Dense Wavelength Division Multiplexing Devices Research Articles

Monolithic Strong Coupling of Topological Surface Acoustic Wave Resonators on Lithium Niobate.

Coherent phonon transfer via high-quality factor (Q) mechanical resonator strong coupling has garnered significant interest. Yet, the practical applications of these strongly coupled resonator devices are largely constrained by their vulnerability to fabrication defects. In this study, topological strong coupling of gigahertz frequency surface acoustic wave (SAW) resonators with lithium niobate is achieved. The nanoscale grooves are etched onto the lithium niobate surface to establish robust SAW topological interface states (TISs). By constructing phononic crystal (PnC) heterostructures, a strong coupling of two SAW TISs, achieving a maximum Rabi splitting of 22MHz and frequency quality factor product fQm of ≈1.2 × 1013Hz, is realized. This coupling can be tuned by adjusting geometric parameters and a distinct spectral anticrossing is experimentally observed. Furthermore, a dense wavelength division multiplexing device based on the coupling of multiple TISs is demonstrated. These findings open new avenues for the development of practical topological acoustic devices for on-chip sensing, filtering, phonon entanglement, and beyond.

Precise geometric error model based on z-axis motion platform of micro v-groove machine tools

The z-axis motion platform is an important part of micro v-groove machine tools. A v-groove structure is the most important basic component of fiber array, dense wavelength division multiplexing device, fiber optic splitter, planar lightwave circuit, and so on. The core pitch of v-groove structure which determines the quality of micro v-groove is the most important machining parameter. Its machining precision is mostly dominated by the compensation accuracy of geometric error in the z-axis direction. The precise geometric error model of z-axis motion platform is the basis and key of precision compensation of geometric error. It is very difficult to calculate the precise geometric error with the traditional modeling method. A new modeling method of geometric error is proposed based on the z-axis motion platform of micro v-groove machine tools. The difference between the simultaneously events and the successively events is intuitively explained by comparing the new modeling method and the traditional modeling method. The results show that the new modeling method of geometric error based on the z-axis motion platform is effective and practical.

Multiplexed entangled photon-pair sources for all-fiber quantum networks

The ultimate goal of quantum information science is to build a global quantum network, which enables quantum resources to be distributed and shared between remote parties. Such quantum network can be realized by all fiber elements, which takes advantage of low transmission loss,low cost, scalable and mutual fiber communication techniques such as dense wavelength division multiplexing. Therefore high quality entangled photon sources based on fibers are on demanding for building up such kind of quantum network. Here we report multiplexed polarization and timebin entanglement photon sources based on dispersion shifted fiber operating at room temperature. High qualities of entanglement are characterized by using interference, Bell inequality and quantum state tomography. Simultaneous presence of entanglements in multichannel pairs of a 100GHz DWDM shows the great capacity for entanglements distribution over multi-users. Our research provides a versatile platform and moves a first step toward constructing an all fiber quantum network.

Dense wavelength division demultiplexing using photonic crystal waveguides based on cavity resonance

We demonstrated a photonic crystal waveguide based dense wavelength division multiplexing device using the resonances in the cavities. The demultiplexing is achieved through filtering. This filtering is achieved by varying the radii of the surrounding holes of the cavity, which in turn changes the resonant wavelength of the cavity. The four wavelengths demultiplexed in the design are 0.8nm apart in the optical region centered on 1.55 and 1.56μm. The device designed and simulated has easy to realize structure as well as high quality factor. Two-dimensional Finite Difference Time Domain (FDTD) is chosen to do the simulation of this work.

Mode-matched ion-exchanged glass-waveguide bridge for high-performance dense wavelength division multiplexer

Data bit rate, 1-dB passband, and device dimensions are the key properties of dense wavelength division multiplexing (WDM) devices. For blazed-grating-based dense WDM devices, analysis shows that all these three properties can be enhanced by reducing the output fiber-array channel spacing. In this paper, we propose an ion-exchanged glass waveguide to reduce the output channel spacing. To fabricate the low-loss fiber-compatible waveguide, a field-assisted ion-exchange process is developed. The waveguides fabricated by this process have a propagation loss of 0.16 dB/cm and a coupling loss to single-mode fiber (SMF) of 0.1 dB. A 47-channel 100-GHz-spacing dense WDM integrated with the glass waveguide is then packaged and demonstrated. The device performance has verified the effectiveness of the proposed solution and the successfulness of the ion-exchanged glass-waveguide technique in this application.

Bandwidth-enhanced volume grating for dense wavelength-division multiplexer using a phase-compensation scheme

A phase-compensation scheme is proposed and demonstrated to overcome the intrinsic tradeoff between the dispersion and the bandwidth of a volume grating. Its application to a volume grating-based dense wavelength-division multiplexing (DWDM) device is explored. A DWDM device is fabricated by using a 45°/82° configuration. To achieve phase compensation of the Bragg condition, a wavelength-dependent incident angle for a dispersion-enhanced holographic grating at 82° is generated through a prestaged volume hologram at 45°. The 3dB dispersion bandwidth is increased five times by using such a device configuration. A 21-channel DWDM device centered at 1555nm with 200GHz spacing is demonstrated within its 3dB bandwidth.