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Multiplexed ultrafast fiber laser emitting multi-state solitons
摘要： Ultrafast fiber lasers have been serving as an ideal playground for spreading the extensive industrial applications and exploring the optics nonlinear dynamics. Here, we report a bidirectional fiber laser scheme for validating the possibility of a multiplexed laser system, which is passively mode-locked by the nonlinear polarization rotation (NPR) technique. In particular, the proposed fiber laser consists of one main cavity and two counter-propagating branches with different dispersion distributions. Thus, different formation mechanisms are introduced into the lasing oscillator. Consequently, stable conventional solitons (CSs) and dissipative solitons (DSs) are respectively formed in the clockwise (CW) and counterclockwise (CCW) directions of the same lasing oscillator. Moreover, attributing to the strong birefringence filtering effect, the wavelength selection mechanism is induced. Through the proper management of intra-cavity birefringence, wideband wavelength tuning and switchable multi-wavelength operations are experimentally observed. The central wavelength of CS can be continuously tuned from 1560 nm to 1602 nm. Additionally, the evolution process of different multi-wavelength operations is also elucidated. Benefiting from this multiplexed laser scheme, bidirectional lasing oscillation, multi-state soliton emission, wavelength tuning and multi-wavelength operations are synchronously realized in a single laser cavity. To the best of our knowledge, it is the first time for such a multiplexed fiber laser has been reported. The results provide information for multifunctional ultrafast fiber laser system, which is potentially set for telecommunications, fiber sensing and optics signal processing, etc.
关键词： multi-wavelength operations,nonlinear polarization rotation,wavelength tuning,Ultrafast fiber lasers,dissipative solitons,conventional solitons
更新于2025-11-28 14:24:03
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Poincaré sphere-based technique for tuning flat-top fiber comb filter
摘要： We propose a universal method for designing flat-top passband and wavelength tuning of transmission spectrum of a fiber comb filter based on a polarization-diversified loop structure using Poincaré sphere representation. The proposed method gives a clear visualization of the evolution of polarization state through birefringent optical elements comprising the filter, and the design results are experimentally verified. Our method can also suggest which optical components are necessary for a specifically desired transmission spectrum of the comb filter.
关键词： flat-top passband,polarization-diversified loop structure,fiber comb filter,Poincaré sphere,wavelength tuning
更新于2025-09-23 15:21:01
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<i>In situ</i> wavelength tuning of quantum-dot single-photon sources integrated on a CMOS-processed silicon waveguide
摘要： Silicon quantum photonics provides a promising pathway to realize large-scale quantum photonic integrated circuits (QPICs) by exploiting the power of complementary-metal-oxide-semiconductor (CMOS) technology. Toward scalable operation of such silicon-based QPICs, a straightforward approach is to integrate deterministic single-photon sources (SPSs). To this end, hybrid integration of deterministic solid-state SPSs, such as those based on InAs/GaAs quantum dots (QDs), is highly promising. However, the spectral and spatial randomness inherent in the QDs poses a serious challenge for scalable implementation of multiple identical SPSs on a silicon CMOS chip. To overcome this challenge, we have been investigating a hybrid integration technique called transfer printing, which is based on a pick-and-place operation and allows for the integration of the desired QD SPSs on any locations on the silicon CMOS chips at will. Nevertheless, even in this scenario, in situ fine tuning for perfect wavelength matching among the integrated QD SPSs will be required for interfering photons from dissimilar sources. Here, we demonstrate in situ wavelength tuning of QD SPSs integrated on a CMOS silicon chip. To thermally tune the emission wavelengths of the integrated QDs, we augmented the QD SPSs with optically driven heating pads. The integration of all the necessary elements was performed using transfer printing, which largely simplified the fabrication of the three-dimensional stack of micro/nanophotonic structures. We further demonstrate in situ wavelength matching between two dissimilar QD sources integrated on the same silicon chip. Our transfer-printing-based approach will open the possibility for realizing large-scale QPICs that leverage CMOS technology.
关键词： wavelength tuning,transfer printing,quantum photonics,single-photon sources,silicon CMOS,quantum dots
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Wide and Continuous Tunable Mode-Locked Erbium-Doped Fiber Laser Based on the Graphene Oxide
摘要： In addition to the artificial saturable absorber (SA) like the nonlinear polarization rotation (NPR), the investigation of peculiar soliton dynamics from passive mode-locked fiber laser (PML-FL) can be produced based on the semiconductor saturable absorber mirror (SESAM) and various nanomaterials, like the carbon nanotube (CNT), graphene, graphene oxide (GO), topological insulator (Bi2Se3) with lower mode-locked threshold. In comparison with other SAs, GO reveals various advantages including relative widely operation bandwidth, easy fabrication, low saturation intensity, ultrashort recovery time. For specific application, the wavelength tuning of PML-FL is required but is limited for the SESAM or CN. Recently, the wavelength tuning of mode-locked Er-doped fiber laser (EDFL) around 1570-1600 nm has been demonstrated based on graphene because of its relative wide absorption range. In this work, we demonstrated the fine tuning of emission peak wavelength of EDFL based on the GO/PVA film.
关键词： Erbium-doped fiber laser,mode-locked,graphene oxide,wavelength tuning
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Live Multi-Color Coherent Raman Imaging Enabled by Millisecond Wavelength Tuning
摘要： We present multi-color coherent Raman imaging (CRI) with a frame rate of 8 Hz and rapid wavelength tuning within only 5 ms between successive images, enabled by a novel fiber optical parametric oscillator (FOPO). In CRI the limited tuning speed of conventional laser systems (>1 s) prevents the acquisition of successive images per second at more than one vibrational resonance and is considered as a bottleneck for multi-color assessments of medical specimen and rapidly evolving samples, such as living cells. Recent approaches to CRI with wavelength switching on a timescale of (sub-) milliseconds were based on two synchronized oscillators [1], being limited to two resonances, and parallel laser amplifiers [2] or spectral focusing techniques [3], both the latter with a limited tuning bandwidth of less than 300 cm-1. In contrast, the energy difference of the pump and Stokes pulses, emitted by the here presented FOPO, is tunable across the wide spectral range between 865 and 3050 cm-1 within only 5 ms. Assuming an equal time span for tuning and acquisition, up to 100 user-selectable vibrational components could be imaged per second, when imaging with 100 frame/s. The rapid tuning was achieved by a novel tuning concept for OPOs, based on the dispersive matching of the repetition frequency change of the pump pulses to the associated repetition frequency change of the resonant signal pulses in the FOPO. No alteration of the FOPO, e.g., via a mechanical delay line [4], was required for tuning the signal wavelength and the light source could be composed of all-spliced fiber components. Compared to previously presented FOPOs, the system runs at a high repetition rate of 40 MHz. The pump and Stokes pulses exhibit equal durations of 7 ps and an average power of 500 and 200 mW, respectively. As a first proof-of concept of the CRI capabilities, Fig. 1 shows three images of a sample consisting of water, oil and beads of PMMA and PS, taken successively with an acquisition time of 125 ms for each frame, limited only by the sampling rate of our detection setup. The energy difference was tuned in a frame-by-frame manner between 2850, 2950 and 3050 cm-1 in a time of 5 ms, a negligible time span compared to the acquisition time.
关键词： vibrational resonance,living cells,medical specimen,rapid wavelength tuning,fiber optical parametric oscillator,multi-color coherent Raman imaging
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Widely Tunable Watt-Level MOPA Systems Emitting at 976 nm
摘要： Tunable diode laser sources are key components in absorption spectroscopy, biomedical imaging and in optical telecommunication systems, to mention a few examples. The term tunable refers here to laser sources with a mechanism for precise control of the emission wavelength, while maintaining a narrow spectral linewidth. In addition, multiple applications require high output power with good beam quality. In this work, we present results on recently developed light sources that fulfil these different requirements. These are based on a hybrid master oscillator power amplifier (MOPA) concept, which utilizes a tunable MO combined with a tapered power amplifier (TPA). The MO serves as the wavelength selective element, while the PA ensures amplification to the Watt-level from a nearly diffraction limited beam. These miniaturized systems are constructed on micro benches, on top of 25 mm × 25 mm laser mounts.
关键词： high output power,wavelength tuning,tunable diode laser,MOPA,beam quality
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Advances in MOEMS-Based External Cavity QCLs
摘要： The combination of broadband quantum cascade lasers (QCLs) with a micro-electro-mechanical system (MOEMS) scanner with integrated diffraction grating as a wavelength-selective and optical feedback providing element enables the realization of compact, portable and robust spectroscopy systems. As previously showed [1–2], such MOEMS-based external cavity (EC)-QCLs configurations lead to measurement times as low as ~1 millisecond per QCL-tuning range (hundreds of cm-1) while eliminating the need of homodyne detection systems, such as lock-in electronics. Also non-resonant (quasistatic) MOEMS grating scanners providing scan rates of tens of Hz as well as static setting of arbitrary wavelengths are possible, keeping the advantage of using small MOEMS footprints, ruggedness, and low power consumption. Here we review our latest developments in MOEMS-based EC-QCLs made by Fraunhofer IAF and IPMS. We present a miniaturized, non-resonant MOEMS EC-QCL that allows scan frequencies of few tens of Hz (as well as static operation) together with an excellent wavelength reproducibility within a small and compact device. Static-controllable MOEMS EC-QCLs are of high interest for spectroscopy applications that require both arbitrary tuning speeds (e.g. large time constants as in photothermal or photoacoustic spectroscopy) and discrete wavelength tuning. Such tuning speeds are not achievable with resonantly-driven MOEMS scanners, as their mechanical resonance frequency remains >120 Hz. Both requirements can be well fulfilled with static-controllable MOEMS EC-QCLs independently of the QCL gain bandwidth characteristics. We also present a resonantly-driven continuous wave (cw) MOEMS EC-QCL with cavity-length control to enable fast high-resolution fast spectroscopy over a spectral range of >100 cm-1 and discuss our progress towards a dispersion-free beam spot radius for MOEMS EC-QCLs and our approach to operate MOEMS EC-QCLs in a permanent low-noise regime.
关键词： wavelength tuning,QCL,external cavity,spectroscopy,MOEMS
更新于2025-09-11 14:15:04
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Electronically Tunable Distributed Feedback (DFB) Laser on Silicon
摘要： An electronically tunable distributed feedback (DFB) laser heterogeneously integrated on a silicon photonics platform is experimentally demonstrated. Tuning is achieved through carrier injection into the tuning layer of a tunable twin-guide III–V membrane on silicon. A 2 nm continuous tuning range is achieved with a single tuning current. Continuous-wave single-mode laser operation with a side-mode suppression ratio larger than 44 dB across the tuning range is obtained. Measured wavelength switching times are on the order of 3 ns and non-return-to-zero on-o? keying direct modulation at 12.5 Gbit s?1 is readily achieved. This work can be a major advance toward the realization of optical burst or packet switching systems for future data center networks.
关键词： silicon photonics,electronic wavelength tuning,distributed feedback lasers,semiconductor lasers
更新于2025-09-11 14:15:04