Patent ID: 8724101

Claim:
An optical fiber characteristic measuring device which includes: a light source which emits laser light modulated at a predetermined modulation frequency; an incident section which causes the laser light from the light source as continuous light and pulsed light to be incident from one end and other end of an optical fiber respectively; a timing adjuster which causes light emitted from the optical fiber to pass therethrough at a predetermined timing; and a light detector which detects the light which passes through the timing adjuster, and measures a characteristic of the optical fiber by using a detection result of the light detector, the device comprising: a frequency setter configured to calculate a frequency from an equation, the frequency setter configured to divide the modulation frequency by an odd multiple of the calculated frequency to calculate a value, the frequency setter configured to determine whether the value is an integer, the frequency setter configured to change the calculated frequency by a predetermined amount in a case where the frequency setter has determined that the value is an integer, the frequency setter configured to decide to use the calculated frequency in a case where the frequency setter has determined that the value is not an integer; and a synchronous detector configured to use a synchronization signal having the calculated frequency which the frequency setter has decided to use, the synchronous detector configured to synchronously detect the detection result of the light detector by using the synchronization signal.