A regenerative fiber optic amplifier system comprising: a fiber optical pump module including a plurality of VCSEL emitters and an optical fiber to output a pump beam generated in said optical pump module; a first reflector (1550; 846); a second reflector (1540; 840), the first reflector having a reflectivity significantly higher than a reflectivity of the second reflector; a fiber gain element having a core doped with a plurality of optically active ions, wherein said optical fiber is connected to the first reflector so as to transmit the pump beam from the pump module to the fiber gain element across the first reflector; an acousto-optic switch including at least three ports (1561, 1562, 1563), wherein a first port of the acousto-optic switch is connected to a second end of the fiber gain element, and a second port of the acousto-optic switch is connected to the second reflector, so as to form a regenerative resonant cavity between the first and second reflectors enclosing the fiber gain element via the acousto-optic switch; a circulator having at least three ports (1571, 1572, 1573) wherein a first output port of the circulator is connected to a third port of the acousto-optic switch; an optical signal pulse source connected to a second port of the circulator to transmit a signal pulse to the regenerative resonant cavity through the first output port of the circulator and the acousto-optic switch, wherein upon closing the acousto-optic switch in synchronization with pulse operation of the pump module, the pump beam recirculates until the signal in the regenerative resonant cavity amplifies to a saturation limit, and subsequently upon opening the acousto-optic switch, an amplified signal pulse is transmitted from the gain element to a third port of the circulator via the acousto-optic switch. a fiber optical pump module including a plurality of VCSEL emitters and an optical fiber to output a pump beam generated in said optical pump module; a first reflector (1550; 846); a second reflector (1540; 840), the first reflector having a reflectivity significantly higher than a reflectivity of the second reflector; a fiber gain element having a core doped with a plurality of optically active ions, wherein said optical fiber is connected to the first reflector so as to transmit the pump beam from the pump module to the fiber gain element across the first reflector; an acousto-optic switch including at least three ports (1561, 1562, 1563), wherein a first port of the acousto-optic switch is connected to a second end of the fiber gain element, and a second port of the acousto-optic switch is connected to the second reflector, so as to form a regenerative resonant cavity between the first and second reflectors enclosing the fiber gain element via the acousto-optic switch; a circulator having at least three ports (1571, 1572, 1573) wherein a first output port of the circulator is connected to a third port of the acousto-optic switch; an optical signal pulse source connected to a second port of the circulator to transmit a signal pulse to the regenerative resonant cavity through the first output port of the circulator and the acousto-optic switch, wherein upon closing the acousto-optic switch in synchronization with pulse operation of the pump module, the pump beam recirculates until the signal in the regenerative resonant cavity amplifies to a saturation limit, and subsequently upon opening the acousto-optic switch, an amplified signal pulse is transmitted from the gain element to a third port of the circulator via the acousto-optic switch.