Differences
This shows you the differences between two versions of the page.
| |
d2:offset_phase_lock_servo [2021/08/26 14:26] – external edit 127.0.0.1 | d2:offset_phase_lock_servo [2023/11/16 00:02] (current) – external edit 127.0.0.1 |
---|
<imgcaption opls_schematic|Schematic of the D2-135 Offset Phase Lock Servo, D2-160 Beat Note Detector, and D2-150 Heterodyne Module>{{ :d2:d2-135:block_diagram.png?600|}}</imgcaption> | <imgcaption opls_schematic|Schematic of the D2-135 Offset Phase Lock Servo, D2-160 Beat Note Detector, and D2-150 Heterodyne Module>{{ :d2:d2-135:block_diagram.png?600|}}</imgcaption> |
| |
A schematic of the OPLS, along with the [[d2:beat_note_detector|D2-160]] Beat Note Detector and [[d2:heterodyne_module|D2-150]] Heterodyne module is shown in <imgref opls_schematic>. The key component in the OPLS is a phase-frequency detector (PFD). The PFD compares the phase and frequency of the divided-by-N beat note to the reference frequency. The PFD outputs a signal proportional to the phase difference between the two input frequencies when there are no phase-slips between the two signals. This output provides a true phase-lock error signal. When there are phase slips, the PFD acts as a frequency comparator, aiding initial lock-up and enabling the OPLS to function as a //frequency//// ////offset//// ////lock// for laser sources with significant phase noise such as DFB and DBR laser diodes. The output of the PFD is fed to a charge pump and finally to the loop filter, where it is then fed back to the slave laser to control the frequency of the beat note. | A schematic of the OPLS, along with the [[d2:beat_note_detector|D2-160]] Beat Note Detector and [[d2:heterodyne_module|D2-150]] Heterodyne module is shown in <imgref opls_schematic>. The key component in the OPLS is a phase-frequency detector (PFD). The PFD compares the phase and frequency of the divided-by-N beat note to the reference frequency. The PFD outputs a signal proportional to the phase difference between the two input frequencies when there are no phase-slips between the two signals. This output provides a true phase-lock error signal. When there are phase slips, the PFD acts as a frequency comparator, aiding initial lock-up and enabling the OPLS to function as a //frequency//// ////offset//// ////lock// for laser sources with significant phase noise. The output of the PFD is fed to a charge pump and finally to the loop filter, where it is then fed back to the slave laser to control the frequency of the beat note. |
| |
The loop filter has user-adjustable proportional-integral-differential (PID) feedback and an additional high-frequency roll-off frequency. Tuning the values of the PID loop filter allows the user to optimize the feedback to the laser for best offset locks. This is further discussed below. | The loop filter has user-adjustable proportional-integral-differential (PID) feedback and an additional high-frequency roll-off frequency. Tuning the values of the PID loop filter allows the user to optimize the feedback to the laser for best offset locks. This is further discussed below. |
| |
{{ :d2:d-sub_power_pinout.jpg?nolink&150 |}} | {{ :d2:d-sub_power_pinout.jpg?nolink&150 |}} |
| |
| While it is infrequent, the D2-005 power supply may occasionally radiate noise from the side of its chassis onto nearby electronics. This only occurs in some system configurations, and will appear as a signal at the frequency of your mains electricity (typically either 50 Hz or 60 Hz). This noise can easily be removed by moving the D2-005 at least 18 inches (45cm) away from other electronics, rotating it 90° such that the sides of the D2-005 face away, or by moving the entire power supply to a different shelf. To accommodate this, all D2-005's are shipped with a 5' DB9 cable as of January 1, 2022. |
| |
| |
**Computer Control (9-pin D-sub)** | **Computer Control (9-pin D-sub)** |
| |
<WRAP clear></WRAP> | <WRAP clear></WRAP> |
| \\ |
| |
**Ref. Freq. In** | **Ref. Freq. In** |