公开(公告)号：WO2018213251A1

公开(公告)日：2018-11-22

申请号：PCT/US2018/032672

申请日：2018-05-15

Applicant: THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIVERSITY

Inventor： PERIN, Jose, Krause ,  KAHN, Joseph, M. ,  SHASTRI, Anujit, K.

IPC: H04B10/60 ,  H04B10/61 ,  H04B10/63 ,  H04B10/69 ,  H04L27/06 ,  H04L27/227 ,  H04L27/14

CPC classification number: H04L27/227 ,  H04B10/6151 ,  H04L27/0014 ,  H04L27/14

Abstract: Disclosed are systems, methods, and structures for DSP-free coherent receiver architectures applicable for short-reach optical links. Operationally, a received optical signal is down-converted by mixing it with a local oscillator (LO) laser signal using a 90-degree hybrid followed by balanced photodiodes. Other receiver functions are performed using analog signal processing thereby avoiding power-hungry, high-speed analog-to-digital converters and high-speed digital signal processing. Carrier phase recovery is performed by an electrical phase-locked loop employing a multiplier-free phase estimator stage that - while designed for quaternary phase-shift keying signals - may be employed in designs exhibiting higher modulation formats. Since carrier phase recovery is performed in the electrical domain, LO laser frequency modulation or LO laser integration is not employed. Polarization demultiplexing - if employed - may be performed by the addition of an optical polarization controller prior to the hybrid and may advantageously be realized by cascading multiple phase shifters driven by low- speed circuitry.