Fiber Optic Wiki

Comparison with time lens imaging

September 27, 2011

Another technique, that involves a time lens, can also be used to slow down (mostly optical) signals in time. The time-lens concept relies on the mathematical equivalence between spatial diffraction and temporal dispersion, the so called space-time duality. A lens held at fixed distance from an object produces a magnified image visible to the eye. The lens imparts a quadratic phase shift to the spatial frequency components of the optical waves; in conjunction with the free space propagation (object to lens, lens to eye), this generates a magnified image. Owing to the mathematical equivalence between paraxial diffraction and temporal dispersion, an optical waveform can be temporally imaged by a three-step process of dispersing it in time, subjecting it to a phase shift that is quadratic in time (the time lens itself), and dispersing it again. Theoretically, a focused aberration-free image is obtained under a specific condition when the two dispersive elements and the phase shift satisfy the temporal equivalent of the classic lens equation. Alternatively, the time lens can be used without the second dispersive element to transfer the waveform’s temporal profile to the spectral domain, analogous to the property that an ordinary lens produces the spatial Fourier transform of an object at its focal points.

Relative intensity noise

September 27, 2011

Relative intensity noise (RIN), describes the instability in the power level of a laser. The noise term is important to describe lasers used in fiber-optic communication and LIDAR remote sensing.

Optical networking

September 27, 2011

Multiwavelength optical networking (MONET), is a method for communicating digital information using lasers over optical fiber. The method provides the next level of communication networks after SONET optical networks. MONET optical networks provide an even greater bandwidth capacity. This new method employs Wave division multiplexing (WDM) technology for transporting large amounts of telephone and data traffic and allow for interoperability between equipment from different vendors.

Electrical portion

September 26, 2011

Once on private property, the signal typically travels the final distance to the end user's equipment using an electrical format.

FTTx open questions

September 26, 2011

While fiber as a technology is well defined, there are still many open questions concerning Internet access services that can be provided over optical fiber.

10 Optical buffer

September 26, 2011

In telecommunications, an optical buffer is a device that is capable of temporarily storing light. Just as in the case of a regular buffer, it is a storage medium that enables compensation for a difference in time of occurrence of events. More specifically, an optical buffer serves to store data that was transmitted optically (i.e., in the form of light), without converting it to the electrical domain.

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