Title :
Reflection-type delayed self-homodyne/heterodyne method for optical linewidth measurements
Author :
Iiyama, Koichi ; Hayashi, Ken-Ichi ; Ida, Yoshio ; Ikeda, Hitoshi ; Sakai, Yoshihisa
Author_Institution :
Dept. of Electr. & Comput. Eng., Kanazawa Univ., Japan
fDate :
5/1/1991 12:00:00 AM
Abstract :
The reflection-type delayed self-homodyne (RDSH) method presently described is based on the same principle as the delayed self-homodyne/heterodyne (DSH) method but no beam splitter or fiber coupler is required. The delayed beam is produced by utilizing a round-trip propagation passing through a solitary long optical fiber delay line. Therefore, the optical configuration is very simple, and the beat signal has a resolution twice that of the DSH method. However, the RDSH method´s drawback is that a large intensity difference between the two beams reduces the level of the beat signal. This can be improved by increasing the reflectivities of the fiber ends by dielectric coating. In this case, multiple reflection at the fiber ends should be taken into account
Keywords :
fibre optic sensors; laser variables measurement; reflectometry; spectral line breadth; beat signal; delayed beam; dielectric coating; fiber ends; multiple reflection; optical configuration; optical linewidth measurements; reflection type delayed self-homodyne/heterodyne method; reflectivities; round-trip propagation; solitary long optical fiber delay line; Delay lines; Dielectrics; Optical coupling; Optical fiber couplers; Optical fibers; Optical mixing; Optical propagation; Propagation delay; Reflectivity; Signal resolution;
Journal_Title :
Lightwave Technology, Journal of