# US 9,435,958 B2 · Optical demultiplexing system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,958 B2 - Document ID: US9435958B2 - Status: Granted - Kind: B2 - Application number: 14/695,009 - Filed: 2015-04-23 - Published: 2015-08-13 - Granted: 2016-09-06 - Earliest claimed: 2010-07-01 - Assignees: Newport Corporation - Applicants: Newport Corporation - Inventors: Jamie Knapp - Web page: https://patentgrep.com/patent/US9435958B2 ## CPC - G02B 6/2938: {for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM} - G01J 1/0403: {Mechanical elements; Supports for optical elements; Scanning arrangements} - G01J 1/0407: {Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings} - G01J 3/02: Details - G01J 3/0256: {Compact construction} - G01J 3/0262: {Constructional arrangements for removing stray light} - G01J 3/36: Investigating two or more bands of a spectrum by separate detectors - G01J 3/513: {having fixed filter-detector pairs} - G02B 6/12007: {forming wavelength selective elements, e.g. multiplexer, demultiplexer} - G02B 27/1006: {for splitting or combining different wavelengths (G02B27/1086, G02B27/141 take precedence)} - G02B 27/141: {using dichroic mirrors} - G02B 27/145: {having sequential partially reflecting surfaces} - H04J 14/0209: {Multi-stage arrangements, e.g. by cascading multiplexers or demultiplexers} - H04J 14/0307: {Multiplexers; Demultiplexers} - G01J 3/51: using colour filters - G01J 2001/061: {Baffles} - G02B 6/29394: {Compensating wavelength dispersion (G02B6/29376 takes precedence; dispersion compensated optical transmission systems H04B10/2507)} - G02B 2006/12109: {Filter} - G02B 2006/12164: {Multiplexing; Demultiplexing} - H04Q 2011/0016: {using wavelength multiplexing or demultiplexing} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) ## Abstract Demultiplexing systems and methods are discussed which may be small and accurate without moving parts. In some cases, demultiplexing embodiments may include optical filter cavities that include filter baffles and support baffles which may be configured to minimize stray light signal detection and crosstalk. Some of the demultiplexing assembly embodiments may also be configured to efficiently detect U.V. light signals and at least partially compensate for variations in detector responsivity as a function of light signal wavelength. ## Claims ### Claim 1 An optical demultiplexing device, comprising: an array of photo detector elements; a plurality of optical channels, each optical channel including a bandpass reflector, a bandpass filter and an active portion of the array of photo detector elements; and a demultiplexing assembly which is optically coupled to the array of photo detector elements, the demultiplexing assembly comprising a baffle assembly that includes: a plurality of filter cavities with each filter cavity corresponding to one of the plurality of optical channels, a support baffle corresponding to each filter cavity, each support baffle including an output aperture and a support surface disposed about the output aperture which is configured to provide a ledge for engaging and supporting a respective bandpass filter of the plurality of optical channels such that a bottom surface of the respective bandpass filter is in contact with the support surface of the support baffle, and a filter baffle that light cannot pass through disposed between adjacent bandpass filters with a bottom edge of each filter baffle being disposed on a top surface of a corresponding support baffle with no gap between the corresponding support baffle and filter baffle and wherein each filter baffle extends vertically above an input surface of each adjacent corresponding bandpass filter. ### Claim 2 (depends on 1) The device of claim 1 wherein the demultiplexing assembly is less than about 3 inches in overall length. ### Claim 3 (depends on 1) The device of claim 1 wherein the demultiplexing assembly is less than about 2 inches in overall length. ### Claim 4 (depends on 1) The device of claim 1 wherein a support baffle of an optical channel disposed adjacent an input aperture of the demultiplexing assembly includes a largest output aperture of the assembly. ### Claim 5 (depends on 1) The device of claim 1 wherein the support baffles form a rim around a bottom of each corresponding filter cavity with the output aperture in the middle which is disposed adjacent an active portion of the array of photo detector elements. ### Claim 6 (depends on 1) The device of claim 1 further comprising a housing having an interior volume that surrounds the bandpass reflectors, bandpass filters and baffle assembly. ### Claim 7 (depends on 6) The device of claim 6 wherein an interior surface of the interior volume of the housing comprises a matte black finish configured to absorb stray light signal. ### Claim 8 (depends on 6) The device of claim 6 wherein the bandpass reflectors extend transversely completely across the interior volume of the housing. ### Claim 9 (depends on 1) The device of claim 1 wherein each bandpass reflector is separated from one or more adjacent bandpass reflectors by a distance of less than about 4 mm. ### Claim 10 (depends on 1) The device of claim 1 wherein each optical channel corresponds to a unique active portion of the array of photo detector elements separated by inactive portions of the array of photo detector elements and the active portions of the array of photo detector elements are separated from one or more adjacent active portions by a distance of less than about 1 mm. ### Claim 11 (depends on 1) The device of claim 1 wherein each bandpass reflector is disposed at an angle of about 45 degrees with respect to an input optical axis of the demultiplexing device. ### Claim 12 An optical demultiplexing device, comprising: an array of photo detector elements; a plurality of optical channels, each optical channel including a bandpass reflector, a bandpass filter and an active portion of the array of photo detector elements; and a demultiplexing assembly which is optically coupled to the array of photo detector elements, the demultiplexing assembly comprising a baffle assembly that includes: a plurality of filter cavities with each filter cavity corresponding to one of the plurality of optical channels, a support baffle corresponding to each filter cavity, each support baffle including an output aperture and a support surface disposed about the output aperture which is configured to provide a ledge for engaging and supporting a respective bandpass filter of the plurality of optical channels such that a bottom surface of the respective bandpass filter is in contact with the support surface of the support baffle, and a filter baffle that light cannot pass through disposed between adjacent bandpass filters with a bottom edge of each filter baffle being disposed on a top surface of a corresponding support baffle with no gap between the corresponding support baffle and filter baffle; and wherein a band wavelength of each optical channel increases as a function of increased distance from an input aperture of the demultiplexing assembly to compensate for lower responsivity of the photo detector elements as a function of shorter wavelength. ### Claim 13 An optical demultiplexing device, comprising: a continuous linear array of photo detector elements with each photo detector element thereof being disposed in contact or near contact with adjacent photo detector elements of the continuous linear array of photodetector elements; and a demultiplexing assembly which is optically coupled to the array, the demultiplexing assembly comprising a baffle assembly that includes a continuous monolithic structure formed from a single piece of material and the demultiplexing assembly further comprising multiple optical channels, each optical channel formed from at least one bandpass reflector and at least one optical filter, each bandpass reflector being disposed substantially along an input signal axis of the demultiplexing assembly and each channel configured to transmit an optical signal within a selected wavelength range to an active portion of the array of photo detector elements. ### Claim 14 (depends on 13) The device of claim 13 wherein each active portion of the linear array of photo detector elements comprises a single photo detector element. ### Claim 15 (depends on 13) The device of claim 13 wherein each active portion of the linear array of photo detector elements comprises a plurality of photo detector elements. ### Claim 16 (depends on 13) The device of claim 13 wherein the demultiplexing assembly is less than about 3 inches in overall length. ### Claim 17 (depends on 16) The device of claim 16 wherein the demultiplexing assembly is less than about 2 inches in overall length. ### Claim 18 (depends on 13) The device of claim 13 wherein the linear array of photo detector elements comprises about 10 photo detector elements to about 100 photo detector elements. ### Claim 19 (depends on 13) The device of claim 13 wherein each bandpass reflector is separated from one or more adjacent bandpass reflectors by a distance of less than about 4 mm. ### Claim 20 (depends on 13) The device of claim 13 wherein each active portion of the linear array is separated from one or more adjacent active portions of the linear array of photo detector elements by a distance of less than about 1 mm. ### Claim 21 An optical demultiplexing device, comprising: an array of photo detector elements; a plurality of optical channels, each optical channel including a bandpass reflector, a bandpass filter and an active portion of the array of photo detector elements; and a demultiplexing assembly which is optically coupled to the array of photo detector elements, the demultiplexing assembly including a baffle assembly that comprises a continuous monolithic structure formed from a single piece of material and the baffle assembly further comprises: a plurality of filter cavities with each filter cavity corresponding to one of the plurality of optical channels, a support baffle corresponding to each filter cavity, each support baffle including an output aperture and a support surface disposed about the output aperture which is configured to provide a ledge for engaging and supporting a respective bandpass filter of the plurality of optical channels such that a bottom surface of the respective bandpass filter is in contact with the support surface of the support baffle, and a filter baffle that light cannot pass through disposed between adjacent bandpass filters with a bottom edge of each filter baffle being disposed on a top surface of a corresponding support baffle with no gap between the corresponding support baffle and filter baffle.