MXPA97010246A - Switched opt dealer - Google Patents

Abstract

The present invention relates to a switched optical distributor of gain ie commutator, which is achieved by employing an optical amplifier of fibers adulterated with rare earths, such as the switching element per se. Each of the optical amplifiers of fibers adulterated with rare earths acts as an ON / OFF switch. Also, the switched-gain optical distributor of this invention is a natural complement in optically-amplified optical communication systems. In one embodiment, this is achieved by employing a pump selection circuit in conjunction with a plurality of pumps and a plurality of optical amplifiers of adulterated fibers with corresponding rare earths. The corresponding particular amplifier and pump are chosen by use of a monitor structure to determine which signal is to be selected and directed to an output. In another embodiment, a so-called tuned pump structure, an assembly with a plurality of filters and a corresponding plurality of optical amplifiers of fibers adulterated with rare earths is employed. A pump tuning structure is employed to control the tuneable pump in order to select the appropriate one of a plurality of optical power signals at any of a plurality of determined wavelengths.

Description

OPTICAL SWITCHED DISTRIBUTOR Related Requests Patent applications of the U.S.A. Serial number 08/777891 (M.T. Fatehi-W.H. Knox Case 16-21), Serial No. 08/777890 (M.T. Fatehi-W.H. Knox Case 12-17) and Serial No. 08/777892 (M.T. Fatehi-W.H. Knox Case 18-23) were presented concurrently with the present. TECHNICAL FIELD This invention relates to elements of optical communications and more specifically to optical distributors also known as optical switches. BACKGROUND An electrical lxN distributor, i.e. a switch, is a lxN switching device that directs the signal or signals from a single power port to any of the N output ports, as illustrated in FIGURE 1. A lxN distributor switch Optical is the optical analog of the electrical distributor switch lxN, where the input and output ports are optical fibers that carry one or more optical communication signals at a certain wavelength or a plurality of wavelengths. Certain distributing switches may allow directing the signal from the power line to two or more of the output ports N, thereby dividing the signal energy from the input line between the target output ports. This is termed REF: 26187 appropriately the diffusion or bridging capacity of the distributor switch. Former known distributors employ mechanical switching elements. These previous structures that employ mechanical distributors were limited to selecting only one output line at a time, their speed was slow and their reliability was less than convenient. Such a structure is illustrated in FIGURE 1, wherein an incoming optical fiber line 100 is supplied to the distributor 101 and switching element 103. The switching element 103 under control of the actuator 102, will then direct the optical signal (s) in the fiber lines 100 to one of the optical output lines 104-1 to 104-N. A number of electromechanical optical distributor switches are currently available. These devices are based on mechanically moving the input and / or output fibers or using various reflective or diverting optical elements to spatially direct a beam of light from the exit pupil of the feeding fiber and direct it to the input pupils of the fibers of exit. Clearly, these mechanical switches are slow and in most cases do not allow diffusion capacity, a convenient feature in communications systems. In some cases, the optical loss associated with these elements is significant.

Solid state waveguide distributing switches based on lithium niobate (see for example U.S. Patent No. 5,181,134) or indium phosphide optical switching devices are also available that solve speed problems. The disadvantage involved with these optical switching devices includes polarization dependence and significant optical losses. The large losses of optical insertion connected to these devices soon become intolerable when these devices are concatenated. SUMMARY OF THE INVENTION The problems and limitations of the mechanical distributors of the prior art and various solid-state optical distributors are overcome, in one embodiment of the invention, by employing an optical amplifier of fibers adulterated with optical rare earths such as the switching element. per se, of a switched optical distributor of gain. Each of the optical amplifiers of fibers adulterated with optical rare earths acts as an ON / OFF switch. Also, the switched-gain optical distributor of this invention is a natural complement in optically amplified optical communication systems today. In one embodiment, this is achieved by employing a pump selection circuit in conjunction with a plurality of pumps and a plurality of corresponding optical amplifiers of fibers adulterated with rare earths. The corresponding optical amplifier and particular pump are chosen by the use of a monitor structure to determine which port or output ports will be connected to the input port. In another modality, a so-called tuned pump structure is used in conjunction with a plurality of filters and a corresponding plurality of optical amplifiers of fibers adulterated with rare earths. A pump tuning structure is employed to control the tuneable pump in order to choose the appropriate one of a plurality of optical amplifiers to be activated, thereby directing the power signals to any of a plurality of wavelengths determined to the line of corresponding output (or lines if diffusion capacity is used). Brief Description of the Figures FIGURE 1 is an electromechanical distributing structure of the prior art; FIGURE 2 illustrates one embodiment of the invention employing so-called switched pumps with optical fiber amplifiers adulterated with rare earths; FIGURE 3 illustrates a tuned pump structure including optical amplifiers of fibers adulterated with rare earths; and FIGURE 4 shows a tuned pump structure that includes a plurality of pumps and comprises fiber amplifiers adulterated with rare earths. Detailed Description FIGURE 2 shows in simplified form, one embodiment of the invention which includes the optical fiber line 201 which supplies optical signals at predetermined wavelengths or sets of wavelengths with the optical amplifier of fibers adulterated with rare earths (a "amplifier" continuation) 203 and the amplifier 204, respectively by the optical star coupler (hereinafter "coupler") 202. The optical fiber adulterated with rare earth, for example may be a section of adulterated fiber with a herb coupled with a coupler selective wavelength, for example a split coupling with wavelength division through which a pump is coupled. It should also be noted that the loss is compensated by the length of the fiber adulterated with rare earth, and the gain is compensated by the energy of the pump. As illustrated, the pump 204 is coupled to the amplifier 203 and the pump 206 is coupled to the amplifier 205. As is known in the art, each of the pumps 204 and 206 respectively energizes the amplifiers 203 and 205. Additionally, the pumping It can be co-directional or counter directional. Without doubt, pumping can also be bi-directional. The feeds of the amplifiers 203 and 205 are identical copies of the feed signal on the line 201 which is provided by the coupler 202, which this example is a 2xN coupler, in a well known manner. The outputs of the amplifiers 203 and 204 are connected to the output gates 207 and 208, by the optional optical check tappings (hereinafter "taps") 209 and 211. The taps 209 and 211 derive a small fraction (eg 1 to 10%) of the optical output signals and direct the optical signals to the photodetectors (optical to electric converters), O / E 210 and 212 respectively. The O / Es 210 and 212 assist in the processes to determine which of the amplifiers 203 and 204 are currently chosen by the energy level of the selected line and determine the identification (ID) labels and parameters with selected lines (see for example U.S. Patent Application Co-pending Serial No. 08/579529, filed December 27, 1995). The O / Es information 210 and 212 is supplied to the pump selector 213, which then selects either the pump 204 or the pump 206 according to the desired parameters and commands for the command and control unit 214. It will be noted that However, this verification structure is optional and other optical control and verification structures known in the art can also be used. This will be apparent to those with skill in the specialty. The pump selector circuit 213, control and command information of the command and control unit 214 which is used with the information of other network elements in an optical system is also provided in order to select which of the pumps 204 and 206 to be chosen and in accordance with this which of the amplifiers 203 or 205 will be switched to ON and that will be switched to OFF. It should be noted, however, that although we have shown the use of O / Es 210 and 212 in this example, other structures can be used to verify different parameters in order to choose which of the pumps 204 and 206 and accordingly which of the amplifiers 203 and 205 will switch to ON. FIGURE 3 shows in simplified form another embodiment of the invention for a line of feed optical fibers 301 which will be distributed to a plurality of optical fiber output lines 311-1 to 311-N and a corresponding plurality of amplifiers 303-1 to 303-N. In this embodiment of the invention, only a tunable pump 309 is required, which gives us the technical advantage of cost savings. Associated with the tunable pump 309 is another optical star coupler (hereinafter "coupler") 310 and a plurality of fixed (or pre-adjustable) optical bandpass filters (hereinafter "filters") 304-1 to 304- N, which are associated in a 1-al base with amplifiers 302-1 to 302-N, respectively. In practice, these filters 302-1 to 302-N can be constructed in the selective wavelength coupler (s) used to construct amplifiers 303-1 through 303-N (see literature for structural details of various designs). of optical amplifiers). Again, the outputs of amplifiers 302-1 to 302-N are supplied to the optional taps 305-1 to 305-N for the purpose of verifying integrity by monitors 306-1 through 306-N before addressing the system output ports 311-1 to 311-N. Again, the outputs of the O / E devices 306-1 through 306-N are combined in the pump tuning circuit 307, with information from the command and control unit 308 to tune the wavelength of the tunable pump 309 FIGURE 4 shows a simplified block diagram of another embodiment of the invention employing a single power line 401 and a plurality of output fiber optic lines 409-1 to 409-N and a corresponding plurality of 403-1 amplifiers to 403-N. In this embodiment of the invention, a corresponding plurality of pumps 404-1 to 404-N are associated with amplifiers 403-1 to 403-N, respectively. Again the output of amplifiers 403-1 to 403-N are supplied to leads 405-1 to 405-N for the purpose of verifying integrity by O / Es 406-1 to 406-N, before going to the output gates of the 409-1 to 409-N system. Again, the outputs of the O / E devices 406-1 to 406-N are combined in the pump selection circuit 407 with information from the command and control unit 408, to activate one (or more if diffusion is desired) of the pumps 404-1 to 404-N and consequently pass the corresponding amplifier (s) 403-1 to 403-N to ON (ON) or OFF (OFF). It should be noted, however, that the other optical coupling and verification structures known in the art can likewise be used instead of the optical couplers 405-1 to 405-N and the associated components. This will be apparent to those with skill in the specialty. Specifically, in this example, O / Es 403-1 to 403-N each check the energy level of an optical signal of an associated optical fiber 405-1 to 405-N and determine the parameters and ID tags associated with that signal, for verification of the operation and quality of the distributor switch. 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, the content of the following is claimed as property:

Claims (9)

1. CLAIMS 1. An optical distributor that has a power supply and a plurality of outputs, characterized in that it comprises: a plurality of optical amplifiers that correspond to the plurality of outputs, each used as a switching element; a coupling element for coupling an optical input signal to each of the plurality of optical amplifiers; a pump structure that responds to a command signal to control the ON / OFF states of each of the plurality of optical amplifiers, such that the optical input signals are supplied to one or more of the plurality of outputs.
2. 2. The optical distributor according to claim 1, characterized in that each of the optical amplifiers comprises an optical fiber adulterated with rare earths, having a predetermined length and a corresponding pump that responds to the command signals to pass the amplifier. optical ON / OFF (ON / OFF).
3. 3. The optical distributor according to claim 2, characterized in that the fiber is adulterated with erbium.
4. 4. The optical distributor according to claim 2, characterized in that the pump structure associated with the adulterated fiber with rare earths is arranged to provide co-directional pumping of the optical fiber amplifier adulterated with rare earths.
5. 5. The optical selector according to claim 2, characterized in that the pump structure associated with the fiber adulterated with rare earths, is arranged to provide directional pumping of the optical amplifier of adulterated fiber with rare earths.
6. 6. The optical selector according to claim 1, characterized in that each of the optical amplifiers comprises an optical fiber adulterated with rare earth having a predetermined length and a corresponding filter, the pump structure includes a tunable pump and a circuit of pump tuning, and a coupler for an output from the tunable pump to each of the filters corresponding to the plurality of optical amplifiers, the pump tuning circuit responds to the command and control signals, to control the synchronizable pump to supply pumping signals to ON / OFF one or more of the plurality of optical amplifiers, the filters separate the pump signal to perform ON / OFF of one or more of the plurality of amplifiers. optical
7. 7. The optical selector according to claim 4, characterized in that the fiber is adulterated with erbium.
8. 8. The optical selector according to claim 6, characterized in that the pump structure associated with the rare earth adulterated fiber is arranged to provide co-directional pumping of the optical amplifier of fibers adulterated with rare earths.
9. 9. The optical selector according to claim 6, characterized in that the pump structure associated with the fiber adulterated with rare earths is arranged to provide counter-directional pumping of the optical fiber amplifier adulterated with rare earths. SUMMARY OF THE INVENTION The present invention relates to a switched optical distributor of gain ie commutator, which is achieved by employing an optical amplifier of fibers adulterated with optical rare earths, such as the switching element per se. Each of the optical amplifiers of fibers adulterated with optical rare earths acts as a switch ON / OFF (ON / OFF). Also, the switched-gain optical distributor of this invention is a natural complement in today's optically amplified optical communication systems. In one embodiment, this is achieved by employing a pump selection circuit in conjunction with a plurality of pumps and a plurality of fiber optic amplifiers adulterated with corresponding rare earths. The corresponding particular amplifier and pump are chosen by use of a monitor structure to determine which signal is to be selected and directed to an output. In another modality, a so-called tuned pump structure is used in conjunction with a plurality of filters and a corresponding plurality of optical amplifiers of fibers adulterated with rare earths. A pump tuning structure is employed to control the tuneable pump in order to select the appropriate one of a plurality of optical power signals at any of a plurality of determined wavelengths.