Patent ID: 8073018

Claim:
A laser pulse generating apparatus comprising: a laser beam generating device; a driving device; a first light guide path comprising a first optical fiber; an optical filter; a second light guide path comprising a second optical fiber; and a reflecting device, wherein the laser beam generating device is configured to generate a laser beam having a predetermined wavelength spectrum and emit the laser beam to the first light guide path in a first direction, wherein the driving device is configured to drive the laser beam generating device to generate a pulse of the laser beam, wherein the first light guide path is configured to guide to the optical filter the pulse entering from the first direction from the laser beam generating device, and guide to the laser beam generating device a portion of optical power of the pulse fed back to the laser beam generating device in a second direction opposite to the first direction, wherein the optical filter is a bandpass filter configured to transmit a portion of the predetermined wavelength spectrum of the pulse of the laser beam entering from the first light guide path to the second light guide path and transmit the portion of the predetermined wavelength spectrum of the pulse of the laser beam entering from the second light guide path to the first light guide path, wherein the portion of the predetermined wavelength spectrum of the pulse of the laser beam includes a first half of the pulse but not a second half of the pulse, wherein the second light guide path is configured to guide the pulse between the optical filter and the reflecting device, wherein the reflecting device is configured to reflect only a portion of optical power of the pulse guided through the second light guide path to feed the portion back to the laser beam generating device via the second light guide path, the optical filter, and the first light guide path, and wherein a timing of the feedback of the portion of the optical power of the pulse to the laser beam generating device is adjusted such that the portion of the optical power of the pulse is fed back to the laser beam generating device just before a subsequent pulse is generated.