An optical beam delivery device configured to generate, from an optical beam , selectable intensity profiles, the optical beam delivery device comprising: a first length of fiber (104; 204; 1100; 1300; 1400; 1406; 1500; 1500; 1600; 2912) having a first refractive index profile (RIP) (212; 1102; 1202; 1302; 1402; 1412; 1504; 1602), the first RIP enabling, in response to an applied perturbation, modification of the optical beam to form an adjusted optical beam, the adjusted optical beam defining, at an output end of the first length of fiber, different intensity distributions based on different states of the applied perturbation; and a second length of fiber (108; 208; 1700; 1800; 1900; 2000; 2100; 2920) having an input end coupled to the output end of the first length of fiber, the second length of fiber formed with coaxial confinement regions (216, 218, 220; 1704, 1706, 1708; 1808, 1810, 1812; 1904, 1906, 1908, 1910; 2004, 2006, 2008; 2104, 2106, 2108) defining a second RIP (1702; 1802; 1902; 2002; 2102) that is different from the first RIP, wherein a first confinement region and a second confinement region of the coaxial confinement regions are separated by a cladding structure having a refractive index that is lower than the indexes of the first confinement region and the second confinement region, the coaxial confinement regions arranged to confine at least a portion of the adjusted optical beam, the confined portion corresponding to an intensity distribution of the different intensity distributions, and in which the intensity distribution is established by a corresponding state of the different states of the applied perturbation such that the confined portion is configured to provide, at an output of the second length of fiber, a selected intensity profile of the selectable intensity profiles (2940 A , 2940 B, 2940 C , 2940 D ). a first length of fiber (104; 204; 1100; 1300; 1400; 1406; 1500; 1500; 1600; 2912) having a first refractive index profile (RIP) (212; 1102; 1202; 1302; 1402; 1412; 1504; 1602), the first RIP enabling, in response to an applied perturbation, modification of the optical beam to form an adjusted optical beam, the adjusted optical beam defining, at an output end of the first length of fiber, different intensity distributions based on different states of the applied perturbation; and a second length of fiber (108; 208; 1700; 1800; 1900; 2000; 2100; 2920) having an input end coupled to the output end of the first length of fiber, the second length of fiber formed with coaxial confinement regions (216, 218, 220; 1704, 1706, 1708; 1808, 1810, 1812; 1904, 1906, 1908, 1910; 2004, 2006, 2008; 2104, 2106, 2108) defining a second RIP (1702; 1802; 1902; 2002; 2102) that is different from the first RIP, wherein a first confinement region and a second confinement region of the coaxial confinement regions are separated by a cladding structure having a refractive index that is lower than the indexes of the first confinement region and the second confinement region, the coaxial confinement regions arranged to confine at least a portion of the adjusted optical beam, the confined portion corresponding to an intensity distribution of the different intensity distributions, and in which the intensity distribution is established by a corresponding state of the different states of the applied perturbation such that the confined portion is configured to provide, at an output of the second length of fiber, a selected intensity profile of the selectable intensity profiles (2940 A , 2940 B, 2940 C , 2940 D ). <EOS>