Abstract

In a previous paper we reported that the wavelength of a broadband laser without tuning elements is extremely sensitive to external power feedback. By using the confocal feedback technique one may exploit this effect for high resolution distance measurements.¹ Recently we discovered that with superluminescent laser diodes not only the wavelength, but also the bias current are sensitive to feedback. The feedback light need not to stay coherent with the light in the laser cavity, hence allows a feedback distance much longer than the short coherence length of superluminescent laser diodes. By detecting bias current instead of wavelength change, one eliminates dispersive optics and light paths which occupy space, and makes the whole measurement system compatible with integrated optics.

© 1994 Optical Society of America