195
Performance Tests
V. Polarization Dependent Loss (PDL): Optional
a. Select the λ/2 Retarder Plate.
Press λ/2
b. Modi fy the λ/2 plate setting to the same angle as the
polarization filter found in item 6c.
c. Press ENTER
d. Note the angle as "λ/2 Plate Setting, Linear Horizontal
Polarization" in the Test Recor d.
Determine settings for Linear Vertical, Linear Diagonal, and
Right Hand Circular Polarization
9. In order to get the required polarization, the λ/2 and λ/4 retarder
plates need to be set to the appropriate values. The corrected
positions of the polarizer plates depend on the actual wavelength
and have to be taken fr om Table D-3.
In the case of Linear Horizontal polarized light no correction is
to be done. The tab le lists cor rections fo r every 20 n m step . For
wavelengths between listed values, a linear approximation
should be used.
The value taken from the table (possible by approximation) is to
be added to the values of the λ/4 and λ/2 retarder plate setting for
Linear Horizontal polarized light determined in steps 7. and 8.
respectively:
• Get the values for the wavelength dep endent offset
positions for each type of polarization from Table D-3.
• Add these values to those for Linear Horizontal polarized
light.
• Note the calculated "corrected wavelength dependent
position" values in the Test Record for the λ/4 Plate
Setting and the λ/2 Plate setting for Linear Vertical,
Linear Diagonal and Right Hand Circular polarization.
Example: actual wavelength 1552 nm. Find the maxim um
transmission for the Linear Horizontal polarized light at a
polarization filter setting of 15.4°.
In Table D-3, wavelength dependent positions can be found and