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.

All-optical link for direct comparison of distant optical clocks

Abstract: We developed an all-optical link system for making remote comparisons of two distant ultra-stable optical clocks. An optical carrier transfer system based on a fiber interferometer was employed to compensate the phase noise accumulated during the propagation through a fiber link. Transfer stabilities of $2\times10^{-15}$ at 1 second and $4\times10^{-18}$ at 1000 seconds were achieved in a 90-km link. An active polarization control system was additionally introduced to maintain the transmitted light in an adequate polarization, and consequently, a stable and reliable comparison was accomplished. The instabilities of the all-optical link system, including those of the erbium doped fiber amplifiers (EDFAs) which are free from phase-noise compensation, were below $2\times10^{-15}$ at 1 second and $7\times10^{-17}$ at 1000 seconds. The system was available for the direct comparison of two distant $^{87}$Sr lattice clocks via an urban fiber link of 60 km. This technique will be essential for the measuring the reproducibility of optical frequency standards.

Fiber to the home office (FTTHO) architecture employing multiple wavelength bands as an overlay in an existing hybrid fiber coax (HFC) transmission system

Abstract: A method of operating a hybrid fiber coax transmission system to provide Fiber to the Home Office (FTTHO) functionality comprises directing, via a fiber portion of the transmission system, first wavelength division multiplexed (WDM) optical signals corresponding to a first category of subscriber service. The first wavelength division multiplexed WDM optical signals, which are within a first wavelength band, originate at a primary hub or headend and are sent to a plurality of fiber nodes where they are converted to respective electrical signals. The converted electrical signals are transmitted, via a coaxial cable portion of the transmission system, to the homes of individual subscribers. The method further comprises a step of exchanging, via a fiber portion of the transmission system, demultiplexed second WDM optical signals corresponding to fiber-to-the-home office (FTTHO) service between a headend and the home of at least one of the individual subscribers.

Optical signal equalizer for wavelength division multiplexed optical fiber systems

Abstract: This invention disclosure describes the application of a polarization insensitive acoustically-tuned optical filter used in a multichannel WDM system to equalize variations in the power level of the WDM channels. The invention also describes a simple means for providing a low frequency control system which enables the equalizer to determine the signal levels of N optical carriers prior to equalizing the signals.

Toward terabit-per-second capacities over multimode fiber links using SCM/WDM techniques

Abstract: This paper outlines the progress made on the use of subcarrier multiplexing (SCM) for high-speed datacommunications links over multimode fiber. Results include the demonstration of penalty-free transmission of 2.5 Gb/s data over worst case multimode fiber (MMF). A complete link demonstration of an SCM transmission system is reported, based on a quadrature phase-shift keying modulator and demodulator capable of a record 5.1 Gb/s per subcarrier data transmission. Superior performance compared with conventional baseband modulation techniques is shown. It is also demonstrated that when SCM is combined with dense wavelength-division multiplexing (WDM), aggregate data capacity of 200 Gb/s is feasible. Preliminary results demonstrate the possibility of 20-GHz WDM channel spacings, which if scaled show the potential for 1-Tb/s aggregate rates with a bandwidth-length product of 3 Tb/s/spl middot/km.

Network applications of cascaded passive code translation for WDM-compatible spectrally phase-encoded optical CDMA

Abstract: Recently, there has been a renewed interest in optical code-division multiple access (OCDMA) due to its potential for offering increased levels of security at ultrahigh data rates as well as for simplifying key networking functions, such as replacing (active) wavelength translation with cascaded passive all-optical code translation (CT). Much of the research done in this area has focused on homogeneous OCDMA networking, where it is assumed that the fiber bandwidth is used only for OCDMA signals. In contrast to other proposed OCDMA systems, we have developed a novel narrowband (NB) spectrally phase-encoded (SPE) OCDMA that is compatible with existing transparent reconfigurable dense-WDM (DWDM) networks and has high spectral efficiency. In this paper, we experimentally demonstrate, for the first time, the feasibility of multistage CT in the proposed WDM-compatible SPE OCDMA system, and we also describe how cascaded CTs can play a central role in ring- and star-network architectures. Specifically, we describe a star-network architecture in which both unicast and multicast interconnections among ends are passively "routed" by means of such cascaded CTs, a ring-network architecture in which CT and fast optical switching enable a code-based equivalent to add/drop wavelength multiplexing, and a shared code-scrambling application for increased signal obscurity.