# Polarimetry / PMD measurement

### Polarimetry

- Measurement of all 4 Stokes parameters, display on Poincaré sphere and in oscilloscope mode. Also available: power, normalized Stokes vector and degree-of-polarization (DOP).
- Three choices for the normalization of Stokes parameters/vectors:
- Standard: Normalized Stokes vectors are normalized to unit length. Regardless of power and DOP, they appear at the surface of the Poincaré sphere.
- Exact: Normalized Stokes vectors are normalized only with respect to optical power. For DOP<1 they appear inside the Poincaré sphere. Unpolarized light is displayed at the coordinate origin.
- Non-normalized: Display of the non-normalized Stokes parameters. This means, the DOP and the optical power determine the length of the displayed S1-S2-S3 Stokes vector.
- Only the PM1000 polarimeter is needed.

### Mueller and Jones matrix measurement

- In addition to the PM1000 polarimeter, an device for generating a number of polarization states is needed.
- This can be the EPS1000 polarization scrambler/transfomer or any other polarization state generator or scrambler which generates a repeatable sequence of polarization states and can be synchronized with the PM1000, for example by a trigger output or input or via USB. For simplicity you can use a PMS1000 polarimeter and polarization scrambler/transfomer
(= combination of PM1000 and EPS1000). - With PMS1000 or additional EPS1000, any specified polarization state can be generated.
- The Mueller matrix of the device under test is thus determined. Subsequent calculations yield:
- Mueller-Jones matrix (= the Mueller matrix made non-depolarizing) and Jones matrix
- Eigenmodes, retardation, mean loss and polarization-dependent loss (PDL)
- Decomposition of Mueller and Jones matrices into sequences SBA + PPPS + SBA. Definitions: PPPS = horizontal
**p**artial**p**olarizer and**p**hase**s**hifter. SBA =**S**oleil-**B**abinet = retarder having a retardation between 0 and π and eigenmodes anywhere on the S2-S3 great circle of the Poincaré sphere. See also here (Section II.A). An SBA does to horizontal polarization the same as a Soleil-Babinet compensator to circular polarization: partial or full mode conversion with adjustable phase shift.**a**nalog

### PMD measurement

- An optional tunable laser is built into the PM1000 polarimeter or PMS1000 polarimeter and polarization scrambler/transformer. Else, an available tunable laser is suitably controlled.
- This way Mueller and Jones matrices can be measured as a function of optical frequency, and PMD is determined.