| Both sides previous revisionPrevious revisionNext revision | Previous revision |
| ffc:100 [2023/06/08 21:35] – external edit 127.0.0.1 | ffc:100 [2023/08/22 23:46] (current) – external edit 127.0.0.1 |
|---|
| Click here for the [[http://www.vescent.com/manuals/doku.php?id=manuals|Vescent manuals page]].\\ | Click here for the [[http://www.vescent.com/manuals/doku.php?id=manuals|Vescent manuals page]].\\ |
| Click here for the [[ffc:100:api|FFC-100 API]].\\ | Click here for the [[ffc:100:api|FFC-100 API]].\\ |
| | Click here for the [[ffc:locking_electronics:slice-fpga|SLICE-FPGA Locking Manual]]\\ |
| Click here for the [[ffc:locking_electronics:slice-fpga-ii|SLICE-FPGA-II Locking Manual]]\\ | Click here for the [[ffc:locking_electronics:slice-fpga-ii|SLICE-FPGA-II Locking Manual]]\\ |
| Click here for the [[https://www.vescent.com/products/lasers/ffc-100-frequency-comb/|FFC-100 web page]].\\ | Click here for the [[https://www.vescent.com/products/lasers/ffc-100-frequency-comb/|FFC-100 web page]].\\ |
| Click here for the [[https://github.com/Vescent/FFC_Firmware_Upgrade-and-FPGA-Software-Firmware|Github page for FFC-100 firmware revisions]]\\ | /*Click here for the [[https://github.com/Vescent/FFC_Firmware_Upgrade-and-FPGA-Software-Firmware|Github page for FFC-100 firmware revisions]]\\ */ |
| Click here for the [[https://www.vescent.com/manuals/doku.php?id=ffc:100m|FFC-100 Manual]]\\ | /*Click here for the [[https://www.vescent.com/manuals/doku.php?id=ffc:100m|FFC-100 Manual]]\\ */ |
| Please check back for added functionality. Contact [[[email protected]|sales [at] vescent [dot] com]] for questions and corrections, or to request added functionality. | Please check back for added functionality. Contact [[[email protected]|sales [at] vescent [dot] com]] for questions and corrections, or to request added functionality. |
| |
| |
| ===== Absolute Maximum Ratings and Power Input ===== | ===== Absolute Maximum Ratings and Power Input ===== |
| Note: All modules designed to be operated in a laboratory environment. | Note: Reported specs are under laboratory conditions. Performance degradation can occur in deployed operation depending on the environment |
| |
| <WRAP center round box 60%><tabcaption abs_max_rat |Absolute Maximum Ratings> | <WRAP center round box 60%><tabcaption abs_max_rat |Absolute Maximum Ratings> |
| | **Parameter** | **Rating** | | | **Parameter** | **Rating** | |
| | Environmental Temperature | >15°C and <30°C| | | Environmental Temperature | 15°C<T<30°C| |
| | Environmental Humidity | <60% | | | Environmental Humidity | <60% | |
| | Environmental Dew Points | <15°C | | | Environmental Dew Points | <15°C | |
| |
| =====Initial Set-up===== | =====Initial Set-up===== |
| - Download and install software according to [[https://github.com/Vescent/FFC_Firmware_Upgrade-and-FPGA-Software-Firmware|instructions found here.]] | |
| - Ensure all cables and fibers are connected according to the connection diagram <imgref conn>.((Single frequency reference laser: for instance a [[https://rio-lasers.com/1550nm-laser-diode/|RIO Planex]]<sup>TM</sup> 1550 nm laser.)) | - Ensure all cables and fibers are connected according to the connection diagram <imgref conn>.((Single frequency reference laser: for instance a [[https://rio-lasers.com/1550nm-laser-diode/|RIO Planex]]<sup>TM</sup> 1550 nm laser.)) |
| - Turn on the power to the Fiber Frequency Comb (FFC) and the FPGA, as well as the reference laser.\\ | - Ensure the RF input amplitudes to the FPGA are between -30 dBm and -15 dBm. If power levels are higher than -15 dBm, utilize an appropriate RF attenuator. |
| <imgcaption conn|FFC-100 electrical and optical connection diagram (Click for larger image)>{{ ffc-100_connection_diagram2.png | - Turn on the power to the Fiber Frequency Comb (FFC) and the FPGA, as well as the reference laser. |
| ?700 |ffc-100_connection_diagram2.png}}</imgcaption>\\ | - Ensure the optical input power to the ƒOPT input port is < 1.5 mW. |
| | |
| | <imgcaption conn|FFC-100 electrical and optical connection diagram (Click for larger image)>{{ :ffc:updated_ffc_connection_diagram.png?direct&600 |}}</imgcaption>\\ |
| | |
| |
| <WRAP center round box 60%><tabcaption set_up |Operating Parameters> | <WRAP center round box 60%><tabcaption set_up |Operating Parameters> |
| =====FFC-100 Operation===== | =====FFC-100 Operation===== |
| ====FFC Start Up GUI==== | ====FFC Start Up GUI==== |
| - Touch the “System Off” button at the top of the front panel screen (<imgref gui_off>) to bring up a drop-down menu. Select “Standby” (<imgref system_state>) to turn on temperature control of the pump diodes and oscillator cavity.\\ <imgcaption gui_off|The FFC-100 GUI in off state>{{ffc_gui_off.png?400 |ffc_gui_off.png}}</imgcaption><imgcaption system_state|Select Standby laser state>{{ ffc_gui_choose_state.png?400 | ffc_gui_choose_state.png}}</imgcaption>\\ | - Touch the “System Off” button at the top of the front panel screen (<imgref gui_off>) to bring up a drop-down menu. Select “Standby” (<imgref system_state>) to turn on temperature control of the pump diodes and oscillator cavity. Temperatures will appear yellow as they approach stability, and turn green when stabilized within a predefined temperature range around the setpoint.\\ <imgcaption gui_off|The FFC-100 GUI in off state>{{updated_off_state.png?400 |ffc_gui_off.png}}</imgcaption><imgcaption system_state|Select Standby laser state>{{ updated_standby.png?400 | ffc_gui_choose_state.png}}</imgcaption>\\ |
| - Once the temperature servos have stabilized and “Standby” has stopped blinking, touch the “Standby” drop-down menu (<imgref stdby>) and select “Laser On” (<imgref stdby_to_on>). The FFC should commence lasing and the Mode-locked indicator should turn green (<imgref sys_on>). \\ <imgcaption stdby|The FFC-100 GUI: in Standby mode>{{ffc:ffc_gui_standby.png?400 | ffc:ffc_gui_standby.png}}</imgcaption> <imgcaption stdby_to_on|The FFC-100 GUI: Standby to System On>{{ ffc:ffc_gui_standby_to_on.png?400 | ffc:ffc_gui_standby_to_on.png}}</imgcaption><imgcaption sys_on|System On>{{ ffc:ffc_gui_on.png?400 | ffc:ffc_gui_on.png}}</imgcaption> \\ | - Once the temperature servos have stabilized and “Standby” has stopped blinking, touch the “Standby” drop-down menu (<imgref stdby>) and select “Laser On” (<imgref stdby_to_on>). After a 5 second safety delay where the Laser On button blinks, the FFC should commence lasing and the Laser On button should turn solid white (<imgref sys_on>). \\ <imgcaption stdby|The FFC-100 GUI: in Standby mode>{{ffc:updated_standby_on.png?400 | ffc:updated_standby_on.png}}</imgcaption> <imgcaption stdby_to_on|The FFC-100 GUI: Standby to System On>{{ ffc:updated_laser.png?400 | ffc:updated_laser.png }} \\ </imgcaption><imgcaption sys_on|System On>{{ ffc:updated_laser_on.png?400 | ffc:ffc_gui_on.png }}</imgcaption> \\ |
| - If necessary, adjust oscillator current by either holding down the “Osc” touch screen button and typing in a desired set-point (<imgref osc_curr>), or briefly pressing the button and using the two control knobs (left changes digits, right adjusts values) to set a desired value.\\ <imgcaption osc_curr|Adjust oscillator current via keypad>{{ ffc:ffc_gui_adjust_oscillator_current.png?400 | ffc:ffc_gui_adjust_oscillator_current.png}}</imgcaption> | - Touch the “PZT” touch screen button (<imgref pzt>) to bring up a drop-down menu and select “Full Range x10” to enable the PZT servo.\\ <imgcaption pzt|Select PZT Gain>{{ :ffc:updated_pzt_menu.png?direct&400 |}}</imgcaption> |
| - Cavity temperature can be adjusted in the same way. | |
| - Touch the “PZT” touch screen button (<imgref pzt>) to bring up a drop-down menu and select “Full Range x20” to enable the PZT servo.\\ <imgcaption pzt|Select PZT Gain>{{ ffc:ffc_gui_select_pzt_mode.png?400 | ffc:ffc_gui_select_pzt_mode.png}}</imgcaption> | |
| | |
| ====FPGA Control==== | ====FPGA Control==== |
| For locking the FFC-100 with the Vescent SLICE-FPGA-II Module, [[ffc:locking_electronics:slice-fpga-ii|click here]]. Otherwise, if using the SLICE-FPGA, follow the instructions below. | |
| |
| The SLICE-FPGA dual-channel Offset Phase Lock Servo can be used to phase lock ƒ<sub>CEO</sub> to a reference (TBD) and ƒ<sub>opt</sub> to a reference laser such as the Rio Planex. | | {{ :take-note.png?50&nolink }} | Visit these pages for the appropriate offset phase lock servo manual \\ [[ffc:locking_electronics:slice-fpga|SLICE-FPGA manual]] \\ [[ffc:locking_electronics:slice-fpga-ii|SLICE-FPGA-II manual]] |\\ |
| |
| If you have not already done so, install [[ffc:python|Python]] and the [[ffc:fpga|FPGA software]] for controlling the SLICE-FPGA dual Offset Phase Lock Servo. | The two channels of the SLICE-FPGA or SLICE-FPGA-II Offset Phase Lock Servo can be used to control a self-referenced phase lock of ƒ<sub>CEO</sub> and a lock of ƒ<sub>opt</sub> to a reference laser such as [[https://stabilaser.dk/stabilized-laser/|the Sabilaser 1542]] or [[https://rio-lasers.com/1550nm-laser-diode/|the RIO Planex]]. |
| | {{ :ffc:updated_ss_home_menu_off.svg |}}====Slow Loop Feedback==== |
| | Slow servo functionality is designed to allow indefinite FOPT locking times despite long-term drifts in the reference laser’s frequency outside the dynamic range of the FFC’s PZT feedback. This is achieved by slow temperature feedback to the oscillator of the FFC, which locks the PZT output voltage to a setpoint voltage near the middle of its dynamic range. To enable the slow servo, first lock FOPT normally, with the DAC 1 slider as close to centered as possible. Next, navigate to the home screen of the FFC-100 and press the “Slow Servo” button at the top of the screen (<imgref ss_home> and <imgref ss_enabled> ). |
| |
| ===Software Startup=== | <imgcaption ss_home|The slow servo button is located on the home screen to the right of the System Off/Laser On button.>{{ :ffc:updated_ss_home_menu_off.png?400 |}}</imgcaption> |
| - Open a WinPython command window and navigate to the folder “GUI and Firmware”. | |
| - Start the SLICE-FPGA control GUI by typing “python XEM_GUI3_VPv4.py”, <imgref gui_start>).\\ <imgcaption gui_start|Start FPGA GUI from Terminal>{{ ffc:terminal_directory.png?800 | ffc:terminal_directory.png}}</imgcaption>\\ | |
| - A start-up menu should appear (<imgref gui_start_scr>). Make sure “superlaserland_v12.bit” is selected and select an appropriate clock option. Press OK.\\ <imgcaption gui_start_scr|FPGA GUI Start Screen>{{ ffc:fpga_gui_startup.png?800 | ffc:fpga_gui_startup.png}}</imgcaption>\\ | |
| - Navigate to the “Filter Settings” tab and select “Narrowband (6MHz)” for both DDC0 and DDC1 (<imgref gui_filt>).\\ <imgcaption gui_filt|Set Loop Filter Bandwidth>{{ ffc:fpga_filter_set.png?800 |ffc:fpga_filter_set.png}}</imgcaption>\\ | |
| | |
| === Locking ƒ(CEO) === | |
| - Navigate to the “CEO Lock” tab and adjust the “Offset DAC 0” slider near the top left by clicking and dragging the slider until the the data in the Baseband IQ plot is circular (<imgref ceo_bbiq>). This centers the beat note near the reference frequency. It is also possible to adjust the FFC-100 oscillator current on its front panel to make this adjustment.\\ <imgcaption ceo_bbiq|Centering ƒ(CEO) on reference frequency (Baseband IQ optimization)>{{ ffc:fpga_ceo_lock.png?800 |ffc:fpga_ceo_lock.png}}</imgcaption>\\ | |
| - Press the “Lock” button (<imgref ceo_lock>, top middle). If the system doesn’t lock, change the VCO sign to the opposite polarity (top right) and try again. If the system still won't lock, try lowering the K<sub>p</sub> value (bottom left).\\ <imgcaption ceo_lock|Locking ƒ(CEO)>{{ ffc:fpga_ceo_lock_2.png?800 |ffc:fpga_ceo_lock_2.png}}</imgcaption>\\ | |
| | |
| ===Locking ƒ(opt)=== | |
| - Navigate to the “Optical Lock” window. Center the beat note near the reference frequency: adjust the “Offset DAC 1” slider (or your reference laser frequency) until you see a circular Baseband IQ diagram (<imgref opt_bbiq>).\\ <imgcaption opt_bbiq|Centerig ƒ(opt) on reference frequency (Baseband IQ optimization)>{{ ffc:fpga_optical_bbiq.png?800 |ffc:fpga_optical_bbiq.png}}</imgcaption>\\ | |
| - Press the “Lock” button (<imgref fopt_lock>). If ƒ<sub>opt</sub> doesn’t lock, change the VCO sign to the opposite polarity and try again. If the system continues to not lock, lower the K<sub>p</sub> value.\\<imgcaption fopt_lock|Locking ƒ(opt)>{{ ffc:fpga_optical_lock.png?800 |ffc:fpga_optical_lock.png}}</imgcaption>\\ | |
| - Adjust PID settings (bottom middle of <imgref fopt_lock>) accordingly to lower the integrated phase noise of each parameter (f<sub>CEO</sub> and f<sub>opt</sub>). The default settings provided in the software are a good place to start but tweaking the values can often improve performance. | |
| | |
| | |
| ====Slow Loop Feedback==== | |
| ===Firmware Version FL-V1.2=== | |
| Slow loop functionality will be provided in a near-term software update. | |
| - Open your computer’s device manager from the control panel and find the COM port number for “STMicroelectronics”. Never assume that this number is the same as previous times. (If it doesn’t appear, make sure your computer is connected to the FFC.) | |
| - Navigate to the “Slow Loop” tab in the GUI and enter the COM port number into “FFC COM Port”. | |
| - The PZT setpoint is set to an intermediate value (50V) to keep the servo from railing. This can be adjusted if desired. | |
| - Click “Activate Temperature Slow Loop”. | |
| | |
| ===Firmware Version G2-V1.2=== | |
| Slow servo functionality is designed to allow indefinite F<sub>OPT</sub> locking times despite long-term drifts in the reference laser’s frequency outside the dynamic range of the FFC’s PZT feedback. This is achieved by slow temperature feedback to the oscillator of the FFC, which locks the PZT output voltage to a setpoint voltage near the middle of its dynamic range. To enable the slow servo, first lock FOPT normally, but set the DC offset as close to 3V as possible (PZT output range spans 0-60 V with 10V/V transfer function). Next, navigate to the home screen of the FFC-100 and press the “Slow Servo” button at the top of the screen | |
| | |
| | |
| <imgcaption ss_home|The slow servo button is located on the home screen to the right of the System Off/Laser On button.>{{ :ffc:ss_home_menu_off.png?400 |}}</imgcaption> | |
| |
| This will activate the slow servo but does not turn on the feedback. You can tell that the slow servo has been activated by the blue background on the “Setpoint [°C]” button. | This will activate the slow servo but does not turn on the feedback. You can tell that the slow servo has been activated by the blue background on the “Setpoint [°C]” button. |
| |
| <imgcaption ss_enabled | When the slow servo is activated, the background of "Setpoint [°C]" turns blue>{{ :ffc:ss_enabled.png?400 |}}</imgcaption> | <imgcaption ss_enabled | When the slow servo is activated, the slow servo button will turn green, and the temperature “Target [°C]” and “Actual [°C]” buttons will turn yellow or green according to the current state.>{{ :ffc:updated2_ss_enabled.png?400 |}}</imgcaption> |
| | |
| Next, press and hold the “Setpoint [°C]” button until the slow servo menu comes up. The menu allows a user to set the temperature setpoint as normal, and to set the voltage setpoint that the slow servo will try to keep constant by changing the temperature of the oscillator. We recommend setting this to 30V, which is right in the middle of the FFC-100's range. The gain comes preconfigured for each unit, but can also be changed through this menu (WE DO NOT ADVISE changing the gain without input from the Vescent technical staff). The polarity button will toggle the direction that the slow servo adjusts the temperature to keep the setpoint voltage constant (this will be preset by Vescent staff and should not be changed). Setting this to the incorrect value can result in temperature runaway. To change a value, simply touch the field to edit with the rotary knobs, or press and hold to bring up the keypad. To turn the slow servo on, press the “OFF” button. It should change to a white background which says “ON”. To turn it back off, simply press the button again. | |
| |
| <imgcaption ss_menu | The slow servo menu allows the user to change the setpoint, gain, and polarity of the servo, and also to turn it on or off.>{{ :ffc:ss_menu.png?400 |}}</imgcaption> | This will activate the slow servo. On the FPGA software under the “Optical Lock” tab, the “DAC 1” slider should be gradually pushed and eventually stabilize in the center of its dynamic range. The gain of the slow servo comes preconfigured for each unit but can be adjusted via a menu accessed by pressing and holding the “Slow Servo” button on the FFC GUI (<imgref ss_menu>) **(We do not advise changing the gain without input from the Vescent technical staff)**. |
| |
| While the slow servo is on, the color of the “Setpoint [°C]” button will indicate the difference between the setpoint voltage, and the actual voltage. If the difference is ≤ ±6V, the background will turn green. If it is ≥ ±6V, it will turn yellow, and if it is ≥ ±54V it will turn red. If the background is blue, this means the slow servo has turned off. | <imgcaption ss_menu | The slow servo menu allows the user to change the setpoint, gain, and polarity of the servo, and also to turn it on or off.>{{ :ffc:updated2_ss_menu.png?400 |}}</imgcaption> |
| |
| <imgcaption ss_green| The slow servo indicating the Voltage is within ±6V of the setpoint.>{{ :ffc:ss_servoing.png?400 |}}</imgcaption> | While the slow servo is on, the color of the “Setpoint [°C]” button will change as the slow servo adjusts the temperature setpoint. A yellow color indicates that the PZT voltage is > 6V away from the setpoint (30V) and the temperature setpoint is being changed to compensate. This box will turn green when the PZT voltage is within the range of ±6V of the voltage setpoint. The color of the “Actual [°C]” box may also momentarily turn yellow as the temperature control servo corrects the cavity temperature when the temperature setpoint changes. |
| <imgcaption ss_yellow| The slow servo indicating the Voltage is more than ±6V away from the setpoint, but less than ±54V.>{{ :ffc:ss_servoing_yellow.png?400 |}}</imgcaption> | |
| <imgcaption ss_red| The slow servo indicating the Voltage is more than ±54V away from the setpoint. This scenario is very unlikely.>{{ :ffc:ss_servoing_red.png?400 |}}</imgcaption> | |
| |
| Remember to shut off the slow servo, either by disabling it from the home menu or by pressing the On/Off button in the slow servo menu, when unlocking the FFC-100. | Remember to shut off the slow servo by pressing the On/Off button in the slow servo menu, when unlocking the FFC-100. |
