Abstract: Apparatus for correcting distortion on an optical transmission link carrying a multiplicity of optical transmission channels, the apparatus comprising: an adjustable optical equalizer, through which a plurality of said channels pass; a field sampler that samples signals passing through said equalizer, such that a plurality of channels passing through the adjustable equalizer are separately sampled; and a controller that receives the samples, determines control parameters for the equalizer therefrom and adjusts the equalizer, responsive to said determined control parameters.

Abstract: A method for characterizing optical pulses in a pulse train wherein pulses in the pulse train have substantially a same shape, the method comprising: a) detecting photons from pulses in the pulse train with a probability of detecting a photon per pulse being substantially less than one; b) determining a time lapse between detection of a first photon and a subsequent second photon and storing the time lapse in a memory; c) repeating b to accumulate a plurality of time lapses; and d) using the plurality of time lapses to characterize the pulses.

Abstract: A method for scanning an inner surface through an outer layer of material, the method including the steps of a) creating an energy beam with a wavelength, intensity, cross-section, and impact angle that, when impacted onto the outer layer of material, is sufficient to be at least partly reflected by the outer layer of material, thereby forming an outer-layer reflected beam to be at least partly transmitted in a first direction through the outer layer of material and onto the inner surface, to be at least partly reflected by the inner surface, thereby forming an inner-surface reflected beam, and to be at least partly transmitted in a second direction through the outer layer of material, b) impacting the energy beam onto the outer layer of material, c) detecting the outer-layer reflected beam and inner-surface reflected beam, d) distinguishing between the outer-layer reflected beam and inner-surface reflected beam, and e) determining from the inner-surface reflected beam a point of incidence between the energy

Abstract: Apparatus for producing a three-dimensional model including apparatus for depositing, layer upon layer, a photopolymer material in a selectable configuration and apparatus for curing each photopolymer layer following deposition thereof and prior to deposition thereon of a succeeding layer of photopolymer.