Optical isolator core

Abstract

In some embodiments, the optical isolator core (110) includes a Faraday rotator (112) and a plurality of birefringent crystal plates (114). The plurality of birefringent crystal plates (114) may include a first birefringent crystal plate (114‑1) for separating input light into light having a first polarization and light having a second polarization, and a second birefringent crystal plate (114‑2) for combining the light having the first polarization and the light having the second polarization in an output light laterally shifted by the single-stage optical isolator. The Faraday rotator (112) may be disposed between the first birefringent crystal plate (114‑1) and the second birefringent crystal plate (114‑2). In some embodiments, the plurality of birefringent crystal plates (114) further include a third birefringent crystal plate (114‑3) disposed between the Faraday rotator (112) and the second birefringent crystal plate (114‑2). Additionally or alternatively, the optical isolator core (110) may further include a half-wave plate (116) arranged between the Faraday rotator (112) and the first birefringent crystal plate (114‑1).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Patent Cooperation Treaty (PCT) application PCT / CN2020 / 088952, entitled “Optical Isolator Core inBetween Fiber and Collimator Lens,” filed on May 7, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates generally to optical systems and optical isolator core designs to provide lateral walk-off for light received at the optical isolator core. Background Art

[0004] An optical isolator (sometimes called an optical diode or Faraday isolator, etc.) is an optical device that transmits light in a specific direction and blocks light in the opposite direction. Optical isolators are often used to prevent unwanted feedback from outside an optical oscillator (such as a laser cavity). For example, in some cases (e.g., at high powers), optical feedback can damage or destroy the operation of the laser system. To reduce optical feedback, an optical isolator can be inserted into the laser system. An optical isolator can be a passive unidirectional, non-reciprocal device that uses the phenomenon of magneto-optical rotation to isolate the source and protect the laser oscillator from reflections. Summary of the invention

[0005] In some embodiments, an optical component includes: a first optical fiber and a second optical fiber; a pump laser for providing pump light having a first wavelength, the pump light being coupled into the first optical fiber through a first collimating lens, a wavelength division multiplexing filter, a second collimating lens, and a compensator arranged between the first optical fiber and the second collimating lens; and an isolator arranged between the second optical fiber and the second collimating lens to transmit a signal light having a second wavelength, wherein the isolator includes a Faraday rotator and a plurality of birefringent crystal plates to laterally shift the signal light.

[0006] In some embodiments, a single-stage optical isolator includes a Faraday rotator and a plurality of birefringent crystal plates, wherein the plurality of birefringent crystal plates include a first birefringent crystal plate and a second birefringent crystal plate, the first birefringent crystal plate being used to separate input light into light having a first polarization and light having a second polarization, the second birefringent crystal plate being used to combine the light having the first polarization and the light having the second polarization in output light, the output light being laterally shifted by the single-stage optical isolator, wherein the Faraday rotator is disposed between the first birefringent crystal plate and the second birefringent crystal plate.

[0007] In some embodiments, a dual-stage optical isolator includes a first isolator core and a second isolator core, wherein the first isolator core includes a first group of layers, the first group of layers including a first Faraday rotator and a first half-wave plate arranged between a first pair of birefringent crystal plates; and a second isolator core, which includes a second group of layers, the second group of layers including a second Faraday rotator and a second half-wave plate arranged between a second pair of birefringent crystal plates, wherein the first group of layers and the second group of layers have the same thickness and corresponding magnetic orientation to offset material tolerances and assembly tolerances relative to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1A-1E One or more exemplary embodiments of a single-stage isolator are shown.

[0009] Figure 2A-2C One or more exemplary embodiments of a double-stage isolator including two isolator cores arranged in parallel are shown.

[0010] Figure 3A-3C One or more exemplary embodiments of a double-stage isolator including two isolator cores arranged in series are shown. DETAILED DESCRIPTION

[0011] The following detailed description of example embodiments refers to the accompanying drawings.The same reference numbers in different drawings may identify the same or similar elements.

[0012] An optical isolator is a device that is typically designed to allow light to travel in the forward direction while blocking reflections that would travel in the backward direction. Optical isolators are important in many optical systems and applications. For example, single-frequency semiconductor lasers are very sensitive to external optical feedback. Among other examples, even very low levels of optical reflections (e.g., levels of about -50 dB) from external optical circuits are sufficient to cause a significant increase in laser phase noise, intensity noise, and / or wavelength instability. Therefore, in applications that require low optical noise and a stable single optical frequency, an optical isolator is typically provided at the output of each laser diode. Another example is in an optical amplifier that requires unidirectional optical amplification. In this case, if external optical reflections from, for example, connectors and other optical components are strong enough, the bidirectional nature of the optical amplification of the optical gain medium will cause self-oscillation.

[0013] Conventional optical isolators are based on a Faraday rotator disposed between two polarizers (e.g., an input polarizer and an output polarizer). In this configuration, the input light received at the optical isolator passes through an input polarizer having an optical axis that matches the polarization orientation of the input light. The Faraday rotator then rotates the polarization of the input light signal 45 degrees in a clockwise direction. The optical axis of the output polarizer is oriented 45 degrees relative to the input polarizer, which allows the light signal to pass through with little attenuation. If there is a reflection from one or more components downstream of the output polarizer, the reflected light must pass through the output polarizer and the Faraday rotator. Because the Faraday rotator is a non-reciprocal device, the polarization state of the reflected light will be rotated an additional 45 degrees in the same direction as the input light, becoming orthogonal to the optical axis of the input polarizer. Therefore, the input polarizer effectively blocks the reflected light and ensures unidirectional light transmission through the optical isolator.

[0014] Thus, in conventional optical isolator designs, the optical core deflects a collimated beam at a small angle, which can be used in collimated beam applications. For example, one collimated beam application may involve integrating the isolator core with a wavelength division multiplexer filter and a pump chip in an optical component (e.g., a pump combiner) that combines beams having different wavelengths. For example, the optical component may include an input branch that receives an input signal having a first wavelength (e.g., 1550 nanometers (nm)) and an output branch in which the input signal having the first wavelength is combined with a pump light having a second wavelength (e.g., 980 nm). A typical approach in such collimated beam applications is to place the optical isolator in an area between the WDM filter and the collimating lens, which has the largest physical space to integrate the optical isolator within the device. However, if the optical isolator is placed in an area between the WDM filter and the collimating lens, the optical isolator may block pump light traveling in the opposite direction relative to the input light (e.g., because the optical isolator typically includes a material that has high absorption of 980 nm pump light, such as garnet).

[0015] Some embodiments described herein provide an isolator core and / or an optical system (e.g., an optical assembly and / or an optical device) comprising an isolator core designed to provide lateral displacement away. For example, instead of deflecting light in an input beam received at the isolator core, the isolator core may include a Faraday rotator, a plurality of birefringent crystal plates and / or a half-wave plate (HWP) arranged to spatially separate and / or combine orthogonal polarization components of the input beam with low polarization mode dispersion (PMD), polarization dependent loss (PDL) and / or insertion loss (IL). In addition, the isolator core may have a design that prevents backward-traveling light entering the output side of the optical isolator from coupling to the input side of the optical isolator, which may achieve optical isolation. In some embodiments, the isolator core may be located between an optical fiber and a collimating lens in an optical assembly to achieve same-side input / output fiber (i.e., same side of the assembly), integrated 980nm / 1550nm WDM functionality, self-compensating PMD and / or self-compensating PDL. In some embodiments, the isolator core can have a design that saves space by utilizing the space between the optical fiber and the collimating lens. In addition, the isolator core design can provide the flexibility of placing the isolator core in the input branch of the optical component, the output branch of the optical component, or both the input branch and the output branch of the optical component. For example, in a forward-pumped erbium-doped fiber amplifier (EDFA), where 980nm pump light is coupled into the output branch through a WDM filter, the isolator core can be arranged in the input branch (e.g., because the isolator core may otherwise block the 980nm pump light). In another example, in a reverse-pumped EDFA, where 980nm pump light is coupled into the input branch through a WDM filter, the isolator core can be arranged in the output branch. In some embodiments, the optical isolator design can enable the input fiber and the output fiber to be located on the same side of the component, which can enable integration with a 980nm pump laser chip and / or a monitor photodiode.

[0016] Figure 1A-1E One or more exemplary embodiments 100 of a single-stage isolator 110 are shown. Figures 1A-1C As shown, for a forward pumped EDFA, a single-stage isolator 110 (which may be referred to herein as an isolator core 110) may be arranged in an optical component to laterally shift an input light beam received at the isolator core 110. For example, as shown, the isolator 110 may be used in an optical component such as a pump combiner, the optical component including or docking with a dual-fiber pigtail 120, the dual-fiber pigtail 120 including an input fiber in an input branch of the optical component and an output fiber in an output branch of the optical component. Figures 1A-1CAs shown, the single-stage isolator core 110 can be located between the dual-fiber pigtail 120 and the first collimating lens 130-1 (e.g., a first aspheric lens (A lens)). The optical assembly can also include a pump chip (or pump laser) 160 to provide pump light having a first wavelength (e.g., 980 nm), which can be coupled into the output branch through the second collimating lens 130-2 (e.g., a second A lens), the WDM filter 140, the first collimating lens 130-1, and the compensator 150 arranged between the dual-fiber pigtail 120 and the first collimating lens 130-1.

[0017] like Figure 1A-Figure 1C As shown, the optical component can be a pump combiner, a forward pumped EDFA, or other suitable device, in which the single-stage isolator core 110 is arranged in the input branch to receive the signal light having the second wavelength (e.g., 1550 nm), which is combined with the pump light from the pump chip 160 in the output branch. In this case, the pump light can be coupled into the output branch through the second collimating lens 130-2, the WDM filter 140 (which is transmissive at the wavelength of the pump light), the first collimating lens 130-1, and the compensator 150. Alternatively, in a reverse pumped EDFA (not shown) or another suitable device in which the pump light is to be coupled into the input branch, the single-stage isolator core 110 can be arranged in the output branch, and the pump light can be coupled into the input branch through the second collimating lens 130-2, the WDM filter 140, the first collimating lens 130-1, and the compensator 150. Thus, the isolator core 110 and the compensator 150 may be arranged adjacent to each other in the input branch and the output branch (or vice versa) between the dual fiber pigtail 120 and the first collimating lens 130-1.

[0018] In some embodiments, the optical components can be arranged in an integrated module with a highly integrated pump platform design. Figure 1AAs shown, the integrated module may include various mechanical components, such as metal brackets 170, to secure or otherwise support optical components, such as dual fiber pigtails 120, isolator cores, compensators 150, collimating lenses 130, and WDM filters 140. Additionally, where the isolator core 110 is integrated with the pump chip 160, the integrated module may include a package 180 for mounting the pump chip 160 and package pins 190 for interfacing with one or more external components. In another example, the isolator core 110 may be used in an input branch and / or output branch of a free space optical device configuration or another suitable configuration that may be part of a larger assembly without having optical fibers directly coupled into and / or out of the isolator core 110 and the compensator 150. Therefore, it should be understood that the assemblies described herein are exemplary only, and the isolator core 110 and / or variations thereof may be used in any suitable optical device or application.

[0019] In some embodiments, by positioning the isolator core 110 and the compensator 150 between the dual fiber pigtail 120 and the first collimating lens 130-1, an optical isolation of greater than 18 decibels (dB) can be achieved between the input branch and the output branch. In some embodiments, the compensator 150 can compensate the optical path between the input branch and the output branch. Figure 1A In the optical assembly shown, the fiber core of the input branch and the fiber core of the output branch can have a fiber core-to-fiber core distance of 460 microns (μm), the collimating lens 130 can have a focal length of 2.7 millimeters (mm), and the WDM filter 140 can be a 980nm (transmission) / 1550nm (reflection) filter. The input branch and the output branch can be thermally expanded core (TEC) fibers that expand the fiber mode diameter from 6μm to 9μm. In this way, the optical device including the isolator core 110 can have a diameter of 3.0mm or less.

[0020] In some embodiments, as described herein, the isolator core 110 can be configured to receive and provide a lateral walk-off to transmit the signal light toward the first collimating lens 130-1, which produces a collimated light beam reflected by the WDM filter 140 (e.g., the WDM filter 140 is transmissive at a wavelength associated with the pump light and reflective at a wavelength associated with the signal light). In this manner, the pump light and the signal light are combined and coupled into the compensator 150 through the first collimating lens 130-1. In addition, by positioning the isolator core 110 between the dual-fiber pigtail 120 and the first collimating lens 130-1 (rather than between the first collimating lens 130-1 and the WDM filter 140), the isolator core 110 does not block the pump light that propagates in the opposite direction relative to the (input) signal light. In some embodiments, in order to shift the signal light laterally, the isolator core 110 may include a set of layers or components designed to spatially separate and combine orthogonal polarization components of the signal light with low PMD, low PDL and / or low IL. As described herein, the isolator core 110 may include a Faraday rotator, an input polarizer (e.g., a first birefringent crystal plate), an output polarizer (e.g., a second birefringent crystal plate), and additional components (e.g., a third birefringent crystal plate or a half-wave plate) that are bonded together (e.g., by an adhesive material such as epoxy resin, etc.). In addition, as described herein, the thickness and angle of the various layers or components of the isolator core 110 can be controlled to produce a lateral shift away.

[0021] For example, Figure 1D As shown, the isolator core 110 may include a Faraday rotator 112 made of garnet, and a first birefringent crystal plate 114-1 to receive input light including orthogonal polarization components (e.g., O light and E light, which may refer to light having horizontal polarization and light having vertical polarization, respectively). In some embodiments, the input light may be spatially separated into the orthogonal polarization components by the first birefringent crystal plate 114-1. For example, the first birefringent crystal plate 114-1 may include a birefringent material, such as yttrium orthovanadate (YVO 4 ), or another suitable material having a refractive index that depends on the polarization and propagation direction of the light. Therefore, because the orthogonal polarization components have different polarizations, the first birefringent crystal plate 114-1 has different refractive indices relative to the O light and the E light, which causes the O light and the E light to be spatially separated. However, at the output of the isolator core 110, the O light and the E light must be accurately combined together to avoid polarization-related losses or other performance issues. Therefore, after the O light and the E light pass through the first birefringent crystal plate 114-1, the O light and the E light are rotated by the Faraday rotator 112, and another pair of birefringent crystal plates 114-2, 114-3 are provided to combine the O light and the E light.

[0022] Typically, controlling the thickness and angle of the Faraday rotator 112 and the three birefringent crystal plates 114 during the assembly process may be challenging because the Faraday rotator 112 and the three birefringent crystal plates 114 may have different material tolerances (e.g., plus or minus ten microns relative to a desired thickness) and different assembly tolerances (e.g., plus or minus a certain degree relative to a desired angle). Therefore, in some embodiments, the Faraday rotator 112 may have a fixed orientation relative to one of the adjacent birefringent crystal plates 114 (e.g., birefringent crystal plate 114-1 or birefringent crystal plate 114-2), and the other two birefringent crystal plates 114 may be rotated with two degrees of freedom to adjust the necessary angles to ensure that the O light and the E light are accurately combined at the output from the third birefringent plate 114-3. For example, in some embodiments, the Faraday rotator 112 and the first birefringent crystal plate 114-1 may be fixed, and the other birefringent crystal plates 114-2, 114-3 may be rotated to compensate for different material and / or assembly tolerances. Alternatively, the Faraday rotator 112 and the second birefringent crystal plate 114-2 may be fixed, and the other birefringent crystal plates 114-1, 114-3 may be rotated to compensate for material and / or assembly tolerances. Figure 1D As shown, the O light and the E light can be combined in the light output from the isolator core 110 or otherwise transmitted by the isolator core 110. In one example, the following Table 1 shows the design characteristics of the isolator core 110 that can achieve lateral shifting away, where α, β, and γ are the azimuth angles of the optical axis of each birefringent crystal plate 114, one of which is fixed relative to the Faraday rotator 112, and two of which are rotatable.

[0023]

[0024] Table 1

[0025] Alternatively, in some embodiments, the single-stage isolator core 110 may have Figure 1E The design shown in FIG. 1 is a schematic diagram of an isolator comprising a first birefringent crystal plate 114-1, a half-wave plate (HWP), a Faraday rotator 112, and a second birefringent crystal plate 114-2. In this case, the different layers (e.g., the first birefringent crystal plate 114-1 and the second birefringent crystal plate 114-2) can be made from a larger block (e.g., YVO 4 ) cut. Therefore, Figure 1D The design shown achieves precise control of the thickness and angle of components of the isolator core 110 by rotating two of the three birefringent crystal plates 114. Figure 1EThe design shown can ensure that the O light and the E light are combined to minimize PDL and / or insertion loss because the different layers have the same material tolerances. In this way, even if the layers in the isolator core 110 are not perfectly adjusted, the O light and the E light will be combined at the output from the isolator core 110 because the birefringent crystal plates 114-1, 114-2 layers have the same thickness and corresponding magnetic orientations (e.g., opposite or same magnetic orientations) to offset material tolerances and assembly tolerances relative to each other.

[0026] In some embodiments, as described above, the Faraday rotator 112 can be made of garnet. For example, the Faraday rotator 112 can be made of a rare earth iron garnet (RIG) single crystal, which generally requires a magnetic field to function as the Faraday rotator 112 and / or a non-magnetic garnet (referred to herein as a latching garnet). For example, when the Faraday rotator 112 is made of a RIG single crystal and the RIG is exposed to an external magnetic field greater than a saturation field, the magnetic domains in the direction opposite to the external magnetic field are neutralized, and a single magnetic domain is formed in a direction aligned with the magnetization direction. In this way, because light passing through the RIG having a single magnetic domain undergoes Faraday rotation in one direction, the RIG single crystal can be used as the Faraday rotator 112. Alternatively, in the case where the Faraday rotator 112 is made of a latching (or non-magnetic) garnet, once magnetized in a strong external magnetic field, the Faraday rotator 112 can maintain its single-domain structure even if the external magnetic field is later removed (although the single-domain structure can be reversed by applying a strong external magnetic field). Therefore, when used as a Faraday rotator 112, the latching garnet does not require an external magnetic field. In other words, the latching garnet functions as a Faraday rotator 112 without being exposed to an external magnetic field.

[0027] As mentioned above, Figure 1A-1E is provided as one or more examples. Other examples may be related to Figure 1A-1E The examples described are different.

[0028] Figure 2A-2C One or more exemplary embodiments 200 of a double-stage isolator including two isolator cores arranged in parallel are shown. Figure 2A-2C As shown, the double-stage isolator may include a first isolator core 210-1 and a second isolator core 210-2 arranged in parallel. Figure 2A As shown, the first isolator core 210-1 can be disposed in the input branch of the optical component, and the second isolator core 210-2 can be disposed in the output branch of the optical component. In this case, the double-stage isolator can be used with the collimating lens 230 and the WDM filter 240 in a separate isolator application to transmit only light having a specific wavelength (e.g., 1550 nm) without integration with a pump.

[0029] like Figure 2B As shown, the first isolator core 210-1 and the second isolator core 210-2 (collectively referred to as the dual-stage isolator 210) include a first set of layers and a second set of layers cut from the same block. For example, the first isolator core 210-1 includes a first HWP 216-1 and a first Faraday rotator 212-1 arranged between a first pair of birefringent crystal plates 214-11, 214-12, and the second isolator core 210-2 includes a second HWP 216-2 and a second Faraday rotator 212-2 arranged between a second pair of birefringent crystal plates 214-22, 214-21. In this case, the first isolator core 210-1 and the second isolator core 210-2 each have four crystal layers, the first isolator core 210-1 and the second isolator core 210-2 are both cut from a large block, and the first isolator core 210-1 and the second isolator core 210-2 are arranged adjacent to each other, and the crystal layers are oriented differently. For example, in some embodiments, the first Faraday rotator 212-1 and the second Faraday rotator 212-2 can be oriented so that the magnetic domain direction of the first Faraday rotator 212-1 is opposite to the magnetic domain direction of the second Faraday rotator 212-2. Therefore, because the layers are cut from the same raw material, the dual-stage isolator 210 can include two isolator cores 210-1, 210-2, wherein the layers have certain properties (e.g., opposite orientations, same thickness, same angles, etc.) that allow the isolator cores 210-1, 210-2 to eliminate each other's material and / or assembly tolerances. In this way, the input light received at the input polarizer (e.g., the birefringent plate 214-11) of the first isolator core 210-1 can be spatially separated into components with orthogonal polarizations (e.g., O light and E light), and these components can be recombined at the output polarizer (e.g., the birefringent plate 214-12) of the first isolator core 210-1 even if the first set of layers is not perfectly adjusted. In a similar aspect, after the light laterally shifted by the first isolator core 210-1 passes through the collimating lens 230 and is reflected back toward the output branch by the WDM filter 240, the reflected light received at the input polarizer (e.g., the birefringent plate 214-21) of the second isolator core 210-2 can be spatially separated into orthogonal components, which are again recombined at the output polarizer (e.g., the birefringent plate 214-22) of the second isolator core 210-2, so that the second isolator core 210-2 laterally shifts the light received at the input polarizer. In addition, as Figure 2CAs shown, and indicated by reference numeral 250, any backward-traveling light reflected from the output branch to the input branch is split into components having orthogonal polarizations. In this manner, the design of the dual-stage isolator 210 causes the backward-traveling light to be directed or otherwise diverted away from the location or point at which the light was input through the input branch. In this manner, the backward-traveling light is not coupled into the input branch, which achieves high isolation between the input branch and the output branch.

[0030] As mentioned above, Figure 2A-2C is provided as one or more examples. Other examples may be related to Figure 2A-2C The examples described are different.

[0031] Figure 3A-3C One or more exemplary embodiments 300 of a double-stage isolator including two isolator cores arranged in series are shown. Figures 3A-3C As shown, the double-stage isolator may include a first isolator core 310-1 and a second isolator core 310-2 arranged in series. Figure 3A As shown, both the first isolator core 310-1 and the second isolator core 310-2 can be disposed in the input branch of the optical component, wherein the compensator 350 is disposed in the output branch. Alternatively, in some embodiments, both the first isolator core 310-1 and the second isolator core 310-2 (collectively referred to as the dual self-compensating isolator core 310) can be disposed in the output branch of the optical component, wherein the compensator 350 is disposed in the input branch. In this case, the double-stage isolator can be used with the collimating lens 330 and the WDM filter 340 in a stand-alone isolator application to transmit only light having a specific wavelength (e.g., 1550 nm) without being integrated with a pump, or the double-stage isolator can be used in a pump combiner or another suitable device or application to achieve higher isolation relative to the single-stage design described above.

[0032] like Figure 3BAs shown, the first isolator core 310-1 and the second isolator core 310-2 include a first group of layers and a second group of layers cut from the same block, respectively. For example, the first isolator core 310-1 includes a first HWP 316-1 and a first Faraday rotator 312-1 arranged between a first pair of birefringent crystal plates 314-11, 314-12, and the second isolator core 310-2 includes a second HWP 316-2 and a second Faraday rotator 312-2 arranged between a second pair of birefringent crystal plates 314-22, 314-21. In this case, in the case where the first isolator core 310-1 and the second isolator core 310-2 are arranged in series, the first Faraday rotator 312-1 and the second Faraday rotator 312-2 can be oriented so that the magnetic domain direction of the first Faraday rotator 312-1 is the same as the magnetic domain direction of the second Faraday rotator 312-2. Therefore, because the respective layers are made from the same raw material (e.g., the same garnet and / or YVO 4 The double-stage isolator 310 may include two isolator cores 310-1, 310-2 having specific properties (e.g., the same magnetic orientation, thickness, angle, etc.) cut from a block. In this way, input light received at the input polarizer (e.g., birefringence plate 314-11) of the first isolator core 310-1 may be spatially separated into components having orthogonal polarizations (e.g., O light and E light), and the components may be recombined at the output polarizer (e.g., birefringence plate 314-12) of the first isolator core 310-1 even if the first set of layers is not perfectly adjusted. In a similar aspect, light laterally displaced by the first isolator core 310-1 is received at the input polarizer (e.g., birefringence plate 314-21) of the second isolator core 310-2, where the light is again spatially separated into orthogonal components, which are recombined at the output polarizer (e.g., birefringence plate 314-22) of the second isolator core 310-2. Therefore, after the light laterally shifted by the second isolator core 310-2 passes through the collimating lens 330, the light including the component having the orthogonal polarization is reflected back to the output branch by the WDM filter 340. Figure 3C As shown, and indicated by reference numeral 350, any backward-traveling light reflected from the output branch to the input branch is separated into components having orthogonal polarizations. In this manner, the design of the double-stage isolator 310 causes the backward-traveling light to be directed or otherwise diverted away from the location or point at which the light was input through the input branch, whereby the backward-traveling light is not coupled into the input branch, and high isolation is achieved between the input branch and the output branch.

[0033] As mentioned above, Figure 3A-3C is provided as one or more examples. Other examples may be related to Figure 3A-3C The examples described are different.

[0034] The foregoing disclosure provides illustrations and descriptions, but is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Modifications and variations may be made based on the foregoing disclosure, or modifications and variations may be obtained from the practice of the embodiments. In addition, unless the foregoing disclosure explicitly provides a reason why one or more embodiments may not be combined, any embodiment described herein may be combined.

[0035] As used herein, the terms circuit, integrated circuit, chip, chipset, die, semiconductor device, electronic device and / or the like are intended to be broadly interpreted as being applicable to the various embodiments described herein, as these terms can be used interchangeably in the electronic field. With respect to circuits, integrated circuits and / or the like, power, grounding and various signals can be coupled between circuit elements (e.g., resistors, inductors, capacitors, transistors and / or the like) via physical conductive connections. Such connections can be referred to as input, output, input / output (I / O), terminals, lines, pins, pads, ports, interfaces or similar variations and combinations. Although connections between and within circuits can be made by electrical conductors, circuits and other circuit elements can be coupled additionally or alternatively by optical, mechanical, magnetic, electrostatic, electromagnetic and / or other suitable interfaces.

[0036] It is apparent that the systems and / or methods described herein can be implemented in various forms of hardware, software, circuits, or combinations thereof. The actual dedicated control hardware, software code, or circuits used to implement these systems and / or methods do not limit the implementation. Therefore, the operation and behavior of the systems and / or methods are described herein without reference to specific software code—it should be understood that software and hardware (e.g., integrated circuits) can be designed to implement the systems and / or methods based on the description herein.

[0037] Although particular combinations of features are recited in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of the various implementations. In fact, many of these features may be combined in ways not specifically recited in the claims and / or disclosed in the specification. Although each dependent claim listed below may be directly dependent on only one claim, the disclosure of the various implementations includes the combination of each dependent claim with every other claim in the claim set.

[0038] Unless clearly described as such, the elements, actions or instructions used herein should not be interpreted as key or necessary. In addition, as used herein, the article "one" is intended to include one or more projects, and can be used interchangeably with "one or more". In addition, as used herein, the article "the" is intended to include one or more projects quoted in conjunction with the article "the", and can be used interchangeably with "one or more". In addition, as used herein, the term "set" is intended to include one or more projects (e.g., related projects, unrelated projects, combinations of related and unrelated projects, etc.). In the case of only intending a project, the phrase "only one" or similar language is used. In addition, as used herein, the term "have", "have", "have" etc. are intended to be open terms. In addition, unless otherwise clearly stated, the phrase "based on" is intended to represent "at least partially based on". In addition, as used herein, the term "or" is intended to be inclusive when used in series, and can be used interchangeably with "and / or", unless otherwise clearly stated (e.g., if used in combination with "any one" or "only one").

[0039] In addition, for ease of description, spatially relative terms, such as "below," "lower," "above," "upper," etc., may be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device, apparatus, and / or element in use or operation in addition to the orientation depicted in the figures. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein may likewise be interpreted accordingly.

Claims

1. An optical component, comprising: a first optical fiber and a second optical fiber; a pump laser for providing pump light having a first wavelength, wherein the pump light is coupled into the first optical fiber through a first collimating lens, a wavelength division multiplexing filter, a second collimating lens, and a compensator arranged between the first optical fiber and the second collimating lens; as well as an isolator disposed between the second optical fiber and the second collimating lens to transmit a signal light having a second wavelength, wherein the isolator comprises a Faraday rotator and a plurality of birefringent crystal plates to laterally shift the signal light, wherein the signal light received at the isolator includes light having a first polarization and light having a second polarization, and Wherein, the isolator comprises: Faraday rotator, a first birefringent crystal plate having a first orientation relative to the Faraday rotator, and Two birefringent crystal plates are rotatable to respective angles that allow light having a first polarization and light having a second polarization to be combined in a laterally shifted signal light.

2. The optical assembly according to claim 1, wherein: The first optical fiber is coupled to an output branch of the optical component and the second optical fiber is coupled to an input branch of the optical component.

3. The optical assembly according to claim 1, wherein: The first optical fiber is coupled to an input branch of the optical component, and the second optical fiber is coupled to an output branch of the optical component.

4. The optical assembly according to claim 1, wherein: The Faraday rotator, the first birefringent crystal plate, and the two birefringent crystal plates are bonded together by an adhesive material.

5. The optical assembly according to claim 1, wherein: The Faraday rotator includes a garnet material.

6. The optical assembly according to claim 1, wherein: The first birefringent crystal plate and the two birefringent crystal plates include yttrium orthovanadate material.

7. The optical assembly according to claim 1, wherein: The first collimating lens and the second collimating lens are aspherical lenses.

8. The optical assembly according to claim 1, wherein: The first wavelength is 980 nanometers and the second wavelength is 1550 nanometers.

9. The optical assembly according to claim 1, wherein: The isolator has a diameter less than or equal to 3 mm.

10. A single-stage optical isolator comprising: Faraday rotator; as well as a plurality of birefringent crystal plates, wherein the plurality of birefringent crystal plates comprises: a first birefringent crystal plate for separating input light into light having a first polarization and light having a second polarization, wherein the first birefringent crystal plate has a fixed orientation relative to the Faraday rotator, a second birefringent crystal plate for combining light having a first polarization and light having a second polarization in output light laterally shifted by the single-stage optical isolator, wherein the Faraday rotator is disposed between the first birefringent crystal plate and the second birefringent crystal plate, and a third birefringent crystal plate, disposed between the Faraday rotator and the second birefringent crystal plate, The second birefringent crystal plate and the third birefringent crystal plate are capable of being rotated to respective angles such that light having the first polarization and light having the second polarization are combined in the output light.

11. The single-stage optical isolator according to claim 10, wherein: The Faraday rotator includes a garnet material, and the plurality of birefringent crystal plates include a yttrium orthovanadate material.

12. The single-stage optical isolator according to claim 10, wherein: The single-stage optical isolator is coupled in an optical assembly between a collimating lens and an input branch of the optical assembly.

13. The single-stage optical isolator according to claim 10, wherein the Faraday rotator and the plurality of birefringent crystal plates are bonded together by an adhesive material.

14. The single-stage optical isolator according to claim 10, wherein: The single-stage optical isolator is coupled in an optical assembly between a collimating lens and an output branch of the optical assembly.

15. A single-stage optical isolator comprising: Faraday rotator; as well as a plurality of birefringent crystal plates, wherein the plurality of birefringent crystal plates comprises: a first birefringent crystal plate for separating input light into light having a first polarization and light having a second polarization, a second birefringent crystal plate for combining light having a first polarization and light having a second polarization in output light laterally shifted by the single-stage optical isolator, wherein the Faraday rotator is disposed between the first birefringent crystal plate and the second birefringent crystal plate, and The first birefringent crystal plate and the second birefringent crystal plate are rotatable to respective angles that allow light having a first polarization and light having a second polarization to be combined in the output light, and a third birefringent crystal plate, disposed between the Faraday rotator and the second birefringent crystal plate, Wherein the third birefringent crystal plate has a fixed orientation relative to the Faraday rotator.

16. The single-stage optical isolator according to claim 15, wherein: The Faraday rotator includes a garnet material.

17. The single-stage optical isolator according to claim 15, wherein: The plurality of birefringent crystal plates include yttrium orthovanadate material.

18. The single-stage optical isolator according to claim 15, wherein: The single-stage optical isolator is coupled in an optical assembly between a collimating lens and an input branch of the optical assembly.

19. The single-stage optical isolator according to claim 15, wherein: The single-stage optical isolator is coupled in an optical assembly between a collimating lens and an output branch of the optical assembly.

20. The single-stage optical isolator according to claim 15, wherein: The Faraday rotator and the plurality of birefringent crystal plates are bonded together by an adhesive material.

Images