Demultiplexing of 168-Gb/s data pulses with a hybrid-integrated symmetric Mach-Zehnder all-optical switch

All-optical switching due to state filling in quantum dots

“…We present the nonlinearity as a function of the absorbed laser power, since this is the relevant quantity for all-optical switching, when the pump beam excites one arm of the MZI through a separate third waveguide. 1,2 In conclusion, we observe all-optical switching in a Mach-Zehnder switch containing a single layer of QDs. The switching efficiency is 5 rad/͑W absorbed power͒.…”

“…͓DOI: 10.1063/1.1751617͔ All-optical switching has mainly been performed using active elements such as semiconductor optical amplifier gates. [1][2][3] Photonic switching in passive materials 4 -7 suffer from small all-optical nonlinearities, requiring a too high switching energy. Semiconductor quantum dots ͑QDs͒ are expected to provide improved all-optical nonlinearities 8,9 due to their delta-function-like density of states.…”

Machzehnder Interferometer and it’s Applications

“…Integrated Mach-Zehnder interferometers (MZIs) incorporating semiconductor optical amplifiers SOAs in the interferometer arms have recently been developed as very high-speed all-optical switching devices [23].Various SOA based switching configurations have been demonstrated, such as terahertz optical asymmetric demultiplexers (TOADs) [24],ultrafast nonlinear interferometers(UNIs) [25] and Mach Zehnder Interferometers [26][27][28], out of which MZI switches are most efficient. An MZI with two SOAs in two branches(see Fig.8) can also demultiplex an OTDM signal at high speeds and can be fabricated in the form of an integrated compact chip using InGaAsP/InP technology [26,31].MZI switches have demonstrated single-channel OTDMs at up to 168Gb/s and might even be used for higher data rates [29][30]. MZI-SOA switch is utilized for designing a tree-net architecture in all-optical domain, which is successfully exploited for all-optical logic and arithmetic operations (halfadder, half-subtractor, full-adder, full-subtractor, data comparator) [23] …”

Compact 160-Gb/s demultiplexer using a single-stage electrically gated electroabsorption modulator

“…While fiber-based technology has been demonstrated up to 640 Gb/s [1], semiconductor-based technology has the advantages of compactness and a higher level integration potential. Several semiconductor-based optically gated approaches have been reported including the GT-UNI [2], SOA-MZI [3], [4], and PD-EAM [5]. Two issues with these previous approaches are the presence of bit-error rate floors and the requirement for high-quality optical pulses for the gating signal.…”