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[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - High-Power Long-Waveguide 1300nm Directly Modulated DFB Laser for 45Gb/s NRZ and 50Gb/s PAM4
摘要： A 1300-nm high-speed high-power directly modulated distributed-feedback laser using floating feeding electrode has been demonstrated. A 5-μm-thick benzocyclobutene was used for planarization to float a coplanar waveguide, connecting a reversed-mesa ridge waveguide of a laser. Low parasitic capacitance was then formed. A long waveguide can thus be fabricated with low roll-off at high-frequency modulation, further enabling high-output optical power. A 250-μm-long waveguide was fabricated, leading to >28-mW optical power with linear operation and ?3-dB bandwidth of 26 GHz. Furthermore, improvement in high-frequency regime and the reduction near resonance peak were found, attaining a broadband and flat frequency response at high current. A 45-Gb/s non-return-to- zero and 50-Gb/s four-level pulse amplitude modulation with 35-km fiber transmission were successfully shown through mod- ulating high-output optical power.
关键词： Coplanar waveguide (CPW),distributed feedback (DFB) lasers,reversed-ridge waveguide (RRW),planarization
更新于2025-09-11 14:15:04
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Contra-Directional Ridge Waveguide Couplers: Design and Applications
摘要： This article presents novel wideband contra-directional couplers based on single conductor ridge waveguide, and their applications. The couplers exhibit wide bandwidths and tight coupling while occupying very small volume due to the compactness of ridge waveguides. The methodology to design the couplers is presented. It is inspired by the even and odd modes used to design TEM coupled lines couplers but implemented with TE modes in this novel approach. The design starts with designing the coupling section in a quadruple-ridge waveguide that supports two independent even and odd TE modes. Proper choice of the cross section allows the designer to achieve the required impedance levels for the required coupling values. An S-band proof of concept prototype of a single coupler was synthesized, fabricated, and tested, demonstrating excellent measured results without any tuning. The couplers can be exploited in versatile applications, such as power sampling, beamforming, or high-power combiners. As an additional proof of concept design, a C-band three-way combiner was also designed and tested, showing the potential of the novel coupler for different applications.
关键词： ridge waveguide,power combiner,divider,Backward coupling,directional coupler
更新于2025-09-11 14:15:04
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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) - Efficient Er and Nd:Ti:LiNbO <sub/>3</sub> Ridge Waveguide Lasers for the Development of Mid Infrared Sources
摘要： The ferroelectric crystal lithium niobate (LiNbO3) is an attractive material for a variety of photonics applications due to its excellent electro-optic and nonlinear properties. Another benefit of rare-earth doped LiNbO3 is the easy implementation of low-loss waveguides leading to the development of waveguide amplifiers as well as waveguide lasers. In the past, a great deal of attention was attracted to the development of optically pumped Er3+- and Nd3+-doped LiNbO3 waveguide lasers emitting around the 1.5 μm telecom wavelength range and 1.08 μm, respectively. Up to date, Er- and Nd-doped LiNbO3 channel waveguide lasers with slope efficiencies up to 30 % [1] and 40 % [2], respectively, have been reported. However, a further improvement of the laser performance can be achieved by using a ridge waveguide geometry due to the smaller mode fields and improved overlap of modes at different wavelengths as well as the reduction of photorefractive damage. In this work, we report on our novel fabrication method for the development of highly efficient Er: and Nd:Ti:LiNbO3 ridge waveguide amplifiers and lasers [3,4]. To improve the amplifier/laser performance a fabrication technique comprised of ridge definition by diamond blade dicing followed by three-side Er/Nd/Ti deposition and in-diffusion (Fig. 1a) was developed and refined allowing higher Er/Nd doping concentrations and overlap of Er/Nd diffusion profiles with guided modes. An internal gain of 3.0 dB/cm has been measured in 4.6 cm long Er:Ti:LiNbO3 ridge waveguides for a coupled pump power of 200 mW at 1486 nm [3]. Utilizing this high internal gain, we achieved efficient lasing with a slope efficiency of 33 % at 1561 nm (see Fig. 1b) [3]. Furthermore, we demonstrated a Nd:Ti:LiNbO3 ridge waveguide laser with a slope efficiency of 34 % at a wavelength of 1084.7 nm pumped by a Ti:Sapphire laser emitting at 814 nm (see Fig. 1b) [4]. Due to improved photorefractive damage resistance by indium tin oxide (ITO) coating we achieved stable laser operation with a maximum output power of 108 mW for a coupled pump power of 402 mW corresponding to an intensity of ~490 kW/cm2 [4]. Recently, a novel method to achieve local periodic poling of Ti-diffused ridge waveguides in zx-cut LiNbO3 has been demonstrated [5]. In contrast to previous approaches, this method for periodic poling allows an optimization of the ridge waveguide geometry for nonlinear optics applications such as quasi-phase-matched (QPM) difference frequency generation (DFG). The ability to develop highly efficient Er- and Nd-doped ridge waveguide lasers in LiNbO3 and to achieve local QPM allows for the development of efficient hybrid optical devices in the same ridge waveguide emitting in the mid-infrared suitable for applications such as gas sensing.
关键词： Nd-doped,ridge waveguide lasers,lithium niobate,photonics applications,Er-doped
更新于2025-09-11 14:15:04
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[IEEE 2019 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - Taiyuan, China (2019.7.18-2019.7.21)] 2019 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - Ridged Waveguide Slot Phased Array for 5G Millimeter-wave Application
摘要： A slotted waveguide phased array based on a single-ridged waveguide (SRWG) with enhanced scanning angle, wide impedance bandwidth and side lobes bandwidth, as well as low cross-polarization is designed. A transition structure is designed to feed the ridge waveguide with polarization torsion and conversion from the ridge waveguide to a standard rectangular waveguide. A single waveguide is divided into two subarrays to achieve small angle scanning in vertical dimension (yoz plane). An 8 × 8 array is designed and simulated to validate the slot antenna design. The bandwidth for VSWR＜2.0 is 3 GHz at the center frequency of 28 GHz. The realized gain at the center frequency is 24.0 dBi with antenna efficiencies better than 83%. The side lobes are controlled lower than -15dB over the entire working frequency, and the array can achieve a horizontal (xoz plane) scanning angle of ±45 °, and vertical scanning angle of ± 3 °, respectively.
关键词： ridge waveguide slot antenna,phased array,low sidelobe
更新于2025-09-11 14:15:04
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A Silicon Shallow-Ridge Waveguide Integrated Superconducting Nanowire Single Photon Detector Towards Quantum Photonic Circuits
摘要： A silicon shallow-ridge waveguide integrated superconducting nanowire single photon detector is designed and fabricated. At the bias current of 11.6 ??A, 4% on-chip detection efficiency near 1550 nm wavelength is achieved with the dark count rate of 3 Hz and a timing jitter of 75 ps. This device shows the potential application in the integration of superconducting nanowire single photon detectors with a complex quantum photonic circuit.
关键词： quantum photonic circuits,silicon shallow-ridge waveguide,superconducting nanowire single photon detector
更新于2025-09-11 14:15:04