of the detector 24 is fed back to the safe and arm circuit 14 to provide a monitor of the continuity of the optical circuit the initiator 22 may be one of several devices well known to those skilled in the art used to detonate explosives or the like in response to the optical energy supplied by the laser diode 16 the initiator may have an explosive mix of zr kclo 4 as shown in fig2 the laser diode 16 is a typical laser type semiconductor having an n substrate 26 an n cladding layer 28 an active layer 30 a p cladding layer 32 an oxide cap layer 34 and metallic contacts 36 and 38 the laser diode is initially operated at low power spontaneous emission levels for the light there from to illuminate the initiator but the power is low enough to avoid ignition the reflected light from the initiator is detected by the detector to indicated whether or not there is continuity in the optical circuit referring to fig3 the electronic safe and arm circuit is shown incorporating the principles of this invention a mosfet safe and arm switch 40 controls the application of a firing voltage to the laser diode 16 a self check current limit switch 42 continuously monitors the ready.