Author Affiliations
1Key Laboratory of Light Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China2e-mail: bqjiang@nwpu.edu.cn3e-mail: xuetaogan@nwpu.edu.cnshow less
Fig. 1. Schematical demonstration of the generation and tuning system of Fano-like resonance. (a) Configuration of an FBG in one arm of an MZI. The inset shows the model of graphene-coated FBG. (b) Theoretical calculations of the spectral line shapes at different phase shifts Δφad=0, π/2, π, 3π/2 (please see the detailed evolution in Visualization 1). ASE, amplified spontaneous emission; TL, tunable laser; C1/C2, coupler 1/2; FBG, fiber Bragg grating, S/MU, source/measure unit; ODL, optical delay line; PD, photodetector; OSA, optical spectrum analyzer; OSC, oscilloscope.
Fig. 2. (a) Optical microscope and (b) scanning electron microscope (SEM) images of the graphene-coated FBG with Au electrodes. (c) Transmission spectrum at the applied voltage of 10 V, showing a distinct Fano-like line shape. (d) Volt–ampere characteristic curve of the device.
Fig. 3. (a) Spectral evolution at different voltages of 0 V, 9 V, 13 V, and 17 V (please see the detailed evolution in Visualization 2). (b) Changes of the wavelength shift Δλ of the interference dip [dip A in Fig. 2(c)], FSR near 1550 nm, and calculated Fano parameter q with the square of current on the graphene layer. (c) ER and SR of Fano-like line shapes for the first evolution period with the square of current of 1–6.8 mA2.
Fig. 4. Observation of electrically induced thermo-optic switching effect. (a) Periodically modulated voltage (top) and switch of reversed Fano-like line shapes (bottom) with applied voltage. (b) Temporal response of optical switching effect.