Edge emitting semiconductor laser system

Abstract

A laser system includes an edge emitting semiconductor laser, and an optical fiber, wherein the laser emits one or more laser beams coupled into the optical fiber and the laser includes a semiconductor body including a waveguide region that includes first and second waveguide layers and an active layer arranged between the first and second waveguide layers and generates laser radiation, the waveguide region is arranged between first and second cladding layers disposed downstream of the waveguide region, a phase structure is formed in the semiconductor body, includes a cutout extending from a top side of the semiconductor body into the second cladding layer, at least one first intermediate layer composed of a semiconductor material different from the material of the second cladding layer is embedded therein, and the cutout extends from the top side of the semiconductor body at least partly into the first intermediate layer.

1 . A laser system comprising:
 an edge emitting semiconductor laser, and   
       an optical fiber, 
       wherein the semiconductor laser is configured to emit one or a plurality of laser beams coupled into the optical fiber, 
       the edge emitting semiconductor laser comprises a semiconductor body comprising a waveguide region, 
       the waveguide region comprises a first waveguide layer, a second waveguide layer and an active layer arranged between the first waveguide layer and the second waveguide layer and generates laser radiation, 
       the waveguide region is arranged between a first cladding layer and a second cladding layer disposed downstream of the waveguide region in a growth direction of the semiconductor body, 
       a phase structure for selection of lateral modes of the laser radiation emitted by the active layer is formed in the semiconductor body, wherein the phase structure comprises a cutout extending from a top side of the semiconductor body into the second cladding layer, 
       at least one first intermediate layer composed of a semiconductor material different from the semiconductor material of the second cladding layer is embedded into the second cladding layer, and 
       the cutout extends from the top side of the semiconductor body at least partly into the first intermediate layer. 
     
     
         2 . The laser system according to  claim 1 , wherein the semiconductor material of the intermediate layer contains at least one element selected from the group consisting of main group III and V which is not contained in the second cladding layer. 
     
     
         3 . The laser system according to  claim 1 , wherein the second cladding layer comprises Al x Ga i-x As where 0≦x≦1 and the intermediate layer contains In and/or P. 
     
     
         4 . The laser system according to  claim 1 , wherein the intermediate layer has a thickness of 10 nm to 100 nm. 
     
     
         5 . The laser system according to  claim 1 , wherein a second intermediate layer is embedded into the second cladding layer and the cutout extends at least partly into the second intermediate layer. 
     
     
         6 . The laser system according to  claim 5 , wherein the cutout extends into the first intermediate layer at at least one first point, and extends into the second intermediate layer at at least one second point, and the cutout has a spatially varying depth between the first point and the second point. 
     
     
         7 . The laser system according to  claim 1 , wherein the second cladding layer contains a first partial layer adjoining the waveguide region, and a second partial layer adjoining the first partial layer, and the first partial layer has a greater refractive index than the second partial layer. 
     
     
         8 . The laser system according to  claim 7 , wherein the at least one intermediate layer is embedded into the first partial layer of the second cladding layer. 
     
     
         9 . The laser system according to  claim 1 , wherein the phase structure is at least partly provided with a cover layer, the cover layer comprising a silicon oxide, a silicon nitride, a silicon oxynitride, an aluminum oxide, zinc selenide, germanium or benzocyclobutene. 
     
     
         10 . The laser system according to  claim 1 , wherein at least one contact strip is applied to the semiconductor body, and the contact strip has a width b of 10 μm to 500 μm. 
     
     
         11 . The laser system according to  claim 10 , wherein the edge emitting semiconductor laser comprises a plurality of contact strips, and the contact strips have a distance d and a width b, and 0.01≦b/d≦0.5. 
     
     
         12 . The laser system according to  claim 1 , wherein the semiconductor laser emits laser radiation in the infrared spectral range having a wavelength of 780 nm to 1500 nm during operation. 
     
     
         13 . The laser system according to  claim 1 , wherein the one or the plurality of laser beams is coupled into the optical fiber by one or a plurality of optical elements arranged between the semiconductor laser and the optical fiber. 
     
     
         14 . The laser system according to  claim 13 , wherein the edge emitting semiconductor laser is a laser bar comprising a plurality of contact strips, and the active layer comprises a plurality of emission regions each arranged below the contact strips. 
     
     
         15 . The laser system according to  claim 14 , wherein the one or a plurality of optical elements comprises a microlens array, and wherein each emission region is assigned a microlens bringing about beam shaping of a respective laser beam. 
     
     
         16 . A laser system comprising:
 an edge emitting semiconductor laser, and   an optical fiber,   wherein the semiconductor laser is configured to emit one or a plurality of laser beams coupled into the optical fiber,   the edge emitting semiconductor laser comprises a semiconductor body comprising a waveguide region,   the waveguide region comprises a first waveguide layer, a second waveguide layer and an active layer arranged between the first waveguide layer and the second waveguide layer and generates laser radiation,   the waveguide region is arranged between a first cladding layer and a second cladding layer disposed downstream of the waveguide region in a growth direction of the semiconductor body,   a phase structure for selection of lateral modes of the laser radiation emitted by the active layer is formed in the semiconductor body, and the phase structure comprises at least one cutout extending from a top side of the semiconductor body into the second cladding layer,   side facets form a laser resonator, and the laser radiation crosses from a main region to the phase structure region of the semiconductor laser when progating between the side facets,   at least one first intermediate layer comprising a semiconductor material different from the semiconductor material of the second cladding layer is embedded into the second cladding layer,   a second intermediate layer is embedded into the second cladding layer,   the cutout extends from a top side of the semiconductor body into the first intermediate layer at at least one first point and extends into the second intermediate layer at at least one second point, and   the cutout has a spatially varying depth between the first point and the second point and the depth of the cutout in the second cladding layer increases or decreases between the first point and the second point continuously or in stepped fashion in a plurality of steps in a direction parallel to the direction of the laser radiation propagating between the side facets, thereby reducing coupling losses when the laser radiation crosses from the main region to the phase structure region.   
     
     
         17 . The laser system according to  claim 16 , wherein the one or the plurality of laser beams is coupled into the optical fiber by one or a plurality of optical elements arranged between the semiconductor laser and the optical fiber. 
     
     
         18 . A laser system comprising;
 an edge emitting semiconductor laser, and   an optical fiber,   wherein the semiconductor laser is configured to emit one or a plurality of laser beams coupled into the optical fiber,   the edge emitting semiconductor laser comprises a semiconductor body comprising a waveguide region,   the waveguide region comprises a first waveguide layer, a second waveguide layer and an active layer arranged between the first waveguide layer and the second waveguide layer and generates laser radiation,   the waveguide region is arranged between a first cladding layer and a second cladding layer disposed downstream of the waveguide region in the growth direction of the semiconductor body,   a phase structure for the selection of lateral modes of the laser radiation emitted by the active layer is formed in the semiconductor body, and the phase structure comprises at least one cutout extending from a top side of the semiconductor body into the second cladding layer,   at least one first intermediate layer composed of a semiconductor material different from the semiconductor material of the second cladding layer is embedded into the second cladding layer,   the cutout extends from the top side of the semiconductor body at least partly into the first intermediate layer,   the second cladding layer contains a first partial layer adjoining the waveguide region, and a second partial layer arranged above the first partial layer, and the first partial layer has a greater refractive index than the second partial layer, and   the at least one intermediate layer is embedded into the first partial layer of the second cladding layer.   
     
     
         19 . The laser system according to  claim 18 , wherein the one or the plurality of laser beams is coupled into the optical fiber by one or a plurality of optical elements arranged between the semiconductor laser and the optical fiber.