| Both sides previous revisionPrevious revisionNext revision | Previous revisionNext revisionBoth sides next revision |
| d2:laser_controller [2018/11/26 19:53] – Michael Radunsky | d2:laser_controller [2019/03/25 21:41] – Michael Radunsky |
|---|
| </WRAP> | </WRAP> |
| |
| | |
| | =====Purchase Includes:===== |
| <WRAP group> | <WRAP group> |
| <WRAP half column> | <WRAP half column> |
| =====Purchase Includes:===== | |
| * D2-105 Laser Controller | * D2-105 Laser Controller |
| * D2-007 Laser Controller Breakout Board (See <imgref 007>.) | * D2-007 Laser Controller Breakout Board (See <imgref 007>.) |
| </WRAP> | </WRAP> |
| <WRAP half column> | <WRAP half column> |
| |
| |
| <WRAP round box 250px><imgcaption 007|D2-007 Breakout board.>{{ :d2:d2-105:d2-007.jpg?200}}</imgcaption> | <WRAP round box 250px><imgcaption 007|D2-007 Breakout board.>{{ :d2:d2-105:d2-007.jpg?200}}</imgcaption> |
| </WRAP> | </WRAP></WRAP> |
| </WRAP> | |
| |
| ===== Absolute Maximum Ratings ===== | ===== Absolute Maximum Ratings ===== |
| 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. |
| |
| 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===== |
| 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. |
| |
| ====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>. The set of click switches labeled "Integral" controls the PI (ω<sub>1</sub>) pole. Clicking the first switch, labeled "proportional," into the on position removes the integral gain. If the "proportional" switch is in the off position, then the sum of the times for all switches in the on position gives the RC time-constant for the PI pole. For example, if the 2<sup>nd</sup> (0.47s) switch and the 4<sup>th</sup> (2.2s) switch are in the on position (and the rest off), then the time constant is 2.7s and ω<sub>1</sub> = 1/2.7s = 0.37 Hz. | 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>. The set of click switches labeled "Integral" controls the PI (ω<sub>1</sub>) pole. Clicking the first switch, labeled "proportional," into the on position removes the integral gain (but not the differential gain). If the "proportional" switch is in the off position (integral gain is now on), then the sum of the times for all switches in the on position gives the RC time-constant for the PI pole. For example, if the 2<sup>nd</sup> (0.47s) switch and the 4<sup>th</sup> (2.2s) switch are in the on position (and the rest off), then the time constant is 2.7s and ω<sub>1</sub> = 1/2.7s = 0.37 Hz. |
| |
| Similarly, the switches labeled "Differential" control the D (ω<sub>2</sub>) pole. If the first switch, labeled "Diff On" is in the off position, then there is no differential pole. If the "Diff On" switch is on, then the D pole has an RC time-constant given by the sum of the times of all the switches in the on position, same as with the Integral bank of switches. | Similarly, the switches labeled "Differential" control the D (ω<sub>2</sub>) pole. If the first switch, labeled "Diff On" is in the off position, then there is no differential pole. If the "Diff On" switch is on, then the D pole has an RC time-constant given by the sum of the times of all the switches in the on position, same as with the Integral bank of switches. |
