Abstract: A reflectivity-tunable fiber reflector is disclosed. The Bragg reflectivity of the fiber grating is modulated by exciting the transverse vibration of the fiber through an acoustic wave. The excitation of the transverse vibration, leading to fiber grating tilting and fiber micro-bending, induces the coupling of the fiber core mode into cladding modes. This leads to the reduction of core-mode power and hence that of Bragg reflection. This mechanism is applied by this invention to control the reflectivity of a fiber optic Bragg grating after fabrication. The fiber reflector is suitable for fiber-compatible acousto-optical switching.

Abstract: The invention provides a compound of the following formula: ##STR1## wherein R.sup.1 is C.sub.1-6 alkyl; or phenyl;R.sup.2 is hydrogen;an acyl group of the formula --COR.sup.a wherein R.sup.a is C.sub.1-6 alkyl or phenyl; oran acetylalkylcarbonyl group of the formula --CO(CH.sub.2).sub.n COCH.sub.3 wherein n=1-3; andR.sup.3 and R.sup.4 are substituents at different position(s) of the acridine ring (i.e. C-1'-C-8'), and R.sup.3 and R.sup.4 may be the same or different and independently represent:hydrogen;C.sub.1-6 alkyl;C.sub.1-6 alkyloxy;a nitro group;an amino group of the formula --NR.sup.b R.sup.c wherein R.sup.b and R.sup.c may be the same or different and independently represent hydrogen or C.sub.1-6 alkyl;an aminoalkylamino group of the formula --NH(CH.sub.2).sub.n NR.sup.d R.sup.e wherein R.sup.d and R.sup.e may be the same or different and independently represent hydrogen, C.sub.1-6 alkyl, a hydroxyalkyl group of the formula --(CH.sub.2).sub.n OH wherein n=1-3, or C.sub.

Abstract: An IEEE Std. 1149.1 boundary scan circuit which is capable of performing built-in self-testing includes a logic circuit, cascaded input boundary-scan cells that form an input boundary-scan register connected to input nodes of the logic circuit, cascaded output boundary-scan cells that form an output boundary-scan register connected to output nodes of the logic circuit, and a test access port system for controlling operation of the input and output boundary-scan cells. The test access port system provides a built-in self-test control signal to the input and output boundary-scan cells when executing built-in self-testing. The input boundary-scan register is reconfigurable to operate as a test pattern generator that provides test patterns to the logic circuit for a predetermined number of clock cycles upon receipt of the built-in self-test control signal.