Efficient amplification of a single-mode laser diode via photorefractive beam combination using an injection locked laser diode array pump

Powers in excess of 100mW have been obtained in a near-diffraction-limited, single-mode laser-diode output by photorefractive two-beam coupling in BaTiO3, using an injection-locked 1W diode-laser array as the pump source. Signal gains of as much as 8.1 are obtained, corresponding to pump transfer efficiencies of 49%. Calculations suggest that powers as high as 225mW should be obtainable, given suitable antireflection-coated optics

Photorefractive techniques for diode laser beam combination

Techniques for high-power laser array beam combination processes involving photorefractive materials are reviewed. Details of an all semiconductor laser scheme for the amplification and subsequent photorefractive beam clean-up of a diffraction limited single-mode laser output is presented. Powers in excess of 100 mW ( > 220 mW accounting for Fresnel losses) are obtained in a diffraction limited signal beam, corresponding to an array to diffraction limited beam transfer efficiency of 33%. Details of the reflection geometry phase conjugate master oscillator-power amplifier scheme which offers the possibility of power scaling between a number of high-power semiconductor laser amplifiers are presented. Using this technique, a 13-dB amplification of a diffraction limited signal beam is obtained using a commercially available, 10-stripe gain-guided device with no special coatings

Single-longitudinal-mode operation from a semiconductor laser array via feedback from a modified collimating objective

A technique for obtaining single-longitudinal-mode collimated output from a ten-stripe laser diode array using feedback from a single modified microscope objective is described. An optimum main mode to side mode ratio of 14 dB is obtained for a feedback reflectivity of 10%

Sequential power transfer between stripes of a diode laser array via photorefractive two-wave mixing in BaTiO₃

We report the transfer of 48% of the incident power from a semiconductor laser array into a diffraction-limited beam by means of photorefractive coherent beam combination in BaTiO3, using a progressive two-wave mixing geometry. A single-element, photorefractive beam combiner is described which should allow the transfer of 88% of the power of a suitable array into a single diffraction-limited beam

High power diode laser array beam combination via injection locking and photorefractive beam coupling

The attainment of a high power, diffraction limited output from semiconductor laser arrays is currently a subject of great interest for many applications such as increasing optical fiber launch efficiency and improvement of solid state laser pumping. The output from a single stripe, single mode semiconductor laser is essentially diffraction limited but power output from these devices is limited due to problems with dissipation of heat from the lasing region, the current highest cw operating power being 100 mW. Diode laser arrays and bars present a solution to the problem of higher output powers but their output is generally far from diffraction limited