Author Affiliations
Abstract
1 Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
2 Key Laboratory of Light Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
We have observed various polarization domains and a giant self-mode-locked pulse in a 130 m long erbium-doped fiber laser without any mode-locking devices. By adjusting the intracavity polarization controller, we investigated the evolution process of the polarization domain with the varying cavity birefringence. When the birefringence was close to zero, the polarization domains split into multidomains, and finally a giant self-mode-locked pulse formed for the first time. We analyzed that the generation of the self-mode-locked pulse was related to the multiple subdomains ascribed to the strong coherent cross coupling between the orthogonal polarization light components in the long fiber cavity.
fiber lasers polarization domains self-mode-locked pulse nonlinear optics Chinese Optics Letters
2023, 21(3): 031402
Author Affiliations
Abstract
1 State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment, School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006, China
2 Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
3 Institute of Photonic and Technologies, Aston University, Birmingham B4 7ET, UK
We propose and demonstrate a sensitive vector twist sensor based on a small period long period fiber grating (SP-LPFG) fabricated with a femtosecond (fs) laser. The fabricated SP-LPFG is compact in size (2.8 mm) and shows strong polarization dependent peaks in its transmission spectrum due to the vectorial behavior of high-order cladding modes. Twist sensing is realized by monitoring the polarization dependent peaks, since the polarization of input light changes with fiber twist. The proposed sensor can be interrogated by the peak intensity and wavelength, with high twist sensitivity that reaches 0.257 dB/deg and 0.115 nm/deg, respectively.
fiber optical sensor long period fiber grating twist sensor Chinese Optics Letters
2021, 19(9): 090601
Author Affiliations
Abstract
1 Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
2 School of Optical and Electrical Information, Huazhong University of Science and Technology, Wuhan 430074, China
3 e-mail: yuan_yu@hust.edu.cn
4 e-mail: yuyu@mail.hust.edu.cn
We demonstrate a silicon-based microwave photonic filter (MPF) with flattop passband and adjustable bandwidth. The proposed MPF is realized by using a 10th-order microring resonator (MRR) and a photodetector, both of which are integrated on a photonic chip. The full width at half-maximum (FWHM) bandwidth of the optical filter achieved at the drop port of the 10th-order MRR is 21.6 GHz. The ripple of the passband is less than 0.3 dB, while the rejection ratio is 32 dB. By adjusting the deviation of the optical carrier wavelength from the center wavelength of the optical bandpass filter, the bandwidth of the MPF can be greatly changed. In the experiment, the FWHM bandwidth of the proposed MPF is tuned from 5.3 to 19.5 GHz, and the rejection ratio is higher than 30 dB.
Photonics Research
2019, 7(2): 02000110
Author Affiliations
Abstract
1 School of Electronics and Information Engineering, Foshan University, Foshan 528000, China
2 Wuhan National Laboratory for Optoelectronics and School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
3 School of Electrical and Information Engineering, The University of Sydney, Sydney, NSW 2006, Australia
We propose a return-to-zero on-off keying (RZ-OOK) to non-return-to-zero (NRZ) OOK conversion scheme based on a single custom-designed fiber Bragg grating (FBG). The custom-made FBG is designed and syn-thesized using discrete layer-peeling algorithm. It is shown that such a FBG can replace the combination of interferometer and the cascaded filter that are invariably employed together in the reported schemes for -RZ-OOK to NRZ-OOK format conversion. Simulation results show that the input 20-Gb/s RZ-OOK signals with different duty cycles can be converted into NRZ-OOK signals with high Q-factor.
060.3735 Fiber Bragg gratings 060.2340 Fiber optics components 060.4080 Modulation Chinese Optics Letters
2014, 12(9): 090603
