The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 03, 2013
Filed:
Mar. 01, 2012
Takashi Inoue, Tokyo, JP;
Kazutaka Nara, Tokyo, JP;
Takashi Inoue, Tokyo, JP;
Kazutaka Nara, Tokyo, JP;
Furukawa Electronic Co., Ltd., Tokyo, JP;
Abstract
The invention provides a PLC-type DP-QPSK demodulator that reduces connection loss between a polarization beam splitter and a 90-degree hybrid circuit and aims at reducing the manufacturing cost and an optical transmission system using the same. In an embodiment of the invention, a PLC-type DP-QPSK demodulator that receives a DP-QPSK signal includes one PLC chip having a planar lightwave circuit. Input ports and output ports of signal light are provided at an input end and at an output end of the PLC chip, respectively. Within the planar lightwave circuit, there are integrated a polarization beam splitter that splits the DP-QPSK signal into an X-polarization QPSK signal and a Y-polarization QPSK signal, and two 90-degree hybrid circuits that mix the X-polarization QPSK signal and local oscillation light and the Y-polarization QPSK signal and local oscillation light, respectively, split each QPSK signal into orthogonal components I, Q and output them.