The real-time, in-line analysis of light polarization is critical in optical networks, currently suffering from complex systems with numerous bulky opto-electro-mechanical elements tandemly arranged along the optical path. Here, we design and fabricate a fiber-integrated polarimeter by vertically stacking three photodetection units based on six-layer van der Waals materials, including one bismuth selenide (Bi 2 Se 3 ) layer for power calibration, two twisted black phosphorus (BP) layers for polarization detection, and three hexagonal boron nitride (hBN) layers for encapsulation. The self-power-calibrated, self-driven, and unambiguous detection of both linearly polarized (LP) and circularly polarized (CP) light is realized by the broken symmetry–induced linear photogalvanic effects (LPGEs) and circular photogalvanic effects (CPGEs) in the two BP units. Moreover, the device enables single-pixel polarimetric imaging to acquire spatial polarization information. The ultracompact device structure, free from external optical and mechanical modules, may inspire the development of miniaturized optical and optoelectronic systems.

The use of multicore fiber (MCF) aims to increase the fiber density with downsized fiber systems, which is constrained by a de-multiplexer with a large footprint that converts the MCF into numerous single-mode fibers and corresponding number of infrared photodetectors. In this study, we demonstrate an ultracompact seven-core fiber de-multiplexer by integrating a patterned single-layer graphene (SLG) photodetector array on a single fiber endface. An optimized electrode configuration was successfully fabricated with a strongly asymmetrical structure on patterned SLG. Owing to the efficient photocarrier separation at the built-in electric field across the metal-doped junction in graphene, we realized self-powered seven-core photodetection using the device. Remarkably, our device exhibits a coupling-free, miniaturized device volume with zero power consumption, a high transmittance, and low manufacturing cost. This device downsizes traditional bulky receiver modules to the micrometer scale with an atomical thickness, which may inspire the development of next-generation highly integrated optical and optoelectronic systems.

A fiber‐end‐face‐integrated electrically tunable optical modulator based on graphene field‐effect transistor and the fabrication technique are proposed and demonstrated. The all‐fiber device features a scheme of compactness and high integration when applied to fiber optical system, as well as a low insertion loss since spatial coupling of light is avoided. A reflecting structure is used and the electro‐optic modulator shows vivid modulation when gate voltage gets tuned, with maximum optical reflectance modulation depth over 1% in demonstration. To the best of the authors’ knowledge, it is the first time to build an all‐solid gate‐control modulator directly on fiber facet. The fabrication methods introduce workflows of silicon‐on‐insulator processing into the optical fiber end‐face micromachining domain which can be applied to more comprehensive configurations, broadening the path of fiber‐end‐face integrated device.