MXPA96006708A - Optical communication system and remote sensor interrogation - Google Patents

Abstract

A sensing system including an optical receiver for receiving downstream optical signals and for converting the downstream optical signals to downstream electrical signals. An optical transducer impresses information in an upstream data signal onto upstream optical signals. At least one sensor responsive to an external stimulus provides sensor information signals. A processor receives the downstream electrical signals and establishes communication channels to at least one communication terminal providing communication information signal, and to the at least one sensor. The at least one terminal and the at least one sensor provide the communication and sensor information signals, respectively, to the processor which forwards the information signals to the optical transducer as the upstream data signal.

Description

OPTICAL COMMUNICATION SYSTEM AND REMOTE SENSOR INTERROGATION AMTgCgPgNTBS PB U, INVEN ?? $ y i- C? «F?) pg A INVEHCÍQ The present invention relates to an optical communication system and more particularly to an optical communication system that has the ability to interrogate remote sensing devices. 2. DESCRIPTION OF THE RELATED TECHNIQUE Fiber optic technology has completely penetrated the telephony network of long or long distances due to its inherent low loss and high bandwidth. In the area of applications of local circuits, financially attractive options have been developed more slowly. Recently, substantial research efforts have been directed towards the development of technology to implement optical fibers within applications of local circuits (for example, fibers in a local circuit). However, cost, capacity and switching problems still need to be resolved.

REF: 23632 Recently, technologies have been developed in an effort to introduce fibers in a more cost-effective way in a local circuit. For example, a passive optical network (PON) is an optical transmission system that does not require active components to direct optical signals between a central office (CO) or a digital guest terminal, and the terminal equipment of a subscriber of a network. . The PONs usually comprise a first star formed of a plurality of optical fibers which extend Q from a CO to each of a plurality of remote nodes.

Each remote node can be considered as a hub for a second star formed by a second plurality of optical fibers extending from the remote node, each to one of the plurality of optical network units (ONU). ! 5 The two well-known PON architectures consider the development of optical fibers in the local circuit are "Telephone Over Passive Optical Networks" ("Passive optical networks over telephones" (TPON) and "Passive Photonic Loops" ("Passive photonic circuits") (PPL). 20 In the TPON architecture, the CO emits a common signal for all end users serviced by a given node. The information is segregated within the transmission signal at individual time intervals as a multiplexed signal in time condition (TDM). A coupler of star on the remote node distributes the signals transmitted to the optical network units. The information upstream is transmitted from each ONU within a particular time interval, received at the remote node, optically multiplexed and directed to the CO. The handling of collisions in time and a concession between the supplied optical energy and the number of end users limits the expansion and development capacity of the conventional TPON architecture. The PPL architecture is a multiplexed architecture with wavelength division (WDM) in which each ONU is assigned a single wavelength by the CO, and the optical information is segregated by wavelength within a transmitted signal. The optical information is transmitted within the CO to a plurality of remote nodes. Each remote node optically demultiplexes its received signals by wavelength and directs the multiplexed signals to each ONU. For the upstream transmission, each ONU includes a separate optical transmitter at a wavelength assigned to the ONU. Each ONU transmits signals to the remote node where the signals are incorporated by optical multiplexing into a composite signal and transferred to the CO. While WDM PONs have excellent overall energy costs, because all the light designed for a subscriber is directed to that subscriber, the current PON implementation of WDM is very expensive.

In an effort to reduce the implementation costs of WDM PON for fibers in circuit applications and decrease operations, an optimal network system based on remote terminal equipment interrogation (RITE-NetMR) has been developed and described in the application for US patent Serial No. 08/333, 926 filed on November 3, 1994 and which is incorporated herein by reference. The RITE-NetMR system operates in accordance with the wavelength division multiplexing, but avoids the need for individual optical sources (ie transmitters) in each ONU. Therefore, the RITE-NetMR system decreases the cost for the equipment required in each UN. In addition, the RITE-NetMR system provides high potential capacity at reduced cost, the RITE-NetMR system is sufficiently flexible to allow the additional arrival that occurs when it is incorporated into an existing system. The present invention is provided for introducing fibers into a local circuit, preferably such as a WDM system, so that there is an inherent potential within the system for a network owner to assume part of the initial costs of implementing the system. In other words, to provide a system in which the initial investment costs are recovered more quickly with respect to time through income derived through the additional services provided by the network. One such service that can be provided by the network for recovery of part of the initial investment is to provide the system with remote sensor interrogation. Such remote sensor interrogation, for example, can be used to provide services such as surveillance systems (eg, fires, robberies, etc.).

SUMMARY OF THE INVENTION According to one embodiment of the present invention, a detector system includes an optical receiver for receiving downstream optical signals and for converting optical signals downstream to electrical signals upstream, in an optical transducer for printing information from the signal of upstream data on the upstream optical signals and at least one sensor responsive to an external stimulus to provide sensor information signals. A processor receives the downstream electrical signals and establishes the communication channels so that at least one communication terminal provides communication information signals to at least one sensor. At least one terminal and at least one sensor provide the communication and sensor information signals, respectively, to the processor which sends the signals to the optical transducer as the upstream data signals. The sensor can be constituted of means to verify changes in temperature, humidity, chemical residues, etc., or to detect intrusion in a monitored area.

BRIEF DESCRIPTION OF THE DRAWINGS Those skilled in the art to which the subject matter of the invention pertains will better understand how to carry out the present invention, the preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings, in which Figure 1 illustrates a block diagram of an RITE-NetMR of a passive optical network, - Figure 2 illustrates a block diagram of an optical network unit and a remote sensor according to an embodiment of the present invention, - Figures 3A and 3B illustrate block diagrams of an optical network unit and an optical detector system according to the embodiments of the present invention, - Figure 4 illustrates a transponder according to an embodiment of the present invention, - figures 5A-5C illustrate various types of transponders according to the embodiments of the present invention; Figure 6 illustrates another type of transponder according to a further embodiment of the present invention; Figure 7 illustrates an optical network unit and a transponder according to an embodiment of the present invention; Figure 8 illustrates an optical network unit and a plurality of transponders and / or terminals according to an embodiment of the present invention, and Figure 9 illustrates an optical network unit and an intermediate wavelength division multiplexer of according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Figure 1 shows a RITE-NetMR passive optical network. The network includes one or more multiple wavelength transmitters 12 iZirngibl et al., "A 12-Frequency WDM Laser Based On a Transmissive Waveguide Grading Router, Electronics Letters, Vol. 30, pages 701-702 (1994).) Tunable (for example a laser) and one or more receivers 16 provided in a CO 20. The transmitters 12 encode optical information within a multiplexed wavelength division signal and transmit the downstream signal on the fibers 25D forming a primary star Each downstream fiber 25D links CO 20 to a remote node 30. A wavelength division multiplexer, preferably a wavelength division multiplexer / router (32) coupler (Dragone et al., "Integrated Optics NxN Multiplexer On Silicon", IEEE Phot. Technol.Lett., Vol. 3, pages 896-899 (1991) C. Dragone, "An NxN Optical Multiplexer Using a Planar Arrangement of Two Star Couplers," IEEE Phot Technol Lett., Vol. 3, pages 812-815 (1991).) (WDM / R), hereinafter referred to as a "Dragone router" is located at each remote node. WDM / R 32 demultiplexes and directs the downstream light received at each remote node 30 to each plurality of ONU 40 via downstream fibers 35D as a function of wavelength. RN 30 is the center of a secondary star constituted of a plurality of ONU 40. In each UN 40, an optical coupler 42 divides the downstream signal portions arriving at the ONU 40 into two or more signal portions. A portion of the separated light is overmodulated with data from the subscriber within the modulator 44, and a return cycle is formed through the remote node 30 via fibers 35u upstream and toward CO 20 via fibers 25u upstream. That is, the modulator 44 records information in a portion of the divided light, which is then directed upstream by means of the fibers 35u and 25u to the CO 20. While each of the ONUs can be considered as being the For the final optical destination, it is possible for an ONU to serve more as an active unit (that is, with more than one final subscriber). It will be appreciated by a person of ordinary skill in the art that variations of the network shown in Figure 1 are possible. For example, although shown in the present application as individual fibers, the fibers 35u and 35- can be single fibers and fibers 250 and 25D can be a single fiber. Furthermore, it should be clear that the modulator 44 can provide gain modulation, phase modulation, etc., as desired. Of course, coupler 42 and modulator 44 can also be integrated into a single device, as desired. As described in the above, one of the main impediments to the introduction of fiber optic communications for local subscribers within the telephone network is their initial cost. In an effort to maximize the benefit in terms of the initial basket of the system, the present invention implements a communication system within which an optical network J terminating unit is used to provide services in addition to conventional communication services.

The present invention defines an optical communication system in which a first ONU forms an optical communication link to / from a CO. The optical communication link can be used to join the first ONU to a terminal device. The optical communication link can also link the first ONU to a sensor or to a sensor array. Preferably, the first ONU is a telecommunications subscriber, and the sensor or array of sensors are sensitive to changes within the local environment in the home or business (for example, they are capable of certain types of processes to generate a signal of sensor for communication with the CO). Sensors can be provided to verify changes in temperature, sound pressure, chemical residues, smoke or other environmental changes, for example. In addition, different types of security sensors can be provided to verify intrusion in a house or a business, for example. One embodiment of the present invention, as illustrated in Figure 2, is mentioned as a type of system that "reports electrical signal". That is, in this embodiment of the present invention, a sensor informs an electronic device with information. The electronic device then informs the central office. At the ONU 40, the lid coupler 42 divides the downstream optical signal portions arriving at the ONU 40 via fiber 35D downstream into two or more signal portions 205 and 210. The 205 portion of the downstream light signal received is applied to the optical detector 215 wherein the signal is detected and converted to an electrical signal in the path 211. The signal in the path 211 is provided to a processor 225 which conditions and processes the signal to provide a "data" signal. output "of the representative subscriber of the respective downstream information, by way of the path 220. The information on the path 220 may represent information that is to be received by the communication terminal 230, for example. The information upstream for terminal 230 is transmitted through a path 220 to processor 225. In addition, a sensor or sensor array 240 can be provided to transmit information along path 220 or along a separate path 241 provided for the sensor information. The information transmitted along the path 220 and / or the path 241 is processed by the processor 225, which outputs data encoded in the path 242. The data encoded in the path 242 is used by the modulator 44 to overmodulate (record) data in the light signal on the path 210 which is then returned to the remote node 30 via a fiber 35 and upstream. The sensor 240 can be made up of any type of well-known sensor or sensor arrangement circuits. For example, an intrusion alarm sensor that verifies the electrical continuity of a circuit can be provided. When continuity breaks (for example, through a window with wiring or a door that is open), such a sensor can automatically dial a security station, for example, and provide a warning that an intrusion has occurred. In the alternative, the sensor 240 may provide an emergency alert signal that may be interpreted by the ONU and / or the central office as indicating that an intrusion has occurred. Such sensors may also include devices for verifying changes in temperature, humidity, chemical residues, movement, etc. The sensor or array of sensors 240 can be selectively called by the processor 225 to provide sensor information signals in response to a downstream optical signal or the sensor can interrupt the processor 225 in response to an external stimulus. The processor 225 may provide upstream data signals that correspond to a predetermined number or the processor may provide an emergency alert signal in response to the predetermined group of sensor information signals. It will be clear to a person ordinarily skilled in the art that the coupler 42 can be a four-door device, for example, a modulator 44 that can be a reflective modulator. In this case, the fiber 35a may be coupled to the coupler 42, instead of being to the modulator 44. As previously described, the fibers 35D and 35u may be a single fiber, the modulator 44 may provide a gain phase, phase modulation, etc. and the coupler 42 and the modulator 44 can be integrated into a single device, as desired. Other embodiments of the present invention are shown in Figures 3A and 3b and are referred to as "optical signal report" types systems. The ONU 300, instead of converting an optical signal to an electrical signal and distributing the electrical signal to the sensor device, distributes an optical signal to the reporting device. For example, as shown in Figure 3A, optical signals are provided from an RN (not shown) via path 35D. The optical coupler 42, preferably a WDM device, divides the optical signal into the path 35D into two or more portions of signals in the paths 410, 411 and 412. Of course, it will be appreciated by those skilled in the art that, for reducing or alleviating optical interference, the coupler 42 can be replaced with a switch. The portion of the optical signal in the path 410 is provided to the device 315. The portion of the optical signal in the path 411 is provided to the receiver 215, which converts it into an electrical signal in the path 312. The electrical signal in the Path 312 is provided to the communication terminal 330 in which the information of the downstream communication is received. The terminal 330 also provides electrical communication information signals upstream on the path 313 to the modulator 316. The modulator 316 otherwise regulates or records the communication information on the line 313 on the optical signal on the path 412 and provides it to coupler 317 via path 318. Normally, the interrogation signal of the optical sensor on path 410 passes through device 315 and is returned to ONU 300 via path 420. Coupler 317 couples optical signals in the paths 318 and 420 to provide a composite signal upstream for the upstream transmission by means of the path 35u. The device 315 may consist of a device which, in response to a stimulus such as: *. To an electrical or optical signal, interrupts or modifies the optical signal in the path 410 passing through it and other means. returns upstream in the path -O The purpose of the device 315 is to report the Je-sensor state 325 by modifying the light from the path 410 before being sent upstream. That is, the sensor 325 can be selectively called by the device 315 e :? response to a downstream sensor interrogation signal. The sensor 325 can be any well-known sensor type which detects variations and temperature, pressure, humidity, chemical residues or other environmental factors and which generates a signal in the path 320 when the predetermined condition is present (for example, when a default temperature, pressure or humidity level). In the alternative, a signal may be provided on the path 320 that changes linearly or in some other way in response to changes in a predetermined condition. In addition, the sensor 325 may be constituted by an intrusion detection system that generates a signal in the path 320 when the sound motion detector is activated or when the continuity of a circuit is broken (i.e., when an intrusion is detected). ). The sensor 325 may be a device that generates and transmits an optical signal on the optical path 320 when a predetermined threshold is present or when the intrusion detection system detects an intrusion. For example, the sensor 325 may have a device that generates an infrared signal that is emitted along the path 320 and received by an infrared receiver in the device 315. In the alternative, the sensor 325 may be a device that generates and transmits a electrical signal in the path 320 when the intrusion detection system detects an intrusion, for example. In this case, the path 320 may consist of one or more electrical wires. In the alternative, the path 320 may represent a path in which an electromagnetic signal is transmitted from an antenna provided in the sensor 325 to a receiving antenna that is provided in the device 315. In other words, the path 320 represents any type of path to transmit an electrical, acoustic, electromagnetic or optical signal, for example. According to this embodiment, of the present invention, the sensor 325 desires communication with the central office, the signal transmitted along the path 320 causes the device 315 to interrupt or otherwise modify the optical signal in the path 410 which is returned to the ONU 300 in the path 420. The modified signal in the path 420 can then be detected in a remote monitoring station (not shown). The device 315 may consist of a mechanical device, for example, which moves in a position to block the optical signal and prevent it from passing from the path 410 to the path 420 when the signal is present in the path 320. The sensor 325 also it can communicate with terminal 330 through a communication path (not shown) to receive instructions or change some state of the ONU. It will also be appreciated that trajectories 410 and 412 may be a single fiber and trajectories 318 and 420 may be a single fiber, with devices 315 and 316 provided in series. The device 315 can be integrated with, and identical or in series with the modulator 316 and / or the devices 42 and 315-317 can be integrated into the physical device. As described in the foregoing, the coupler 42 may be a switch and not a WDM device. In the alternative, the coupler 42 can be a standard or conventional coupler, with the terminal 330 coordinating the information that is provided to the devices 315 and 316 to avoid interference. It will be appreciated that the alternative, the optical condition of the device 315 can be monitored by conventional techniques (OTDR) by studying the optical signals returning in the path 35u. Another variation of this embodiment of the present invention is shown in Figure 3B. The coupler 42 (preferably a WDM) divides the optical signal into the path 35D in the paths 410 and 411. The signal in the path 411 provides optical communication information downstream for the communication terminal 335. The terminal 335 provides optical communication information upstream of the coupler 317 via the path 319. The coupler 317 couples the optical communication information signal in the path 319 with the sensor signal in the path 420 to provide a current composite signal up on the 35u path According to variations in this embodiment of the present invention, the device 315 can be provided as a terminal subassembly 335 or in series, with the terminal 335. If the device 42 is provided as a coupler and not as a WDM device, the Devices 315 and 335 must cooperate with each other so that one is locked while the other is operating in order to avoid possible interference of the composite signal upstream. Of course, it will be appreciated that devices 42 and 317 may also be provided as switches. In Figure 4 another embodiment of the present invention is shown, and referred to in the following as an "optical transducer" type system. This is, in the following embodiments of the present invention, the sensor itself acts as a transducer that reports its status directly to the central office. In accordance with this embodiment of the present invention, the device 315 is replaced with the device 400 which in itself is directly responsive to an external stimulus (many interferometric and intensity modulation techniques are known). An optical signal transmitted along the path 410 normally passes through the device 400 and upstream in the path 420. However, when an external stimulus is present, the optical signal is transmitted along the path 410 is blocked or it is modified in some other way in its upstream path in the path 420. The change in the optical signal in the path 420 can then be detected in the remote monitoring station. Different types of devices 400 may be used to block or otherwise modify the optical signal on path 410, according to the various embodiments of the present invention. For example, as shown in Figure 5A, the device 400 may consist of collimators 500 and 510. The optical signal transmitted along the path 410 is formed in a collimated beam of free space and exits through the collimator 500. The collimator 510 normally collects the output of the optical signal by the collimator 500 and the signal is passed upstream by way of the path 420. The use of a collimated light r.az allows the light to travel additionally, 1J which allows Collimators 500 and 510 can be placed separately. This type of device is sensitive to objects that enter the line of light between the collimator 500 and the collimator 510. That is, an object entering the line J light will be interrupted and will otherwise prevent or modify the light emitted by the light. the collimator 500 when collected by the collimator 510. Accordingly, when an object enters between the collimator 500 and the collimator 510, the light beam is interrupted or modified as it passes upstream via the path 420. The interruption or modification of the beam of light can then be detected in the remote monitoring station, for example. Of course, variations to this detector scheme are possible. For example, according to the embodiment of the present invention shown in Figure 5B, the collimator 500 emits an optical signal which is collected by the collimator 510, similar to that described in the foregoing, with respect to Figure 5A . However, according to this embodiment in the present invention, an optical signal blocking device 520, in response to a measurement, selectively blocks the light beam to reach the collimator 510. The optical signal blocking device 520 includes a member 520 mobile optical blocker that is able to assume position A or position B, as shown in Figure 5B. In position A, the optical signal emitted by the collimator 500 is collected by the collimator 510 and returned upstream to the ONU 300 via the path 420. In the position B, the optical blocking member 530 blocks the light that is emitted by the collimator 500 which is collected by the 510 collimator. The interruption of the light beam can be detected at the remote monitoring station.

The optical signal blocking device 520 may consist of a device that moves the blocking member 530 between the position A and the position B based on the temperature. For example, as shown in Figure 5C, the optical signal blocking device 520 may include a pallet 530 of two materials. Such a palette of two materials consists of a first strip of material 540 having a first coefficient of thermal expansion. A second strip of material 550, having a coefficient of thermal expansion different from the first material, adheres to the first strip of material 540. Such blade 530 of two materials usually shows a characteristic of change of form with variations in temperature. Accordingly, such a device may be useful for monitoring and detecting variations in temperature. The device can be placed so that during a normal room temperature, the pallet 530 of two materials acquires the position A (Figure 5B). During a remarkable increase in temperature (for example during a fire) the pallet 530 of two materials can assume the position B, whereby it blocks the optical signal emitted from an optical emitter 500 which is collected by the optical receiver 510. The interruption of the beam of light can then be detected in a remote monitoring station, interpreted as fire and the appropriate action can be taken.

The optical block device 520 can also be designed to respond to variations in pressure (eg changes in water pressure or atmospheric pressure, etc.) or water level, for example. Such variations can be used to move the optical blocking member 530 from the position A to the position B. The blocking member 530 can also be moved mechanically between the position A and the position B by an actuator, for example. The device 520 can also be integrated into the "optical signal report" equipment system as described above with respect to Figures 3A and 3B. For example, an electrical signal to activate the actuator can be supplied from the detector device 325 which provides a signal to the optical blocking device 520 when it detects a predetermined variation in temperature, pressure, etc., for example. According to another embodiment of the present invention, as shown in Figure 6, a modulator material 600 can be provided in the path of the collimated light beam. The modulator material 600 may consist of a material that is sensitive to variations in an external stimulus. For example, the modulator material 600 can be a technically sensitive material that obtains different attenuation of light properties based on temperature. Such a material, at room temperature, normally passes a relatively large percentage of optical light energy. Consequently, at room temperature, a large percentage of light energy emitted by the collimator 500 is collected by the collimator 510. However, after a temperature change, the material 600 attenuates or absorbs a percentage of the optical energy of the signal luminous emitted by the collimator 500 so that the light signal collected by the collimator 510 is attenuated. This attenuation of the light energy can then be detected in a remote monitoring station. In the alternative, the characteristics of the modulator material 600 may be such that its polarization characteristics vary based on temperature, for example. At room temperature, the material shows a first polarization which allows the light emitted from the collimator 500 to pass through to the collimator 510. At different temperatures, the polarization of light that passes through the material 600 changes, so that a portion or 'all of the light emitted by the collimator 500. Examples of materials showing different polarizations at different temperatures include liquid crystals, for example. Of course, it will be appreciated that the plastic devices for implementing this embodiment of the present invention may require more than one optical path through the material 600.

According to another embodiment of the present invention, the modulator 600 material 600 consists of a material that, when incised with the light energy emitted by the collimator 500, enters a first state. In this first state, the material shows the optical signal emitted by the collimator 500 so that it passes to the collimator 510. When the modulator material 600 stimulated by an external stimulus, for example the temperature, pressure, etc., enters a second state . In this second state, the optical signal emitted by the collimator 500 is attenuated. The attenuated optical signal is collected by the collimator 510, routed upstream in the path 420 and can be verified by a remote monitoring station to determine the state of the material and therefore the temperature or pressure. The optical condition of the material 600 can also be monitored with conventional techniques (OTDR) by studying the optical signals returning in the path 350. Another embodiment of the present invention is shown in Figure 7. In accordance with this embodiment of the present invention, the sensor information may be provided at a separate wavelength and different data (eg, telecommunication information, etc.) which are communicated by the system. The plurality of wavelengths of the light transmit along the optical path 35D to the ONU 715. The ONU 715 may include wavelength division multiplexers (WDM 700 and 755). The WDM 700 sends the light signal? N + 1 in an optical path 740 and a sensor 710. The light signal? N + 1 is then used to optically interrogate the sensor 710 in an appropriate manner as indicated in one of the modalities described in the above. The light signal? N is sent along the optical path 730 to an optical communication terminal 720, in a manner not unlike the ONU 40, which regulates the optical signal with information analogous to the light in the path 210 in Figure 2. The optical signal from the sensor 710 is transferred along the optical path 725 and WDM 755. The optical signal for the optical communication terminal 720 has information modulated therein and transferred along the path optical 735 as well as WDM 755. Optical signals are combined in WDM 755 into a composite signal and sent upstream along optical path 35 ... Of course, it will be appreciated that WDMs can include multiple ports. For example, as shown in FIG. 8, the WDM 800 includes four different output ports for sending a plurality of optical signals? X? 4 of different wavelength along the optical paths 805-808, to a different sensor, sensor arrays or optical communication terminal 801-804 to interrogate each one with a different wavelength of light. For example, one sensor may be sensitive to variations in temperature, another may be sensitive to variations in pressure (water or ambient pressure, for example), etc. The optical signals returning from the sensor and the terminals by means of the optical paths 809-812 are then combined in WDM 820 and sent upstream as an upstream signal composed by way of the path 35". As in the above, if the device 800 is not a WDM, then the control of signals in the paths must be provided in order to avoid interference in the upstream path. In Figure 9 another additional embodiment of the present invention is shown. Devices 905 and 940 form a remote node 900 and ONU 901 includes an intermediate wavelength division multiplexer 925 (IWDM). The selectivity of IWDM 952 is comparable with the free spectral range of WDM / R 905 in the remote node. A wide-spectrum signal is introduced into path 25D for WDM / R 905. WDM / R 905 is a "Dragone" router which has the characteristic of separating the broad spectrum signal x as shown. The wavelengths? 1 (? N + 1,? 2N .., etc. they are sent along path 35D. The wavelengths? N (? 2M, etc. can be sent along other paths 920 to other ONUs for example.The IWDM 925 additionally separates the optical signals in path 910 into their constituent parts. ? 1 is sent along the path 926, the optical signal? N + 1 is sent along the path 927 and the optical signal? 2n + 1, is sent along the path 928. Each of Optical signals from IWDM 925 can then be used to optically interrogate sensors 929, 930 and 931, respectively, in one or more of the ways previously described.The optical signals typically pass through the sensors and are sent along of the paths 932, 933 and 934 which are combined in the IWDM 935 and sent upstream of the path 35u The signals in the path 35u can then be combined in WDM / R 940 and sent upstream via the path 25". Like in The above, WDM / R 940 and WDM / R 905 can be the same physical device. It will be appreciated that the foregoing description and drawings are only designed to be illustrative of the present invention. The variations, changes, substitutions and modifications of the present invention can occur to a person skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is considered that the present invention is limited only by the scope of the appended claims.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, property is claimed as contained in the following:

Claims (29)

1. A sensor system characterized in that it comprises: an optical receiver for receiving downstream optical signals and for converting the downstream optical signals to downstream electrical signals, - an optical transducer for recording information in an upstream data signal on upstream optical signals , - at least one sensor or detector responsive to an external stimulus for providing information signals from the sensor, - and a processor for receiving the electrical signals downstream to establish communication channels with at least one communication terminal providing signals for communication information and with at least -: *. sensor, wherein at least one terminal and at least one sensor provides the communication information signals and the sensor information signals. respectively, to the processor, which sends the information signals to the optical transducer as the upstream data signal.

2. The sensor system according to claim 1, characterized in that the optical transducer is a source for converting electrical signals into optical signals.

3. The sensor system according to claim 2, characterized in that the source is a LASER.

4. The sensor system according to claim 2, characterized in that the source is a broadband optical source.

5. The sensor system according to claim 1, characterized in that the downstream optical signal is coupled to the upstream optical signal.

6. The sensor system according to claim 5, characterized in that the optical signal upstream is amplified by the optical transducer.

7. The sensor system according to claim 5, characterized in that the optical transducer regulates or modulates the optical signals upstream.

8. The sensor system according to claim 1, characterized in that at least one sensor is selectively called by the processor to provide the sensor information signals.

9. The sensor system according to claim 8, characterized in that at least one sensor is selectively called in response to a downstream optical signal.

10. The sensor system according to claim 8, characterized in that the processor determines the moment in which it performs the selective call to at least one sensor.

11. The sensor system according to claim 1, characterized in that the sensor interrupts the processor in response to an external stimulus.

12. The sensor system according to claim 1, characterized in that the processor provides upstream data signals corresponding to a predetermined number in response to a predetermined group of sensor information signals.

13. The sensor system according to claim 1, characterized in that the processor elicits an emergency alert signal that is sent as a data signal upstream in response to a predetermined group of sensor information signals.

14. The sensor system according to claim 1, characterized in that the upstream optical signal includes identification information.

15. The sensor system according to claim 1, characterized in that the upstream optical signal causes instructions to be sent on the downstream electrical signal.

16. A sensor or detector system, characterized in that it comprises: an optical coupler for receiving at least one optical coupler for receiving at least a portion of a downstream optical signal and for providing an optical sensor interrogation signal downstream and a signal for downstream communication information; a communication device for receiving the downstream communication information signal and for providing an upstream communication information signal, - at least one sensor responsive to an external stimulus to provide sensor information signals; an optical signal modification device for receiving the downstream optical sensor interrogation signal and for modifying at least a portion thereof to provide a signal sent upstream in response to the sensor information signals, - and a coupler optical upstream to combine the upstream communication information signal and the detected upstream signal in a composite upstream optical signal.

17. The sensor system according to claim 16, characterized in that the optical coupler comprises a WDM device.

18. The sensor system according to claim 16, characterized in that at least one sensor is selectively called by the optical signal modification device in response to the interrogation signal of the sensor.

19. The sensor system according to claim 16, characterized in that at least one sensor provides an electrical signal to the optical signal modification device in response to the external stimulus.

20. The sensor system according to claim 16, characterized in that at least one sensor provides an optical signal to the optical signal modification device in response to the external stimulus.

21. The sensor system according to claim 16, characterized in that at least one sensor provides an electromagnetic signal to the device for modifying the optical signal in response to the external stimulus.

22. A sensor system, characterized in that it comprises - an optical coupler for receiving at least a portion of the downstream optical signal and for providing an interrogation signal of the downstream optical sensor and a downstream communication information signal; a communication device to receive the signal from. downstream communication information and to provide an upstream communication information signal, an optical signal modification device for receiving the interrogation signal from the downstream optical sensor and for modifying at least a portion thereof to provide a signal detected upstream in response to an external stimulus, - and an upstream optical coupler for combining the upstream communication information signal and the upstream detected signal to form a composite upstream optical signal.

23. The sensor system according to claim 22, characterized in that the optical signal communication device attenuates the optical sensor interrogation signal downstream in response to the external stimulus.

24. The sensor system according to claim 23, characterized in that the device modifying the optical signal blocks the signal Je interrogation of the optical sensor downstream in response to an external stimulus.

25. The sensor system according to claim 22, characterized in that the optical signal modification device includes a material in which a polarization of the interrogation signal of the optical sensor downstream passes through the material changes in response to a stimulus external.

26. The sensor system according to claim 22, characterized in that the optical signal modification device shows a change of state and becomes sensitive to the external stimulus in response to the interrogation signal of the downstream optical sensor.

27. An optical information technique, characterized in that it comprises the steps of: receiving downstream optical signals and converting them to downstream electrical signals, - providing sensor information signals from a sensor sensitive to an external stimulus, - receiving electrical signals downstream and establishing communication channels with at least one communication terminal that provides communication information signals and for establishing a communication channel with the sensor, and providing the communication information signals and the sensor information signals as a signal Upstream data that is recorded on an upstream optical signal.

28. An information technique with optical report, characterized in that it comprises the steps of - receiving at least a portion of an optical signal downstream and providing a downstream optical sensor interrelation signal and a downstream communication information signal, - receiving the downstream communication information signal and providing an upstream communication information signal, - providing a sensor information signal in response to an external stimulus, - modifying the downstream optical sensor interrogation signal in response to the sensor information signal to provide a signal detected upstream, and combining the upstream communication information signal and the upstream detected signal.

29. An optical information technique, characterized in that it comprises the steps of: receiving at least a portion of the optical signal downstream and providing an optical sensor interrogation signal downstream and a downstream communication information signal, - determining the information communication downstream and providing an upstream communication information signal, - receiving the interrogation signal from the downstream optical sensor and modifying at least a portion thereof to provide a signal detected upstream in response to an external stimulus, - and combining the communication information signal and the signal detected upstream.