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

• US 5,682,255 A
• Filed: 11/13/1995
• Issued: 10/28/1997
• Est. Priority Date: 02/26/1993
• Status: Expired due to Fees

• Current Assignee: Yeda Research and Development Co. Ltd. (Weizmann Institute of Science)
• Original Assignee: Yeda Research and Development Co. Ltd. (Weizmann Institute of Science)
• Inventors: Amitai, Yaakov, Friesem, Asher Albert
• Primary Examiner(s): Henry, Jon W.
• Application Number:
  US08/505,315
• Time in Patent Office: 715 Days
• Field of Search: 359/15, 359/16, 359/19, 359/24, 359/629, 359/634, 385/24, 385/37
• US Class Current: 359/15
• CPC Class Codes: G02B 5/188 Plurality of such optical elements formed in or on a supporting substrate
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/2848 having refractive means, e.g. imaging elements between light guides as splitting, branching and/or combining devices, e.g. lenses, holograms
• CPC Class Codes: G02B 6/29323 Coupling to or out of the diffractive element through the lateral surface of the light guide evanescent grating couplers G02B6/29332
• CPC Class Codes: G02B 6/29325 of the slab or planar or plate like form, i.e. confinement in a single transverse dimension only integrated circuit planar waveguide arrangements G02B6/12007; specially adapted for lighting G02B6/0011
• CPC Class Codes: G02B 6/29328 Diffractive elements operating in reflection
• CPC Class Codes: G02B 6/29329 Diffractive elements operating in transmission
• CPC Class Codes: G02B 6/29373 utilising a bulk dispersive element, e.g. prism
• CPC Class Codes: G02B 6/2938 for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
• CPC Class Codes: G02B 6/43 Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
• CPC Class Codes: G03H 1/0408 Total internal reflection [TIR] holograms, e.g. edge lit or substrate mode holograms
• CPC Class Codes: G03H 1/22 Processes or apparatus for obtaining an optical image from holograms G03H1/26 - G03H1/34 take precedence

Abstract

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.

Claims

1. A holographic optical device, for the transmission of optical signals of a plurality of channels each of a different wavelength between (a) a plurality of optical transmission paths, one for each channel, and (b) a single optical transmission path for all the channels, comprising:

a light-transmissive substrate;

a first holographic optical element carried by said substrate; and

at least two further holographic optical elements carried by said substrate laterally of said first holographic optical element;

characterized in that;

at least one of said holographic optical elements is diffraction grating that can handle a multiplicity of plane waves and/or spherical waves having a range of wavelengths; and

said holographic optical elements include a single hologram associated with said single optical transmission path and having a plurality of optical elements, one for each of said channels and a plurality of holograms, each aligned with one of said plurality of optical transmission paths, and having a single hologram optical element for the channel of the respective path.

2. The device according to claim 1, wherein said device is a demultiplexer for demultiplexing the optical signals transmitted from the single optical transmission path to the plurality of optical transmission paths;

said single hologram of the holographic device being aligned with said single optical transmission path, and its plurality of holographic optical elements being effective to collimate the light of the plurality of channels and to diffract said light in a different direction for each channel;

each of said plurality of holograms of the holographic device being aligned with one of said plurality of optical transmission paths, and its holographic optical element being effective to focus the collimated light of the respective channel onto its respective optical transmission path.

3. The device according to claim 1, wherein said device is a multiplexer multiplexing the optical signals transmitted from the plurality of optical transmission paths to the single optical transmission path;

each of said plurality of holograms of the holographic device being aligned with one of said plurality of optical transmission paths, and its holographic optical element being effective to collimate the light of the respective channel and to diffract it in a different direction for each channel;

said single hologram of the holographic device being aligned with said single optical transmission path, and its plurality of holographic optical elements being effective to focus the collimated light of the respective channel onto the single optical transmission path.

4. The device according to claim 3 for multiplexing the optical signals transmitted through the plurality of optical transmission paths to the single optical transmission path and also comprising a demultiplexer for demultiplexing the optical signals transmitted through the single optical transmission path to the plurality of optical transmission paths.

5. The device according to claim 1, wherein each of said optical transmission paths is defined by an optical fiber.

6. The device according to claim 1, wherein each of said holographic optical elements has high diffraction efficiency for the wavelength of its respective channel and low diffraction efficiency for all other wavelengths.

7. The device according to claim 1, wherein said substrate includes a light transparent plate and an emulsion coating thereon on which said holographic optical elements are recorded.