Compact ultra-short pulse source amplifiers

Abstract

The present invention relates to compact, low noise, ultra-short pulse sources based on fiber amplifiers, and various applications thereof. At least one implementation includes an optical amplification system having a fiber laser seed source producing seed pulses at a repetition rate corresponding to the fiber laser cavity round trip time. A nonlinear pulse transformer, comprising a fiber length greater than about 10 m, receives a seed pulse at its input and produces a spectrally broadened output pulse at its output, the output pulse having a spectral bandwidth which is more than 1.5 times a spectral bandwidth of a seed pulse. A fiber power amplifier receives and amplifies spectrally broadened output pulses. A pulse compressor is configured to temporally compress spectrally broadened pulses amplified by said power amplifier. Applications include micro-machining, ophthalmology, molecular desorption or ionization, mass-spectroscopy, and/or laser-based, biological tissue processing.

What is claimed is: 
     
         1 . An optical amplification system, comprising:
 a fiber laser seed source producing seed pulses at a repetition rate corresponding to the fiber laser cavity round trip time, said seed source producing seed pulses having a pulse width greater than about 5 picoseconds (ps);   a nonlinear pulse transformer comprising a fiber length greater than about 10 m and less than 3000 m, said pulse transformer receiving a ps seed pulse at its input and producing a spectrally broadened ps output pulse at its output;   a fiber power amplifier receiving and amplifying said spectrally broadened ps output pulse; and   a pulse compressor configured to temporally compress spectrally broadened pulses amplified by said power amplifier.   
     
     
         2 . The optical amplification system according to  claim 1 , wherein said fiber power amplifier receives and amplifies said spectrally broadened pulse to produce a pulse energy greater than about 5 μJ. 
     
     
         3 . The optical amplification system according to  claim 1 , wherein said seed source generates a pulse width>10 ps. 
     
     
         4 . The optical amplification system according to  claim 1 , wherein a pulse width generated with said ps seed source is compressible to a pulse width less than 5 ps. 
     
     
         5 . An optical amplification system according to  claim 1 , wherein said nonlinear pulse transformer spectrally broadens a pulse injected to its input by a factor>1.5. 
     
     
         6 . The optical amplification system according to  claim 1 , wherein said nonlinear pulse transformer spectrally broadens a pulse injected to its input by a factor>4. 
     
     
         7 . The optical amplification system according to  claim 1 , said amplification system further comprising a down counter. 
     
     
         8 . The optical amplification system according to  claim 1 , wherein said nonlinear pulse transformer comprises lengths of amplifier fiber and passive undoped fiber. 
     
     
         9 . The optical amplification system according to  claim 1 , wherein said fiber seed source comprises a modelocked fiber laser. 
     
     
         10 . The optical amplification system according to  claim 1 , wherein said amplification system is further configured to substantially optimize the pulse quality of the pulses coupled out of the pulse compressor by insertion of elements with optimized values of third or fourth order dispersion. 
     
     
         11 . The optical amplification system according to  claim 1 , further comprising: a nonlinear frequency conversion stage. 
     
     
         12 . An optical amplification system according to  claim 1 , wherein said amplification system is configured as an element of a system for micro-machining, ophthalmology, molecular desorption, ionization, mass spectroscopy, or laser-based biological tissue processing. 
     
     
         13 . The amplification system according to  claim 1 , comprising a nonlinear fiber power amplifier disposed between said seed source and said compressor. 
     
     
         14 . The amplification system of  claim 1 , wherein said seed source comprises: a fiber-based modelocked laser, a semiconductor mode locked laser, a Fourier domain mode locked laser, or a gain-switched laser diode. 
     
     
         15 . The amplification system according to  claim 1 , comprising: a fiber oscillator generating pulses at its cavity round trip time; a down-counter, said down-counter disposed between said fiber oscillator and said fiber power amplifier; and a pump source configured to optically pump both said fiber oscillator and said fiber power amplifier. 
     
     
         16 . A modelocked fiber oscillator generating ps pulses, said modelocked fiber oscillator comprising: a fiber grating; and a saturable absorber, wherein said modelocked fiber oscillator is characterized by having a low susceptibility to Q-switching instabilities, said low susceptibility to Q-switching instabilities arising from selecting a grating bandwidth Δλ[nm] and negative grating dispersion D grat [ps 2 ], where the grating bandwidth Δλ[nm] is selected to be smaller than 5/√(D grat [ps 2 ]). 
     
     
         17 . A modelocked fiber oscillator generating ps pulses according to  claim 16 , configured as a Fabry-Perot cavity. 
     
     
         18 . A modelocked fiber oscillator generating ps pulses according to  claim 16 , configured as a ring cavity. 
     
     
         19 . A modelocked fiber oscillator generating ps pulses according to  claim 16 , configured as a twisted cavity. 
     
     
         20 . A modelocked fiber oscillator generating ps pulses according to  claim 16 , further comprising photonic crystal or Kagome fiber. 
     
     
         21 . A system for amplifying pulses, comprising: a picosecond (ps) seed source, said seed source producing pulses with a pulse width greater than about 5 ps; a nonlinear pulse transformer, said pulse transformer receiving a ps pulse at its input and producing a spectrally broadened, near linearly chirped and near parabolic ps output pulse, said ps output pulse having a temporal waveform with substantially smaller pulse wings compared to a seed input pulse waveform; a nonlinear fiber power amplifier; and a pulse compressor configured to temporally compress pulses amplified by said nonlinear power amplifier. 
     
     
         22 . A system for amplifying pulses, comprising: a picosecond (ps) seed source, said seed source producing pulses with a pulse width greater than about 5 ps; a nonlinear pulse transformer, said pulse transformer receiving a ps pulse at its input and producing a spectrally broadened ps pulse at its output; a nonlinear fiber power amplifier; and a pulse compressor configured to temporally compress pulses amplified by said power amplifier, wherein said nonlinear pulse transformer is configured to substantially optimize the pulse quality obtained after the compressor.