Patent ID: 7606273

Claim:
An efficient and low-noise solid-state laser comprising: an optical cavity containing a solid-state laser material, serving as a laser gain medium, at least part of which is population-inversed in response to an excitation, and a pair of resonator mirrors; a laser diode serving as a pump source that emits light with an emission spectrum matching the absorption spectrum of the gain medium; a set of optical elements for beam shaping so that the beam emitted from the laser diode spatially matches the solid-state laser gain medium; a control circuit further comprising a DC generator for generating DC bias and a local oscillator for generating RF signal to modulate the DC bias, the resultant RF modulated drive current energizes said laser diode, whereby the laser operation is repetitively on-off or is continuously perturbed, whereby the output spectrum of the laser diode is stable, whereby the laser gain medium is stably excited and the output power of the solid-state laser monotonically changes with the DC bias of the laser diode drive current; one or more automatic temperature controller(s) affixed to said laser diode, and to said solid-state laser material, for active temperature control such that the temperature of the laser diode and the solid-state laser gain medium can be controlled dependently or independently; and an automatic power control loop for adjusting drive current DC bias to maintain output power of the solid-state laser at a predetermined level; wherein said automatic power control loop further comprising: a photon-to-electron conversion device for detecting the solid-state laser output power and for providing a feedback signal to laser diode drive circuit in response to drift in the solid-state laser output power, a beam splitter for dividing the solid-state laser output into two portions and delivering a fraction of laser light into said photon-to-electron conversion device, a feedback loop including an amplifier for amplifying the feedback signal, a reference voltage predetermined according to the initial value of the solid-state laser output power, a comparator that compares the fed back signal with the reference voltage and adjusts the drive current DC bias according to the comparison result; wherein: said photon-to-electron conversion device is external to the solid-state laser system: it exposes only to the interior of a sealed box so designed that said photon-to-electron conversion device only accepts light split from the solid-state laser output beam, stray light is completely isolated; wherein: said solid-state laser includes fiber laser.