Radiant energy – Invisible radiant energy responsive electric signalling – Infrared responsive
Reexamination Certificate
2001-09-20
2004-10-05
Hannaher, Constantine (Department: 2878)
Radiant energy
Invisible radiant energy responsive electric signalling
Infrared responsive
C250S458100
Reexamination Certificate
active
06800856
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates broadly to telecommunications equipment. More particularly, the present invention is useful in the fiber-optic segment of the telecommunications industry as a device for monitoring scattered light in an optical switch.
BACKGROUND OF THE INVENTION
Over the past several decades, the telecommunications industry has exploded, and the incorporation of optical fiber into this industry is revolutionizing the way information is transmitted. Communication systems which use optical fiber as the transmission media offer some significant advantages over past wire-based systems, such as higher bandwidths and transmission rates, lower transmission losses, lower implementation costs, and greater electrical isolation.
In a fiber-optic communications system, communications signals are carried by light beams transmitted through the optical fibers. These light beams are generally infrared (IR) light beams, because IR light is less attenuated in optical fibers than other types of light. To connect users of these systems, light beams must be switched from one fiber to another. Such switching is typically accomplished using an optical cross-connect, or optical switch. Optical switches typically switch multiple light beams simultaneously. Each light beam is switched from any of multiple input fibers to any of multiple output fibers. To accomplish this switching, these switches incorporate optical elements such as mirrors, prisms, fiber collimators, and complicated drive mechanisms. In a switch that incorporates mirrors to do the switching, for example, each mirror can be tilted to reflect a light beam from an input fiber to any of one of several output fibers. Each light beam to be switched requires a separate mirror, or beam directing element.
A problem in fiber-optic communications systems is loss of part or all of a light beam that carries a signal. This is a problem because when part or all of a light beam is lost, the signal carried by it is also degraded or lost. Such loss can be due in part to a variety of causes. For instance, a user can lose light upstream due to fiber breaks, or a bad connection, a bd laser, or a bad switch. In optical switches that incorporate mirrors, for example, while most of a light beam may be reflected in the desired direction, part may be scattered due to imperfections in the mirror.
Some users of optical switches desire to monitor scattered light in optical switches. More particularly, some users desire to monitor the light scattered from each of multiple optical elements (e.g., mirrors) in an optical switch. Consequently, there is a need for a system to monitor scattered light in an optical switch.
One way to do this is to provide a detector sensitive to such light, situated so that it receives scattered light from one or more optical elements. A problem with this solution is that, if the detector is used with multiple elements, the detector cannot discern from which element or elements any scattered light might have come; the detector only detects the aggregate of light entering it from all sources in its view. If a camera is used with a lens focussed on the region of interest, it can determine the source, however, such a camera is expensive.
Accordingly, it is an object of the present invention to provide a relatively simple and inexpensive system to monitor light scattered by any one or more of one or more optical elements in an optical switch.
SUMMARY OF THE PRESENT INVENTION
The Light Sampling System of the present invention includes four (4) basic components, including an imaging lens, a multi-channel liquid crystal light valve (LCLV), a collecting lens, and a light sensor. Light scattered by each of one or more optical elements, is collected by the imaging lens, which re-images the light onto the LCLV. The LCLV is divided into multiple regions, one for each optical element to be monitored. Each region can independently be made opaque (“closed”) or transparent (“open”) to light reaching it. Light passing through all open regions of the LCLV is collected by the collecting lens, which focuses the light onto the light sensor. If light is passing through the LCLV, then the light sensor will register a response. Each region of the LCLV can be programmed to be open or closed for any length of time, in any combination or sequence with any other region or regions, depending on how the user wishes to monitor the light scattered by the optical elements.
REFERENCES:
patent: 4045670 (1977-08-01), Anderson et al.
patent: 5389788 (1995-02-01), Grinberg et al.
patent: 5440114 (1995-08-01), Barbier et al.
patent: 5465284 (1995-11-01), Karellas
patent: 5642125 (1997-06-01), Silverstein et al.
patent: 5710429 (1998-01-01), Alfano et al.
patent: 5805243 (1998-09-01), Hatano et al.
patent: 5864146 (1999-01-01), Karellas
patent: 6201559 (2001-03-01), Wada et al.
patent: 6377346 (2002-04-01), Vaisala et al.
Eastman Gary
Gabor Otilia
Hannaher Constantine
Trey Enterprises Corp.
LandOfFree
Light sampling system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Light sampling system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Light sampling system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3276291