Single sweep polarization dependent loss measurement

A polarization scan module comprising:

• a swept-wavelength optical source providing a light signal that sweeps over a range of optical wavelengths, the light signal having a state of polarization;
• and
• a first optical stage having a first eigenstate to which the light signal is input, the state of polarization being oriented at a first angle with respect to the first eigenstate, and providing a first output light signal;
• and
• a second optical stage having a second eigenstate to which the first output light signal is input, the first eigenstate and second eigenstate being oriented at a second angle relative to each other, and providing a second output light signal as a test optical signal, the relative optical lengths and orientations of the two optical stages being such as to cause the state of polarization to rotate over a Poincare sphere as the light signal changes wavelength within the range to produce the test optical signal.

A single sweep polarization dependent loss measurement system comprising:

• means for rotating a state of polarization for a light signal over a Poincare sphere as the light signal sweeps over a range of optical wavelengths;
• means for measuring an optical power for the state of polarization at four different orientations within the range of optical wavelengths at both an input and an output of an optical component being tested;
• and
• means for computing polarization dependent loss for the optical component as a function of the measured optical powers and corresponding known wavelengths of the state of polarization at the four different orientations.

A method of measuring polarization dependent loss using a swept-wavelength optical source comprising the steps of:

• at a start optical wavelength of a light signal from the optical source measuring a state of polarization and transmitted optical power at an input and output of an optical component being tested;
• changing the state of polarization for the light signal at a new optical wavelength so as to cause the state of polarization to rotate over a Poincare sphere;
• measuring the state of polarization and transmitted optical power for the optical component at the input and output at the new optical wavelength;
• repeating the changing and measuring steps until sufficient different states of polarization and transmitted optical powers are measured to provide a set of measurement data;
• and
• calculating from the set of measurement data the polarization dependent loss for the optical component.

A single sweep polarization dependent loss measurement system comprising:

• a polarization rotator that rotates a state of polarization for a light signal over a Poincare sphere as the light signal sweeps over a range of optical wavelengths;
• a detector system that measures an optical power for the state of polarization at four different orientations within the range of optical wavelengths at both an input and an output of an optical component being tested;
• and
• a processor that computes polarization dependent loss for the optical component as a function of the measured optical powers and corresponding known wavelengths of the state of polarization at the four different orientations.