Reliable and Repeatable High Voltage in Photonics (Part 1 of 3: Lasers)
At recent photonics conferences, researchers and designers from laboratories and corporations worldwide have been introducing exciting technologies and solutions in the field of optoelectronics. These devices will enable the latest products for reliable and repeatable results in science, research, analytical instruments, industrial process, and medical applications. Optoelectronics utilize lasers, electro-optics, and detectors to bring light and electronics together. In part one of this three-part blog series, we’ll focus on lasers. Later, we’ll cover electro-optics and detectors.
A laser is a device that generates an intense beam of coherent monochromatic light (or other electromagnetic radiation) by stimulated emission of photons from excited atoms or molecules. Most lasers are semiconductor diode-based or gas tube-based. While single-diode lasers often use a low-voltage power source at high current, most higher-powered lasers use a pulsed high voltage through an array of laser diodes or a gas laser tube.
Pulsed lasers require precision, high-voltage (HV), pulsed power to achieve accurate pulse-to-pulse repeatability, essential to long-term electronics reliability and repeatable results in science, research, analytical instrument, industrial, and medical applications. One key element—over-shoot, varying from pulse to pulse—will dramatically affect the energy of each pulse (voltage squared) and can damage high-voltage switches. An error of 10% in charge voltage results in a change of 20% in joules stored, and the same 10% error can cause over-voltage to HV switches directly or during any resonant ringing. In pulsed-power applications directly driving the laser, it’s critical that the high-voltage, capacitor-charging power supplies feature very low over-shoot and high-accuracy, pulse-to-pulse repeatability (< 0.1%) to achieve consistent energy levels, and to protect high-voltage switching devices. Advanced Energy offers the C series and CC series DC-to-HVDC capacitor-charging supplies to deliver these specific performance results from 30 W to 1 kW with industry-leading performance and package size for power and voltage density.
Continuous wave (CW) lasers require a precision, current-regulated, high-voltage power supply that delivers accurate and repeatable current while protecting the laser and electronics with programmable limits for output voltage and current. This run power supply typically requires specifications of 1.0% and often < 0.1% or better for accuracy and stability over time, temperature, and load.
If the CW laser is gas-based, an additional low-power strike power supply is needed at 3X to 10X higher voltage to ionize the gas to a conduction state that a high-voltage, diode-isolated run supply can sustain. Advanced Energy offers the C series and CC series DC-to-HVDC supplies and MV series and OL series AC-to-HVDC supplies to deliver specific run power supply results from 30 W to 10 kW+. Advanced Energy also offers the A series and AA series DC-to-HVDC supplies and optional second outputs on the AC-to-HVDC supplies to deliver the strike power supply results needed.