated results. However, the signal-to-noise ratio of the cross-correlation signal is not large enough perform pattern recognition without errors. The model is used to simulate the operation of the SSOA in a Mach-Zehnder interferometer and demonstrate that this setup is capable of identifying four-bit patterns at a data rate of 180 Gbit/s. In addition, when a the probe signal is detected using a balanced receiver error-less pattern recognition can be performed with 8-bti patterns at 85 Gbit/s and four-bit patterns at 250 Gbit/s. |
