A direct frequency-modulated (FM) laser diode light source without light power variation is developed. The amplitude variation of the FM laser diode is compensated by means of a feedback system with use of a superluminescent diode as an external light power controller. Output power greater than 1 mW is obtained at the modulation frequency to 5 kHz with a >10 stabilization factor. By use of the amplitude-stabilized FM laser diode, we measured subfringes with high accuracy in FM continuous wave interferometry, increased the dynamic range of the displacement measurement, and improved the stabilization factor in the laser diode feedback interferometer.
© 1997 Optical Society of America
[Optical Society of America ]
Yoshitaka Takahashi, Toshihiko Yoshino, and Nobuyuki Ohde, "Amplitude-stabilized frequency-modulated laser diode and its interferometric sensing applications," Appl. Opt. 36, 5881-5887 (1997)