Apparatus and method for increasing the bandwidth of a laser beam
The present invention comprises a novel method and apparatus that, by sinusoidal cross-phase modulation, can provide a laser pulse having a very broad bandwidth while substantially retaining the input laser`s temporal shape. The present invention may have use in a master oscillator system for a laser having a master oscillator-power amplifier (MOPA) configuration. The present invention comprises a first laser providing an output wavelength {lambda} and a second laser providing a output wavelength shifted by a small amount to {lambda} + {Delta}{lambda}. Each beam has a single, linear polarization. Each beam is coupled into a length of polarization-preserving optical fiber. The first laser beam is coupled into the optical fiber with the beam`s polarization aligned with the fiber`s main axis, and the second beam is coupled into the fiber with its polarization rotated from the main axis by a predetermined angle. Within the fiber, the main axis` polarization defines an interference beam and the orthogonal axis` polarization defines a signal beam. In the interference beam, the first laser beam and the parallel polarized vector component of the other beam interfere to create areas of high and low intensity, which modulates the signal beam by cross phase modulation. Upon exit from the optical fiber, the beams are coupled out and the modulated signal beam is separated out by a polarization selector. The signal beam can be applied to coherence reducing systems to provide an output that is temporally and spatially incoherent.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- Assignee:
- Dept. of Energy
- Patent Number(s):
- PATENTS-US-A7664700
- Application Number:
- ON: DE93002011
- OSTI ID:
- 10185889
- Resource Relation:
- Other Information: PBD: 5 Mar 1991
- Country of Publication:
- United States
- Language:
- English
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Apparatus and method for increasing the bandwidth of a laser beam
Apparatus and method for increasing the bandwidth of a laser beam