(51) International Patent Classification: G02F 1/01 (2006.0 1) G02B 6/13 (2006.0 1) G02F 1/025 (2006.01) (21) International Application Number: (22) International Filing Date: (25) Filing Language: (26) Publication Language: (30) Priority Data: 10201809247Q 19 October 2018 (19. 10.2018) SG (71) Applicant: ADVANCED MICRO FOUNDRY PTE. LTD. [SG/SG]; 11 Science Park Road, Singapore Science Park 2, Singapore 117685 (SG). (72) Inventors: LUO, Xianshu; c/o Advanced Micro Foundry PTE. LTD., 11 Science Park Road, Singapore Science Park 2, Singapore 117685 (SG). LO, Guo-Qiang; c/o Advanced Micro Foundry PTE. LTD., 11 Science Park Road, Singa‹ pore Science Park 2, Singapore 117685 (SG). (74) Agent: NANYANGLAW LLC; P.O. Box 1861, Robinson Road Post Office, Singapore 90371 1 (SG). (81) Designated States (unless otherwise indicated, for every kind of national protection available ) : AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DJ, DK, DM, DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL, IN, IR, IS, JO, JP, KE, KG, KH, KN, KP, KR, KW, KZ, LA, LC, LK, LR, LS, LU, LY, MA, MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SA, SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW. (84) Designated States (unless otherwise indicated, for every kind of regional protection available ) : ARIPO (BW, GH, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, SM, TR), OAPI (BF, BJ, CF, CG, Cl, CM, GA, GN, GQ, GW, KM, ML, MR, NE, SN, TD, TG). PCT/SG20 19/0505 19 18 October 2019 (18. 10.2019) English English Published: — with international search report (Art. 21(3)) (54) Title: OPTICAL WAVEGUIDE TUNING ELEMENT (57) Abstract: A tunable element for an optical waveguide device, such as an Optical Phased Array (OPA), is described. Tunable ele‹ ment comprises three waveguide sections arranged such that light propagates through the first waveguide section, then through the sec‹ ond waveguide section and then through the third waveguide sec‹ tion, with light being either evanescently or directly coupled from one waveguide section to the next. The tunable element further com‹ prises one or more resistive heating pad formed proximate to the sec‹ ond waveguide section. The first and third waveguide sections are formed from a first material and the second waveguide section is formed from a second, different material and the second material is more thermo-optically sensitive than the first material. 304 30 303 203 [Fig. 3DJ