Abstract: An optical system allows sharing of optical components and seed and pump light to achieve desired optical amplification in laser light while reducing the number of optical components and complexity of the overall optical system and achieving improved performance in lasers and reduced cost in fabrication and final lasers for large scale production of such lasers. Different optical gain sections can be used to allow for sharing of seed and pump light and sharing of optical components while providing multi-stage optical amplification.

Abstract: An optical system allows sharing of optical components and seed and pump light to achieve desired optical amplification in laser light while reducing the number of optical components and complexity of the overall optical system and achieving improved performance in lasers and reduced cost in fabrication and final lasers for large scale production of such lasers. Different optical gain sections can be used to allow for sharing of seed and pump light and sharing of optical components while providing multi-stage optical amplification.

Abstract: An optical fiber side coupler apparatus comprising a first optical fiber and at least one multimode (MM) optical fiber having a core, the MM optical fiber for delivering light to the first optical fiber. The MM optical fiber can comprise a first length having a first location therealong wherein the core comprises a first cross sectional area A1, a second length having a second location therealong wherein the core comprises a second cross sectional area A2 that is less than the first cross sectional area A1, and a transition section, located between the first and second locations, wherein the cross sectional area of the core of the MM optical fiber is reduced. The second length can be secured alongside a selected length of the first optical fiber so as to provide optical coupling between the MM optical fiber and the first optical fiber.

Abstract: A laser assembly (10) comprises a multimode laser (12) having at least one output and operating at a given wavelength. It also includes a double-clad optical fiber (20) having a free end (22) coupled to the output of the laser (12). The optical fiber (20) comprises a core (24) in registry with the output of the laser (12), a multimode inner cladding (26) surrounding the core (24), and an outer cladding (28) surrounding the inner cladding (26), the outer cladding (28) being provided to contain light in the inner cladding (26). A fiber Bragg grating (30) is written in the core (24) of the fiber (20) at a given distance from the free end (22) thereof. The Bragg grating (30) has a reflection spectrum within the gain spectrum of the laser (12). In use, it generates a sufficient feedback and stabilizes the laser (12) at the reflection spectrum of the Bragg grating (30). This provides a low cost laser assembly that is simple, suitable for volume manufacturing and small in size.