Wavelength-division multiplexing

About: Wavelength-division multiplexing is a research topic. Over the lifetime, 25059 publications have been published within this topic receiving 332027 citations. The topic is also known as: WDM.

Low-loss Si3N4 arrayed-waveguide grating (de)multiplexer using nano-core optical waveguides.

Abstract: A 16-channel 200 GHz arrayed-waveguide grating (AWG) (de)-multiplexer is demonstrated experimentally by utilizing Si3N4 buried optical waveguides, which have 50 nm-thick Si3N4 cores and a 15 μm-thick SiO2 cladding. The structure with an ultra-thin core layer helps to reduce the scattering due to the sidewall roughness and consequently shows very low loss of about 0.4~0.8 dB/m. When using this type of optical waveguide for an AWG (de)multiplexer, there is no problem associated with gap refill using the upper-cladding material even when choosing a small (e.g., 1.0 μm) gap between adjacent arrayed waveguides, which helps to reduce the transition loss between the FPR (free-propagation region) and the arrayed waveguides. Therefore, the demonstrated AWG (de)multiplexer based on the present Si3N4 buried optical waveguides has a low on-chip loss. The fabricated AWG (de)multiplexer is characterized in two wavelength ranges around 1310 nm and 1550 nm, respectively. It shows that the crosstalk from adjacent and non-adjacent channels are about -30 dB, and -40 dB, respectively, at the wavelength range of 1310 nm. The Si3N4 AWG (de)multiplexer has a temperature dependence of about 0.011 nm/°C, which is close to that of a pure SiO2 AWG device.

A self-protected architecture for wavelength-division-multiplexed passive optical networks

Abstract: We propose a novel network architecture for wavelength-division-multiplexed passive optical networks which can provide bidirectional 1:1 protection against any fiber cut between the remote node and the optical network units (ONUs). In case of such fiber cut, the affected ONU can still communicate with the optical line terminal by rerouting the wavelength channels via the adjacent ONU.

Non-intrusive fiber optic pressure sensor for measuring unsteady pressures within a pipe

Abstract: Non-intrusive pressure sensors (14-18) for measuring unsteady pressures within a pipe (12) include an optical fiber (10) wrapped in coils (20-24) around the circumference of the pipe (12). The length or change in the length of the coils (20-24) is indicative of the unsteady pressure in the pipe. Bragg gratings (310-324) impressed in the fiber (10) may be used having reflection wavelength μ that relate to the unsteady pressure in the pipe. One or more of sensors (14-18) may be axially distributed along the fiber (10) using wavelength division multiplexing and/or time division multiplexing.

Tunability of polarization-insensitive wavelength converters based on four-wave mixing in semiconductor optical amplifiers

Abstract: Optically transparent wavelength converters, in which the output is a wavelength-converted replica of the input, may be required to improve performance and ease management in future "mixed-mode" wavelength division multiplexed networks. Four-wave mixing (FWM) in semiconductor optical amplifiers (SOA's) is an attractive optically transparent wavelength conversion technique because it allows pump tunability. So far, three schemes for polarization-insensitive FWM in SOA's have been demonstrated, using two copolarized pumps, two orthogonal pumps, and polarization diversity. This paper presents a comparison of their output signal-to-noise ratio, and hence their ultimate tunability. A simple analytical model for FWM in SOA's is used to predict that when each scheme has the same inputs and produces the same frequency shift, the polarization-diversity scheme has the highest output signal-to-noise ratio of the three schemes, and hence promises the greatest tunability.

Ultra-broadband on-chip twisted light emitter for optical communications.

Abstract: On-chip twisted light emitters are essential components of orbital angular momentum (OAM) communication devices1, 2. These devices address the growing demand for high-capacity communication systems by providing an additional degree of freedom for wavelength/frequency division multiplexing (WDM/FDM). Although whispering-gallery-mode-enabled OAM emitters have been shown to possess some advantages3, 4, 5, such as compactness and phase accuracy, their inherent narrow bandwidths prevent them from being compatible with WDM/FDM techniques. Here, we demonstrate an ultra-broadband multiplexed OAM emitter that utilizes a novel joint path-resonance phase control concept. The emitter has a micron-sized radius and nanometer-sized features. Coaxial OAM beams are emitted across the entire telecommunication band from 1,450 to 1,650 nm. We applied the emitter to an OAM communication with a data rate of 1.2 Tbit/s assisted by 30-channel optical frequency combs (OFCs). The emitter provides a new solution to further increase capacity in the OFC communication scenario.