Signal-monitoring characteristics for laser-diode optical switches

Signal-monitoring characteristics of terminal voltage change across laser-diode optical switches (LDSW) have been studied. The terminal voltage changes are caused by the photovoltaic effect in the OFF state and by the quasi-Fermi level change in the ON state. The baseband frequency response characteristics are analyzed by small-signal analysis and coincide well with the measured characteristics. The 6-dB down frequency response bandwidths are verified to be very wide in both the ON and OFF states.