Laser wavelength stabilization unit LWSU

Laser wavelength stabilization unit LWSU

The laser wavelength stabilization unit LWSU is designed to link the frequency of the tunable laser to resonances formed by an absorbing medium or an external optical resonator. 

It consists of a power supply, a triangular signal generator, a sine wave generator, a phase shifter, an analog multiplier and a PID controller with adjustable gain bands. 

Optionally, the laser wavelength stabilization unit LWSU can have a high-voltage output for controlling piezoelectric elements (model LWSU-102). The appearance of the LWSU is shown in Fig.1.

Fig.1. Appearance laser wavelength stabilization unit LWSU

The block diagram (Fig. 2) reflects the purpose and interconnection of electronic components.

The operating principle of unit LWSU is based on the fact that the value of the product of two sinusoidal signals of the same frequency is proportional to the phase difference of these signals:

At the extreme point, the phase of the detected modulation signal changes sign, and it is possible to register it. To do this, the high-frequency component is filtered out, and the remaining dispersion-shaped signal allows for mutual binding of the laser and the reference resonance source.

Fig.2. Block diagram of the LWSU. 1 – input amplifier; 2 – bandpass filter; 3 – sine wave generator; 4 – phase shifter; 5 – multiplier; 6 – proportional amplifier; 7 – integrated amplifier; 8 – differential amplifier; 9 – triangular signal generator; 10 – power amplifier; 11 – summing amplifier.

The LWSU specification is shown in Table 1.

Table 1.