Patent ID: 8873136

Claim:
An optical amplifier for amplifying optical pulses, comprising: a gain-element in the form of a slab of a solid-state gain-medium having first and second opposite faces, first and second opposite ends, and first and second opposite sides, the gain-medium being selected from a group of gain-media consisting of thulium-doped gain-media, ytterbium-doped gain-media, titanium-doped sapphire, chromium-doped forsterite, and chromium-doped zinc selenide; a plurality diode-lasers, providing optical pump-radiation for energizing the gain-element; a reflective layer located adjacent the second face of the slab, said layer being reflective to the optical pump radiation; a pump-radiation router including a reflector spaced from the slab and arranged to receive pump-radiation from the plurality of diode-lasers and to cause the pump-radiation to make repeated passes through the slab, entering the first face thereof and being reflected back into the slab by the reflective layer and passing out through the first face to be reflected back into the slab by the reflector, the repeated passes forming an elongated gain-region in the slab extending between the first and second ends thereof; and wherein an optical pulse being amplified propagates through the elongated gain-region in a length direction thereof between the first and second ends of the slab.