Broadband Wavelength Conversion Research Articles

Efficient and Broadband All-Optical Wavelength Conversion between C and O Bands in Nanophotonic Lithium Niobate Waveguides

Efficient and Broadband All-Optical Wavelength Conversion between C and O Bands in Nanophotonic Lithium Niobate Waveguides

Broadband optical wavelength conversion through four-wave mixing in W3-type AlGaAs photonic crystal waveguides

We realized a wide-band wavelength conversion method through four-wave mixing in W3-type AlGaAs photonic crystal waveguides. AlGaAs exhibits a large third-order nonlinearity. Furthermore, because of its large bandgap, two-photon absorption can be avoided in the 1550 nm range. A four-wave mixing efficiency of −7 dB was obtained for a pump peak power of 7 W. Furthermore, by utilizing the two even guided bands of the W3-type photonic crystal waveguide, a conversion bandwidth greater than 38 nm was achieved with a conversion efficiency of −22 dB.

Broadband Wavelength Conversion for Hybrid Multiplexing Signals Based on a Parallel Dispersion-Engineered Silicon Waveguide

Broadband all-optical wavelength conversion (AOWC) for hybrid wavelength- and mode-division multiplexing (WDM-MDM) signals is experimentally demonstrated based on degenerate four-wave mixing in a silicon chip with a parallel dispersion-optimized multimode nonlinear waveguide and mode (de)multiplexers. By simultaneously coupling two modes into the waveguide using an optical fiber array, the intermodal crosstalk is measured to be as low as −25.9 dB for the fundamental mode of the transverse electric mode (TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ) (or −23.6 dB for the first-order mode TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> ), and the conversion efficiency is −25.4 dB for TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (or −26.3 dB for TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> ) mode. A wide conversion bandwidth of ∼68 nm is measured except for the influence of the crosstalk, which is the first time to experimentally demonstrate the broadband wavelength conversion for MDM signal. Using a 4 × 10 Gbit/s on-off keying (OOK) hybrid WDM-MDM signal, four AOWC channels are obtained on the idlers and the power penalty of each channel is less than 2.7 dB at the bit-error-ratio of 1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−9</sup> .

Broadband optical parametric amplification using PPLN waveguide pumped by detuned second harmonic.

Optical parametric amplification in the range of 1.3-1.8 µm was demonstrated by using a periodically poled LiNbO3 (PPLN) waveguide as a nonlinear medium by varying the detuning of the pump wavelength. A wide range of detuning was enabled by using a multiple-quasi-phase-matched (M-QPM) LiNbO3 waveguide for pump generation through second harmonic generation (SHG) and temperature control of the PPLN waveguide. Broadband optical amplification and wavelength conversion through difference frequency generation (DFG) are considered useful for widening the bandwidth of optical communication.

Wavelength conversion of KTP crystal based Stark-chirped rapid adiabatic passage

The nonlinear wavelength conversion can generate the laser wavelengths which are not directly available, thereby broadening the laser spectrum range. However, the phase mismatch greatly limits the development and application of nonlinear optical technology. The wavelength conversion schemes in a manner analogous to population transfer in atomic rapid adiabatic passage, stimulated Raman adiabatic passage (STIRAP), and Stark chirped rapid adiabatic passage (SCRAP) provide feasible solutions for efficient and broadband wavelength conversion. The SCRAP uses the Stark shift caused by the Stark field to generate energy level crossings, therefore, the population in initial state can be efficiently converted into the target state. It does not require the two-photon resonance, and can be applied to multi-photon transition. In this paper, by approximate analogy to the adiabatic population theory, a wavelength conversion model with the KTP crystals based SCRAP is established, the influence of the coupling delay parameters, width parameters, pump intensity, temperature, and incident wavelength on the conversion process are systematically studied. The results show that the signal laser energy can be almost converted into output laser energy, while the intermediate laser energy is kept extremely low in the conversion process. The conversion process is sensitive to changes in coupling delay parameters, width parameters, and pump intensity. The farther away fromits optimal value the coupling delay parameter, the lower the conversion efficiency is. When the width parameter &lt;inline-formula&gt;&lt;tex-math id="M1"&gt;\begin{document}$ d_2^2 $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M1.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M1.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt; is fixed, as the width parameter &lt;inline-formula&gt;&lt;tex-math id="M2"&gt;\begin{document}$ d_1^2 $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M2.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M2.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt; increases, the conversion efficiency first increases to a maximum value, and then slowly decreases. At the same time, the greater the value of the width parameter &lt;inline-formula&gt;&lt;tex-math id="M3"&gt;\begin{document}$ d_2^2 $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M3.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M3.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;, the greater the achievable maximum conversion efficiencies, and the greater the bandwidth that can achieve high-efficiency wavelength conversion. The conversion efficiency increases as the pump intensity increases. When the conversion efficiency value reaches a maximum value, the increase in pump intensity has almost no effect on the conversion efficiency. However, changes in temperature and incident wavelength have little effect on the conversion efficiency. The above research can provide a theoretical basis for the acquisition of ultraviolet to mid-infrared light sources and the manufacture of photonic devices.

Numerical Study of Broadband Wavelength Conversion Based on InP/In1-xGaxAsyP1-y Strip-loaded Waveguide

Numerical Study of Broadband Wavelength Conversion Based on InP/In1-xGaxAsyP1-y Strip-loaded Waveguide

Single‐beam dual‐color alternate‐pathway two‐photon spectroscopy: Toward an optical toolbox for redox biology

AbstractWe demonstrate a versatile single‐laser platform for single‐beam dual‐color two‐photon spectroscopy that combines a short‐pulse laser source with a tunable broadband wavelength converter based on a highly nonlinear photonic‐crystal fiber (PCF). We show that the short‐pulse PCF output can be tailored, via dispersion and nonlinearity management, to deliver a broadband optical driver whose spectral structure is ideally suited for a single‐beam two‐photon absorption (2PA) spectroscopy of the next‐generation genetically encodable fluorescent‐protein (FP) sensors of pH and redox‐responsive contrast agents. As a promising spectroscopic resource for redox biology, the short‐pulse PCF output can be finely sculpted to alternately drive an FP system via a one of its two 2PA‐allowed quantum pathways, yielding a high‐contrast fluorescence readout for a highly sensitive detection of redox reactions and signaling, pH sensing, and oxidative‐stress diagnosis.

High-Q titanium dioxide micro-ring resonators for integrated nonlinear photonics.

We report on the nonlinear characterizations of the titanium dioxide micro-ring resonators (TiO2 MRRs). By utilizing optimized fabrication processes, high quality factors (Q∼1.4 × 105) doubling that of the previous work are achieved here for TiO2 MRRs with high-confinement TiO2 waveguides. The four-wave mixing (FWM) experiment results with low and high signal power demonstrate that, the fabricated TiO2 MRRs can perform broadband (∼40 nm) wavelength conversion and cascaded FWMs. These achievements pave the way for key nonlinear photonic applications with TiO2 waveguides and provide an efficient platform for various integrated photonic devices.

Four-Wave Mixing-Based Wavelength Conversion and Parametric Amplification in Submicron Silicon Core Fibers

Silicon core fibers represent a versatile platform for all-fiber integrated nonlinear optical applications. This paper describes the state of the art in four-wave mixing-based parametric amplification, and wavelength conversion in silicon fibers that have been tapered to improve the material quality, and engineer the dispersion profile. Fibers with submicron core dimensions have been fabricated, and used to demonstrate high gain parametric amplification in the C-Band, and broadband wavelength conversion extending out to the S-, and L-bands. The potential to use these fibers for all-optical signal processing of 20 Gbit/s data signals has also been demonstrated, with a robust all-fiber coupling scheme presented to improve the efficiency, and practicality of these devices. These results highlight the potential of silicon core fibers for use in nonlinear signal processing within future telecommunication systems.

Kerr nonlinearity induced four-wave mixing of CMOS-compatible PECVD deposited ultra-Si-rich-nitride

Benefitting from low propagation loss and complementary metal–oxide–semiconductor compatibility, Si3N4 is heavily explored for the applications of nonlinear optical signal processing. However, the Si3N4 waveguide is limited by its low optical Kerr nonlinearity. In this work, we introduce highly nonlinear ultra-Si-rich-nitride (USRN) deposited by the plasma enhanced chemical vapor deposition system. The measured linear refractive index of USRN is 3.09 at a wavelength of 1550 nm, while the Kerr nonlinearity of the USRN waveguide is experimentally extracted with a value of 2.25×10−17 m2/W. Moreover, a broadband wavelength conversion ranging from S-band to L-band by a four-wave-mixing experiment is realized via designed USRN waveguide with a relatively short length of 3 mm. The measured bandwidth is 190 nm with a continuous-wave pump laser located at 1530 nm. The conversion efficiency is measured approximately −48 dB under a relatively low pump power of 7 dBm.

Silicon Photonics Chip for Inter-modal Four Wave Mixing on a Broad Wavelength Range

We design, fabricate and test an integrated silicon photonics chip for inter-modal four wave mixing, whose phase-matching relays on the modal dispersions of different waveguide modes. This phase-matching technique allows for tunable and broadband wavelength conversion and generation. We demonstrate that idler and signal photons can be generated with 800 nm spectral distance in between. We measure several inter-modal combinations, with up to the third order mode involvement. We demonstrate a maximum conversion efficiency of -12.4 dB from 1468.5 nm to 1641.1 nm with a bandwidth of 11 nm. We also prove the high and broadband tunability of the generated signal by scanning the pump wavelength when the signal wavelength is fixed. All these features make the inter-modal four wave mixing a viable solution for all optical processing in the near as well as in the mid infrared and for quantum applications.

Dynamic O-band to C-band wideband wavelength converter for integrated VCSEL-based optical interconnects

ABSTRACTReal-time wavelength conversion and traffic routing at key network nodes is a fundamental requirement for current optical interconnects. This work experimentally demonstrates a broadband wavelength conversion from O-band to C-band employing commercially available, power efficient VCSELs. A 1310 nm VCSEL is directly modulated with 8.5 Gbps data and transmitted over 22 km G. 652 fibre with a 0.53 dB penalty. The received data is used to run a 1550 nm VCSEL located at the network integration node, achieving the first reported wavelength conversion from O-to-C-band. VCSEL wavelength tuneability with changing bias current functionality is further exploited to route the converted wavelength over 400 GHz spectra range for integration into wavelength flexible networks. The newly converted wavelength is transmitted over 24.7 km of G. 655 fibre, incurring a maximum penalty of 1.86 dB. Results from this work proves an enabling development technology for wavelength converters for transparent contention resolution in current and future optical Interconnects.

Continuous-Wave Pumping Supercontinuum Generation in Random Distributed Feedback Laser Cavity

In this paper, we demonstrated a continuous-wave pumping supercontinuum generation in a random distributed feedback fiber laser with a completely open laser cavity. A broadband wavelength conversion was obtained by pumping a 36-km long TrueWaveREACH fiber in anomalous dispersion regime with a high power continuous-wave Raman laser. The spectral broadening was assisted via nonlinear mechanism such as modulation instability and stimulated Raman scattering. An extended 10-dB flat supercontinuum with 129-nm bandwidth spanning over C-, L-, and U-band wavelengths was generated in the forward direction of lasing cavity under 3.65-W pump power. The super-continuum exhibited excellent bandwidth stability in 60 minutes of lasing operation. A simultaneous generation of random Raman laser operating in the backward direction of cavity was also demonstrated within the same gain fiber. The simple laser cavity presented significant versatility in its generation of novel light sources for both telecommunication and applied science applications.

VCSEL-based broadband wavelength converter for ultra-wideband flexible spectrum data routing in optical interconnects

Abstract High-speed real-time wavelength conversion at key data centre network nodes is an emerging fundamental functionality requirement for transparent content resolution, wavelength assignment and routing towards better utilization of network resources under dynamic traffic patterns. In this paper, we experimentally demonstrate the first vertical cavity surface emitting laser (VCSEL)-based broadband wavelength converter for ultra-wide wavelength routing in Datacom. An 850 nm multimode VCSEL is directly modulated with 8.5 Gbps data and successfully transmitted error-free over 100 m OM3 multimode fibre (MMF) with a receiver sensitivity of −16.04 dBm, and a total transmission penalty of 1.14 dB. The received data is then used to run two cascaded single mode VCSELs at 1550 nm within the network integration node, therefore achieving the first reported real-time inter-band wavelength converter to C-band. By exploiting VCSEL wavelength tuneability with changing bias current, we show that the converted wavelengths can be routed over 3.2 nm spectra range for integration into ITU-T 50 GHz flexible grid and beyond. The newly converted wavelengths are successfully transmitted over 24.7 km of G 655 single mode fibre, achieving a minimum receiver sensitivity of −14.28 dBm, with a maximum transmission penalty of 2.72 dB. This work offers a viable enabling development technology for broadband wavelength converters for real-time wavelength routing in optical interconnects to address content resolution and wavelength assignment problem for current and future Datacom.

Broadband Wavelength Conversion Based on Parallel-Coupled Micro-Ring Resonators

We propose a broadband and high-efficiency four-wave-mixing wavelength converter based on parallel-cascaded micro-ring resonators (PCMRRs). By optimizing the distance between the mutually uncoupled ring resonators, we demonstrate that the PCMRR has a transmission spectrum with interleaved narrow and broad passbands. Broadband and high-efficiency wavelength conversion can be achieved by placing the pump and the signal in the narrow and broad passbands, respectively. We experimentally demonstrate a 25-GHz bandwidth wavelength converter based on optimally designed 3-ring PCMRR. Compared with the conventional single-ring-resonator-based wavelength converter with the same bandwidth, there is a 15-dB enhancement of conversion efficiency for the 3-ring PCMRR when the input pump power is 10 dBm.

Design of mid-infrared nonlinear silicon–germanium waveguides for broadband/discrete-band wavelength conversion

A dispersion-engineered silicon–germanium (Si0.8Ge0.2) waveguide is designed for mid-infrared (MIR) broadband or discrete-band wavelength conversion by using its advantages of high nonlinearity and tight mode-field confinement. The dispersion of this waveguide is engineered by optimizing the waveguide geometry. The zero-dispersion wavelength is tuned to about 2 μm, and the dispersion curve is flattened to reduce the dispersion slope. In the MIR band, the 3 dB bandwidth for the four-wave mixing effect reaches 795 nm, and the peak conversion efficiency is −25.0 dB when the pump power is 500 mW, which can support the broadband all-optical wavelength conversion for next-generation MIR optical communications. Discrete-band wavelength conversion between the MIR (2.5–3.8 μm) and telecommunication (1.30–1.72 μm) bands is realized by using the pair of phase-matching wavelengths far away from the pump. Moreover, by choosing proper waveguide geometries, the signals in the band of 2.0–3.8 μm can be efficiently converted to the idler with fixed wavelength of 1.55 μm, which exhibits the potential to realize indirect detection by using telecommunication-band detectors to detect MIR signals.

Detecting a pronounced delocalized state in third-harmonic generation phenomenon; a quantum chaos approach

Nonlinear optics (NLO) deserves special attention in new optical devices, making it possible to generate coherent light more efficiently. Among the various NLO phenomena the third-harmonic generation (THG) is at the core of the effective operating mechanism of broadband wavelength conversion, in all-optical devices. Here, we aim to understand how the third-order susceptibility and the electric field may be effectively effect on the localization properties of the light in the THG process when included in a two-mode cavity coherently perturbed by a classical field. We address a stable–unstable transition due to the combination effect of the aforementioned factors. We report a reliable evidence confirming the appearance of chaos in THG under suitable conditions. By tracing the signatures of adjacent-spectral-spacing-ratio (ASSR) distribution and participation ratio, we also find a critical point (ϵc,κc)=(3.1,0.35) for which a pronounced delocalized response is seen. This study may have profound findings for practical devices, and ushers in new opportunities for practical exploitation of the electric field and the third-order susceptibility effect in nonlinear optical devices.

Broadband wavelength conversion in a silicon vertical-dual-slot waveguide

We propose a silicon waveguide structure employing silica-filled vertical-dual slots for broadband wavelength conversion, which can be fabricated using simple silicon-on-insulator technology. We demonstrate group-velocity dispersion tailoring by varying the width of the core, the slots and the side strips, and put forward a method to achieve spectrally-flattened near-zero anomalous group-velocity dispersion at telecom wavelengths. A proposed structure provides a group-velocity dispersion parameter β2 of −60 ps2/km with an effective mode area Aeff of 0.075 µm2 at 1550 nm. This structure is predicted to significantly broaden the bandwidth of wavelength conversion via four-wave mixing, which is validated with experimentally measured 3 dB bandwidth of 76 nm.

Magnetic actuation and feedback cooling of a cavity optomechanical torque sensor

Cavity optomechanics has demonstrated remarkable capabilities, such as measurement and control of mechanical motion at the quantum level. Yet many compelling applications of optomechanics—such as microwave-to-telecom wavelength conversion, quantum memories, materials studies, and sensing applications—require hybrid devices, where the optomechanical system is coupled to a separate, typically condensed matter, system. Here, we demonstrate such a hybrid optomechanical system, in which a mesoscopic ferromagnetic needle is integrated with an optomechanical torsional resonator. Using this system we quantitatively extract the magnetization of the needle, not known a priori, demonstrating the potential of this system for studies of nanomagnetism. Furthermore, we show that we can magnetically dampen its torsional mode from room-temperature to 11.6 K—improving its mechanical response time without sacrificing torque sensitivity. Future extensions will enable studies of high-frequency spin dynamics and broadband wavelength conversion via torque mixing.

Broadband wavelength conversion in hydrogenated amorphous silicon waveguide with silicon nitride layer

Broadband wavelength conversion based on degenerate four-wave mixing is theoretically investigated in a hydrogenated amorphous silicon (a-Si:H) waveguide with silicon nitride inter-cladding layer (a-Si:HN). We have found that enhancement of the non-linear effect of a-Si:H waveguide nitride intermediate layer facilitates broadband wavelength conversion. Conversion bandwidth of 490 nm and conversion efficiency of 11.4 dB were achieved in a numerical simulation of a 4 mm-long a-Si:HN waveguide under 1.55 μm continuous wave pumping. This broadband continuous-wave wavelength converter has potential applications in photonic networks, a type of readily manufactured low-cost highly integrated optical circuits.