The optical fibers disclosed is a single mode optical fiber comprising a core region and a cladding region surrounding and directly adjacent to the core region. The core region can have a radius r.sub.1 in a range from 3 μm to 7 μm and a relative refractive index profile Δ.sub.1 having a maximum relative refractive index Δ.sub.1max in the range from 0.25% to 0.50%. The cladding region can include a first outer cladding region and a second outer cladding region surrounding and directly adjacent to the first outer cladding region. The first outer cladding region can have a radius r.sub.4a. The second outer cladding region can have a radius rob less than or equal to 45 μm and comprising silica based glass doped with titania.

A disclosed multimode optical fiber comprises a core and a cladding surrounding the core. The core has an outer radius r.sub.1 in between 20 μm and 30 μm. The cladding includes a first outer cladding region having an outer radius r.sub.4a and a second outer cladding region having an outer radius r.sub.4b less than or equal to 45 μm. The second outer cladding region comprises silica-based glass doped with titania. The optical fiber further includes a primary coating with an outer radius r.sub.5 less than or equal to 80 μm, and a thickness (r.sub.5−r.sub.4) less than or equal to 30 μm. The optical fiber further includes a secondary coating with an outer radius r.sub.6 less than or equal to 100 μm. The secondary coating has a thickness (r.sub.6−r.sub.5) less than or equal to 30 μm, and a normalized puncture load greater than 3.6×10.sup.−3 g/micron.sup.2.

A multi-clad optical fiber design is described in order to provide low optical loss, a high numerical aperture (NA), and high optical gain for the fundamental propagating mode, the linearly polarized (LP) 01 mode in the UV and visible portion of the optical spectrum. The optical fiber design may contain dopants in order to simultaneously increase the optical gain in the core region while avoiding additional losses during the fiber fabrication process. The optical fiber design may incorporate rare-earth dopants for efficient lasing. Additionally, the modal characteristics of the propagating modes in the optical core promote highly efficient nonlinear mixing, providing for a high beam quality (M.sup.2<1.5) output of the emitted light.

A multi-clad optical fiber design is described in order to provide low optical loss, a high numerical aperture (NA), and high optical gain for the fundamental propagating mode, the linearly polarized (LP) 01 mode in the UV and visible portion of the optical spectrum. The optical fiber design may contain dopants in order to simultaneously increase the optical gain in the core region while avoiding additional losses during the fiber fabrication process. The optical fiber design may incorporate rare-earth dopants for efficient lasing. Additionally, the modal characteristics of the propagating modes in the optical core promote highly efficient nonlinear mixing, providing for a high beam quality (M.sup.2<1.5) output of the emitted light.

The present disclosure provides an optical fibre. The optical fibre includes a core region, a primary trench region and a secondary trench region. The core region has a radius r.sub.1. In addition, the core region has a relative refractive index .sub.1. Further, the primary trench region has a relative refractive index .sub.3. Furthermore, the primary trench region has a curve parameter .sub.trench-1. Moreover, the secondary trench region has a relative refractive index .sub.4. Also, the secondary trench region has a curve parameter .sub.trench-2.

A multi-clad optical fiber design is described in order to provide low optical loss, a high numerical aperture (NA), and high optical gain for the fundamental propagating mode, the linearly polarized (LP) 01 mode in the UV and visible portion of the optical spectrum. The optical fiber design may contain dopants in order to simultaneously increase the optical gain in the core region while avoiding additional losses during the fiber fabrication process. The optical fiber design may incorporate rare-earth dopants for efficient lasing. Additionally, the modal characteristics of the propagating modes in the optical core promote highly efficient nonlinear mixing, providing for a high beam quality (M.sup.2<1.5) output of the emitted light.

The present disclosure provides a few mode optical fiber (100). The few mode optical fiber (100) includes a core region (102). A core region (102) defined by a region around a central longitudinal axis (116) of the few mode optical fiber (100). In addition, the core region (102) has a first annular region (106) extended from central longitudinal axis (116) to radius r.sub.1, a second annular region (108) extended from radius r.sub.1 to radius r.sub.2, a third annular region (110) extended from radius r.sub.2 to radius r.sub.3, a fourth annular region (112) extended from radius r.sub.3 to radius r.sub.4 and a fifth annular region (114) extended from radius r.sub.4 to radius r.sub.5. Also, the few mode optical fiber (100) has a cladding defined by the sixth annular region (104) extended from radius r.sub.5 to radius r.sub.6.

The present disclosure provides a few mode optical fiber. The few mode optical fiber includes a core region. A core region defined by a region around a central longitudinal axis of the few mode optical fiber. In addition, the core region has a first annular region extended from central longitudinal axis to radius r.sub.1, a second annular region extended from radius r.sub.1 to radius r.sub.2, a third annular region extended from radius r.sub.2 to radius r.sub.3, a fourth annular region extended from radius r.sub.3 to radius r.sub.4 and a fifth annular region extended from radius r.sub.4 to radius r.sub.5. Also, the few mode optical fiber has a cladding defined by the sixth annular region extended from radius r.sub.5 to radius r.sub.6.

A single-mode fiber with ultralow attenuation includes a core layer and cladding layers. The cladding layers includes an inner cladding layer surrounding the core layer, a trench cladding layer surrounding the inner cladding layer, an auxiliary outer cladding layer surrounding the trench cladding layer, and an outer cladding layer surrounding the auxiliary cladding layer. The core layer has a radius of 3.9-4.8 m and a relative refractive index difference of 0.08% to 0.10%. The inner cladding layer has a radius of 9-14 m and a relative refractive index difference of 0.40% to 0.15%. The trench cladding layer has a radius of 13-25 m and a refractive index difference of 0.7% to 0.3%. The auxiliary outer cladding layer has a radius of 30-50 m and a relative refractive index difference of 0.4% to 0.15%. The outer cladding layer is a pure silicon dioxide glass layer.

The present disclosure provides a few mode optical fiber (100). The few mode optical fiber (100) includes a core region (102). A core region (102) defined by a region around a central longitudinal axis (116) of the few mode optical fiber (100). In addition, the core region (102) has a first annular region (106) extended from central longitudinal axis (116) to radius r.sub.1, a second annular region (108) extended from radius r.sub.1 to radius r.sub.2, a third annular region (110) extended from radius r.sub.2 to radius r.sub.3, a fourth annular region (112) extended from radius r.sub.3 to radius r.sub.4 and a fifth annular region (114) extended from radius r.sub.4 to radius r.sub.5. Also, the few mode optical fiber (100) has a cladding defined by the sixth annular region (104) extended from radius r.sub.5 to radius r.sub.6.