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d2:laser_controller [2019/03/07 14:47]
Michael Radunsky
d2:laser_controller [2019/03/25 16:21] (current)
Michael Radunsky
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 **Temp Servo Input (BNC)** **Temp Servo Input (BNC)**
  
-The temperature servo input is summed to the T2 temperature set point signal and can be used to make electronic perturbations to the laser diode temperature. ​ The Temp Servo Input, has two settings: "​Low"​ and "​High"​ gain. The default settings is "​Low"​ but can be changed by a switch accessible on the right side panel. ​+The temperature servo input is summed to the T2 temperature set point signal and can be used to make electronic perturbations to the laser diode temperature. ​ The Temp Servo Input, has two settings: "​Low"​ and "​High"​ gain. The default settings is "​Low"​ but can be changed by a switch accessible on the right side panel. ​See <imgref VPN00267>​. 
 + 
 +<WRAP center round box 570px><​imgcaption VPN00267|Temp control board with T2 Temp Servo Input gain switch circled>​[{{ d2:​d2-105:​vpn00267.gif?​nolink&​550 | filler text }}]</​imgcaption></​WRAP>​
  
 When the gain is set to "​LOW",​ the slope for changing the set point is  ~95 mK/V. When the gain is set to "​LOW",​ the slope for changing the set point is  ~95 mK/V.
  
-When the gain is set to "​HIGH",​ turn the set point to the lowest desired temperature. Apply a voltage between -10V and 10V to TEMP SERVO INPUT to adjust the set point temperature. With this configuration,​ you can sweep the set point all the way from the low-temperature limit (-1°C) to the high-temperature limit (58°C). //NOTE that the Vescent Photonics Lasers should not be operated above 50°C.// The slope for changing the set point is ~9 K/V. +When the gain is set to "​HIGH",​ turn the set point to the lowest desired temperature. Apply a voltage between -10V and 10V to TEMP SERVO INPUT to adjust the set point temperature. With this configuration,​ you can sweep the set point all the way from the low-temperature limit (-1°C) to the high-temperature limit (58°C). //NOTE that the Vescent Photonics Lasers should not be operated above 50°C or below the dew point for your laboratory conditions.// The slope for changing the set point is ~9 K/V. 
  
 The "​Low"​ mode is designed for slow temperature feedback for long-term (days) stability of the locked laser. ​ Normally the Temp Servo Input is used to drive the dc value from the Current Servo Ouput on the Laser Servo to zero over long time scales. ​ In other words, temperature tuning is used to remove large, slow variations in the laser frequency. ​ To accomplish this, connect the Temp Servo Output from the Laser Servo module to the Temp Servo Input of the Laser Controller (with TEMP SERVO INPUT Gain is set to "​Low"​). ​ This connection is only important if the user is trying to maintain a laser lock continuously over many days or even weeks. ​ Without feedback to Temp Servo In the Laser Servo can eventually run out of range. ​ The "​Low"​ mode is designed for slow temperature feedback for long-term (days) stability of the locked laser. ​ Normally the Temp Servo Input is used to drive the dc value from the Current Servo Ouput on the Laser Servo to zero over long time scales. ​ In other words, temperature tuning is used to remove large, slow variations in the laser frequency. ​ To accomplish this, connect the Temp Servo Output from the Laser Servo module to the Temp Servo Input of the Laser Controller (with TEMP SERVO INPUT Gain is set to "​Low"​). ​ This connection is only important if the user is trying to maintain a laser lock continuously over many days or even weeks. ​ Without feedback to Temp Servo In the Laser Servo can eventually run out of range. ​
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 When disconnected,​ the SETPOINT ENABLE is at 5 V. When disconnected,​ the SETPOINT ENABLE is at 5 V.
 +
 +The Servo Input on the front panel continues to function when the SETPOINT ENABLE is pulled low.
  
 =====Turning on the Laser Diode===== =====Turning on the Laser Diode=====
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 To reset the temperature loop parameters to the approximate settings for a Photodigm TOSA DBR Laser: To reset the temperature loop parameters to the approximate settings for a Photodigm TOSA DBR Laser:
   - The T1 loop is not used as the TOSA only has one TEC.   - The T1 loop is not used as the TOSA only has one TEC.
-  - Set the dip switches to the configuration shown in <tabref factory_set2_post6987_TOSA>​. ​+  - Set the T2 dip switches to the configuration shown in <tabref factory_set2_post6987_TOSA>​. ​
   - Measure the resistance across GND5 and probe point GAIN2. Set this resistance to between 1.01 kΩ and 1.03 kΩ by adjusting trimpot PROPGAIN2.   - Measure the resistance across GND5 and probe point GAIN2. Set this resistance to between 1.01 kΩ and 1.03 kΩ by adjusting trimpot PROPGAIN2.
  
d2/laser_controller.1551998827.txt.gz · Last modified: 2019/03/07 14:47 by Michael Radunsky