Tunable pulse width laser

Abstract

A method of tuning the time duration of laser output pulses, the method including spectrally dispersing optical pulses and further comprising providing an optical pulse having a time duration and a spectral bandwidth; spectrally dispersing ( 243, 245 ) the optical pulse so as to provide a selected change in the time duration of the pulse responsive to the spectral bandwidth of the pulse; outputting ( 226 ) an optical output pulse having a first time duration that is responsive to the selected change in time duration; providing another optical pulse; changing the amount of spectral bandwidth of the another optical pulse ( 272 ) to be different than that of the optical pulse or changing the amount of spectral dispersion so that spectrally dispersing the another optical pulse provides a change in time duration that is different than the selected change; and outputting ( 226 ) another optical output pulse having a second time duration that is responsive to the different change in time duration, the second time duration of the another optical output pulse being different than the first time duration of the optical output pulse.

The invention claimed is: 
     
       1. A method of tuning the time duration of output pulses output from a laser system, wherein the method comprises spectrally dispersing optical pulses and further comprises:
 providing an optical pulse having a time duration and a spectral bandwidth; 
 spectrally dispersing the optical pulse so as to provide a selected change in the time duration of the pulse responsive to the spectral bandwidth of the pulse; 
 outputting an optical output pulse from the laser system having a first time duration that is responsive to the selected change in time duration; 
 providing another optical pulse; 
 changing the amount of spectral bandwidth of the another optical pulse to be different than that of the optical pulse or changing the amount of spectral dispersion so that; 
 in a step separate from the above step of changing the amount of spectral bandwidth of the another optical pulse, spectrally dispersing the another optical pulse provides to provide a change in time duration of the another optical pulse that is different than the selected change; 
 outputting another optical output pulse having a second time duration that is responsive to the different change in time duration, the second time duration of the another optical output pulse being different than the first time duration of the optical output pulse; 
 wherein changing the amount of spectral bandwidth or changing the amount of spectral dispersion comprises changing the amount of spectral bandwidth; 
 wherein changing the amount of spectral bandwidth comprises changing optical power; and 
 wherein changing the optical power comprises amplifying. 
 
     
     
       2. The method of  claim 1  wherein the optical output pulse and the another optical output pulse have time durations that are longer, respectively, than the optical pulse and the another optical pulse. 
     
     
       3. A method of tuning the time duration of output pulses output from a laser system, wherein the method comprises spectrally dispersing optical pulses and further comprises:
 providing an optical pulse having a time duration and a spectral bandwidth; 
 spectrally dispersing the optical pulse so as to provide a selected change in the time duration of the pulse responsive to the spectral bandwidth of the pulse; 
 outputting an optical output pulse from the laser system having a first time duration that is responsive to the selected change in time duration; 
 providing another optical pulse; 
 changing the amount of spectral bandwidth of the another optical pulse to be different than that of the optical pulse or changing the amount of spectral dispersion so that; 
 in a step separate from the above step of changing the amount of spectral bandwidth of the another optical pulse, spectrally dispersing the another optical pulse provides to provide a change in time duration of the another optical pulse that is different than the selected change; 
 
       outputting another optical output pulse having a second time duration that is responsive to the different change in time duration, the second time duration of the another optical output pulse being different than the first time duration of the optical output pulse;
 wherein changing the amount of spectral bandwidth or changing the amount of spectral dispersion comprises changing the amount of spectral bandwidth; 
 wherein changing the amount of spectral bandwidth comprises changing optical power; and 
 wherein changing the optical power comprises attenuating. 
 
     
     
       4. A method of tuning the time duration of output pulses output from a laser system, wherein the method comprises spectrally dispersing optical pulses and further comprises:
 providing an optical pulse having a time duration and a spectral bandwidth; 
 spectrally dispersing the optical pulse so as to provide a selected change in the time duration of the pulse responsive to the spectral bandwidth of the pulse; 
 outputting an optical output pulse from the laser system having a first time duration that is responsive to the selected change in time duration; 
 providing another optical pulse; 
 changing the amount of spectral bandwidth of the another optical pulse to be different than that of the optical pulse or changing the amount of spectral dispersion so that; 
 in a step separate from the above step of changing the amount of spectral bandwidth of the another optical pulse, spectrally dispersing the another optical pulse provides to provide a change in time duration of the another optical pulse that is different than the selected change; 
 
       outputting another optical output pulse having a second time duration that is responsive to the different change in time duration, the second time duration of the another optical output pulse being different than the first time duration of the optical output pulse;
 wherein changing the amount of spectral bandwidth or changing the amount of spectral dispersion comprises changing the amount of spectral bandwidth; 
 wherein changing the amount of spectral bandwidth comprises changing optical power; 
 wherein the method further comprises providing a pulsed laser source; and 
 wherein changing the optical power amount of spectral bandwidth comprises changing the output power of the pulsed laser source. 
 
     
     
       5. A method of tuning the time duration of output pulses output from a laser system, wherein the method comprises spectrally dispersing optical pulses and further comprises:
 providing an optical pulse having a time duration and a spectral bandwidth; 
 spectrally dispersing the optical pulse so as to provide a selected change in the time duration of the pulse responsive to the spectral bandwidth of the pulse; 
 outputting an optical output pulse from the laser system having a first time duration that is responsive to the selected change in time duration; 
 providing another optical pulse; 
 changing the amount of spectral bandwidth of the another optical pulse to be different than that of the optical pulse or changing the amount of spectral dispersion so that spectrally dispersing the another optical pulse provides a change in time duration of the another optical pulse that is different than the selected change; 
 
       outputting another optical output pulse having a second time duration that is responsive to the different change in time duration, the second time duration of the another optical output pulse being different than the first time duration of the optical output pulse;
 wherein changing the amount of spectral bandwidth or changing the amount of spectral dispersion comprises changing the amount of spectral bandwidth; 
 wherein changing the amount of spectral bandwidth comprises changing an amount of self phase modulation; and 
 wherein changing an amount of self phase modulation comprises providing an amplifier and changing the gain of the amplifier. 
 
     
     
       6. A method of tuning the time duration of output pulses output from a laser system, wherein the method comprises spectrally dispersing optical pulses and further comprises:
 providing an optical pulse having a time duration and a spectral bandwidth; 
 spectrally dispersing the optical pulse so as to provide a selected change in the time duration of the pulse responsive to the spectral bandwidth of the pulse; 
 outputting an optical output pulse from the laser system having a first time duration that is responsive to the selected change in time duration; 
 providing another optical pulse; 
 changing the amount of spectral bandwidth of the another optical pulse to be different than that of the optical pulse or changing the amount of spectral dispersion so that; 
 in a step separate from the above step of changing the amount of spectral bandwidth of the another optical pulse, spectrally dispersing the another optical pulse provides to provide a change in time duration of the another optical pulse that is different than the selected change; 
 outputting another optical output pulse having a second time duration that is responsive to the different change in time duration, the second time duration of the another optical output pulse being different than the first time duration of the optical output pulse; and 
 providing a laser source comprising a passively mode locked fiber laser comprising a laser cavity including a SESAM mode locking element and a length of rare earth doped optical fiber having normal dispersion at the output wavelength of the fiber laser cavity, the passively mode locked fiber laser providing pulses having a time duration of no less than 1 ps and no greater than 100 ps and a spectral bandwidth of no greater than 2 nm. 
 
     
     
       7. The method of  claim 5  comprising providing a laser source comprising a passively mode locked fiber laser comprising a laser cavity including a SESAM mode locking element and a length of rare earth doped optical fiber, and wherein providing an amplifier and changing the gain of the amplifier comprises providing a non linear nonlinear fiber amplifier downstream of the laser source and changing the gain thereof to change an amount of self-phase modulation provided by the nonlinear amplifier. 
     
     
       8. The method of  claim 1  wherein changing the amount of spectral bandwidth comprises broadening the spectral bandwidth. 
     
     
       9. A method of tuning the time duration of output pulses output from a laser system, wherein the method comprises spectrally dispersing optical pulses and further comprises:
 providing an optical pulse having a time duration and a spectral bandwidth; 
 spectrally dispersing the optical pulse so as to provide a selected change in the time duration of the pulse responsive to the spectral bandwidth of the pulse; 
 outputting an optical output pulse from the laser system having a first time duration that is responsive to the selected change in time duration; 
 providing another optical pulse; 
 changing the amount of spectral bandwidth of the another optical pulse to be different than that of the optical pulse or changing the amount of spectral dispersion so that spectrally dispersing the another optical pulse provides a change in time duration that is different than the selected change; 
 outputting another optical output pulse having a second time duration that is responsive to the different change in time duration, the second time duration of the another optical output pulse being different than the first time duration of the optical output pulse; and 
 wherein changing the amount of spectral bandwidth or changing the amount of spectral dispersion comprises changing the amount of spectral dispersion. 
 
     
     
       10. The method of  claim 9  wherein changing the amount of spectral dispersion comprises:
 providing first and second spectrally dispersive optical elements that provide different amounts of spectral dispersion; and 
 changing from spectrally dispersing optical pulses with the first spectrally dispersive element to spectrally dispersing optical pulses with the second spectrally dispersive optical element. 
 
     
     
       11. The method of  claim 9  wherein changing the amount of spectral bandwidth or changing the amount of spectral dispersion comprises changing both of the amount of spectral bandwidth and the amount of spectral dispersion. 
     
     
       12. The method of  claim 11  comprising providing at least one criteria related to a pulse characteristic and determining to change both the amount of spectral dispersion and the spectral bandwidth responsive to a determination regarding the at least one criteria. 
     
     
       13. The method of  claim 12  wherein the pulse characteristic comprises the desired temporal pulse width of the second pulse. 
     
     
       14. The method of  claim 12  wherein the pulse characteristic comprises pulse distortion. 
     
     
       15. The method of  claim 9  wherein changing the amount of spectral bandwidth or changing the amount of spectral dispersion comprises changing both the amount of spectral bandwidth and the amount of spectral dispersion so as to provide substantially continuous tuning of the temporal pulse width of optical output pulses of the laser system over a selected range of temporal pulse widths and so as to limit the amount of distortion of optical output pulses having temporal pulse widths within the selected range. 
     
     
       16. The method of  claim 1  wherein optical output pulses provided by the laser system have a temporal time duration of no less than 1 ps and no greater than 1 ns. 
     
     
       17. A method of tuning the time duration of output pulses output from a laser system, wherein the method comprises spectrally dispersing optical pulses and further comprises:
 providing an optical pulse having a time duration and a spectral bandwidth; 
 spectrally dispersing the optical pulse so as to provide a selected change in the time duration of the pulse responsive to the spectral bandwidth of the pulse; 
 outputting an optical output pulse from the laser system having a first time duration that is responsive to the selected change in time duration; 
 providing another optical pulse; 
 changing the amount of spectral bandwidth of the another optical pulse to be different than that of the optical pulse or changing the amount of spectral dispersion so that; 
 in a step separate from the above step of changing the amount of spectral bandwidth of the another optical pulse or changing the amount of spectral dispersion, spectrally dispersing the another optical pulse provides to provide a change in time duration of the another optical pulse that is different than the selected change; 
 
       outputting another optical output pulse having a second time duration that is responsive to the different change in time duration, the second time duration of the another optical output pulse being different than the first time duration of the optical output pulse; and
 refraining from outputting compressed optical output pulses wherein the time duration of the optical output pulses would be less than 50% of their time duration prior to compression. 
 
     
     
       18. The method of  claim 5  wherein optical output pulses provided by the laser system have a temporal time duration of no less than 1 ps and no greater than 1 ns. 
     
     
       19. The method of  claim 9  wherein optical output pulses provided by the laser system have a temporal time duration of no less than 1 ps and no greater than 1 ns. 
     
     
       20. The method of  claim 17  wherein optical output pulses provided by the laser system have a temporal time duration of no less than 1 ps and no greater than 1 ns. 
     
     
       21. The method of claim 5 wherein the spectrally dispersing the another optical pulse to provide a change in time duration of the another optical pulse that is different than the selected change occurs in a separate step from the changing the amount of spectral bandwidth of the another optical pulse.