A test instrument tests an optical component of a fiber optic network. The test instrument determines signal parameters describing pulses to be emitted by lasers of the test instrument to test the optical component, and directly modulates the lasers to repeatedly emit the pulses at different wavelengths on a single fiber optic cable in a time division multiplexing manner. The test instrument triggers powering measurements to coincide with the emitted pulses, and determines performance parameters of the optical component based on the triggered power measurements.