# US 7,412,133 B2 · Wavelength selective optical focusing device using optical fiber and optical module using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,412,133 B2 - Document ID: US7412133B2 - Status: Granted - Kind: B2 - Application number: 11/319,688 - Filed: 2005-12-28 - Published: 2007-03-29 - Granted: 2008-08-12 - Earliest claimed: 2005-09-28 - Assignees: Electronics and Telecommunications Research Institute - Inventors: Shin Young Yoon; Sei Hyoung Lee; Hyun Seo Kang - Web page: https://patentgrep.com/patent/US7412133B2 ## CPC - G02B 6/02066: {Gratings having a surface relief structure, e.g. repetitive variation in diameter of core or cladding} - G02B 6/02085: {characterised by the grating profile, e.g. chirped, apodised, tilted, helical} - G02B 6/4203: {Optical features} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract The present invention provides a wavelength selective optical focusing device using the cladding-etching of an optical fiber and an optical module using the same. The wavelength selective optical focusing device includes a core for transmitting an optical signal therethrough; and a cladding layer surrounding the core and having a plurality of grooves formed in the outer circumferential surface thereof such that the grooves are changed at a designated rate, wherein an optical signal having a designated wavelength guided by the core is focused to the outside of the cladding layer by the grooves. ## Claims ### Claim 1 A wavelength selective optical focusing unit integrated in an optical fiber comprising a core elongated over a length for transmitting an optical signal therethrough and a cladding layer surrounding the outer surface of the elongated core, the wavelength selective optical focusing unit comprising: a plurality of grooves formed in the outer circumferential surface of a portion of the cladding layer of the optical fiber such that each groove has a depth and an interval, the distance between two adjacent grooves, wherein the intervals are gradually increasing or decreasing, and wherein an optical signal having a designated wavelength guided by the core is focused through the cladding layer to the outside of the cladding layer by the grooves, and wherein the optical signal is focused perpendicular to the optical axis. ### Claim 2 (depends on 1) The wavelength selective optical focusing unit of claim 1, wherein widths of the grooves are gradually increased or decreased. ### Claim 3 (depends on 2) The wavelength selective optical focusing device as set forth in claim 2, wherein the widths of the grooves are varied according to the wavelength of the optical signal. ### Claim 4 (depends on 1) The wavelength selective optical focusing unit of claim 1, wherein depths of the grooves are uniform. ### Claim 5 (depends on 1) The wavelength selective optical focusing unit of claim 1, wherein depths of the grooves are gradually increased or decreased. ### Claim 6 (depends on 1) The wavelength selective optical focusing unit of claim 1, wherein the grooves are formed above the core. ### Claim 7 (depends on 1) The wavelength selective optical focusing unit of claim 1, wherein the grooves are filled with a polymer. ### Claim 8 (depends on 1) The wavelength selective optical focusing unit of claim 1, wherein the grooves are filled with an index matching material having the same reflective index as or a different refractive index from that of the cladding layer. ### Claim 9 (depends on 1) The wavelength selective optical focusing unit of claim 1, wherein the grooves are formed by partially etching the outer circumferential surface of the cladding layer to a designated depth by photolithography. ### Claim 10 (depends on 1) The wavelength selective optical focusing device as set forth in claim 1, wherein the plurality of the grooves are formed by partially etching the cladding layer by a dry or wet etching method using photolithography. ### Claim 11 An optical module comprising: a sub-mount; an optical focusing device mounted on the sub-mount, comprising a core having a cross-sectional shape and elongated over a length for transmitting an optical signal therethrough and a cladding layer surrounding the outer surface of the elongated core and having a plurality of grooves formed in the outer circumferential surface of a portion of the cladding layer of an optical fiber such that each groove has a depth and an interval is the distance between two adjacent grooves, wherein the intervals are gradually increasing or decreasing, wherein an optical signal having a designated wavelength guided by the core is focused through the cladding layer to the outside of the cladding layer by the grooves, and wherein the optical signal is focused perpendicular to the optical axis; and an optical element arranged on the sub-mount at a position, onto which the optical signal is focused by the optical focusing device, for receiving or transmitting the optical signal. ### Claim 12 (depends on 11) The optical module as set forth in claim 11, wherein the optical element is a photo diode or a laser diode. ### Claim 13 An optical fiber comprising: a core having a cross-sectional shape and being elongated over a length for transmitting an optical signal therethrough; and a cladding layer surrounding the outer surface of the elongated core, wherein a plurality of grooves are formed to have openings on a portion of the outer circumferential surface such that each groove has a depth and an interval is the distance between two adjacent grooves, wherein the intervals are gradually increasing or decreasing, and wherein an optical signal having a designated wavelength guided by the core is focused through the cladding layer to the outside of the cladding layer by the grooves, and wherein the optical signal is focused perpendicular to the optical axis. ### Claim 14 (depends on 13) The optical fiber of claim 13, wherein widths of the grooves are gradually increased or decreased. ### Claim 15 (depends on 14) The optical fiber of claim 14, wherein the widths of the grooves are varied according to the wavelength of the optical signal. ### Claim 16 (depends on 13) The optical fiber of claim 13, wherein depths of the grooves are uniform. ### Claim 17 (depends on 13) The optical fiber of claim 13, wherein depths of the grooves are gradually increased or decreased. ### Claim 18 (depends on 13) The optical fiber of claim 13, wherein the grooves are formed above the core. ### Claim 19 (depends on 13) The optical fiber of claim 13, wherein the grooves are filled with a polymer. ### Claim 20 (depends on 13) The optical fiber of claim 13, wherein the grooves are filled with an index matching material having the same reflective index as or a different refractive index from that of the cladding layer.