Differences

This shows you the differences between two versions of the page.

--- d2:dbr_laser [2017/10/12 00:39] – [Inputs, Outputs, and Controls] Michael Radunsky
+++ d2:dbr_laser [2019/09/24 21:11] – [Inputs, Outputs, and Controls] Michael Radunsky
@@ Line 48: / Line 48: @@
 |Stage 2 Temperature of DBR Laser Diode|>15°C and <40°C|
 |Laser Diode Current|See datasheet included with your laser.|
+</WRAP>
+<WRAP center round important 60%>
+The laser should never be operated at a temperature below the dew point temperature for your laboratory conditions.  Condensation can form on the laser chip and/or mounting hardware resulting irreparable damage.
 </WRAP>
@@ Line 73: / Line 77: @@
 =====Inputs, Outputs, and Controls=====
-**Vertical and horizontal pointing **
-The vertical and horizontal alignment of the laser system is factory set and should not need adjustment.  However, if your specific application requires it or the system is misaligned, the DBR subassembly has adjustments to steer the beam for alignment to the spectroscopy module or other modules.  The beam pointing is adjusted by loosening the three lock screws ½ turn past the crack point and adjusting the x and y positioning set screws on the top and left side (facing out along the laser beam) of the module (see <imgref DBR_lock_screws>). For more detailed instructions, see  the [[#aligning_the_dbr_laser_module|alignment section]].
-<imgcaption DBR_lock_screws|Lock screws and beam pointing controls>
-{{ :d2:d2-100:dbr-lock-screws.png?nolink&300 |}}
-</imgcaption>
-**Beam Conditioning**
-The collimation of the output beam is set at the factory and should not be adjusted unless absolutely necessary.  Remove the isolator subassembly from the baseplate with the 4 screws accessible from the bottom.  The collimation can be adjusted by turning the lens.  A spanner wrench can be inserted into the two holes on the side of the black lens holder to adjust the lens.
-Laser diodes all have astigmatism, which means the horizontal and vertical axis have different foci.  Vescent uses a powerful asphere with a short focal length and an anamorphic prism pair to create a small diameter circular beam. This reduces the costs of the isolator and other downstream modules by reducing the clear aperture requirements.  While the aspheres and anamorphic prisms produce a circular beam, astigmatism dictates that a single lens will not simultaneously collimate both orthogonal axes of the beam with the result that in the far field the beam is again elliptical.
-The far-field pattern is the most important for ascertaining the quality of the diode output.  The near-field pattern often shows stray light from the diode waveguide and ASE that doesn't propagate as part of the primary beam.  However, aberrations and beam clipping due to an insufficient lens NA will show up as fringes-on the far field pattern.  Vescent has taken care in the design of the DBR laser module to keep aberrations and clipping to a minimum, resulting in a clean beam in the far field.
 **Cable Connector**
-The connections to the TECs and thermisters are made to an 8-pin Hirose connector (see <tabref TECconnectortable> for identity of connectors).  The pin definitions are:
+The connections to the TECs and thermistors are made to an 8-pin Hirose connector (see <tabref TECconnectortable> for identity of connectors).  The pin definitions are:
 <WRAP center round box 300px>
+<tabcaption 105_pinout| Pin assignment for 8-pin Hirose connector>
 ^  Pin  ^  Signal  ^
 |  1  |  TEC1+  |
@@ Line 107: / Line 93: @@
 |  7  |  Rth2  |
 |  8  |  Rth2-RTN  |
+</tabcaption>
 </WRAP>
 <WRAP round center box 320px>