Efficient, Ultrastable 1Watt Laser using Ytterbium Fiber Amplifier

A space-qualifiable laser with extraordinary frequency stability, small size, and high efficiency is required for proposed metrology systems. Nonplanar ring oscillators (NPROs) are the baseline technology for these systems. NPROs can reach the 1-Watt power required for proposed systems. However, we believe that a system built around a single, high-power NPRO is not the best design. An approach which will have lower linewidth, and lower power consumption, is a low-power NPRO amplified to a power of 1-Watt and greater by an Ytterbium-doped fiber amplifier (YDFA.) The advantages of an oscillator / amplifier configuration, compared to the conceptually simpler high-power oscillator, are that the frequency stability of lower-power oscillators is better than that of higher-power oscillators, and that Ytterbium fiber amplifiers are about twice as efficient as Neodymium oscillators, primarily because they do not require active cooling of pump diodes. An amplified system would have the good linewidth of the low-power NPRO, but with the low power consumption of the Ytterbium fiber amplifier. The goal of the proposed research program would be to experimentally demonstrate a laser source with the power, frequency stability and efficiency needed for use in a space-borne interferometer.