A method for on-line, real-time detection of wavelength drifts in laser diodes is proposed. This technique uses the wavelength dependence of the differential propagation constant between the LP01/LPeven11 or LP01/LP02 modes in two-mode fibers to measure wavelength changes that manifest themselves as intensity modulation in the output far field. Theoretical calculations show that wavelength drifts of the order of 10-18 m can be resolved by this technique.
© 1995 Optical Society of America
Vikram Bhatia, Kent A. Murphy, Anbo Wang, Richard O. Claus, and Jonathan A. Greene, "Attometer resolution of wavelength shifts by use of fiber modal interferometers," Opt. Lett. 20, 97-99 (1995)