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T-Cube Position Aligner
In order for the system to operate correctly in different applications, various software
settings (explained in Section 6.2.) may need to be adjusted. However, the default
settings should allow the position aligner to be operated in most cases, straight out of
the box without the need for a PC.
4.2
Detector Head Descriptions
The TPA101 unit is compatible with quadrant detector heads and lateral effect
sensors. Quadrant detectors are used primarily for beam alignment whereas lateral
effect sensors are normally used for position measurement. However, the TPA101
can be used with either type of sensor for both auto-alignment and position
measurement. Both types of sensor output three voltages (XDiff, YDiff and SUM) that
are proportional to the position of the beam and the total optical power, however,
lateral effect sensors like the PDP90A have a defined accurate relationship between
these three voltages. Furthermore, if the user selects the PDP90A sensor type in the
settings panel (see Section 6.2.) the displays shows the XPos and YPos values in
millimeters, whereas if the PDQ80A or PDQ30C sensor type is selected, the display
shows the XDiff and YDiff values that the sensor outputs in Volts. The TPA101 always
reads the voltages, but additionally for the PDP90A sensor, it is capable of calculating
the exact X, Y position from these voltages.
Caution
The TPA101 must be calibrated before it can be used with the PDP90A as
a position measurement tool, so that the analog voltages are read
accurately. New units are calibrated at the factory before shipment.
Existing units (i.e. those units running embedded code V1.0.3 or earlier)
must be returned to the factory for recalibration. Although upgrading the
embedded code on these earlier units will enable the position
measurement functionality, significant positional error s will occur.
Contact Thorlabs for more details.
