Abstract: An optical multiplexing device demultiplexes collimated light from a fiber-optic source into separate individual wavelength sub-ranges or channels, and/or multiplexes separate channels to a common fiber-optic waveguide or other destination. An optical block defines an optical gap between two parallel surfaces having an optical port on a first such parallel surface for passing the multi-channel collimated light into the optical gap. A channel port and at least one other reflective element, e.g., multiple channel ports arrayed in spaced relation to each other, are secured to the optical block at the parallel surfaces, providing an unobstructed, epoxy-free multi-point light path within the optical gap. At each channel port an interference filter secured to the optical block spans the optical gap. Each filter transmits a wavelength sub-range of the multi-channel collimated light passed by the optical port, and reflects other wavelengths.

Abstract: A variable period amplitude grating mask for use in making a long period Bragg grating is realized by a helically coiled spring. Stretching or compressing the spring changes the periodicity of the mask. A photosensitive optical waveguide, planar or fiber, is positioned within the spring coils along the major axis of the spring. Actinic radiation is incident on the masked waveguide, and induces an index perturbation in the waveguide having the periodicity of the mask. Different spring coil sizes and/or orientation of the waveguide with respect to the mask provide linear and nonlinear (chirped) grating periods. A device and method are described.

Abstract: A method and apparatus for producing optical films on substrates having extremely high packing densities of the same quality as those films produced by ion beam sputtering including a vacuum chamber with a conventional magnetron sputtering system and unusually high speed vacuum pump means. The low pressure of inert gas created by said high speed vacuum pump means being in the range of 5.times.10.sup.-5 Torr to 1.5.times.10.sup.-4 Torr and the magnetron sputtering system being at least 16" from said substrates. A gas manifold around the magnetron and target material confines the inert working gas in the vicinity of the magnetron and as the gas diffuses and expands into the chamber the high speed vacuum pump means removes the expanded gas from the chamber at a high speed. An ion gun directs ionized reactant gas toward the substrates which has the effect of improving film stoichometry as well as reducing reactant gas at the magnetron.

Abstract: A method for forming a substantially flat planar lightwave optical circuit which has a substantially flat planar silica substrate and a sintered glassy lightguiding layer over the silica substrate. The structure is given a post treatment at an elevated temperature for a time sufficient to flatten said structure and overcome any distortion caused by the difference in the coefficient of thermal expansion of the substrate and any glassy layers formed over the substrate. Alternatively, the silica substrate may be heated and presagged to a predetermined degree to compensate for distortion or warpage which will occur in later processing.

Abstract: An improved four-port dichroic WDM, for use in a multiwavelength, bi-directional optical amplifier, having a dichroic filter for substantially reflecting a first wavelength band input to the WDM to an output of the WDM for the first wavelength band and for substantially transmitting a second wavelength band input to the WDM to an output of the WDM for the second wavelength band, in which some of a first 3 dB wavelength in the first wavelength band is transmitted by the filter and some of a second 3 dB wavelength in the second wavelength band is reflected by the filter, includes another dichroic filter having a filter function different than the filter function of the WDM filter providing an insertion loss for the first or the second 3 dB wavelengths sufficient to reflect and transmit, respectively, substantially all of the first and second 3 dB wavelengths.