Integrated optical device for measuring the refractive index of a fluid

US5073024A · kind A · utility

Assignee

• COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES · FR

Inventors

• Serge Valette · Grenoble, FR
• Stephane Renard · Le Pont-de-Claix, FR

Key dates

• Filing date: Oct 24, 1989
• Grant date: Dec 17, 1991
• Expiry date: Oct 24, 2009

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2201/0873
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An integrated optical device for measuring the refractive index of a fluid comprises a light guide formed on a substrate and having a guiding layer for carrying light beams, inserted between a lower layer and an upper layer having refractive indices below that of the guiding layer. The device includes an interaction measurement zone of the light guide for coming into contact with the fluid, the upper layer at the measurement zone having a thickness less than the penetration distance of the evanescent wave of the guided light beam. Outside the interaction zone, that upper layer has a thinckness greater than the penetration distance of the same evanescent beam. The device also has an interferometric optical system at least partly formed in the light guide and having a reference optical circuit and a measurement optical circuit including the measurement zone, for measuring the phase shift introduced by an effective index change of the guided mode due to the fluid.