Title :
Helical-grating two-mode fiber spatial-mode coupler
Author :
Poole, Craig D. ; Townsend, C.D. ; Nelson, Katherine T.
Author_Institution :
AT&T Bell Lab., Homdel, NJ, USA
fDate :
5/1/1991 12:00:00 AM
Abstract :
The authors investigate a helical-grating geometry for coupling the spatial modes in a two-mode fiber. The feasibility of making fiber grating filters based on this geometry is investigated. By adding mode strippers at the input and output of a helical-grating spatial-mode coupler, an optical notch filter is demonstrated with 0.3-dB waveguide loss, 24-dB extinction, and 24-nm spectral width. The effect of small ellipticity in the fiber core is also investigated, and it is shown that polarization-insensitive coupling can be achieved in a fiber with a sufficiently circular core
Keywords :
diffraction gratings; fibre optics; optical couplers; optical losses; spatial filters; 0.3 dB; circular core; ellipticity; extinction; fiber core; fiber grating filters; helical-grating geometry; helical-grating spatial-mode coupler; input; mode strippers; optical notch filter; output; polarization-insensitive coupling; spectral width; waveguide loss; Fiber gratings; Fiber nonlinear optics; Optical fiber communication; Optical fiber couplers; Optical fiber devices; Optical fiber filters; Optical fiber polarization; Optical filters; Optical sensors; Optical waveguides;
Journal_Title :
Lightwave Technology, Journal of
