A high resolution optical fiber length meter, live fiber detector, and reflectance tester (instrument) for single mode applications using a low power, long wavelength laser for generating wide and narrow optical pulses that are launched into a single mode fiber under test. The laser output fiber pigtail is fusion spliced to a singlemode coupler whose output is coupled to the instrument bulkhead connector. A PIN photodiode is fusion spliced to the singlemode coupler to receive the reflected light from the fiber under test. The high resolution hand-held instrument is useful in examining singlemode passive optical networks (PON).