81199A Datasheet, PDF (8/17 Pages) Keysight Technologies – Wideband Waveform Center

08 | Keysight | 81195A Optical Modulation Generator Software - Data Sheet
PMD emulation (#OSP)
Overview
Generally the term polarization mode dispersion (PMD) describes an optical effect that
is present when light passes through a concatenation of birefringent elements. It can be
represented by a vector, τ^ ,which points in the direction of the system’s slow principal
state (PSP), p^, and its length is the differential group delay (DGD), τ , between the slow
and the fast PSP. The PMD vector τ^ itself is a frequency-dependent parameter and thus
should be not mixed up with the mean differential group delay of an optical fiber, which is
a statistical scalar value and also often referred to as PMD value in literature.
( ) ( ) The vector difference between two PMD vectors ^{τ ω} and τ^ ω for ^{ω − ω → 0}
is defined as second-order PMD (SOPMD) vector, τ^_ω
1
. Its
parallel
2
1
component,
τ^ _ω
2
, is
referred to as polarization-dependent chromatic dispersion (PDCD) and the perpendicular
component, τ^_ω⊥ , as depolarization.
Implementation: Emulates standard model of concatenation of birefringent elements with
constant length and adjustable axis rotation and output phase. Realized with complex
butterfly FIR filter structure
–– 32 GBaud: Up to 7 segments/taps with 31.25 ps DGD each (at fs = 64 GSa/s)
–– 16 GBaud: Up to 14 segments/taps with 31.25 ps DGD each (at fs = 64 GSa/s)
Load pre-defined states (Zero DGD, minimum pure first order, minimum first order,
maximum first order, random)
Addressable PMD range (at 64 GSa/s, 32 GBaud)
–– Max. DGD: 218.75 ps
–– Second-order PMD: > 11000 ps²
Display
Scalar characteristics: PMD, SOPMD, depolarization, PCD
Spectral characteristics: DGD, SOPMD
s₃
s₃
s₂
p^{^} (ω₁)
s₂
s₁
τ
p^{^}
→_{τ (ω)}
Figure 1. PMD vector in Stokes space
0
ω₁
Frequency
ω₂
Figure 3.DGD spectrum
s₁
p^{^} (ω₂)
Figure 2. PSP spectrum
→_{τ ω}
→_{τ ω||}
→_{τ ω⊥}
→_{τ (ω2)}
→_{τ (ω1)}
Figure 4. Definition of second-order PMD (SOPMD) vector