Variable optical attenuator with shutter MEMS

Abstract

The invention relates to a variable optical attenuator with shutter MEMS. In a variable optical attenuator (VOA) and a method of variably optically attenuating a light beam, an input lens receives an input light beam and an output lens outputs an output light beam. The mirror reflects an input beam as an output beam. The mirror or the movable element is movable in a manner that blocks, transmits and / or reflects at least a portion of the light included in the input beam and the output beam, whereupon the output beam has a reduced or increased brightness or intensity relative to the input beam.

Description

Technical Field

[0001] The present disclosure relates to systems and methods for variable optical attenuation. Background Art

[0002] A variable optical attenuator (VOA) is a device used in fiber optic communication systems to control the power level of an optical signal within an optical fiber. It is designed to attenuate or reduce the intensity of light passing through it without significantly affecting other signal characteristics such as wavelength or data modulation. The VOA is used to manage signal power levels, optimize signal quality, and protect sensitive optical components in the network.

[0003] Components of VOA prior to the present disclosure may include: a first collimating lens and a second collimating lens, an optical path conversion prism, a birefringent crystal, and a pair of liquid crystal elements, where one of the liquid crystal elements includes a mirror (see US10,749,598B2) Summary of the Invention

[0004] Disclosed is a variable optical attenuator (VOA) including: a lens device for receiving an input beam and for outputting an output beam; a reflector or mirror for reflecting the input beam as the output beam; and a movable element that can be at least partially moved into or out of the path of at least one of the input beam and the output beam between the lens device and the reflector or mirror for blocking at least a portion of at least one of the input beam and the output beam.

[0005] Also disclosed is a method for variably optically attenuating a beam, including: (a) passing an input beam through a first lens; (b) reflecting at least a portion of the input beam of step (a) as an output beam by a reflector or mirror; (c) positioning the movable element at least partially in the path of at least one of the input beam and the output beam; and (d) outputting at least a portion of the output beam through a second lens.

[0006] Also disclosed is a variable optical attenuator (VOA) including: a lens device for receiving an input beam and for outputting an output beam; and a reflector or mirror for reflecting the input beam as the output beam, wherein the reflector or mirror can be at least partially moved into or out of the path of the input beam.

[0007] Also disclosed is a method for variably optically attenuating a beam, including: (a) passing an input beam through a first lens; (b) reflecting at least a portion of the input beam of step (a) as an output beam by a reflector or mirror; (c) moving the reflector or mirror at least partially into or out of the path of the input beam; and (d) outputting at least a portion of the output beam through a second lens.

[0008] Also disclosed is a variable optical attenuator (VOA), comprising: a lens device for receiving an input beam and for outputting an output beam; a rotatable mirror positioned and operable to reflect the input beam received from the lens device to different parts of the input surface of a cylindrical lens when rotated, the cylindrical lens outputting the input beam received at different parts of the input surface of the cylindrical lens as a plurality of parallel beams via the output surface of the cylindrical lens; and a reflector positioned to reflect at least a portion of the parallel beams output via the output surface of the cylindrical lens back through the cylindrical lens to the rotatable mirror, the rotatable mirror reflecting the light received from the cylindrical lens as the output beam.

[0009] A shutter or blocker may be positioned between the output surface of the cylindrical lens and the reflector. The shutter or blocker may be positioned to allow at least a portion of the parallel beams to pass to the reflector and to avoid or prevent another portion of the parallel beams output via the output surface of the cylindrical lens from reaching the reflector.

[0010] Also disclosed is a method of variably optically attenuating a beam, comprising: (a) passing an input beam through a first lens; (b) reflecting at least a portion of the input beam of step (a) via a cylindrical lens to a reflector by a rotatable mirror, the cylindrical lens separating the input beam received at different parts of the input surface of the cylindrical lens into a plurality of parallel beams output via the output surface of the cylindrical lens to the reflector; (c) reflecting at least a portion of the parallel beams output via the output surface of the cylindrical lens back through the cylindrical lens to the rotatable mirror by the reflector, the rotatable mirror reflecting the light received from the cylindrical lens as an output beam through a second lens.

[0011] The method may further comprise preventing another portion of the plurality of parallel beams output via the output surface of the cylindrical lens from reaching the reflector by a shutter or blocker. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A and Figure 1B are a perspective side view and an end view of an exemplary VOA in accordance with the principles of the present disclosure, the exemplary VOA including a lens device, a fixed reflector or mirror, and a movable element or shutter movable into and out of the path of at least one of the input beam and the output beam;

[0013] Figure 1C-1D is Figure 1B a perspective end view of the exemplary VOA shown in

[0014] Figure 2A-2CIs a perspective end view of another exemplary VOA according to the principles of the present disclosure, the exemplary VOA including a movable reflector or mirror movable into and out of the path of at least one of an input beam and an output beam;

[0015] Figure 3A Is a perspective side view of another exemplary VOA according to the principles of the present disclosure, the exemplary VOA including a lens device, a rotatable reflector or mirror, a cylindrical lens, and a reflector partially positioned in the path of the parallel beam output by the cylindrical lens;

[0016] Figure 3B-3C Is a view showing Figure 3A How the rotatable reflector or mirror reflects and diffuses the input beam input into the input surface of the cylindrical lens, the cylindrical lens separating the diffused input beam into a plurality of parallel beams output to the reflector via the output surface of the cylindrical lens ( Figure 3C );

[0017] Figure 3D Is Figure 3A And Figure 3C A separate view of the reflector, shown positioned to reflect a portion of the parallel beam output via the output surface of the cylindrical lens back through the cylindrical lens and to transmit another portion of the parallel beam output via the output surface of the cylindrical lens;

[0018] Figure 4A Is a perspective side view of another exemplary VOA according to the principles of the present disclosure, the exemplary VOA including a lens device, a rotatable reflector or mirror, a cylindrical lens, a shutter or blocker positioned to transmit a portion of the parallel beam output via the output surface of the cylindrical lens and block another portion of the parallel beam output via the output surface of the cylindrical lens, and a reflector positioned to reflect the portion of the parallel beam transmitted by the shutter or blocker.

[0019] Figure 4B Is Figure 4A A separate view of the cylindrical lens, shutter or blocker, and reflector of ; and

[0020] Figure 4C Is Figure 4A And 4B A separate view of the shutter or blocker and reflector of , showing the shutter or blocker positioned to allow a portion of the parallel beam output via the output surface of the cylindrical lens to pass through to the reflector to be reflected back through the cylindrical lens and to block another portion of the parallel beam output via the output surface of the cylindrical lens. Detailed Description

[0021] As used herein, spatial or directional terms such as "left", "right", "inner", "outer", "above", "below", etc. are related to the present disclosure as shown in the accompanying drawings. However, it should be understood that the present disclosure can take various alternative orientations, and thus, these terms should not be considered restrictive. Additionally, as used herein, all numbers expressing dimensions, physical properties, processing parameters, amounts of ingredients, reaction conditions, etc. used in the specification and claims should be understood to be modified in all instances by the term "about" or "approximately". Accordingly, unless indicated to the contrary, the numerical values set forth in the following specification and claims may vary depending upon the desired properties sought to be obtained by the present disclosure.

[0022] At a minimum, and without attempting to limit the application of the doctrine of equivalents to the scope of the claims, each numerical value should at least be construed in accordance with the number of significant digits reported and by application of ordinary rounding techniques. Additionally, all ranges disclosed herein should be understood to encompass the beginning and ending range values, as well as any and all sub-ranges subsumed therein. For example, a stated range of "1 to 10" should be considered to include any and all sub-ranges between the minimum value of 1 and the maximum value of 10, inclusive; that is, all sub-ranges starting with a minimum value of 1 or more and ending with a maximum value of 10 or less, such as 1 to 3.3, 4.7 to 7.5, 5.5 to 10, etc. "A" or "an" means one or more.

[0023] As used herein, the terms "coupled", "coupling", and like terms refer to two or more elements that are joined, linked, fastened, connected, in communication with, or otherwise associated with each other (e.g., mechanically, electrically, fluidically, optically, electromagnetically). In various examples, the elements can be associated directly or indirectly. As an example, element A can be directly associated with element B. As another example, element A can be indirectly associated with element B via, for example, another element C. It will be understood that not all associations between the various disclosed elements are necessarily represented. Thus, there can also be couplings other than those depicted in the figures.

[0024] As used herein, the phrase "at least one" when used in conjunction with a list of items means that different combinations of one or more of the listed items can be used and only one of each item in the list may be required. For example, "at least one of item A, item B, and item C" can include, but is not limited to, item A or item A and item B. This example can also include item A, item B, and item C, or item B and item C. In other examples, "at least one of..." can be, for example but not limited to, two of item A, one of item B, and ten of item C; four of item B and seven of item C; and other suitable combinations.

[0025] In this document, the terms "reflector" and "mirror" may be used interchangeably. The shapes of the light rays or light beams shown in the drawings are strictly for the purposes of this disclosure and should not be construed in a limiting sense.

[0026] Various non-limiting examples will now be described with reference to the drawings, where like reference numerals correspond to like or functionally equivalent elements.

[0027] Reference Figure 1A-1D , an example variable optical attenuator (VOA) 2 in accordance with the principles of the present disclosure includes a lens assembly 3 that is optically coupled, for example via a dual pigtail, to an input optical fiber 4 and an output optical fiber 6. In the example, the lens assembly 3 may include an input lens 3-1 and an output lens 3-2 (shown in dashed lines in Figure 1A ) that are optically coupled to the input optical fiber 4 and the output optical fiber 6, respectively. The lens assembly 3 may include a lens array that includes the input lens 3-1 and the output lens 3-2.

[0028] An input light beam 8 exiting the input optical fiber 4 may pass through the input lens 3-1, which focuses and transmits the input light beam 8 to a reflector or mirror 10. The input light beam 8 incident on the surface of the reflector or mirror 10 may thereby be reflected as an output light beam 12 that passes through the output lens 3-2 of the lens assembly 3, which focuses and transmits the output light beam 12 to the output optical fiber 6.

[0029] The VOA 2 may include an optional beam splitter 10 that may reflect portions 8-1 and 12-1 of the input light beam 8 and the output light beam 12 to optional input and output photodiodes 16 and 18 for conversion into electrical signals having values related to the brightness or intensity of the input light beam 8 and the output light beam 12, respectively. These electrical signals may be provided to an optional controller 22 that may be programmed or configured to control the movement of the movable shutter 20 in the manner described hereinafter.

[0030] Portions of the input light beam 8 and the output light beam 12 that impinge on the beam splitter 12 and are not reflected by the beam splitter 12 to the input and output photodiodes 16 and 18 may pass through the beam splitter 14 to the reflector or mirror 10 (for the input light beam 8) and the output lens 3-2 (for the output light beam 12).

[0031] The movable shutter 20 may be positioned or deployed between the lens assembly 3 or the beam splitter 14 (if provided) and the reflector or mirror 10. The shutter 20 may be moved partially or fully into or out of the path of at least one of the input light beam 8 and the output light beam 12 manually or under the control of the optional controller 22.

[0032] In fromFigure 1B In an example starting from the state where the shutter 20 is deployed or positioned outside the paths of the input beam 8 and the output beam 12 as shown, the input beam 8 received from the input optical fiber 4 is focused by the input lens 3-1 and reflected by the reflector or mirror 10 as the output beam 12, and the output beam 12 is focused by the output lens 3-2 and provided to the output optical fiber 6.

[0033] If it is determined from the values of the electrical signals output from one or both of the photodiodes 16 and 18 manually (e.g., empirically) or via the optional controller 22 that the output beam 12 has too much or too great brightness or intensity, then the shutter 20 can be partially moved into the path of the input beam 8 in the direction of the arrow 24, as Figure 1C shown. In response to this movement, the shutter 20 causes a portion 26 of the input beam 8 to partially pass through to the reflector or mirror 10 and partially blocks the remaining portion of the input beam 8, i.e., the shutter 20 partially blocks the input beam 8 and allows the portion 26 of the input beam 8 to pass through to the reflector or mirror 10.

[0034] For illustrative purposes, in Figure 1C , the input beam 8 before being partially blocked by the shutter 20 is shown by a thicker line width (indicating the greater brightness or intensity of the input beam 8 incident on the shutter 20), while the portion 26 of the input beam 8 that passes through to the reflector or mirror 10, and thus the output beam 12, is shown by a thinner line width (indicating the reduced brightness or intensity of the portion 26 of the input beam 8 that passes through to the reflector or mirror 10 and thus the output beam 12). Herein, in all figures, a thicker line width can be used to indicate the greater brightness or intensity of a beam, and a thinner line width can be used to indicate the smaller or reduced brightness or intensity of a beam relative to the greater brightness or intensity indicated by the thicker line width.

[0035] As can be seen, the brightness or intensity of the output beam 12 can be controlled by selectively moving the shutter 20 as needed and / or desired to block as little or as much of the input beam 8 as possible, thereby achieving the desired attenuation level between the input beam 8 and the output beam 12.

[0036] As Figure 1D shown, if desired, the shutter 20 can be fully moved into the path of the input beam 8 such that the VOA 2 achieves complete attenuation of the input beam 8, and thus there is no output beam 12. Conversely, although Figure 1A-1D not shown, the shutter 20 can be fully moved out of the path of the input beam 8, so that the input beam 8 is not attenuated and the input beam 8 and the output beam 12 have the same intensity brightness.

[0037] In Figure 1B-1D , for simplicity,Figure 1A the input and output photodiodes 16 and 18, and optional controller 22 shown in Figure 1A . However, Figure 1A-1D the example VOA shown in Figure 1A-1D may include an optional optical splitter 14, optional input and output photodiodes 16 and 18, and optional controller 22, or some or all of these elements may be excluded depending on the application or desired capabilities of the VOA. Thus, in the example VOA shown in Figure 1A-1D , the presence or absence of one or more of the optional optical splitter 14, optional input and output photodiodes 16 and 18, and optional controller 22 should not be construed in a limiting sense. Figure 1A-1D In the example VOA shown in Figure 1A-1D , the presence or absence of one or more of the optional optical splitter 14, optional input and output photodiodes 16 and 18, and optional controller 22 should not be construed in a limiting sense.

[0038] In the above example, the shutter 20 starts at a position to the left of the input beam 8 and moves partially or fully to the right (in the direction of arrow 24) into the path of the input beam 8. In Figure 1B-1C another example shown in Figure 1B-1C , the shutter 20 can be repositioned to a starting position to the right of the output beam 12 (shown in dashed lines) and can move partially or fully to the left (in the direction of the dashed arrow 28) into the path of the output beam 12, thereby reducing the brightness or intensity of the output beam 12 (or blocking the output beam 12) without first reducing the brightness or intensity of the input beam 12.

[0039] In the example, the position of the shutter 20 that blocks all or part of the input beam 8 or output beam 12 can be changed as desired to achieve a desired attenuation level. For example, starting from the state where the shutter 20 (shown as a solid line in Figure 1C ) partially blocks the input beam 8, the shutter can be moved to the left to allow more of the input beam 8 to pass through and be reflected by the reflector or mirror 10 as the output beam 12. Similarly, starting from the state where the shutter 20 (shown as a dashed line in Figure 1C ) partially blocks the output beam 12, the shutter can be moved to the right to allow more of the output beam 12 to pass through to the lens device 3. Figure 1C shown as a solid line in Figure 1C ) partially blocks the input beam 8, the shutter can be moved to the left to allow more of the input beam 8 to pass through and be reflected by the reflector or mirror 10 as the output beam 12. Similarly, starting from the state where the shutter 20 (shown as a dashed line in Figure 1C ) partially blocks the output beam 12, the shutter can be moved to the right to allow more of the output beam 12 to pass through to the lens device 3. Figure 1C shown as a dashed line in Figure 1C ) partially blocks the output beam 12, the shutter can be moved to the right to allow more of the output beam 12 to pass through to the lens device 3.

[0040] The example VOA discussed below may be described and / or illustrated as including an optional optical splitter 14 and not including the optional input and output photodiodes 16 and 18 and optional controller 22 shown in

[0040] . However, depending on the application, each example VOA discussed below may include an optional optical splitter 14, optional input and output photodiodes 16 and 18, and optional controller 22, or some or all of these elements may be excluded for simplicity, as determined by the application or desired capabilities of the VOA. Thus, in the example VOA described and illustrated in the figures below, the presence or absence of one or more of the optional optical splitter 14, optional input and output photodiodes 16 and 18, and / or optional controller 22 should not be construed in a limiting sense. Figure 1A In the example VOA described and illustrated in the figures below, the presence or absence of one or more of the optional optical splitter 14, optional input and output photodiodes 16 and 18, and / or optional controller 22 should not be construed in a limiting sense.

[0041] Reference Figure 2A-2C , another example variable optical attenuator (VOA) 2 according to the principles of the present disclosure may include, for example, lens means 3 optically coupled to input and output optical fibers 4 and 6 via a bi-tail fiber (such as shown in Figure 1A . In an example, the lens means 3 may include an input lens 3-1 and an output lens 3-2 (shown in dashed lines) optically coupled to the input optical fiber 4 and the output optical fiber 6, respectively. The lens means 3 may include a lens array that includes the input lens 3-1 and the output lens 3-2.

[0042] The input beam 8 exiting the input optical fiber 4 passes through the input lens 3-1, which focuses and transmits the input beam 8 to a reflector or mirror 10. The input beam 8 incident on the surface of the reflector or mirror 10 is thus reflected as an output beam 12, which passes through the output lens 3-2 of the lens means 3, which focuses and transmits the output beam 12 to the output optical fiber 6.

[0043] In an example, starting from the state shown in Figure 2A where the reflector or mirror 10 may be fully deployed or positioned in the path of the input beam 8, the input beam 8 received from the input optical fiber 6 is focused by the input lens 3-1 and reflected by the reflector or mirror 10 as an output beam 12, which is focused by the output lens 3-2 and provided to the output optical fiber 6.

[0044] If it is determined, either manually (e.g., empirically) or via an optional controller 22, from the electrical signal values output from one or both of the optional photodiodes 16 and 18 ( Figure 1A shown in Figure 2B ) that the output beam 12 has too much or too great a brightness or intensity, then the reflector or mirror 10 may be partially moved out of the path of the input beam 8, for example, in the direction of arrow 24, as shown in

[0045] For purposes of illustration, in Figure 2BIn [the figure], the input beam 8 before being partially transmitted and partially reflected by the reflector or mirror 10 is shown by a thicker line width (indicating a greater brightness or intensity of the input beam 8 close to the reflector or mirror 10), while the part 26 of the input beam 8 transmitted by the reflector or mirror 10 and the part of the input beam 8 reflected by the reflector or mirror 10 as the output beam 12 are shown by a thinner line width (indicating a reduced brightness or intensity of the part 26 of the input beam 8 transmitted by the reflector or mirror 10 and the part of the input beam 8 reflected by the reflector or mirror 10 as the output beam 12).

[0046] As can be seen, the brightness or intensity of the output beam 12 can be controlled by selectively moving the reflector or mirror 10 as needed and / or desired to reflect as little or as much of the input beam 8 as possible, thereby achieving the desired attenuation level between the input beam 8 and the output beam 12.

[0047] As Figure 2C shown in [the figure], if desired, the reflector or mirror 10 can be completely moved out of the path of the input beam 8 such that the VOA 2 achieves complete attenuation of the input beam 8 and thus there is no output beam 12.

[0048] Referring Figure 3A-3D to [the figure], another example variable optical attenuator (VOA) 2 according to the principles of the present disclosure can include, for example, lens means 3 optically coupled to the input and output optical fibers 4 and 6 via twin-tail fibers (such as shown in Figure 1A [the figure]). In the example, the lens means 3 can include an input lens 3-1 and an output lens 3-2 (shown in dashed lines) optically coupled to the input optical fiber 4 and the output optical fiber 6, respectively. The lens means 3 can include a lens array that includes the input lens 3-1 and the output lens 3-2.

[0049] The input beam 8 exiting the input optical fiber 4 passes through the input lens 3-1, which focuses and transmits the input beam 8 to the rotating reflector or mirror 10. The input beam 8 impinging on the rotating reflector or mirror 10 is thereby reflected to the cylindrical lens 32. The rotating reflector or mirror 10 is configured such that the input beam 8 reflected thereby diverges, for example, in a cone 30 to the cylindrical lens 32, and the cylindrical lens 32 separates the diverging 30 input beam 8 received at different parts of the input surface 34 of the cylindrical lens 32 into a plurality of parallel beams 36 output to the reflector 40 via the output surface 38 of the cylindrical lens 32.

[0050] In the example, the reflector 40 can be positioned to reflect or return a first portion or part 42 of the parallel light beam 36 output from the output surface 38 of the cylindrical lens 32 back to the output surface 38 of the cylindrical lens 32 and transmit a second portion or part 44 of the parallel light beam 36 output from the output surface 38 of the cylindrical lens 32. In this example, the second portion or part 44 of the parallel light beam 36 output from the output surface 38 of the cylindrical lens 32 and transmitted by the reflector or mirror 40 is not used.

[0051] The cylindrical lens 32 converges a first portion or part 42 of the parallel light beam 36 reflected or returned by the reflector 40 to the output surface 38 of the cylindrical lens 32. The converged first portion or part 42 is output by the cylindrical lens 32 as a converging light beam 30' to the rotating reflector or mirror 10, which reflects the incident converging light beam 30' as an output light beam 12, and the output light beam 12 is focused by the output lens 3-2 and provided or output to the output optical fiber 6.

[0052] If it is determined, manually (e.g., empirically) or via the optional controller 22, from the value of the electrical signal output from one or both of the optional photodiodes 16 and 18 that the output light beam 12 has too low a brightness or intensity, then the reflector 40 can be further moved into the path of the parallel light beam 36 in the direction of arrow 24, thereby allowing less of the parallel light beam 36 to be transmitted by the reflector 40 and more of the parallel light beam 36 to be reflected back to the output surface 38 of the cylindrical lens 32, thus increasing the brightness or intensity of the output light beam 12.

[0053] On the other hand, if it is determined that the output light beam 12 has too high a brightness or intensity, then the reflector 40 can be further moved out of the path of the parallel light beam 36 in a direction opposite to arrow 24, thereby allowing more of the parallel light beam 36 to be transmitted by the reflector 40 and less of the parallel light beam 36 to be reflected back to the output surface 38 of the cylindrical lens 32, thus reducing the brightness or intensity of the output light beam 12.

[0054] Although not specifically shown, it is also contemplated that the reflector 40 can be fully moved into or out of the path of the parallel light beam 36, thereby respectively reflecting the parallel light beam 36 fully back to the output surface 38 of the cylindrical lens 32, so that the input light beam 8 is attenuated little or not at all, or allowing the parallel light beam 36 to pass through completely without reflection, so that the input light beam 8 is completely attenuated and there is no output light beam 12.

[0055] In the example, the rotating mirror 10 can be a microelectromechanical system (MEMS) mirror, which can be configured and rotated at a necessary and / or desired speed to reflect the input beam 8 towards the cylindrical lens 32, while causing the input beam 8 reflected thereby to diverge, for example, in a conical shape to the input surface 34 of the cylindrical lens 32. The rotating mirror 10 can also be configured and rotated at a necessary and / or desired speed to reflect the converging beam 30' returning from the input surface 34 of the cylindrical lens 32 as the output beam 12 to the output lens 3-2, which focuses the output beam 12 and provides or outputs it to the output optical fiber 6. The situation where the input beam 8 and the output beam 12 converge on the rotating mirror 10 in the figure is strictly for illustrative purposes and should not be construed in a limiting sense.

[0056] Reference Figure 4A-4C , another example variable optical attenuator (VOA) 2 according to the principles of the present disclosure can include, for example, lens means 3 optically coupled to the input optical fiber 4 and the output optical fiber 6 via a twin-tail fiber (as shown, for example, in Figure 1A . In the example, the lens means 3 can include an input lens 3-1 and an output lens 3-2 (shown in dashed lines) optically coupled to the input optical fiber 4 and the output optical fiber 6, respectively. The lens means 3 can include a lens array that includes the input lens 3-1 and the output lens 3-2.

[0057] The input beam 8 exiting the input optical fiber 4 passes through the input lens 3-1, which focuses and transmits the input beam 8 to the rotating reflector or mirror 10. The input beam 8 incident on the rotating reflector or mirror 10 is thereby reflected to the cylindrical lens 32. The rotating reflector or mirror 10 is configured such that the input beam 8 reflected thereby diverges, for example, in a conical shape 30 to the cylindrical lens 32, and the cylindrical lens 32 separates the diverging 30 input beam 8 received at different portions of the input surface 34 of the cylindrical lens 32 into a plurality of parallel beams 36 output to the reflector 40 via the output surface 38 of the cylindrical lens 32. In this example, the reflector 40 is stationary and is fully positioned in the path of the plurality of parallel beams 36 output via the output surface 38 of the cylindrical lens 32.

[0058] Disposed between the output surface 38 of the cylindrical lens 32 and the reflector 40 is a movable shutter or blocker 46 that can be moved at least partially into and / or out of the path of the plurality of parallel light beams 36. In an example, the shutter or blocker 46 can be positioned to block or impede a first portion or part 42 of the parallel light beams 36 output from the output surface 38 of the cylindrical lens 32 from reaching the reflector 40 and to allow a second portion or part 42 of the plurality of parallel light beams 36 output from the output surface 38 of the cylindrical lens 32 to pass to the reflector 40. The reflector 40 reflects a second portion or part 44 of the parallel light beams 36 back to the output surface 38 of the cylindrical lens 32. In this example, the first portion or part 42 of the parallel light beams 36 blocked or impeded by the shutter or blocker 46 is thereby absorbed, so that little or no absorbed light is reflected and none is used.

[0059] The cylindrical lens 32 converges a second portion or part 44 of the parallel light beams 36, where the second portion or part 44 of the parallel light beams 36 is reflected by the reflector 40 or returned to the output surface 38 of the cylindrical lens 32. The converged second portion or part 44 is output by the cylindrical lens 32 as a converging light beam 30' to a rotating reflector or mirror 10, which reflects the incident converging light beam 30' as an output light beam 12 that is focused by the output lens 3-2 and provided or output to the output optical fiber 6.

[0060] If it is determined, either manually (e.g., empirically) or via an optional controller 22 from the value of an electrical signal output from one or both of the optional photodiodes 16 and 18, that the output light beam 12 has too little brightness or intensity, then the shutter or blocker 46 can be moved further out of the path of the parallel light beams 36 in a direction opposite to the arrow 24. This movement allows more of the parallel light beams 36 to be passed by the shutter or blocker 46 to be reflected by the reflector 40 back to the output surface 38 of the cylindrical lens 32, thereby increasing the brightness or intensity of the output light beam 12.

[0061] On the other hand, if it is determined that the output light beam 12 has too much brightness or intensity, then the shutter or blocker 46 can be moved further into the path of the parallel light beams 36 in the direction of the arrow 24, thereby blocking more of the parallel light beams 36 from reaching the reflector 40 and being reflected by the reflector 40 back to the output surface 38 of the cylindrical lens 32, thereby reducing the brightness or intensity of the output light beam 12.

[0062] Although not specifically shown, it is also conceivable that the shutter or blocker 46 can be fully moved into or out of the path of the parallel beam 36, thereby absorbing all of the parallel beam 36, respectively, so that the input beam 8 is fully or substantially fully attenuated and there is no output beam 12, or allowing the parallel beam 36 to pass through to the reflector 40 without any absorption by the shutter or blocker 46, so that the input beam 8 is hardly attenuated.

[0063] In the example, the rotating mirror 10 can be a microelectromechanical system (MEMS) mirror, which can be configured and rotated at a necessary and / or desired speed to reflect the input beam 8 to the cylindrical lens 32, while causing the reflected input beam 8 to diverge, for example, in a conical shape to the input surface 34 of the cylindrical lens 32. The rotating mirror 10 can also be configured and rotated at a necessary and / or desired speed to reflect the converging beam 30' returning from the input surface 34 of the cylindrical lens 32 as the output beam 12 to the output lens 3-2, which focuses the output beam 12 and provides or outputs it to the output optical fiber 6. The situation where the input beam 8 and the output beam 12 converge on the rotating mirror 10 in the figure is strictly for illustrative purposes and should not be construed in a limiting sense.

[0064] Other non-limiting examples or aspects of the present disclosure are set forth in the following illustrative and exemplary numbered clauses:

[0065] Clause 1: A variable optical attenuator (VOA) includes lens means for receiving an input beam and for outputting an output beam; a reflector or mirror for reflecting the input beam as the output beam; and a movable element that can be at least partially moved into or out of the path of at least one of the input beam and the output beam between the lens means and the reflector or mirror for blocking at least a portion of at least one of the input beam and the output beam.

[0066] Clause 2: The VOA of Clause 1 can include a beam splitter in the path of the input beam and the output beam between the lens means and the movable element, where the beam splitter can be operative to reflect portions of the input beam and the output beam, to transmit another portion of the input beam to the reflector or mirror, and to transmit another portion of the output beam to the lens means. An input photodiode can be positioned and operative to receive the reflected portion of the input beam and convert it into an input electrical signal. An output photodiode can be positioned and operative to receive the reflected portion of the output beam and convert it into an output electrical signal.

[0067] Clause 3: The VOA of Clause 1 or 2 can include a controller programmed or configured to control the movement of the movable element.

[0068] Clause 4: The VOA of any one of Clauses 1-3, where the movable element can include a shutter.

[0069] Clause 5: A method of variably optically attenuating a beam, comprising: (a) passing an input beam through a first lens; (b) reflecting at least a portion of the input beam of step (a) as an output beam by a reflector or mirror; (c) positioning a movable element at least partially in the path of at least one of the input beam and the output beam; and (d) outputting at least a portion of the output beam through a second lens.

[0070] Clause 6: A variable optical attenuator (VOA) comprises lens means for receiving an input beam and for outputting an output beam; and a reflector or mirror for reflecting the input beam as the output beam, wherein the reflector or mirror is movable at least partially into or out of the path of the input beam.

[0071] Clause 7: The VOA of Clause 6 may comprise a beam splitter in the path of the input beam and the output beam between the lens means and the movable element, wherein the beam splitter may be operative to reflect portions of the input beam and the output beam, to transmit another portion of the input beam to the reflector or mirror, and to transmit another portion of the output beam to the lens means. An input photodiode may be positioned and operative to receive the reflected portion of the input beam and convert it into an input electrical signal. An output photodiode may be positioned and operative to receive the reflected portion of the output beam and convert it into an output electrical signal.

[0072] Clause 8: The VOA of Clause 6 or 7 may comprise a controller programmed or configured to control the movement of the reflector or mirror.

[0073] Clause 9: A method of variably optically attenuating a beam, comprising: (a) passing an input beam through a first lens; (b) reflecting at least a portion of the input beam of step (a) as an output beam by a reflector or mirror; (c) moving the reflector or mirror at least partially into or out of the path of the input beam; and (d) outputting at least a portion of the output beam through a second lens.

[0074] Clause 10: A variable optical attenuator (VOA) comprises: lens means for receiving an input beam and for outputting an output beam; a rotatable mirror positioned and operative to, when rotated, reflect the input beam received from the lens means to different portions of an input face of a cylindrical lens, the cylindrical lens being such that the input beam received at different portions of the input face of the cylindrical lens is output as a plurality of parallel beams via an output face of the cylindrical lens; and a reflector positioned to reflect at least a portion of the parallel beams output via the output face of the cylindrical lens back through the cylindrical lens to the rotatable mirror, the rotatable mirror reflecting the light received from the cylindrical lens as the output beam.

[0075] Clause 11: The VOA of Clause 10, wherein the reflector can be positioned to transmit another part of the parallel light beam output via the output surface of the cylindrical lens.

[0076] Clause 12: The VOA of Clause 10 or 11, wherein the reflector can be moved into or out of the path of the parallel light beam output via the output surface of the cylindrical lens.

[0077] Clause 13: The VOA of any one of Clauses 10-12 may include a shutter or blocker located between the output surface of the cylindrical lens and the reflector. The shutter or blocker can be positioned to transmit at least a part of the parallel light beam to the reflector and to avoid or prevent another part of the parallel light beam output via the output surface of the cylindrical lens from reaching the reflector.

[0078] Clause 14: The VOA of any one of Clauses 10-13, wherein the shutter or blocker can be moved into or out of the path of the parallel light beam output via the output surface of the cylindrical lens.

[0079] Clause 15: The VOA of any one of Clauses 10-14 may include a controller that is programmed or configured to control the position of a shutter or blocker that is at least partially in the path of the parallel light beam output via the output surface of the cylindrical lens.

[0080] Clause 16: The VOA of any one of Clauses 10-15 may include a beam splitter in the paths of the input light beam and the output light beam located between the lens device and the rotatable mirror. The beam splitter can be operated to reflect parts of the input light beam and the output light beam, to transmit another part of the input light beam to the rotatable mirror, and to transmit another part of the output light beam to the lens device. The input photodiode can be positioned and operated to receive the reflected part of the input light beam and convert it into an input electrical signal. The output photodiode can be positioned and operated to receive the reflected part of the output light beam and convert it into an output electrical signal.

[0081] Clause 17: The VOA of any one of Clauses 10-16 may include a controller that is programmed or configured to control the position of a reflector that is at least partially in the path of the parallel light beam output via the output surface of the cylindrical lens.

[0082] Clause 18: A method of variably optically attenuating a beam, comprising: (a) passing an input beam through a first lens; (b) reflecting at least a portion of the input beam of step (a) via a cylindrical lens to a reflector by a rotating mirror, the cylindrical lens separating the input beam received at different portions of the input surface of the cylindrical lens into a plurality of parallel beams output to the reflector via the output surface of the cylindrical lens; (c) reflecting at least a portion of the parallel beams output via the output surface of the cylindrical lens back through the cylindrical lens to the rotating mirror by the reflector, the rotating mirror reflecting the light received from the cylindrical lens as output light through a second lens.

[0083] Clause 19: The method of Clause 18 may include passing another portion of the plurality of parallel beams output via the output surface of the cylindrical lens through the reflector.

[0084] Clause 20: The method of Clause 18 or 19 may include blocking another portion of the plurality of parallel beams output via the output surface of the cylindrical lens from reaching the reflector by a shutter or blocker.

[0085] Although the present disclosure has been described in detail for purposes of illustration based on the currently considered most practical and preferred embodiments, it should be understood that such details are for that purpose only and the present disclosure is not limited to the disclosed embodiments, but rather is intended to cover modifications and equivalent arrangements within the spirit and scope of the appended claims. For example, it should be understood that the present disclosure contemplates that, to the extent possible, one or more features of any embodiment may be combined with one or more features of any other embodiment.

Claims

1. A variable optical attenuator (VOA), comprising: a lens device for receiving an input beam and for outputting an output beam; a reflector or mirror for reflecting the input beam as the output beam; and a movable element capable of at least partially moving into or out of the path of at least one of the input beam and the output beam between the lens device and the reflector or mirror for blocking at least a portion of at least one of the input beam and the output beam.

2. The VOA according to claim 1, further comprising: a beam splitter located in the path of the input beam and the output beam between the lens device and the movable element, the beam splitter being operative to reflect portions of the input beam and the output beam, to transmit another portion of the input beam to the reflector or mirror, and to transmit another portion of the output beam to the lens device; an input photodiode positioned and operative to receive the reflected portion of the input beam and convert it into an input electrical signal; and an output photodiode positioned and operative to receive the reflected portion of the output beam and convert it into an output electrical signal.

3. The VOA according to claim 1, further comprising a controller programmed or configured to control the movement of the movable element.

4. The VOA according to claim 1, wherein the movable element comprises a shutter.

5. A method of variably optically attenuating a beam, comprising: (a) passing an input beam through a first lens; (b) reflecting at least a portion of the input beam of step (a) as an output beam by a reflector or mirror; (c) positioning the movable element at least partially in the path of at least one of the input beam and the output beam; and (d) outputting at least a portion of the output beam through a second lens.

6. A variable optical attenuator (VOA), comprising: a lens device for receiving an input beam and for outputting an output beam; and a reflector or mirror for reflecting the input beam as the output beam, wherein the reflector or mirror is capable of at least partially moving into or out of the path of the input beam.

7. The VOA according to claim 6, further comprising: a beam splitter located in the path of the input beam and the output beam between the lens device and the reflector or mirror, the beam splitter being operative to reflect portions of the input beam and the output beam, to transmit another portion of the input beam to the reflector or mirror, and to transmit another portion of the output beam to the lens device; an input photodiode positioned and operative to receive the reflected portion of the input beam and convert it into an input electrical signal; and an output photodiode positioned and operative to receive the reflected portion of the output beam and convert it into an output electrical signal.

8. The VOA according to claim 6, further comprising a controller programmed or configured to control the movement of the reflector or mirror.

9. A method of variably optically attenuating a beam, comprising: (a) passing an input beam through a first lens; (b) reflecting at least a portion of the input beam of step (a) as an output beam by a reflector or mirror; (c) moving the reflector or mirror at least partially into or out of the path of the input beam; and (d)Output at least a portion of the output beam through the second lens.

10. A variable optical attenuator (VOA), comprising: a lens device for receiving an input beam and for outputting an output beam; a rotatable mirror positioned and operable to reflect the input beam received from the lens device to different portions of the input surface of a cylindrical lens when rotated, the cylindrical lens causing the input beam received at the different portions of the input surface of the cylindrical lens to be output as a plurality of parallel beams via the output surface of the cylindrical lens; and a reflector positioned to reflect at least a portion of the parallel beams output via the output surface of the cylindrical lens back through the cylindrical lens to the rotatable mirror, the rotatable mirror reflecting the light received from the cylindrical lens as the output beam.

11. The VOA according to claim 10, wherein the reflector is positioned to transmit another portion of the parallel beams output via the output surface of the cylindrical lens.

12. The VOA according to claim 10, wherein the reflector is capable of moving into or out of the path of the parallel beams output via the output surface of the cylindrical lens.

13. The VOA according to claim 10, further comprising a shutter or blocker located between the output surface of the cylindrical lens and the reflector; wherein the shutter or blocker is positioned to transmit the at least a portion of the parallel beams to the reflector and to avoid or prevent another portion of the parallel beams output via the output surface of the cylindrical lens from reaching the reflector.

14. The VOA according to claim 13, wherein the shutter or blocker is capable of moving into or out of the path of the parallel beams output via the output surface of the cylindrical lens.

15. The VOA according to claim 14, further comprising a controller programmed or configured to control the position of the shutter or blocker, wherein the shutter or blocker is at least partially in the path of the parallel beams output via the output surface of the cylindrical lens.

16. The VOA according to claim 10, further comprising: a beam splitter in the path of the input beam and the output beam between the lens device and the rotatable mirror, the beam splitter operative to reflect portions of the input beam and the output beam, to transmit another portion of the input beam to the rotatable mirror, and to transmit another portion of the output beam to the lens device; an input photodiode positioned and operative to receive the reflected portion of the input beam and convert it into an input electrical signal; and an output photodiode positioned and operative to receive the reflected portion of the output beam and convert it into an output electrical signal.

17. The VOA according to claim 10, further comprising a controller programmed or configured to control the position of the reflector, wherein the reflector is at least partially in the path of the parallel beams output via the output surface of the cylindrical lens.

18. A method of variably optically attenuating a beam, comprising: (a) passing an input beam through a first lens; (b) At least a portion of the input beam of step (a) is reflected by a rotating mirror through a cylindrical lens to a reflector, and the cylindrical lens separates the input beam received at different portions of the input surface of the cylindrical lens into a plurality of parallel beams output to the reflector through the output surface of the cylindrical lens; (c) At least a portion of the parallel beam output through the output surface of the cylindrical lens is reflected back by the reflector through the cylindrical lens to the rotating mirror, and the rotating mirror reflects the light received from the cylindrical lens as the output light through the second lens.

19. The method according to claim 18, further comprising transmitting another portion of the plurality of parallel beams output through the output surface of the cylindrical lens through the reflector.

20. The method according to claim 18, further comprising blocking another portion of the plurality of parallel beams output through the output surface of the cylindrical lens from reaching the reflector by a shutter or a blocker.

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