Patent ID: 8744276
Filing Date: 2014-06-03
Classification: H04B,H04L

Abstract:
1. An optical receiving apparatus comprising: a combining unit that combines signal light and reference light; an optoelectric converting unit that converts, into electrical signals, two or more optical signals that enable reconstruction of a complex electric field signal of the signal light obtained by the combining unit; a free-running sampling clock generating unit that generates a free-running sampling clock that has a frequency preset based on a symbol rate of the signal light and is asynchronous with the signal light; a digital converting unit that samples at the frequency of the free-running sampling clock signal, an electrical signal obtained by the optoelectric converting unit and converts the electrical signal into a digital signal; and a digital signal processing unit that demodulates a received signal based on a complex digital signal obtained from the digital signal obtained by the digital converting unit, wherein the digital signal processing unit includes: wherein the digital signal processing unit uses the complex digital signal sampled by the sampling unit to demodulate the received signal, and wherein the sampling unit includes a decimation/interpolation unit that thins out a signal from the complex digital signal or inserts a signal into the complex digital signal so as to perform sampling at a frequency that is an integral multiple of a half of a frequency of the signal light.