The combination of optical fiber with graphene has greatly expanded the application regimes of fiber optics, from dynamic optical control and ultrafast pulse generation to high precision sensing. However, limited by fabrication, previous graphene-fiber samples are typically limited in the micrometer to centimeter scale, which cannot take the inherent advantage of optical fibers—long-distance optical transmission. Here, we demonstrate kilometers long graphene-coated optical fiber (GCF) based on industrial graphene nanosheets and coating technique. The GCF shows unusually high thermal diffusivity of 24.99 mm2 s-1 in the axial direction, measured by a thermal imager directly. This enables rapid thermooptical response both in optical fiber Bragg grating sensors at one point (18-fold faster than conventional fiber) and in long-distance distributed fiber sensing systems based on backward Rayleigh scattering in optical fiber (15-fold faster than conventional fiber). This work realizes the industrial-level graphene-fiber production and provides a novel platform for two-dimensional material-based optical fiber sensing applications.

Soliton frequency combs generated in microresonators offer powerful tools for optical metrology, due to the high time‐frequency resolution. Here, via exciting the intracavity Brillouin laser in a high Q monolithic fiber resonator, a pair of orthogonal Kerr soliton combs is generated, which share the same repetition (frep ≈ 1.001 GHz) due to the soliton trapping but different central wavelengths (≈ 9.278 GHz). They offer rich dual‐comb beat notes with minimum phase noise down to −166.5 dBc Hz−1@1 MHz. Thanks to the geometric flexibility of the monolithic fiber resonator, the orthogonal soliton pair is found to be mechanically controllable with high precision. Specifically, by applying external stress on the microcavity in a range of ≈ 0–7.33 mN, the difference of their carrier‐envelope‐offset frequencies (Δfceo) is linearly tunable with a response of 0.3 kHz µN−1, meanwhile, tunability of the frep reaches 0.4 kHz µN−1. Such an orthogonally polarized dual soliton with stress controllability combining Brillouin excitation and parametric oscillation can offer a miniature all‐in‐fiber tool for wide applications ranging from frequency‐adjustable photonic microwave sources to highly sensitive gyroscopes.

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Soliton frequency combs generated in microresonators offer powerful tools for optical metrology, due to its high time-frequency resolution. Here, via exciting the intracavity Brillouin laser in a high Q monolithic fiber resonator, we generate a pair of orthogonal Kerr soliton combs, which share the same repetition (≈ 1 GHz) but different central wavelengths (≈ 10 GHz). Difference of their carrier-envelope-offset frequencies (Δfceo) is determined by the Brillouin-resonance overlap spectrally. We find that beat notes of the Δfceo is mechanically sensitive to external force, demonstrating a high sensitivity 0.3 kHz/µN, with a linear measurement range up to 7.3 mN. Leveraging the noise-filtering and lock-in heterodyne measurement, we obtain a detect limit down to 520 pN. This work reveals a novel paradigm of dual-soliton microcomb multiplexing pumped by one single laser, and combines the ultrahigh resolution dual-comb strategy and fiber sensor technology. It may open a way towards the realization of versatile and powerful microcomb based sensors with simple structure, which could be widely attractive in precision measurements such as high precision gyroscope, mechanical tracing, and material science examination.

Leveraging the avoid mode couplings in microsphere resonators, we demonstrated fast soliton slingshot intracavity. Its soliton access range reaches 8 GHz, with success possibility > 90% and single soliton ratio > 60%.