Title :
Measurement of depolarization ratio and ultimate limit of polarization crosstalk in silica-based waveguides by using a POLCR
Author :
Takada, Kazumasa ; Mitachi, Seiko
Author_Institution :
NTT Opto-Electron. Labs., Ibaraki, Japan
fDate :
4/1/1998 12:00:00 AM
Abstract :
A polarization optical low coherence reflectometer (POLCR) is described that enables us to excite only the transverse electric (TE) mode of a test waveguide and to measure its Rayleigh backscatter signal distributions in the TE and transverse magnetic (TM) modes at a spatial resolution of 0.3 mm. The depolarization ratios of silica-based waveguides with relative refractive index differences of Δ=0.45 and 0.75% are obtained as 0.14 and 0.10, respectively, by measuring the bias in the ratio between the distributions in the TM and TE modes of each waveguide. By using the depolarization ratios and the Rayleigh backscatter signal levels, we calculate the ultimate polarization crosstalks to be -53 and -51 dB over 1 km, respectively. The actual polarization crosstalks of previously fabricated waveguides are about 50 dB higher than their ultimate limits for the same length of fiber
Keywords :
Rayleigh scattering; backscatter; light polarisation; measurement theory; optical crosstalk; optical planar waveguides; optical testing; optical time-domain reflectometry; refractive index; silicon compounds; 1 km; POLCR; Rayleigh backscatter signal distributions; Rayleigh backscatter signal levels; TE mode; actual polarization crosstalks; depolarization ratio measurement; depolarization ratios; polarization crosstalk; polarization optical low coherence reflectometer; relative refractive index differences; silica-based waveguides; spatial resolution; test waveguide; ultimate polarization crosstalks; Backscatter; Coherence; Crosstalk; Electric variables measurement; Optical polarization; Optical refraction; Optical variables control; Optical waveguides; Tellurium; Testing;
Journal_Title :
Lightwave Technology, Journal of
