Tsunami - Beckman Institute Laser Resource Center

Tsunami
Aligning the Photodiode PC Board ,
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Prior to aligning the photodiode pc board, the laser must meet power
specifications in order to provide enough signal for alignment. If the laser
cannot meet specifications, align the cavity. Refer to "Cavity Alignment"
earlier in this chapter.
Figure 6-1 1 shows the layout of the Tsunami photodiode pc board. It is
located directly over the beam splitter as shown in Figure 6-12. The
photodiode is a small, round can soldered to the bottom of the board and,
to align the photodiode to the reference beam from the beam splitter, the
pc board is adjusted slightly to center the photodiode in the beam. Looking
at the pc board from the output bezel, note that the right mounting
screw passes through a narrow slot to allow lateral movement while a
large rectangular slot under the left mounting screw allows movement in
all directions. The photodiode is called out as CR1 and is located just to the
right of the left mounting screw. To monitor the photodiode output signal
level as you move the board, observe the PHOTODIODE indicator on the
front of the Model 3955 electronics module.
1. Refer to Table 6-1 and verify the correct photodiode board is installed
for the wavelength you are using. The assembly part number is located
in the lower left comer below the photodiode (Figure 6-1 1). If the
correct board is installed, skip to step 3.
Photodiode PC Board
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Top View
J2
Photodiode
J1 Connect
Side View
Figure 6-11: Photodiode PC board