An important use of the self-mixing effect inside a frequency-modulated single-mode laser diode is in laser velocimetry and range-finding applications. The optical beam reflected by a target and injected into the laser diode cavity modulated by a reshaped current is mixed with the light inside the cavity, causing variations of the optical output power. A theoretical analysis of this effect is proposed, based on the determination of the beat frequencies of the optical power variations, to improve the accuracy of laser distance measurement. A resolution of ∓1.5 mm from 50 cm to 2 m is obtained when thermal effects are taken into account.
© 1998 Optical Society of America
[Optical Society of America ]
(120.4290) Instrumentation, measurement, and metrology : Nondestructive testing
(120.4630) Instrumentation, measurement, and metrology : Optical inspection
(130.6010) Integrated optics : Sensors
(150.5670) Machine vision : Range finding
Flore Gouaux, Noël Servagent, and Thierry Bosch, "Absolute Distance Measurement with an Optical Feedback Interferometer," Appl. Opt. 37, 6684-6689 (1998)