US 6,154,584 A · Optical analyzer with variable attenuators at inputs and outputs

Abstract

An apparatus for controlling attenuation of optical signals routed through a matrix switch capable of optically coupling a selected transmission station of a plurality of transmission stations to a first port and optically coupling a second port to a reception station includes a first variable attenuator that is optically coupled to the first port so that an optical path length exists between the first variable attenuator and the transmission station. The apparatus includes an optical analyzer that has an input port and an output port. The input port is optically coupled to the variable attenuator and the output port is optically coupled to the second port. Thus, the input port is coupled to the first port through the first variable attenuator. A control unit controls the first variable attenuator so as to cause an optical signal passing therethrough to be attenuated by a predetermined amount based on the optical path length between the transmission station and the first variable attenuator so that the optical signal entering the input port has a signal strength within a predetermined range.

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Drawings

Claims16

Dependent claims

An apparatus for controlling attenuation of optical signals routed through a matrix switch capable of optically coupling a selected transmission station, of a plurality of transmission stations, to a first port and optically coupling a second port to a reception station, the apparatus comprising:

a. a first variable attenuator optically coupled to the first port so that an optical path length exists between the first variable attenuator and the transmission station;
b. an optical analyzer having an input port and an output port, the input port optically coupled to the variable attenuator and the output port optically coupled to the second port, the input port being in optical communication with the first port through the first variable attenuator;
and
c. a control unit that controls the first variable attenuator, so as to cause an optical signal passing therethrough to be attenuated by a predetermined amount based on the optical path length between the transmission station and the first variable attenuator so that the optical signal entering the input port has a signal strength within a predetermined range.

1 more element

An apparatus for the controlling attenuation of optical signals routed through a matrix switch capable of optically coupling a selected transmission station of a plurality of transmission stations to a first port and coupling a second port to a selected reception station of a plurality of reception stations, the apparatus comprising:

a. a first variable attenuator optically coupled to the first port, an optical path length existing between the first variable attenuator and transmission station;
b. a second variable attenuator optically coupled to the second port, an optical path length existing between the second variable attenuator and the reception station;
c. an optical analyzer having an input port and an output port, the input port optically coupled to the first variable attenuator so that the input port is in optical communication with the first port through the first variable attenuator and the output port optically coupled to the second variable attenuator so that the output port is in optical communication with the second port through the second attenuator;
d. a control unit that controls the first variable attenuator and the second variable attenuator, so as to cause an optical signal passing through the first variable attenuator to be attenuated by a first predetermined amount based on the optical path length between the transmission station and the first variable attenuator so that the optical signal entering the input port has a signal strength within a first predetermined range and so as to cause an optical signal passing through the second variable attenuator to be attenuated by a second predetermined amount based on the optical path length between the second variable attenuator and the reception station so that the optical signal entering the second port has a signal strength within a second predetermined range;
e. a look Up table having a plurality of data units, each data unit indicating an amount of attenuation required so that the optical signal entering the first variable attenuator has a signal strength within the first predetermined range and the optical signal existing the second variable attenuator has a signal strength within the second predetermined range;
and
f. a circuit that converts a data unit from the look up table to a first signal that controls the first variable attenuator and a second signal that controls the second variable attenuator.

4 more elements

Dependencies are inferred from the claim text.

Description2,748 words

Summary929 words

#1. Field of the Invention

#The present invention relates to optical communications devices and, more specifically, to a device that compensates for different optical path lengths in an optical communications system.

#2. Description of the Prior Art

Brief description of the drawings3 figures

#FIG. 1 is a schematic diagram of a first embodiment of the invention.

#FIG. 2 is a schematic diagram of a second embodiment of the invention, in which only the output of the analyzer employs an attenuator.

#FIG. 3 is a schematic diagram of a third embodiment of the invention, in which only the input of the analyzer employs an attenuator.

Detailed description1,758 words

#A preferred embodiment of the invention is now described in detail. Referring to the drawings, like numbers indicate like parts throughout the views. As used in the description herein and throughout the claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise: the meaning of "a," "an," and "the" includes plural reference, the meaning of "in" includes "in" and "on."

#As shown in FIG. 1, in one embodiment, the invention is an apparatus 100 for controlling attenuation of optical signals routed through a matrix switch 110 capable of optically coupling a selected transmission station of a plurality of transmission stations 112a-12z (collectively 112) to a first port 116a and coupling a second port 116b to a selected reception station of a plurality of reception stations 114a-114z (collectively 114). (Although only a single first port 116a and a single second port 116b is shown in FIG. 1 for the sake of simplicity, actual embodiments of the matrix switch 110 could include a plurality of first ports and a plurality of second ports for use with a plurality of analyzers, without departing from the scope of the invention.) The matrix switch 110 would typically be used for connecting the transmission stations 112 directly to the reception stations 114 as part of a data communications network. For example, the matrix switch 110 could connect transmission station 112a to reception station 114y and reception station 114a to transmission station 112y as part of a duplex data transfer protocol. The matrix switch 110 could be, for example, a matrix switch produced by LanHopper Systems, Inc., 330 Research Ct., Suite 250, Norcross, Ga. 30092.

#FIG. 1 shows that the connections between the transmission stations 112 and the matrix switch 100 and the between the matrix switch 110 and the reception stations 114 have different lengths. While these differing lengths could represent physical lengths of fiber optic cable, they could also represent the optical path lengths of the connections. The optical path length, as used herein, refers to the effective optical path experienced by an optical signal as it propagates through the optical connection. While the optical path length is predominantly influenced by the physical path length, it may also be influenced by other factors, including the amount of bending of the fiber optic cable, environmental factors (such as temperature), and the existence of attenuating devices in the optical path of the optical signal.

Facts

Application

09/243,764Filed 3 Feb 1999

Granted

28 Nov 2000

Term ended

3 Feb 2019

Estimated · how

20 years from earliest known nonprovisional domestic filing. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination. Patent term adjustment is unavailable; no adjustment was added.

Classification7 codes

H04Q 11/0003
Using optical switching: details
G02B 6/266
With optical elements between opposed fibre ends which perform a function other than beam splitting: the optical element being an attenuator
H04Q 2011/0024
Construction: using space switching
H04Q 2011/0049
Operation: crosstalk reduction; Noise; Power budget

Description2,748 words

Summary929 words

#1. Field of the Invention

#The present invention relates to optical communications devices and, more specifically, to a device that compensates for different optical path lengths in an optical communications system.

#2. Description of the Prior Art

Brief description of the drawings3 figures

#FIG. 1 is a schematic diagram of a first embodiment of the invention.

#FIG. 2 is a schematic diagram of a second embodiment of the invention, in which only the output of the analyzer employs an attenuator.

#FIG. 3 is a schematic diagram of a third embodiment of the invention, in which only the input of the analyzer employs an attenuator.

Detailed description1,758 words

Optical analyzer with variable attenuators at inputs and outputs

Life of this patent

Optical analyzer with variable attenuators at inputs and outputs

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims16

Description2,748 words

Drawings

Classification7 codes

Life of this patent

Description2,748 words