# US 2013/0155512 A1 · Optical processing device employing a digital micromirror device (dmd) and having reduced wavelength dependent loss > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0155512 A1 - Document ID: US20130155512A1 - Status: Published application - Kind: A1 - Application number: 13/325,555 - Filed: 2011-12-14 - Published: 2013-06-20 - Earliest claimed: 2011-12-14 - Assignees: Nistica, Inc. - Inventors: Mitchell E. Haller; Jefferson L. Wagener - Web page: https://patentgrep.com/patent/US20130155512A1 ## CPC - G02B 6/29314: {by moving or modifying the diffractive element, e.g. deforming} - G02B 6/3518: {the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device (MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833)} - G02B 6/356: {in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links (switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001)} - G02B 6/3516: {the reflective optical element moving along the beam path, e.g. controllable diffractive effects using multiple micromirrors within the beam} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract An optical arrangement includes an actuatable optical element and a compensating optical element. The actuatable optical element is provided to receive an optical beam having a plurality of spatially separated wavelength components and diffract the plurality of wavelength components in a wavelength dependent manner. The compensating optical element directs the optical beam to the actuatable optical element. The compensating optical element compensates for the wavelength dependent manner in which the wavelength components are diffracted by the actuatable optical element. ## Claims ### Claim 1 An optical arrangement comprising: an actuatable optical element for receiving an optical beam having a plurality of spatially separated wavelength components and diffracting the plurality of wavelength components in a wavelength dependent manner; and a compensating optical element directing the optical beam to the actuatable optical element, said compensating optical element compensating for the wavelength dependent manner in which the wavelength components are diffracted by the actuatable optical element. ### Claim 2 (depends on 1) The optical arrangement of claim 1 further comprising at least two optical input/output ports for receiving the optical beam, wherein the actuatable optical element selectively directs at least one of the diffracted wavelength components to one of the optical input/output ports, said compensating optical element reducing optical coupling loss in the diffracted wavelength component caused by the wavelength dependent manner in which the wavelength components are diffracted by the actuatable optical element. ### Claim 3 (depends on 1) The optical arrangement of claim 1 further comprising a collimating optical element for collimating the plurality of wavelength components, said actuatable optical element including a digital micromirror device (DMD) having an array of individual actuatable mirror elements for selectively reflecting the wavelength components, said array of mirrors being oriented such that without provision of the compensating optical element an optical path length between the collimating optical element and the DMD differs from wavelength component to wavelength component, said compensating optical element adjusting the optical path lengths so that they are equal in length for each wavelength component. ### Claim 4 (depends on 1) The optical arrangement of claim 1 wherein said compensating optical element includes at least one surface configured to compensate for the wavelength dependent manner in which the wavelength components are diffracted by the actuatable optical element. ### Claim 5 (depends on 4) The optical arrangement of claim 4 wherein the surface is cylindrical in shape. ### Claim 6 (depends on 4) The optical arrangement of claim 4 wherein the surface has a shape that conforms to a 5th term in a Zernike polynomial. ### Claim 7 (depends on 4) The optical arrangement of claim 4 further comprising a collimating optical element for collimating the plurality of wavelength components, wherein the compensating optical element includes at least one refractive and/or reflective surface and is further configured to adjust an optical path length experienced by the wavelength components between the collimating optical element and the actuatable optical element so that the wavelength components are focused onto the actuatable optical element. ### Claim 8 (depends on 7) The optical arrangement of claim 7 wherein the compensating optical element includes a prism. ### Claim 9 (depends on 2) The optical arrangement of claim 2 wherein the at least two input/output ports comprises an optical launch arrangement configured to receive at least one input optical beam and output a spatially overlapping, angularly multiplexed optical beam that is focused at a virtual focal point. ### Claim 10 (depends on 9) The optical arrangement of claim 9 wherein the optical launch arrangement includes a fiber assembly for securing an array of optical fibers and an asymmetric lenslet array having a first surface with a pair of collimating lens in registration with each optical fiber in the array and a second surface with a coupling lens in registration with each pair of collimating lenses. ### Claim 11 An optical processing device comprising: at least two optical input/output ports for receiving an optical beam; a dispersion element receiving the optical beam from one of the ports and spatially separating the optical beam into a plurality of wavelength components; a collimating lens for collimating the plurality of wavelength components; and an actuatable optical element for receiving the collimated wavelength components from the collimating element and diffracting the plurality of wavelength components in a wavelength dependent manner; and a compensating optical element located in an optical path between the dispersion element and the actuatable optical element, said compensating optical element compensating for the wavelength dependent manner in which the wavelength components are diffracted by the actuatable optical element. ### Claim 12 (depends on 11) The optical processing device of claim 11 wherein the actuatable optical element selectively directs at least one of the diffracted wavelength components to one of the optical input/output ports, said compensating optical element reducing optical coupling loss in the diffracted wavelength component caused by the wavelength dependent manner in which the wavelength components are diffracted by the actuatable optical element. ### Claim 13 (depends on 11) The optical processing device of claim 11 wherein said actuatable optical element includes a digital micromirror device (DMD) having an array of individual actuatable mirror elements for selectively reflecting the wavelength components, said array of mirrors being oriented such that without provision of the compensating optical element an optical path length between the collimating lens and the DMD differs from wavelength component to wavelength component, said compensating optical element adjusting the optical path lengths so that they are equal in length for each wavelength component. ### Claim 14 (depends on 11) The optical processing device of claim 11 wherein said compensating optical element includes at least one surface configured to compensate for the wavelength dependent manner in which the wavelength components are diffracted by the actuatable optical element. ### Claim 15 (depends on 14) The optical processing device of claim 14 wherein the surface is cylindrical in shape. ### Claim 16 (depends on 14) The optical processing device of claim 14 wherein the surface has a shape that conforms to a 5th term in a Zernike polynomial. ### Claim 17 (depends on 14) The optical processing device of claim 14 wherein the compensating optical element includes at least one refractive and/or reflective surface and is further configured to adjust an optical path length experienced by the wavelength components between the collimating lens and the actuatable optical element so that the wavelength components are focused onto the actuatable optical element. ### Claim 18 (depends on 17) The optical processing device of claim 17 wherein the compensating optical element includes a prism. ### Claim 19 (depends on 11) The optical processing device of claim 11 wherein the at least two input/output ports comprises an optical launch arrangement configured to receive at least one input optical beam and output a spatially overlapping, angularly multiplexed optical beam that is focused at a virtual focal point. ### Claim 20 (depends on 19) The optical processing device of claim 19 wherein the optical launch arrangement includes a fiber assembly for securing an array of optical fibers and an asymmetric lenslet array having a first surface with a pair of collimating lens in registration with each optical fiber in the array and a second surface with a coupling lens in registration with each pair of collimating lenses. ### Claim 21 A method of processing an optical signal, comprising: diffracting a plurality of spatially separated wavelength components in a wavelength dependent manner with an actuatable optical element; and compensating for the wavelength dependent manner in which the wavelength components are diffracted by the actuatable optical element. ### Claim 22 (depends on 21) The method of claim 21 further comprising: collimating the plurality of wavelength components; and adjusting an optical path length experienced by the collimated wavelength components before being diffracted so that the collimated wavelength components all traverse a common optical path length. ### Claim 23 (depends on 22) The method of claim 22 wherein compensation for the wavelength dependent manner in which the wavelength components are diffracted by the actuatable optical element and adjustment of the optical path length are performed by a common optical element.