Patent US7961991 - Delay demodulation devices

62> United States Patent

US00796l99lB2 (10) Patent No.: US 7,961,991 B2

Hasegawa et al. (45) Date of Patent: Jun. 14, 2011 (54) DELAY DEMODULATION DEVICES (56) References Cited (75) Inventors: Junichi Hasegawa, Tokyo (JP); US‘ PATENT DOCUMENTS Kazutaka Nara, Tokyo (JP) 619611492 B2 * 11/ZOO5 Doe” ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~ 385/39 7,259,901 B2 * 8/2007 Parsons et al. 359/237 2007/0177151 A1* 8/2007 Isomura et al. 356/477 (73) Assignee: The Furukawa Electric Co., Ltd., 2010/0073760 Al * 3/2010 Hasegawa ei a1- ~~~~~~~~~~ -~ 359/325 T°kY° OP) FOREIGN PATENT DOCUMENTS JP 2007-60442 3/2007 ( * ) Notice: Subject to any disclaimer, the term of this JP 2()()7-151()26 6/2007 patent is extended or adjusted under 35 QTHER PUBLICATIQNS U.S.C. l54(b) by 90 days. U.S. Appl. No. 12/415,407, filed Mar. 31, 2009, Hasegawa, et al. (21) Appl. No.: 12/412,932 * eited by examiner Primary Examiner — Ellen Kim (22) Filed, Man 27, 2009 (74) Attorney, _ Agent, or Firm —Oblon, Spivak, cean,aier eusa,... MCllldM &N tdtLLP (65) Prior Publication Data (57) ABSTRACT The delay demodulation device 1 comprises an input Us 2010/OO53731A1 Mah 4= 2010 waveguide 2 which receives DQPSK signals; a Y-branch waveguide 3 which splits the light waveguide 2; a first Mach(30) Foreign Application priority Data _Zehr}der interfeéoligiettler (MZI)? and a second I\_/(I1ach8-Z;:lir1id1er in er erome er . o en s o e arm-wavegui es , o e MZI 4 and the both ends of the ann-wave uides 12, 13 of the Mar‘ 27’ 2008 (JP) ............................... .. 2008-083640 MZI 5 are bent toward the Center poniongofthe planar fightwave circuit (PLC) 1A. Thereby, the length of the arm(51) Int‘ Cl‘ waveguides 8, 9 of the MZI 4 and the length of the armwaveguides of the MZI 5 are shortened in the Z-direction. G023 6/12 (200601) And, the length of the input couplers 6, 10 and the output (52) U.S. Cl. ........................................ .. 385/14; 359/325 couplers 7, 11 ofthe MZIs 4, 5 are shortened in the Z-direc(58) Field 61 Classification Search .................. .. 385/14, 11°11 Therefere the eree eevered bythe MZIS 4> 5 eenbe made

385/15, 39; 359/325 See application file for complete search history.

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