THORLABS ERM100, Operation Manual, Page: 16 / 59

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ERM100
3.7 Alignment of a PMF Patchcord
The alignment of a PMF patchcord can be performed also with a narrow bandwidth laser
source. However, there are two disadvantages using such a light source. The first is the manual
handling which is divided into a rotating and a pulling (stress) part. The second and main disad-
vantage is that with this method fibers which have a loose tube are difficult to handle.
Loose tube means that the fiber itself and the buffer (tube) are not fixed to each other over the
entire length. If someone pulls the buffer the fiber inside is not necessarily stressed in the same
way like the buffer.
Therefore, a broadband source like a SLED or ASE is more suitable for this task. The Extinc-
tion Ratio measurement of a PM fiber with a SLED can be done in the following way:
1. The output of the PM fiber is entered to the input of the ERM100 and the ERM100 is
switched on.
2. Connect the SLED to the input of the fiber bench with the polarizer.
3. Connect the input of the PM fiber to the output of the fiber bench.
4. Toggle to the ER display by pressing the button
'SET' .
5. Rotate the input of the PM fiber in respect to the fiber bench until a maximum ER value is
displayed. Typically values between 20dB and 30dB are desired.
6. The shown ER value in the ER display represents the minimum ER value.
3.8 Aligning the connectors key to a main axis of a PM fiber
The alignment of the connectors key can also be done using the ERM100. There are several
ways to perform this alignment depending on the type of connector and the equipment used to
assemble a connector to a fiber.
Assuming the connector is already assembled to fiber and the key can still be moved the align-
ing can be performed as follows:
1. Couple linear polarized light into the main axis which has to be aligned to the connectors
key.
2. Toggle to the ER display by pressing the 'SET' button.
3. Rotate the connector until the displayed misalignment angle shows 0°.
Lock the key in the respect to the connector with adhesive or another adequate method.