Patent ID: 8718467
Filing Date: 2014-05-06
Classification: H04B,H04J,H04Q

Abstract:
1. An optical communication switching system in which dualized lines are formed by selectively connecting a second optical transmission line between first and second optical transmission devices separately from a first optical transmission line, the optical communication switching system comprising: a first optical coupler means in which an optical signal I/O terminal of the first optical transmission device is connected to a first optical I/O terminal, and each of one sides of the first and second optical transmission lines is connected to second and third I/O terminals; a second optical coupler means in which an optical signal I/O terminal of the second optical transmission device is connected to a first optical I/O terminal, and each of the other sides of the first and second optical transmission lines is connected to second and third I/O terminals; a test light source that is connected to a fourth optical I/O terminal of the second optical coupler means and transmits pulse light in which an optical frequency is chirped; an optical measurement device that is connected to a fourth optical I/O terminal of the first optical coupler means and measures pulse light output from the terminal; and a free space optics (FSO) device that is disposed on the second optical transmission line and compensates for a transmission time of pulse light transmitted through the line by expansion and contraction of a spatial optical line length; wherein pulse light transmitted from the test light source is branched by the second optical coupler means, pulse light that has passed through the first optical transmission line and pulse light that has passed through the second optical transmission line are multiplexed by the first optical coupler means and then input to the optical measurement device, an arrival time of pulse light passing through each optical transmission line and an interference waveform generated in an upper part of a pulse waveform are measured by the optical measurement device, an optical line length of the FSO device is adjusted so that the interference waveform becomes appropriate while matching the measured arrival time of the pulse light, and an optical transmission signal between the first and second optical transmission devices is switched from the first optical transmission line to the second optical transmission line; wherein the test light source emits pulse light in which the optical frequency is chirped linearly or in a state close to a linear form, the optical measurement device includes a Fast Fourier transformer (FFT) that performs Fast Fourier transform on an interference waveform generated in an upper part of the pulse light waveform, and for an adjustment of the interference waveform, Fast Fourier transform is performed on the interference waveform, an optical line length of the FSO device is extended or contracted so that using a specific frequency component obtained at that time as a reference, the component moves to a frequency zero side, the optical line length is continuously extended or contracted again until the frequency component as the reference is measured, and the FSO device is adjusted so that the optical line length becomes half the extended or contracted length.