Apparatus and methods for measuring reflectance of optical laser components are disclosed. In one embodiment, when the reflectance of the test optical laser component is higher than 98%, a cavity ring-down (CRD) technique based configuration is employed to measure the reflectance of the test optical laser component. On the other hand, when the reflectance of the test optical laser component is lower than 98% or there is no measurable CRD signal, by removing the output cavity mirror in the CRD apparatus, a photometric configuration is formed to measure the reflectance. The switching between the two techniques can be achieved by removing or inserting the output cavity mirror of the ring-down cavity in the CRD apparatus.