Fibre-bulk hybrid lasers: recent developments and future prospects

Cladding-pumped fibre lasers are becoming increasingly attractive for high power generation due to their high efficiency and immunity from thermal effects. However, due to their small core size and long device length, pulse energies are rather limited. In contrast, conventional 'bulk' solid-state lasers offer the prospect of much higher pulse energies, but suffer from detrimental thermal effects which can degrade beam quality and efficiency. An alternative strategy for scaling output power and pulse energy, which is attracting growing interest, is to use a hybrid laser scheme. In this approach, the fibre laser is used as a high-brightness source for in-band pumping of a bulk solid-state laser. One of the main attractions of the fiber-bulk hybrid laser scheme is that most of the heat generated via quantum defect heating is deposited in the fibre, and thermal effects in the bulk laser are dramatically reduced leading to the prospect of much improved efficiency, beam quality, higher average output power and high pulse energy. This approach has already been successfully applied to a number of different solid-state lasers operating in the eyesafe wavelength regimes around 1.6 μ and 2 μm. This presentation reviews recent progress in power scaling of hybrid lasers in cw and in pulsed modes of operation, and considers the prospects for further improvement in performance