New technique for wavelength-division-multiplexing optical switching utilizing the mode-hopping phenomenon of semiconductor lasers in the visible wavelength region

摘要

Abstract: We have demonstrated a novel WDM and self-routingscheme as well as electro-optical logic-gate operationsbased on the mode-hopping phenomenon previouslyconsidered as a cause of bad noise in the Fabry-Perottype semiconductor lasers. In our routing scheme, datasignals can be sent through adequate routes becausethey have information on their own destinationsassigned by hopped wavelengths in their carrier lightwave form a laser diode. The hopped wavelength can becontrolled by only switching temporarily the d.c. biaslevels of the driving current of the laser diode. Theperformed speed of the 1XN channel wavelength-switchingwas estimated at about 167 nanoseconds, limited byinsufficiencies in our electronics, not by thephenomenon itself. The number of destination channels'N' has been limited to the number of allowed hoppingmodes in the sample laser diode. Since the mode-hoppingphenomenon itself has been reported to be faster thannanoseconds, more efficient and ultra-fast self-routingor WDMA systems based on this phenomenon will beperformed. In addition, we have performedelectro-optical logic-gate operations by modulating theinjection current of the laser diode throughmode-hopping regions. The achieved data rate of ourgate operations for AND, Ex-OR and NOR gates wastypically 3 $MUL 12 Mbit/s with two simultaneouslymodulated input signals. !5