Abstract: A fiber optic access node has input and output fibers terminating at a housing. A module is retractably insertable into the housing to automatically lock into a position in which an output zone of the module aligns with the output fiber and input zone of the module aligns with the input fiber. The input and output zones may be those of fiber optic passive elements such as a bypass fiber, a fiber tap, a fiber extension loop or a wavelength division multiplexed device, or may be those of an active element such as a repeater incorporating a light emitter, a light detector and a control circuit. The fiber optic element may be encapsulated within a plastics block or can be clamped between two plates. The combination of module and housing allows rapid and easy substitution of fiber optic functions within a fiber network.

Abstract: A fiber optic system element for reducing speckle and modal noise resulting from coupling a laser diode to an optical fiber has the form of a short length of fiber through which extend filaments of different refractive indices. Such fiber is fabricated by fusing together a plurality of fibers of different refractive index profiles and drawing the resulting preform into a single fiber.