NEW APPROACH FOR LOSS MEASUREMENTS IN OPTICAL PLANAR WAVE-GUIDES

A new nondestructive method for measuring waveguide losses is presente d. It uses a prism-in coupling method to feed the light into the waveg uide and the end-fire coupling to measure the transmitted light. It is simple both in construction and during the measurements. Such a confi guration enables us to determine the attenuation coefficient which is independent of coupling efficiencies into and out of the guide and of the laser fluctuation. The results obtained, with this method, on H+ a nd He+ implanted LiNbO3 waveguides are presented and discussed. Theref ore, the measurements lead to the calculation of the attenuation with an absolute incertitude of 0.4 dB cm(-1) for a waveguide length of 0.4 cm.