High-resolution and broadband all-fiber spectrometers

Abstract

The development of optical fibers has revolutionized telecommunications by\nenabling long-distance broad-band transmission with minimal loss. In turn, the\nubiquity of high-quality low-cost fibers enabled a number of additional\napplications, including fiber sensors, fiber lasers, and imaging fiber bundles.\nRecently, we showed that a mutlimode optical fiber can also function as a\nspectrometer by measuring the wavelength-dependent speckle pattern formed by\ninterference between the guided modes. Here, we reach a record resolution of 1\npm at wavelength 1500 nm using a 100 meter long multimode fiber, outperforming\nthe state-of-the-art grating spectrometers. we also achieved broad-band\noperation with a 4 cm long fiber, covering 400 nm - 750 nm with 1 nm\nresolution. The fiber spectrometer, consisting of the fiber which can be coiled\nto a small volume and a monochrome camera that records the speckle pattern, is\ncompact, lightweight, and low cost while providing ultrahigh resolution, broad\nbandwidth and low loss.\n