Patent ID: 9667342
Date: 2017-05-30
CPC Classifications: H04B

Claim:
1. An apparatus, comprising: a first measurer configured to measure first phase data indicating a temporal variation in a phase of a non-transferred signal that is an optical signal modulated by an optical phase modulation scheme and output from a transmitting device to an optical transmission path as the non-transferred signal; a second measurer configured to measure second phase data indicating a temporal variation in the phase of the optical signal transferred by the optical transmission path as a transferred signal on a side of a receiving device; a generator configured to generate differential data indicating a difference between the first phase data and the second phase data; and an extractor configured to use the differential data to extract, from the optical signal on the side of the receiving device, optical phase noise generated due to the optical transmission path, and configured to monitor the differential data and, when an amplitude of the differential data is minimal, extract the optical phase noise by reversing a sign of the differential data.