Command Charging Circuit with Energy Recovery for Pulsed Power Supply of Copper Vapor Laser

Abstract

Copper vapor laser (CVL) is the highest power laser in metal vapor laser family. The copper vapor laser has very high gain and it gives output at two wavelengths; 510.5 nm (green) and 578.2 nm (yellow). When this copper vapor laser is used in MOPA (Master Oscillator Power Amplifier) mode in laser chains for high power lasers applications then a common problem arises due to false triggering of power supply pulses to drive this master oscillator and this problem is known as “Jitter”. The conventional power supply for this laser is based on capacitor charge transfer circuit or L-C inversion circuit in which the hydrogen Thyratron is used as a pulse power switch. Thyratron has the inherent limitation of lifetime typically 1200Hrs, as it is gas filled switch. Due to this it results in higher running cost of the laser. This limitation is overcome in pulse excitation circuit based on semiconductor switches & magnetic pulse compressors. Insulated Gate Bipolar Transistor (IGBT) is comparatively recent device used as pulsed power switch in these circuits. IGBT switches offer several advantages over other power semiconductor switches like fast switching, ease of paralleling, simple control circuit, high repetition rate etc. However use of magnetic pulse compressors (MPC) introduces additional jitter in laser because of change in saturation time due to changes in input voltage. In this paper a new design and performance of a capacitor charging power supply for IGBT based pulse power supply for copper vapor laser is reported. The new circuit scheme for the power supply uses modified command charging scheme with energy recovery. This design resulted in reduced jitter for the pulse power supplies using magnetic pulse compressors.