# US 9,521,474 B2 · Wavelength selective switch having multi-layer reflector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,521,474 B2 - Document ID: US9521474B2 - Status: Granted - Kind: B2 - Application number: 14/618,539 - Filed: 2015-02-10 - Published: 2016-08-11 - Granted: 2016-12-13 - Earliest claimed: 2015-02-10 - Assignees: Inlc Technology, Inc. - Applicants: InLC Technology, Inc. - Inventors: Seong Woo Suh; Tae Hwan Kim - Web page: https://patentgrep.com/patent/US9521474B2 ## CPC - H04Q 11/0005: {Switch and router aspects} - G02B 5/3083: {Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001)} - G02B 6/35: having switching means (by changing the optical properties of the medium G02F1/00) - 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 6/3534: {the optical element being diffractive, i.e. a grating} - G02B 26/0858: {the reflecting means being moved or deformed by piezoelectric means} - G02B 27/4244: {in wavelength selecting devices (spectrometry G01J)} - G02F 1/0136: {for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation (G02F1/0353 takes precedence)} - G02F 1/31: Digital deflection, {i.e. optical switching}(G02F1/33 takes precedence) - H04Q 2011/0026: {using free space propagation (e.g. lenses, mirrors)} - H04Q 2011/003: {using switches based on microelectro-mechanical systems [MEMS]} - H04Q 2011/0035: {using miscellaneous components, e.g. circulator, polarisation, acousto/thermo optical} - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract A wavelength selective switch (WSS) apparatus is disclosed, which includes: a plurality of optical ports configured to output light beams at different angles from one another; a wavelength dispersion element configured to disperse the wavelength components of each light beam; a focusing element configured to focus the dispersed wavelength components of the light beams; and a multi-layer reflecting unit configured to reflect the focused light beams to the focusing element, the multi-layer reflecting unit including a multi-layer reflector and a reflection controller operatively connected to the multi-layer reflector, the multi-layer reflector having a main surface for reflecting the light beams on which a plurality of layers are provided, each layer including a plurality of pixels that are individually controllable by the reflection controller. ## Claims ### Claim 1 A wavelength selective switch (WSS) apparatus comprising: a plurality of optical fiber ports configured to output light beams at different angles from one another; a wavelength dispersion element configured to disperse the wavelength components of each light beam; a focusing element configured to focus the dispersed wavelength components of the light beams; and a multi-layer reflecting unit configured to reflect the focused light beams to the focusing element, the multi-layer reflecting unit including a multi-layer reflector and a reflection controller operatively connected to the multi-layer reflector, the multi-layer reflector having a main surface for reflecting the light beams on which a plurality of layers are provided, each layer including a plurality of pixels that are individually controllable by the reflection controller, wherein the WSS apparatus is arranged that a predetermined wavelength component of a light beam output from one of the optical fiber ports is reflected by the multi-layer reflector to travel back to the one of the optical fiber ports. ### Claim 2 (depends on 1) The WSS apparatus according to claim 1, further comprising: a polarization diversity element configured to change polarizations of the light beams input thereto and output the light beams with substantially one polarization; and an anamorphic expansion element configured to anamorphic expand the light beams. ### Claim 3 (depends on 2) The WSS apparatus according to claim 2, wherein the polarization diversity element and the anamorphic expansion element are arranged in a path of the light beams between the plurality of the optical fiber ports and the wavelength dispersion element. ### Claim 4 (depends on 1) The WSS apparatus according to claim 1, wherein the plurality of pixels in each layer on the main surface of the multi-layer reflector are configured to attenuate or block the light beams reflected therefrom by controlling each pixel by the reflection controller. ### Claim 5 (depends on 1) The WSS apparatus according to claim 1, wherein the plurality of optical fiber ports, the wavelength dispersion element, the focusing element, and the multi-layer reflecting unit are configured in such a way that the light beams reflected from the multi-layer reflector travel to the plurality of optical fiber ports. ### Claim 6 (depends on 5) The WSS apparatus according to claim 5, wherein the plurality of optical fiber ports comprise a first optical fiber port and a second optical fiber port, the first optical fiber port outputting a first light beam and the second optical fiber port a second light beam, the multi-layer reflector of the multi-layer reflecting unit comprising a first layer and a second layer, each of the first and second layers including the plurality of pixels that are individually controllable by the reflection controller. ### Claim 7 (depends on 6) The WSS apparatus according to claim 6, wherein the first and second optical fiber ports and the wavelength dispersion element are configured to allow the first and second light beams to cross before reaching the focusing element, whereby the first light beam hits on the second layer of the multi-layer reflector while the second light beam hits on the first layer of the multi-layer reflector. ### Claim 8 (depends on 6) The WSS apparatus according to claim 6, wherein the first and second optical fiber ports, the wavelength dispersion element, and the focusing element are configured to allow the first and second light beams to cross after passing through the focusing element, whereby the first light beam hits on the second layer of the multi-layer reflector while the second light beam hits on the first layer of the multi-layer reflector. ### Claim 9 (depends on 6) The WSS apparatus according to claim 6, wherein the first and second optical fiber ports, the wavelength dispersion element, and the focusing element are configured to keep the first and second light beams from crossing at any point in a light travelling path between the plurality of optical fiber ports and the multi-layer reflecting unit, whereby the first light beam hits on the first layer of the multi-layer reflector while the second light beam hits on the second layer of the multi-layer reflector. ### Claim 10 (depends on 1) The WSS apparatus according to claim 1, wherein each of the plurality of layers on the main surface of the multi-layer reflector comprises a liquid crystal (LC) phase array, the amount of the light beams being controlled by a voltage or current applied to the LC phase array by the reflection controller, and wherein the multi-layer reflector comprises a plurality of mirrors arranged opposite side of the main surface, each mirror being configured such that the light beams reflected therefrom travel in a direction to predetermined one of the plurality of optical fiber ports. ### Claim 11 (depends on 10) The WSS apparatus according to claim 10, wherein the multi-layer reflector further comprises a birefringent material in front of the LC phase array to refract the light beams passing therethrough according to the polarization of the light beams, thereby changing a light path and the amount of the light beams to the predetermined optical fiber port. ### Claim 12 (depends on 1) The WSS apparatus according to claim 1, wherein each of the plurality of layers on the main surface of the multi-layer reflector comprises one selected from the group consisting of a liquid crystal on silicon (LCOS) and a micro-electromechanical system (MEMS) for steering the light beams to one of the plurality of optical fiber ports or to other directions to thereby control the amount of the light beams entering the plurality of optical fiber ports. ### Claim 13 (depends on 1) The WSS apparatus according to claim 1, wherein the plurality of pixels in each layer on the main surface of the multi-layer reflector are configured to attenuate or block the light beams reflected therefrom by controlling each pixel by the reflection controller, wherein the plurality of optical fiber ports, the wavelength dispersion element, the focusing element, and the multi-layer reflecting unit are configured in such a way that the light beams reflected from the multi-layer reflector travel to the plurality of optical fiber ports, wherein the plurality of optical fiber ports comprise a first optical fiber port and a second optical fiber port, the first optical fiber port outputting a first light beam and the second optical fiber port a second light beam, the multi-layer reflector of the multi-layer reflecting unit comprising a first layer and a second layer, each of the first and second layers including the plurality of pixels that are individually controllable by the reflection controller, wherein the first and second optical fiber ports and the wavelength dispersion element are configured to allow the first and second light beams to cross before reaching the focusing element, whereby the first light beam hits on the second layer of the multi-layer reflector while the second light beam hits on the first layer of the multi-layer reflector. ### Claim 14 (depends on 13) The WSS apparatus according to claim 13, further comprising an output fiber port that is connected to the plurality of optical fiber ports via a plurality of circulators. ### Claim 15 A wavelength selective switch (WSS) apparatus comprising: a plurality of optical ports configured to output light beams at different angles from one another; a wavelength dispersion element configured to disperse the wavelength components of each light beam; a focusing element configured to focus the dispersed wavelength components of the light beams; and a multi-layer reflecting unit configured to reflect the focused light beams to the focusing element, the multi-layer reflecting unit including a multi-layer reflector and a reflection controller operatively connected to the multi-layer reflector, the multi-layer reflector having a main surface for reflecting the light beams on which a plurality of layers are provided, each layer including a plurality of pixels that are individually controllable by the reflection controller, wherein the plurality of optical ports comprise N input ports and an output port, where N is a natural number equal to or greater than two, the N input ports being connected to a coupler which is in turn connected to the output port, and wherein the multi-layer reflecting unit is configured to reflect predetermined wavelength components of the light beams to predetermined one of the N input ports and blocks the predetermined wavelength components of the light beams from entering any of the rest N−1 input ports by controlling the plurality of pixels on the multi-layer reflector by the reflection controller. ### Claim 16 (depends on 15) The WSS apparatus according to claim 15, wherein the N input ports are connected to the coupler via N circulators. ### Claim 17 A wavelength selective switch (WSS) apparatus comprising: a plurality of optical ports configured to output light beams at different angles from one another; a wavelength dispersion element configured to disperse the wavelength components of each light beam; a focusing element configured to focus the dispersed wavelength components of the light beams; and a multi-layer reflecting unit configured to reflect the focused light beams to the focusing element, the multi-layer reflecting unit including a multi-layer reflector and a reflection controller operatively connected to the multi-layer reflector, the multi-layer reflector having a main surface for reflecting the light beams on which a plurality of layers are provided, each layer including a plurality of pixels that are individually controllable by the reflection controller, wherein the plurality of optical ports comprise an input port and M output ports, where M is a natural number equal to or greater than two, the input port being connected to a splitter which is in turn connected to the M output ports, and wherein the multi-layer reflecting unit is configured to reflect predetermined wavelength components of the light beams to predetermined one of the M output ports and blocks the predetermined wavelength components of the light beams from entering any of the rest M−1 output ports by controlling the plurality of pixels on the multi-layer reflector by the reflection controller. ### Claim 18 (depends on 17) The WSS apparatus according to claim 17, wherein the splitter is connected to the M output ports via M circulators. ### Claim 19 A method of controlling a wavelength selective switch (WSS) apparatus comprising: outputting light beams, by a plurality of optical fiber ports, at different angles from one another; dispersing the wavelength components of each light beam using a wavelength dispersion element; focusing the dispersed wavelength components of the light beams using a focusing element configured to; and reflecting the focused light beams to the focusing element using a multi-layer reflecting unit, the multi-layer reflecting unit including a multi-layer reflector and a reflection controller operatively connected to the multi-layer reflector, the multi-layer reflector having a main surface for reflecting the light beams on which a plurality of layers are provided, each layer including a plurality of pixels that are individually controllable by the reflection controller, wherein the WSS apparatus is arranged that a predetermined wavelength component of a light beam output from one of the optical fiber ports is reflected by the multi-layer reflector to travel back to the one of the optical fiber ports. ### Claim 20 (depends on 19) The method of claim 19, further comprising: changing polarizations of the light beams input thereto and outputting the light beams with substantially one polarization using a polarization diversity element; and anamorphic expanding the light beams using an anamorphic expansion element.