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Optical device for use as a multiplexer or demultiplexer in accordance with the diffraction grating principle

  • US 4,744,618 A
  • Filed: 04/01/1983
  • Issued: 05/17/1988
  • Est. Priority Date: 05/03/1982
  • Status: Expired due to Fees
First Claim
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1. An optical device selectively operated according to the diffraction grating principles as either a wavelength demultiplexer to separate light of different wavelengths into separate bands or as a wavelength multiplexer to multiplex light of different wavelengths into a single band, said device comprising a compact transparent member having a plurality of surfaces including at least a first surface, a second surface opposite the first surface, a third and fourth surface adjacent the second surface and separated thereby, a fifth surface adjacent the third surface and being separated from the second surface by the third surface and a sixth surface adjacent the fourth surface and being separated from the second surface by the fourth surface;

  • optical means for forming imaging optics having an object space and an image space, said optical means including at least one concavely curved imaging mirror with an optical axis and being disposed on the first surface of the member;

    a diffraction grating being provided on the second surface of the said member opposite said imaging mirror and on said optical axis;

    first coupling means being provided on the fifth surface for coupling light between the member and a first optical waveguide;

    second coupling means being provided on the sixth surface for coupling a group of second waveguides to the member; and

    an additional mirror being disposed on each of the third and fourth surfaces for folding the light path in said transparent member immediately adjacent each of the first and second coupling means, said additional mirrors being totally reflecting mirrors applied directly on the third and fourth surfaces, said fifth surface being at the object space and the sixth surface being at the image space so that light entering either of the first and second coupling means is reflected by the additional mirror onto the optical means which reflects the light onto the diffraction grating which directs the light back at the optical means to be reflected at the other additional mirror, which reflects it to the other of the first and second coupling means to exit the device, and so that the diffraction grating when receiving a beam of more than one wavelength creates a reflection maxima for each of the wavelengths, which maximas are outside of the zero order of diffraction of the grating and are located at the individual second waveguides of the group of second waveguides and when receiving beams of different wavelengths combines the beams into a single beam of a plurality of wavelengths and directs the single beam to the single first waveguide.

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