d2:laser_controller
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d2:laser_controller [2020/05/04 19:02] – Michael Radunsky | d2:laser_controller [2020/10/29 21:09] – Michael Radunsky | ||
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[[http:// | [[http:// | ||
- | ===== Description: | + | ==== Description: |
The laser controller has two temperature controllers capable of sub-mK stability(( Sub-mK stability requires a proper thermal design and proper tuning of the temperature controller to the thermal plant. If you did not purchase a D2-100 Diode Laser with your Laser Controller, please read the section on tuning the temperature controller.)) and a 200 mA or 500 mA precision current source based on the Libbrecht-Hall(( Libbrecht and Hall, A Low-Noise, High-Speed Current Controller, Rev. Sci. Inst. 64, pp. 2133-2135 (1993).)) circuit. | The laser controller has two temperature controllers capable of sub-mK stability(( Sub-mK stability requires a proper thermal design and proper tuning of the temperature controller to the thermal plant. If you did not purchase a D2-100 Diode Laser with your Laser Controller, please read the section on tuning the temperature controller.)) and a 200 mA or 500 mA precision current source based on the Libbrecht-Hall(( Libbrecht and Hall, A Low-Noise, High-Speed Current Controller, Rev. Sci. Inst. 64, pp. 2133-2135 (1993).)) circuit. | ||
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- | ===== Purchase Includes: | + | ==== Purchase Includes: ==== |
<WRAP group> | <WRAP group> | ||
<WRAP half column> | <WRAP half column> | ||
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</ | </ | ||
- | ===== Absolute Maximum Ratings | + | ==== Absolute Maximum Ratings ==== |
Note: All modules designed to be operated in laboratory environment | Note: All modules designed to be operated in laboratory environment | ||
<WRAP center round box 60%> | <WRAP center round box 60%> | ||
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</ | </ | ||
- | =====Specifications===== | + | ====Specifications==== |
<WRAP center round box 550px> | <WRAP center round box 550px> | ||
^ ^ D2-105 | ^ ^ D2-105 | ||
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</ | </ | ||
- | ===== Inputs, Outputs, and Controls | + | ==== Inputs, Outputs, and Controls ==== |
[{{ : | [{{ : | ||
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<WRAP center round tip 80%> | <WRAP center round tip 80%> | ||
- | If the LED indicator does not turn on when the Laser ON-OFF/ | + | If the LED indicator does not turn on when the Laser ON-OFF/ |
If the LED indicator turns on for ~5 seconds and then turns off, check your laser diode connection to see if it is open (or if the diode is backwards). | If the LED indicator turns on for ~5 seconds and then turns off, check your laser diode connection to see if it is open (or if the diode is backwards). | ||
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**Laser Temp Output (8-pin connector)** | **Laser Temp Output (8-pin connector)** | ||
- | An 8-pin Hirose connector (see <tabref TECconnectortable> | + | An 8-pin Hirose connector (see <tabref TECconnectortable> |
<WRAP round center box 230px>< | <WRAP round center box 230px>< | ||
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The Servo Input on the front panel continues to function when the SETPOINT ENABLE is pulled low. Only the Coarse and Fine Current Adjustments are disabled. | The Servo Input on the front panel continues to function when the SETPOINT ENABLE is pulled low. Only the Coarse and Fine Current Adjustments are disabled. | ||
- | =====Turning on the Laser Diode===== | + | ====Turning on the Laser Diode==== |
In compliance with FDA requirements for a Class 3B laser, the Laser Controller has two safety interlocks. If either interlock is tripped, the laser will turn off and stay off until the interlocks are reset AND the laser switch is switched from the "off / reset" position to the " | In compliance with FDA requirements for a Class 3B laser, the Laser Controller has two safety interlocks. If either interlock is tripped, the laser will turn off and stay off until the interlocks are reset AND the laser switch is switched from the "off / reset" position to the " | ||
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To get good temperature stability, the temperature servo response needs to be tuned to match the thermal load. Access to tuning the temperature response is provided on the right side panel of the Laser Controller and requires removing that side panel to access the controls. The Laser Controller provides two independent temperature controllers that are nominally identical. However, stage 2 has front panel adjustment of the temperature set-point, while the stage 1 temperature set-point is a side-panel adjustment. Additionally, | To get good temperature stability, the temperature servo response needs to be tuned to match the thermal load. Access to tuning the temperature response is provided on the right side panel of the Laser Controller and requires removing that side panel to access the controls. The Laser Controller provides two independent temperature controllers that are nominally identical. However, stage 2 has front panel adjustment of the temperature set-point, while the stage 1 temperature set-point is a side-panel adjustment. Additionally, | ||
- | ====Transfer Function and Poles==== | + | ===Transfer Function and Poles=== |
Each stage of temperature control has a transfer function shown below: | Each stage of temperature control has a transfer function shown below: | ||
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< | < | ||
</ | </ | ||
- | ====User Control of the Poles and Gain==== | + | ===User Control of the Poles and Gain=== |
- | If you remove the right side panel on the Laser Controller, for each stage of temperature control, you will see the panel shown in <imgref side_adjustb> | + | If you remove the right side panel on the Laser Controller, for each stage of temperature control, you will see the panel shown in <imgref side_adjustb> |
Similarly, the switches labeled " | Similarly, the switches labeled " | ||
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- | ====Tuning the Thermal Loop==== | + | ===Tuning the Thermal Loop=== |
Although there are numerous methods for tuning the loop parameters, these instructions will use the Ziegler-Nichols tuning method. | Although there are numerous methods for tuning the loop parameters, these instructions will use the Ziegler-Nichols tuning method. | ||
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//NOTE: Depending on the thermal design, nested temperature loops can fight each other, causing oscillations and instability. If you observe this, you will need to reduce the gain and/or increase the time-constants on the slower stage. // | //NOTE: Depending on the thermal design, nested temperature loops can fight each other, causing oscillations and instability. If you observe this, you will need to reduce the gain and/or increase the time-constants on the slower stage. // | ||
- | ====Tuning Temperature Loop for Photodigm Mercury Lasers==== | + | ===Tuning Temperature Loop for Photodigm Mercury Lasers=== |
If you are using the D2-105 laser controller to drive a Photodigm Mercury laser in a TOSA package, the following may be helpful as a starting point for setting the thermal control loop parameters.((Courtesy of [[http:// | If you are using the D2-105 laser controller to drive a Photodigm Mercury laser in a TOSA package, the following may be helpful as a starting point for setting the thermal control loop parameters.((Courtesy of [[http:// | ||
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If the Temperature with the above TIME settings begins to run away, then quickly turn the “PROPGAIN” Potentiometer CCW until it stabilizes. | If the Temperature with the above TIME settings begins to run away, then quickly turn the “PROPGAIN” Potentiometer CCW until it stabilizes. | ||
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+ | We use [[https:// | ||
+ | [[https:// | ||
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d2/laser_controller.txt · Last modified: 2024/03/27 15:33 by Thomas Bersano