Abstract: A control system for a slide centrifuge includes a ratio checking circuit which produces a signal when the ratio between the light passing through the slide and the rate of change of this light passes through a predetermined critical value. When this ratio passes through the critical valve, spinning is stopped. This effectively stops spinning when the rate of reduction of blood cell density on the slide slows, thereby producing better slides for clinical analysis.

Abstract: Coupling among discrete propagation modes of light energy is achieved by providing perturbations of finite length in an optical waveguide. An optimal function characterizing the perturbation is disclosed along with a method of implementing the function to obtain uniform coupling strength over a desired range of modes.

Abstract: In making a preform for an optical waveguide, the bait rod is coated with carbon. After the preform is built up on the bait rod, it is easily removed. The carbon coating produces a smooth improved inner surface in the preform, thereby eliminating flaws which otherwise may be present when the preform is drawn into a waveguide.

Abstract: A system for delivering a siliceous matrix material and selected dopants to an oxidizing reaction flame or the like. Each constituent is maintained in liquified form and transferred by means of an individually controlled metering pump to a nebulizing stage then passed to a burner or the like from which the materials are converted into appropriate soots. The soots are then applied to a starting member which is subsequently subjected to heat to fuse it into a drawing blank.

Abstract: A hydrolyzing flame technique is used to build up glass soots of at least two different compositions upon a rotating starting member. The process is repeated until the soots define at least one helically-oriented body of soot of one composition completely enveloped by a soot of a second composition. The soot-covered starting member is then subjected to heat to fuse it whereupon the soots are fused into compositions exhibiting different indices of refraction. The member can then be drawn into a elongate structure comprising an optical waveguide extending helically through the body of the structure.

Abstract: An optical waveguide for a communication system includes a graded index core formed from at least three glass-forming compounds with a profile having at least two .alpha.-type index profile terms.The core has a refractive index which is n.sub.c at the center of the core and which varies as a function of the radial distance r from the center of the core subststantially as: ##EQU1## where .alpha..sub.i is defined by: ##EQU2## where N.gtoreq.2,.DELTA.=(n.sub.c.sup.2 -n.sub.0.sup.2)/2n.sub.c.sup.2,n.sub.o is the refractive index of said compounds at r=a,N.sub.c =n.sub.c -.lambda.dn.sub.c /d.lambda. where .lambda. is the wavelength of the light source, and the quantities .DELTA..sub.i are parameters which can be varied provided the condition ##EQU3## is satisfied.

Abstract: In drawing an optical waveguide, the blank is heated by a beam of laser radiation which has substantially zero power from the axis of the blank to a prescribed radial position and substantially uniform power from that position to a greater radial position. A rotating spinner splits radiation from the laser into two rotating beams, the paths of which are made to be non-intersecting with the axis of the blank being drawn. A conical reflector forms the radiation into a circumferential beam through which the blank passes.

Abstract: Apparatus for forming a vapor of material to be hydrolyzed and/or oxidized and entraining the vapor in a carrier gas. The source material, in liquid form, is pumped to a point in the column above a porous packing. As the liquid progresses downward through the packing, it encounters a rising countercurrent of carrier gas. The source material vaporizes and is delivered to vapor deposition by the carrier gas. The source material vaporized in the apparatus may alternatively be delivered to an externally heated tubular reactor, or to any other kind of chemical vapor deposition (CVD) reactor.

Abstract: A multiple mode optical waveguide includes a glass core and a glass cladding around the core. In order to promote coupling between guided modes of light propagation, the core has cylindrical perturbations spaced along its length. The perturbations include index of refraction variations in rings within the core.

Abstract: A hand-held device for causing a blood sample to be controllably drawn into a flexible envelope or the like. The envelope is placed between a rigid and a hinged member disposed within the housing of the device, and a roller advanced along the hinged member to progressively compress the envelope. When the wheel is moved back along its path, the envelope is allowed to progressively expand thereby drawing the blood sample into the envelope.

Abstract: In making a preform for an optical waveguide, the bait rod is coated with carbon. After the preform is built up on the bait rod, it is easily removed. The carbon coating produces a smooth improved inner surface in the preform, thereby eliminating flaws which otherwise may be present when the preform is drawn into a waveguide.

Abstract: A hydrolyzing flame technique is used to build up glass soots of at least two different compositions upon a rotating starting member. The process is repeated until the soots define at least one helically-oriented body of soot of one composition completely enveloped by a soot of a second composition. The soot-covered starting member is then subjected to heat to fuse it whereupon the soots are fused into compositions exhibiting different indices of refraction. The member can then be drawn into a elongate structure comprising an optical waveguide extending helically through the body of the structure.

Abstract: A pipetter for drawing fluid into capillary tubes and the like. A capillary tube is forced into an adapter coupled to one end of a vented, flexible tube. A compression wheel rides in a guideway adjacent the tube, and is rolled to continuously vary the point at which the tube is compressed in the manner of a peristaltic pump. Manual rolling of the wheel away from the capillary tube produces sufficient suction in the tube to cause liquid to be drawn into it. The pumping action is reversible in that rolling the wheel back toward the capillary tube will cause fluid to be expelled. Provision is made to prevent undesirable "compression set" as a result of long term static of the flexible tube during periods of non-use.

Abstract: A coating assembly including a recessed housing for receiving a split coating die, and a thrust block for urging the die against a die closing plate. Aligned passages extending through each of the elements are accessed through a split or slot in the side of each element so that an optical waveguide can be inserted into the apparatus from the side, rather than threaded endwise through the apparatus. Liquid coating material is introduced into the passages, the coating die serving to determine the thickness of the coating which is ultimately formed upon the waveguides.

Abstract: A control system for a slide centrifuge includes a ratio checking circuit which produces a signal when the ratio between the light passing through the slide and the rate of change of this light passes through a predetermined critical value. When this ratio passes through the critical value, spinning is stopped. This effectively stops spinning when the rate of reduction of blood cell density on the slide slows, thereby producing better slides for clinical analysis.

Abstract: In a sealed beam incandescent lamp a generally concave reflector member is provided with three or more bosses having flat outer surfaces. The surfaces define a plane perpendicular to the axis of the parabola so that specific points within the parabola can be located with great precision. By using the bosses as reference points, lamp filaments can be accurately placed within the lamp structure, regardless of variations in the reflector member which occur during the manufacturing process.

Abstract: A multiple mode optical waveguide includes a glass core and a glass cladding around the core. In order to promote coupling between guided modes of light propagation, the core has cylindrical perturbations spaced along its length. The perturbations include index of refraction variations in rings within the core.

Abstract: An optical waveguide includes a core of high purity fused silica, a cladding of high purity fused silica and a protective coating of metallic glass. The protective coating is applied as a liquid which contracts more than the glass after it solidifies to place the surface of the glass cladding under compression. Because the waveguide will break only under tension, the force of compression must be overcome before the waveguide can be fractured thereby strengthening the waveguide considerably. The metallic glass coating provides further advantages of abrasion protection and the prevention of fatigue.

Abstract: An optical waveguide having variations in diameter is produced by controlling the drawing rollers. Predetermined diameter variations along the length of an optical waveguide reduce dispersion in multimode waveguides. These diameter variations are produced by varying the rotational speed of the pulling rollers, by varying the diameter of the pulling rollers, by moving the pulling rollers axially or by moving a tensioning roller during the drawing process.

Abstract: In a multimode optical waveguide, coupling is promoted among guided modes while coupling to unguided modes is suppressed. The core includes perturbations having a power spectrum which decreases with increasing mode order and which has a plurality of minima. The length of each perturbation is such that a minimum in the power spectrum of the perturbation occurs at the critical frequency .omega..sub.c and the power spectrum is significantly reduced for high frequencies.