DFB lasers for all-optical signal processing
Main Researcher: Amin Abbasi
All-optical signal-processing devices are playing an essential role in the future of optical-data networks. In order to increase the network efficiency and raise the bandwidth, all optical switching networks are desirable, because they can reduce the switching energy as well as increase speed by avoiding optical-to-electrical or electrical-to-optical signal conversion. Bistable optical devices can be used as the basis of all-optical ﬂip-ﬂops, in which switching happens by set and reset optical short pulses.
Schematic of the DFB laser based on flip flop operation
Our approach for the all optical flip flop switching is based on a λ/4-shifted DFB laser, which becomes bistable by injecting a master laser light, with a wavelength is outside the DFB laser stop-band. This bistability is observed in the lasing light as well as in the ampliﬁcation of the external light and is due to non-linear effects having their origins in the carrier distribution (i.e. longitudinal spatial hole burning).
Bistability diagram of the flip flop system
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