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APA , OFR’s Automatic Polarization Analyzer, is a pre-calibrated, high speed, highly accurate, automated, polarimeter with no moving parts. The small, completely self-contained system gives fast, repeatable measurements of the State of Polarization (SOP) of light in an optical fiber from any source. The APA includes a sensor head, a serial cable, a power supply and user-friendly software. An optical fiber connects to the sensor head on the input end, and data is transferred to the computer via a serial cable on the output end. Power is provided by an A/C power supply. The software calculates the polarimetric quantities of the optical signal and displays the SOP numerically as well as on a dynamic and configurable Poincare Sphere.

What is polarization, and why is it important?

The state of polarization (SOP) of an optical signal is defined by the relative amplitudes and phases of its electric field components. As a signal propagates, it interacts with optical components and other optical signals which modify the magnitude and phase of the electric field of the signal. Polarization effects are the dominant limitation of system performance in fiber optic systems. Therefore, knowledge of the SOP of an optical signal is extremely important. Although polarization is sometimes exploited, as in an isolator or circulator, it is generally considered to be a negative influence. For this reason, precise knowledge of the state of polarization is necessary for optimal performance of an optical system.


The APA is designed based on division of amplitude polarimetry. The input light is split into several paths, and each path passes through a different optical medium. The Stokes Parameters are then calculated from the difference of intensity responses of each path.


An optical fiber is connected to the input receptacle on the sensor head. The collimated beam then transmits through the optical components to the detectors in the system. The intensities are measured, the data is sent to the computer, and the software calculates all of the polarmetric data.



Data Analysis
The software calculates and displays
the following quantities:
• Stokes Parameters
• Degree of polarization (DOP)
• Degree of linear polarization (DOLP)
• Degree of circular polarization (DOCP)
• Polarization ellipse
• Ellipticity
• Orientation angle
• Poincare Sphere

The data is updated at a rate of up
to 200Hz. The user has the option
of recording the Stokes Parameters
to an output file. The output file
contains the total power, the Stokes
Parameters, and the degrees of total,
linear, and circular polarization. In
addition, the output file stores wavelength,
the sample rate of the data,
and the date and time of the test.
The Poincare Sphere can be saved
as a bitmap file.


An application of the APA is the measurement of polarization-dependent loss (PDL). The software has abuilt-in PDL measurement. The software calculates the PDL of a fiber device when the input polarization to that device is scrambled using a polarization controller or by tapping the input fiber.

User Calibration

The APA, like all fiber polarimeters, does not measure the absolute SOP of the light from the input fiber tip into the detector head. In order to take absolute measurements of the SOP from a specific point, the APA first requires a user calibration to remove the polarization effect of the input fiber. The user calibration is straightforward: known polarization states are input into the fiber that is connected to the polarimeter head. The calibration routine then tells the polarimeter which polarization states are being input. This creates a polarization reference frame at that calibration point.

LabVIEW drivers are available.

Wavelength 1510 - 1570nm ( 1460 - 1640nm, inquire)
Input Optical Power Range 20nW - 5mW
Measurement Rate 200Hz (Inquire for faster rates)
Connector Type FC/PC (FC/APC with Adaptor)
Stokes Parameter Accuracy ± 0.01
DOP Accuracy ± 1%
Ellipticity Accuracy 0.01
Azimuth Accuracy < 0.33°
Dimensions 85mm x 76mm, 35mm Thick
Minimum System Requirements 500Mhz, 64MB RAM, Win98 or later
Line Voltage 110VAC / 230VAC
Line Frequency 50Hz / 60Hz
Storage Temperature -30 - 70C
• A/D board, optical system, and electronics integrated into compact polarimeter head
• Cable for connecting the sensor head to the PC serial port
• Wall power supply (115VAC, output 9VDC, 100mA)
• User-friendly software
• Extension serial cable
• Calibration report
• User manual
FFBM-S-1550-X Medium FiberBench with input and output FiberCables


Catalog Number Description
APA-1510/1570 Polarimeter for 1510nm to 1570nm


Optics for Research · Ph 973-579-7227 · Fax 973-300-3600 · Email: info@ofr.com