title: Experimental method for high-accuracy reflectivity-spectrum measurements.
abstract: An experimental method for accurate measurements of the reflectivity spectrum of mirrors is presented. It combines the noise reduction obtained with multiple beam reflections on two identical mirrors; high-beam quality, owing to the use of single-mode optical fibers; and high immunity against intensity variations of the beam. This method is demonstrated for characterizing a 30-period GaAs/Al(0.65)Ga(0.35)As distributed Bragg reflector designed for long-wavelength vertical-cavity surface-emitting lasers. Its peak reflectivity is found to be 99.43 ? 0.04% at 1.562 mum, and an optical absorption coefficient of alpha = 36 ? 6 cm(-1) is derived. The peak internal reflectivity of this distributed Bragg reflector used as the top mirror in a wafer-fused vertical-cavity surface-emitting laser is calculated to be 98.87 ? 0.12%, and the transmission is 0.28%.
authors.forename: C A
authors.initials: CA
authors.lastname: Berseth
authors.forename: A
authors.initials: A
authors.lastname: Schönberg
authors.forename: O
authors.initials: O
authors.lastname: Dehaese
authors.forename: K
authors.initials: K
authors.lastname: Leifer
authors.forename: A
authors.initials: A
authors.lastname: Rudra
authors.forename: E
authors.initials: E
authors.lastname: Kapon