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AssigneeInfinera Corporation
InventorsHai Xu, Michael Francis Van Leeuwen, Emily F. Burmeister, Stephen G. Grubb
Estimating the term…
Consistent with the present disclosure, chromatic dispersion is introduced into an optical communication path including multiple segments or spans of dispersion shifted fiber (DSF). The chromatic dispersion generates phase mismatching between optical signals propagating along the optical communication path, i.e., the optical signals are decorrelated, such that mixing products are reduced inmagnitude, and the noise attributable to four wave mixing is correspondingly reduced.
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Dependencies are inferred from the claim text.
From the US filing history. Foreign family members aren’t listed.
Due to fibre non-linearities, e.g. Kerr effect: four-wave mixing [FWM]
Due to chromatic dispersion: using dispersion-compensating fibres
Using dispersion-compensating fibres: with dispersion management, i.e. using a combination of different kind of fibres in the transmission system
WDM arrangements: in end terminals
About 5 years 6 months of term left · ends 16 Apr 2032 (estimated)
In fiber optic communication systems, optical signals are modulated to carry symbols of data and are transmitted on an optical fiber from an optical transmitter to a receiver, such that a given symbol is transmitted during a symbol period. Although the optical signals are usually at a single nominal wavelength, each signal can include different spectral components. The spectral components of each optical signal can propagate through the transmission fiber at different speeds. This effect, known as “chromatic dispersion”, can result in spectral components of one symbol period arriving at a receiver at substantially the same time as a succeeding symbol period, thereby causing degraded receiver sensitivity. Chromatic dispersion becomes increasingly pronounced at higher bit rates.
Early fiber optic communication systems included transmitters that output light having a wavelength of 1310 nm, which is the wavelength at which conventional single mode optical fiber has a substantially zero dispersion. The absorption of silica, a material from which optical fibers are made, is greater at 1310 nm than the absorption at 1550 nm. Accordingly, subsequent systems were developed to transmit optical signals at or near 1550 nm. Since conventional single mode optical fiber has significant chromatic dispersion at such wavelengths, so-called “dispersion shifted fiber” (DSF) was developed that has zero or substantially zero dispersion at 1550 nm.
In order to increase the data carrying capacity of fiber optic communication systems, wavelength division multiplexing has been deployed in which multiple transmitters output modulated optical signals at different wavelengths. The optical signals are then combined onto an optical fiber and transmitted as a wavelength division multiplexed (WDM) signal.
FIG. 1 illustrates an optical communication system consistent with an aspect of the present disclosure;
FIG. 2 illustrates an example of a receiver block consistent with an aspect of the present disclosure;
FIG. 3 illustrates an example of an optical amplifier consistent with the present disclosure;
Consistent with the present disclosure, chromatic dispersion is introduced into an optical communication path including multiple segments or spans of dispersion shifted fiber (DSF). The chromatic dispersion generates phase mismatching between optical signals propagating along the optical communication path, i.e., the optical signals are decorrelated, such that the sum of the mixing products is reduced in magnitude from one segment of DSF to the next, and the non-linear noise attributable to four wave mixing is correspondingly reduced.
Reference will now be made in detail to the following exemplary embodiments of the present disclosure, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
FIG. 1 illustrates an optical communication system 100 consistent with the present disclosure. Optical communication system 100 includes a plurality of optical transmitter blocks TX-1 to TX-n, each of which supplying a corresponding group of optical signals. Each of optical signal within each group has a corresponding one of a plurality of wavelengths. For example, optical transmitter block TX-1 outputs a first group or first plurality of optical signals, each of which having a corresponding one of a first plurality of wavelengths, such as wavelengths λ1 to λ10. In addition, optical transmitter block TX-n outputs a second group or second plurality of optical signals, each of which having a corresponding one of a second plurality of wavelengths, such as wavelengths λn-9 to λn.