| In this work, novel all-optical switches, which can provide both high-speed and broad-bandwidth switching simultaneously for future telecommunication networks, have been proposed and demonstrated in traveling-wave semiconductor optical amplifiers (TW-SOA).; The design, fabrication and characterization of anti-reflection coating for TW-SOA were presented. Guided mode approach was used to optimize the coating conditions. High quality TW-SOA were fabricated with 21 dB small-signal gain, 0.2 dB gain ripple and {dollar}5times 10sp{lcub}-5{rcub}{dollar} residual reflectivity. The study showed careful selection of the laser wavelength was necessary in order to match the amplifier's operating wavelength.; A new class of an all-optical packet switch--the wavelength recognizing switch (WRS)--was proposed. The device uses a control signal to sense the wavelength of the input data packet and taps the packet to the appropriate output port. The underlying mechanism is nearly-degenerate four-wave mixing (FWM). The implementation of the WRS in a broad-area TW-SOA provided +8.2 dB switching efficiency, {dollar}-{dollar}28.8 dB crosstalk and 32.9 dB signal-to-noise ratio. The switching bandwidth was 42 nm, while the recognition bandwidth was 0.03 A.; Completely filter-free FWM wavelength conversion was also proposed and demonstrated for the first time. The noncollinear configuration provided 29 dB suppression of the straight-through converter beam from the converted signal. Further suppression of the strong pump beam from the converted signal was realized by using an orthogonal polarization technique, with isolation ratio of 19.2 dB achieved. A high conversion efficiency of 4.9 dB, together with a wide efficiency bandwidth of 40 nm and a large signal-to-noise ratio of 28 dB was obtained.; Important material parameters were investigated for the optimization of devices' performance. Ambipolar diffusion coefficient of 8.0 cm{dollar}sp2{dollar}/s and carrier lifetime of 1.33 ns were directly measured. The diffusion coefficient decreased as the current density increased. This represents the first experimental determination of the diffusion coefficient for a strained InGaAsP multiple quantum well device. Linewidth enhancement factor was also measured. It was nearly independent of the current density variation, but increased from 2.5 to 7.8 as the wavelength changed from 1282 nm to 1338 nm. |
