# US 8,570,644 B2 · Optical modulator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,644 B2 - Document ID: US8570644B2 - Status: Granted - Kind: B2 - Application number: 13/141,240 - Filed: 2009-12-25 - Published: 2011-10-20 - Granted: 2013-10-29 - Earliest claimed: 2008-12-26 - Assignees: Sumitomo Osaka Cement Co., Ltd. - Applicants: Hitoshi Oguri - Inventors: Hitoshi Oguri - Web page: https://patentgrep.com/patent/US8570644B2 ## CPC - G02F 1/035: in an optical waveguide structure - G02B 6/126: using polarisation effects {(G02B6/1226 takes precedence)} - G02B 6/272: {comprising polarisation means for beam splitting and combining} - 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: 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 - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract The present invention realizes an enhancement of a fabrication yield and a reduction of a size regarding an optical modulator or an optical device including polarization beam combining means. An optical modulator of the present invention (1) includes: first and second optical modulators (LN optical modulators (101) to (104)) that are formed on a substrate; a polarization beam rotating unit (107) that rotates at least one polarization beam of modulated light beams modulated by the first and second optical modulators; and a polarization beam combining element (110) that is disposed outside the substrate and that combines the polarization beams of the modulated light of which the polarization beams are rotated by the polarization beam rotating unit (107). ## Claims ### Claim 1 An optical modulator comprising: first and second optical modulation units that are formed on a substrate; a polarization beam rotating unit that rotates at least one polarization beam of modulated light beams modulated by the first and second optical modulation units; and a polarization beam combining unit that is disposed outside the substrate and that includes a polarization beam combining element combining the polarization beams of the modulated light of which the polarization beams are rotated by the polarization beam rotating unit, wherein the polarization beam combining unit includes an optical system in which two opposed collimating systems are arranged, wherein the two opposed collimating systems include a first collimator to which the modulated light beams modulated by the first and second optical modulation units are input, and a second collimator to which an output light beam of the polarization beam combining element is input, wherein an input position of the second collimator is substantially located at the center of a position gap varying depending on the polarization beams of the output light of the polarization beam combining element, wherein at least one of the two opposed collimating systems include fiber collimators, respectively, and wherein at least one of the two opposed collimating systems is configured to include a ferrule. ### Claim 2 (depends on 1) The optical modulator according to claim 1, wherein the first collimator is a fiber collimator including a two-hole ferrule and the second collimator is a fiber collimator including a one-hole ferrule. ### Claim 3 (depends on 1) The optical modulator according to claim 1, wherein the polarization beam combining element is a Savart plate. ### Claim 4 (depends on 3) The optical modulator according to claim 3, wherein the Savart plate is configured to compensate for an optical path difference between two polarization beams to be combined. ### Claim 5 (depends on 1) The optical modulator according to claim 1, wherein the polarization beam combining unit includes a condensing unit that condenses the modulated light beams on an output fiber. ### Claim 6 (depends on 1) The optical modulator according to claim 1 wherein the polarization beam combining unit includes an optical element having an inverse dispersion characteristic. ### Claim 7 (depends on 1) The optical modulator according to claim 1, wherein the polarization beam rotating unit is half-wave plate. ### Claim 8 (depends on 1) The optical modulator according to claim 1, wherein the polarization beam combining unit comprises a prism and lens which have a dispersion characteristic that the refractive index becomes higher as the wavelength becomes shorter and the refractive index becomes lower as the wavelength becomes longer. ### Claim 9 (depends on 1) The optical modulator according to claim 1, wherein a modulation method of the first and second optical modulation units is phase shift keying. ### Claim 10 (depends on 1) The optical modulator according to claim 1, wherein the first collimator includes a two-hole used in a portion to which the modulated light beams modulated by the first and second optical modulation units are input, and the second collimator includes a one-hole used in a portion to which the output light beam of the polarization beam combining element is input. ### Claim 11 An optical modulator comprising: first and second optical modulation units that are formed on a substrate; a polarization beam rotating unit that rotates at least one polarization beam of modulated light beams modulated by the first and second optical modulation units; and a polarization beam combining unit that is disposed outside the substrate and that includes a polarization beam combining element combining the polarization beams of the modulated light of which the polarization beams are rotated by the polarization beam rotating unit, wherein the polarization beam combining unit includes an optical system in which two opposed collimating systems are arranged, wherein the two opposed collimating systems include a first collimator to which the modulated light beams modulated by the first and second optical modulation units are input, and a second collimator to which an output light beam of the polarization beam combining element is input, wherein an input position of the second collimator is substantially located at the center of a position gap varying depending on the polarization beams of the output light of the polarization beam combining element, and wherein the first collimator includes a V-grooved block including a two-hole, and the second collimator includes a V-grooved block including a one-hole. ### Claim 12 An optical modulator comprising: first and second optical modulation units that are formed on a substrate; a polarization beam rotating unit that rotates at least one polarization beam of modulated light beams modulated by the first and second optical modulation units; and a polarization beam combining unit that is disposed outside the substrate and that includes a polarization beam combining element combining the polarization beams of the modulated light of which the polarization beams are rotated by the polarization beam rotating unit, wherein the polarization beam combining unit includes an optical system in which two opposed collimating systems are arranged, wherein the two opposed collimating systems include a first collimator to which the modulated light beams modulated by the first and second optical modulation units are input, and a second collimator to which an output light beam of the polarization beam combining element is input, wherein an input position of the second collimator is substantially located at the center of a position gap varying depending on the polarization beams of the output light of the polarization beam combining element, wherein at least one of the two opposed collimating systems include fiber collimators, respectively, and wherein at least one of the two opposed collimating systems is configured to include a V-grooved block. ### Claim 13 An optical modulator comprising: first and second optical modulation units that are formed on a substrate; a polarization beam rotating unit that rotates at least one polarization beam of modulated light beams modulated by the first and second optical modulation units; and a polarization beam combining unit that is disposed outside the substrate and that includes a polarization beam combining element combining the polarization beams of the modulated light of which the polarization beams are rotated by the polarization beam rotating unit, wherein the polarization beam combining unit includes an optical system in which two opposed collimating systems are arranged, wherein the two opposed collimating systems include a first collimator and a second collimator, the first collimator includes a two-hole used in a portion to which the modulated light beams modulated by the first and second optical modulation units are input, and the second collimator includes a one-hole used in a portion to which an output light beam of the polarization beam combining element is input, wherein at least one of the two opposed collimating systems includes a fiber collimator, and wherein the second collimator is located between outputs of both the polarization beams of the modulated light beams modulated by the first and second optical modulation units, the second collimator has such an input position as to reduce a polarization dependency loss.