Optical switching, high-speed

FIGURE 37.46 Sixteeu waveleugth LED module for very high speed waveleugth switching. (Courtesy of Optical Instrument Centre, VTT, Finland.)... 

In order to successfully substitute the role of the electron by the photon in photonic applications, it is necessary to achieve high processing speeds. For applications of the intensity-dependent refractive index, one could define the following figure of merit that evaluates the optical switching performance of a third-order nonlinear optical material [24] ... 

The original idea behind the multiscaler technique is to switch through subsequent memory locations of a high speed memory and to drop the detected photons into the current memory location. The start of the sweeps through the memory is synchronised with the period of the optical signal. The general principle is shown in Fig. 2.8. 

For a long time the most difficult problem of pulse-group multiplexing has been the lasers. Conventional high-repetition rate lasers cannot be turned off and on at sub-ps speed, and simple optical switches of the required speed and on-off ratio do not exist. Picosecond diode lasers, however, can be switehed on within less than a microsecond and switched off within one or two pulse periods. Diode lasers with multiplexing capability are currently available for 375 nm, 405 nm,... 

Qiao L, Ye Q, Gan JL, Cai HW, Qu RH (2011) Optical characteristics of transparent PMNT ceramic and its application at high speed electro-optic switch. Opt Commun 284 3886-3890... 

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