Laser Locking Controller: Preci-Lock
Features
The Preci-Lock controller mainly includes the modulation and the demodulation module, the PID module and the high voltage amplifier module. In addition, it also includes a RS422 protocol communication interface and a ±12V power supply interface. The precilock can be satisfied for most common requirements of laser frequency stabilization.
Modulation & Demodulation Module
Parameters |
Indexes |
Modulation Power Range |
0-1023(Max. 10dBm) |
Modulation Output Frequency |
20MHz/3MHz/10kHz |
Phase Regulation Range |
0-360° |
PD Signal Input Range |
<1Vpp |
PD Signal Input Coupling |
AC Coupling |
PD Signal Input Coupling Impedance |
50 Ω |
The modulation and demodulation module modulate the laser, and demodulate the spectral signal detected by the detector to produce error signal. The modulation frequency can be customized according to customer. |
PID Module
Parameters |
Indexes |
|
Fast Output PID |
Single- Channel PIDP |
|
Fast Output PID |
PIDP+ PI Tandem |
|
PIDP Integral Folding Frequency |
(3.4 kHz-34 kHz) , (1 kHz-10 kHz) , (330 Hz-3.3 kHz) , (100 Hz-1 kHz) , (33 Hz- 330 Hz) , (10 Hz-100 Hz) , (3.3 Hz-33 Hz) , (1 Hz-10 Hz) |
|
PIDP Differential Folding Frequency |
16 kHz , 34 kHz , 59 kHz , 133 kHz , 284 kHz , 483 kHz , 724 kHz |
|
PI Integral Folding Frequency |
33 kHz , 10 kHz , 3.3 kHz , 1 kHz , 330 Hz , 100 Hz , 33 Hz |
|
Fast Output |
Output Bandwidth |
500 kHz |
Output Range |
-9 V-9 V |
|
Bias tuning Range |
0-9 V |
|
Gain tuning Range |
0.0005-25 |
|
|
Outputreverse function |
Inclusion |
Slow Output
|
Output Bandwidth |
500 kHz |
Output Range |
-9 V-9 V |
|
Bias tuning Range |
0-9 V |
|
Gain tuning Range |
0.0003-20 |
|
Outputreverse function |
Inclusion |
|
Scanning frequency |
2 Hz |
|
Scanning waveform |
Triangular Wave |
|
Maximum Scanning Range |
0-9 V |
|
Error signal bias adjustment |
Range |
-2 V- 2 V |
Accuracy |
0.25 mV |
|
Error Signal Input
|
Unsaturated range |
-0.5 V-0.5 V |
InputImpedance |
510 Ω |
|
Lock Reference Input |
Input Range |
-9 V-9 V |
InputImpedance |
MΩ |
|
The frequency of the laser can be controlled by PID module through feedback signal according to the error signal. PID module in Preci-lock is in series PID structure, including two PI, and offering two output ports,the parameters of the module can be adjusted with high preci sion. |
High voltage amplifier module
Some lasers or devices require high dc voltage to drive the PZT. Preci-lock's built-in high dc voltage amplifier module can output a voltage signal of up to 110V with its 15 times amplification. |
Parameters |
Indexes |
magnification |
15 |
|
Output Range |
0-110 V |
|
Bandwith |
High resistance load bandwidth 50 kHz |
|
Capacitive load bandwidth (small signal output (0.1 uF load) 20 kHz |
||
Drive Capability(Max. Output Current) |
50 mA |
Control Software
Preci-Lock interface
For a better laser frequency control, Preci-Lock abandons the physical knobs and buttons. And all parameter changes and locking control are realized by the PC software. Preci-lock software includes the functions of communication control, reference and error signal display, PID module parameters adjustment, locking control and so on. Except the necessaryphysical connection, the laser locking control can be fully realized by Preci Lock software. A pure digital operation is more convenient for user. Another feature of Preci-Lock software is the automatic locking function, which can realize the automatic locking of laser frequency under reasonable parameter settings. In automatic locking mode, Preci-Lock can realize auto locking, unlock judging and re-locking of the laser frequency. This mode can realize the long-term stable locking of laser frequency, especially suitable for the cold atom physics experiment that requires long-term continuous measurement.
Example
As a fully functional locking control module, Preci-Lock can meet the most demands of frequency locking. The frequency locking can be divided into internal modulation and external modulation frequency locking according to the different modulation. The two frequency locking methods are different in principle while the physical connecting of Preci-Lock is also different for them.
Rubidium atom saturation absorption spectrum and corresponding error signal (left);
Internal modulation frequency stabilization results (right).
◆ Stabilization Internal Modulation Frequency
For internal modulation, the modulation signal and feedback signal feedback together to the laser through an adder. The frequency lock point corresponding to the wave peak and wave trough of the spectra. Typical internal frequency stabilization modulation is adopted in lock-in saturation absorption spectrum or absorption spectrum frequency stabilization.
Rubidium atom modulation transfer spectrum and corresponding error signal (left);
External modulation frequency stabilization results (right).
◆ Stabilization External Modulation Frequency
For external modulation, the modulation signal and feedback signal are divided and the external
modulation signal is applied to an external independent modulator. The frequency lock point corresponding to the zero point of the spectra. Typical external frequency stabilization modulation is adopted in modulation transfer spectrum or PDH frequency stabilization.