Optical network analyzer

An optical network analyzer for measuring an optical characteristic of an object to be measured, comprising:

• a first multiplexer for multiplexing a first optical signal which has transmitted or reflected from the object to be measured, and a second optical signal having a frequency different from the first optical signal, and for outputting a third optical signal;
• a first photoelectrical converter for converting the third optical signal into a first electric signal;
• a second multiplexer for multiplexing a fourth optical signal having substantially the same frequency as the first optical signal, and a fifth optical signal having substantially the same frequency as the second optical signal, and for outputting a sixth optical signal;
• a second photoelectrical converter for converting the sixth optical signal into a second electric signal;
• a first divider for dividing a frequency of the first electric signal;
• a second divider for dividing a frequency of the second electric signal;
• and
• a phase measurement block for comparing phases of the first electric signal and the second electric signal, wherein said phase measurement block receives the first electric signal, of which the frequency is divided by said first divider, and the second electric signal, of which the frequency is divided by said second divider, and compares phases of the first electric signal and the second electric signal.