Proc. SPIE. 5629, Lasers in Material Processing and Manufacturing II
KEYWORDS: Ferroelectric materials, Digital signal processing, Modulation, Control systems, Signal processing, Analog electronics, Feedback control, Digital electronics, Beam controllers, Temperature metrology
The new design about a CW, digital all-solid-stated LD pumped Nd:YVO<sub>4</sub> controller is introduced. The stable output power of this digital laser controller which adopts Digital Signal Processor (TMS320C31) is approximately 20mW. The whole system is composed of constant- current source, protection circuit, pulse-width modulation circuit, Si-photo-detector and amplified circuit and Digital Signal Processor control system, etc. In terms of error deviation Based on nonlinear control curves of LD power output by Si-photo-detector, the region control can be obtained by means of the PID control algorithm in the software platform, that is, error amendment and high stability laser power output can be achieved. And the precision of temperature control can reduce from ±0.2°C to ±0.04°C. By adopted integral separated mode PID control algorithm, the LD output power instability (σ%) down to ±2%. By way of adopting the new digital design, the work to protect the laser diode, including the continuous adjustable output power with high accuracy and stability, is easily obtained. The internal-external modulation control of the laser power based on digital optical feedback can be accomplished with stable power output. At last, the bringing reasons of noise are analyzed and the solving methods are put forward in this paper.