Optical time domain reflectometer and testing method of optical time domain reflectometer

An optical time domain reflectometer comprising:

• a pulse width setting unit that sets a pulse width of an optical pulse;
• a light source that generates an optical pulse with the pulse width set by the pulse width setting unit;
• an optical receiver that detects a backscattered light level obtained by scattering of the optical pulse output from the light source in a measurement target optical fiber;
• a storage unit that stores in advance a fourth backscattered light level (PZ(W2)) obtained by adding a difference (ΔPR) between a second backscattered light level (PR(W1)) at a predetermined reference distance (DR) which is measured using a predetermined first pulse width (W1) and a third backscattered light level (PR(W2)) at the predetermined reference distance (DR) which is measured using a second pulse width (W2) larger than the first pulse width to a first backscattered light level (PZ(W1)) at a connection point (DD) to the measurement target optical fiber to be connected which is measured using the first pulse width so as to be associated with the second pulse width before a test;
• and
• an arithmetic processing unit that reads the fourth backscattered light level (PZ(W2)) at the second pulse width corresponding to a pulse width of an optical pulse output from the light source to the measurement target optical fiber for the test from the storage unit and calculates a transmission loss (LT) in the measurement target optical fiber using the fourth backscattered light level (PZ(W2)).