Click to Enlarge
Click for Raw Data
Extinction Ratio Meter Responsivity

Features

• Polarization Extinction Ratio (PER) Measurements of Polarization-Maintaining (PM) Fibers
• Measures PER up to 40 dB at Peak Wavelength
• Three Wavelength Ranges Cover from 400 nm - 2500 nm:
  • 400 nm - 700 nm (Item # ERM210)
  • 600 nm - 1600 nm (Item # ERM200)
  • 1200 nm - 2500 nm (Item # ERM220)
• Control Via Front Panel Display or USB Interface
• Exchangeable Fiber Connector Adapters Sold Separately
• Supported Connectors: Wide- and Narrow-Key FC/PC, Wide- and Narrow-Key FC/APC, LC/PC, and SC/PC

Common Applications

• Optimized Coupling of Linearly Polarized Light into PM Fibers
• Alignment to Connector Key
• Pigtailing (Alignment of Laser Diodes to PM Fibers)
• Active Alignment for PM Fiber Splicing

The ERM2xx Extinction Ratio Meters measure the polarization extinction ratio (PER) and the polarization angle of polarization-maintaining (PM) fibers. These easy-to-use benchtop devices are useful in alignment applications such as connectorization of PM fibers or pigtailing of laser diodes with PM fibers. A rotating polarizer in conjunction with a photodiode for light detection provides fast and accurate measurements of the PER of PM fibers. Additionally, the polarization angle and the power of the input light beam is measured. Three units are available covering wavelengths from 400 nm to 2500 nm: 400 nm - 700 nm (Item # ERM210), 600 nm - 1600 nm (Item # ERM200), and 1200 nm - 2500 nm (Item # ERM220). For active alignment of PM Fibers, the ERM2xx devices have a Monitor Output with 0.1 V/dB conversion factor, which is compatible with our Vytran^® PM Fusion Splicers.

Connector Accessories
The front panel features a port that accepts exchangeable fiber connector adapters (sold separately). This enables the extinction ratio meters to measure fibers in FC/PC, FC/APC, LC/PC, and SC/PC connectors. To discuss custom connector options not available below, please contact Tech Sales.

Module Control
The ERM2xx devices can be controlled via the display and control knob on the front panel. The back of the extinction ratio meter includes a power inlet with a fuse compartment, a banana jack for use with a ground pin, and a BNC for monitor output. See the Front & Back Panel tab for details. In addition, a USB Type B connector allows remote operation using software written by the user in C, C++, C#, LabVIEW™, LabWindows™/CVI, or Visual Studio (see the Driver Package tab).

All technical data are valid at 23 ± 5 °C and 45 ± 15% relative humidity (non-condensing).

Item #	ERM210	ERM200	ERM220
Wavelength Range	400 nm - 700 nm	600 nm - 1600 nm	1200 nm - 2500 nm
Peak Wavelength	700 nm	1550 nm	2300 nm
Maximum Input Powera	+13 dBm	+13 dBm	+8 dBm
PER Resolution	0.1 dB (Display) 0.01 dB (USB)
PER Rangea	0 to 40 dB (for +13 dBm to -12 dBm) 0 to 30 dB (for -12 dBm to -27 dBm) 0 to 20 dB (for -27 dBm to -37 dBm)	0 to 40 dB (for +13 dBm to -12 dBm) 0 to 30 dB (for -12 dBm to -27 dBm) 0 to 20 dB (for -27 dBm to -37 dBm)	0 to 40 dB (for +8 dBm to -12 dBm) 0 to 30 dB (for -12 dBm to -27 dBm) 0 to 20 dB (for -27 dBm to -37 dBm)
PER Accuracy	<0.5 dB
Polarization Angular Resolution	0.1° (Display) 0.01° (USB)
Accuracy of Polarization Angle	<0.5°
Measuring Speed	Approximately 10 Hz
Responsivity (Click for Graph)	Raw Data	Raw Data	Raw Data
Connector Type	M12 x 0.5 Thread for: ERM2F (Wide-Key, 2.2 mm FC/PC) ERM2F2 (Narrow-Key, 2.0 mm FC/PC) ERM2A (Wide-Key, 2.2 mm FC/APC) ERM2A2 (Narrow-Key, 2.0 mm FC/APC) ERM2L (LC/PC) ERM2S (SC/PC)
Monitor Output
Voltage Output	0 V to 5 V (High-Z, Conversion Factor 0.1 V/dB)
Accuracy	±10 mV (Typ.) ±50 mV (Max)
General
Interface	USB Type B
Display	2.42" OLED
AC Input	Universal, 110 V to 220 V, 50/60 Hz
Power On Warm-Up Time	15 minutes
Operating Temperature Rangeb	5 °C to 40 °C
Storage Temperature Range	-20 °C to 40 °C
Relative Humidity	Max 80% up to 31 °C, Decreasing to 50% at 40 °C
Dimensions (W x H x D)	153.2 mm x 85.4 mm x 188.8 mm (6.03" x 3.36" x 7.43")
Weight	1.05 kg

• At Peak Wavelength
• Non-Condensing

Click to Enlarge
Experimental Setup to Align a PM Fiber's Slow Axis with the Transmission Axis of a Polarizer

Light Source Considerations

For common applications using the ERM2xx, Thorlabs recommends the use of a broadband light source such as Amplified Spontaneous Emission (ASE) or Superluminescent Diodes (SLD) rather than a narrowband source to simplify the alignment procedure. Narrowband sources can be used with additional steps. For more details, see the manual.

Example: Aligning a PM Fiber Patch Cable to a Polarizer's Transmission Axis

A PM fiber patch cable can be aligned to the transmission axis of a polarizer using one of the ERM2xx Extinction Ratio Meters, an SLD, and a FiberBench equipped with a polarizer and a FiberPort by following the procedure below:

1. Connect the output connector of the fiber under test to the fiber adapter on the ERM2xx unit and turn on power.
2. Connect the SLD to the input of the FiberBench with the polarizer.* This will produce polarized light at the output of the FiberBench to which the PM patch cable will be aligned.
3. Connect the input of the PM fiber into the output of the FiberBench.
4. Navigate through the menu items until the ER value is shown on the digital display. Consult the manual for details.
5. Rotate the input of the PM fiber relative to the polarizer's transmission axis mounted in the FiberBench until a maximum ER value is displayed. At the point of maximum ER, the slow axis of the fiber patch cable is aligned with the transmission axis of the polarizer in the FiberBench.

*The coupling optics required are dependent on the light source and are not illustrated here.

Item #s ERM200, ERM210, and ERM220 include the following:

• Extinction Ratio Meter
• USB 2.0 Cable Type A-B, 2 m
• Region-Specific Power Cord
• Test Report
• Quick Reference Manual