Atec Agilent-8169A User Manual

Agilent 11896A and 8169A
Polarization Controllers

Product Overview

Automatic polarization state adjustments for polarization­dependent loss measurements and polarization synthesis
applications

Agilent 11896A: 980 nm and 1250 to 1640 nm
Agilent 8169A: 1400 to 1640 nm

Introduction

Developing and manufacturing
competitive, high-value compo­nents and systems for today's
optical industries require precise
attention to polarization sensi­tivity. The Agilent 11896A and
8169A Polarization Controllers
can help by saving time, money
and effort when measuring
and working with polarization
sensitive devices.

Polarization sensitive devices
include EDFAs, single-mode
fiber, polarization maintaining
fiber, isolators, switches, lasers,
couplers, modulators, interfer­ometers, retardation plates and
polarizers. Device performance
will be affected by polarization­dependent efficiency, loss, gain
and polarization mode dispersion.

These polarization phenomena
enhance or degrade performance
depending on the application
area, be it communications,
sensors, optical computing or
material analysis.

An Important Part of a
Measurement System

A polarization controller is an
important building block of an
optical test system because it
enables the creation of all possible
states of polarization. The polar­ized signal stimulates the test
device while the measurement

system receiver monitors the
test device's responses to chang­ing polarization. Sometimes
polarization must be adjusted
without changing the optical
power. At other times, polari­zation must be precisely synthe­sized to one state of polarization
(SOP) and then adjusted to
another SOP according to a
predetermined path. Each of
these needs are met sep-arately
using the Agilent 11896A or
8169A Polarization Controllers
(refer to Table 1 for application
details).

Figure 1. Conceptual block diagram of polarization controller applications.

Polarization

Controller

Lightwave

Source

Agilent 11896A

or 8169A

?

Test

Device

Optical

Receiver

2

The Agilent 11896A
Polarization Controller

Measure very low PDL of DWDM
components

The Agilent 11896A motorized
polarization controller adjusts
polarization and not power. It’s
optical fiber loop design provides
all states of polarization with ex­tremely small optical insertion­loss variations (±0.002 dB) over
a wide spectral range (980 nm and
1250 to 1640 nm.) This performance
combination maximizes measure­ment accuracy for power sensitive
applications, such as polarization­dependent loss and gain, because
the measurement uncertainty
contributed by the polarization
controller is minimized. The 11896A
provides fast measurements of
DWDM components with a rota­tion rate of 360° in <0.5 seconds.

Figure 2. The Agilent 11896A
produces all states of polarization
and covers the entire Poincare
sphere1in a pseudo-random
manner.

Two Types of Polarization Controllers...

Figure 3. Agilent 11896A
Block Diagram

Figure 4. Orthogonal great circles
on the Poincare sphere1show how
the Agilent 8169A synthesizes
relative state-of-polarization points
according to a specified path.

Figure 5. Agilent 8169A
Block Diagram

1

The Poincare sphere is a three dimensional graphing system for viewing all possible states of polarization. Poincare sphere
display is provided by Agilent 8509A/B Lightwave Polarization Analyzer.

Optical

Input

Optical
Output

Linear

Polarizer

λ

/2

Plate

λ

/4

Plate

PDL measurement of DWDM components using Mueller
method is one of the main applications. The Mueller method
stimulates the test path with four precicely known states.
Precise measurement of the corresponding output intensities
allows calculation of the upper row of the Mueller matrix,
from which PDL is in turn calculated. This method is fast,
and ideal for swept wavelength testing of PDL.

The Agilent 8169A
Polarization Controller

´

The Agilent 8169A provides
polarization synthesis relative
to a built-in linear polarizer. The
quarter-wave plate and half-wave
plate are individually adjusted
to create all possible states of
polarization. Predeterministic
algorithms within the Agilent
8169A enable the transition path
from one state of polarization
on the Poincare sphere to another
to be specified along orthogonal great circles. These features
are important because device response data can be correlated
to specific states of polarization input to the test device.

λ

/4 Fiber Loop

Optical

Input

Optical
Output