A wavelength division multiplexer that integrates an axial gradient refractive index element with a diffraction grating to provide coupling from a plurality of input optical sources (each delivering a single wavelength) which are multiplexed to a single polychromatic beam for output to a single output optical receiver. The device comprises means for accepting optical input from at least one optical source, the means including a planar surface (20a); a coupler element (20) comprising an axial gradient refractive index collimating lens (26) having a planar entrance surface onto which the optical input is incident and a homogeneous index boot lens (24, 28) affixed to the axial gradient refractive index collimating lens and having a planar but tilted exit surface (20b); a diffraction grating (22) on the tilted surface of the homogeneous index boot lens which combines a plurality of spatially separated wavelengths from the optical light; and means to output at least one multiplexed, polychromatic output beam, the means including a planar surface (20a). The device may be operated in the forward or reverse direction as a multiplexer or demultiplexer.

Integrated bi-directional axial gradient refractive index/diffraction grating wavelength division multiplexer

A holographic optical device includes a light-transmissive substrate, a first holographic optical element, and a second holographic optical element that is laterally disposed on the substrate from the first holographic optical element At least one of the holographic optical elements is a complex diffraction grating that can handle a multiplicity of plane and/or spherical waves arriving from a range of angles, and having a range of wavelengths Applications for the device include a wavelength division multiplexer/demultiplexer, an image reconstructor, a beam expander/compressor, and a visor/head-up display

Holographic optical devices for the transmission of optical signals of a plurality of channels

A holographic optical device having a light transmissive substrate with a first holographic optical element carried by the substrate, and a second holographic optical element also carried by the substrate but laterally offset from the first holographic optical element. The first holographic optical element diffracts waves from each data point in a display source into a collimated plane wave such that the plane wave is trapped inside the substrate by internal reflection, and the first holographic optical element also corrects field aberrations over the entire field of view by being recorded using at least one aspheric wavefront. The second holographic optical element diffracts the trapped plane waves out of the substrate.

Planar holographic optical device

A holographic optical device includes a light transmissive substrate carrying first and second laternally separated holographic optical elements. The first holographic optical element diffracts incident light into the substrate where it is trapped by internal reflection so that light impinges more than once at different angles at different locations on at least one of the first and second holographic optical elements with a significantly higher efficiency for one angle of incidence. The second holographic optical element diffracts light out of the substrate. The second holographic optical element may be a display hologram for displaying a three-dimensional image.

Planar holographic optical device for beam expansion and display

An optical multiplexing and demultiplexing device includes: a plurality of optical fibers each terminating in a fiber end for radiating and receiving corresponding light beams; a fiber mounting assembly configured to support the optical fibers so that the fiber ends terminate in substantially the same plane, the mounting assembly also being configured to position the fibers in a regular array of N rows and M columns; reflecting means for reflecting beams radiating from the fiber ends; lens means for collimating and focusing beams propagating between the fiber ends and the reflecting means, the lens means having a focal length associated therewith; and diffraction means for diffracting beams propagating between the lens means and the reflecting means. The reflecting means includes a plurality of N reflective elements, each of the N reflective elements being associated with a corresponding one of the N rows. The array is substantially defined by a row axis that is substantially parallel to each of the rows and a column axis that is substantially parallel to each of the columns. Each of the reflective surfaces forms a corresponding first angle of rotation about a first line parallel to the row axis, and a corresponding second angle of rotation about a second line parallel to the column axis. The first angle of rotation of a corresponding one of the reflective surfaces is proportional to a distance measured between the center fiber and the row associated with corresponding reflective surface.

Compact double-pass wavelength multiplexer-demultiplexer having an increased number of channels

A grating multiplexer in Littrow-configuration is presented, whose passband width-normalized to channel spacing-is comparable with grating demultiplexers. As shown by calculation, a wide passband is attainable by very small input fiber spacing. Using a standard-( 50/125 \mu m)-GI-fiber as transmission fiber, a 1-dB pass-band of 30 nm with a channel spacing of 46 nm is achieved in an 8- channel device. The insertion losses for each channel are in the range 1.4-2.5 dB for 8- or 10-channel devices.

http://ieeexplore.ieee.org/iel5/50/23131/01074226.pdf

E. Weidel

Papers

Wide passband grating multiplexer for multimode fibers