Optical isolator and method for manufacturing the same

Abstract

To provide an optical isolator which can obtain a large beam shift amount without impairing optical characteristics and has a small size.SOLUTION: There is provided an optical axis shift type optical isolator including an optical isolator chip having a polarizer and a Faraday rotator, which are joined to and integrated with each other. An incident surface of the optical isolator chip is a surface inclined with respect to the optical axis of the incident light to the optical isolator by a degree of 40° (deg) or less, the incident surface of the optical isolator chip is a surface inclined with respect to the central axis in the travel direction of the light of the optical isolator chip, the central axis of the optical isolator chip is inclined with respect to the optical axis of the incident light to the optical isolator, and a shift length ΔT(mm) of the optical axis of the emission light to the optical axis of the incident light on the optical isolator and an inclination shift length ΔC(mm) on the emission surface side to the incident surface side of the optical isolator chip satisfy |ΔT-ΔC|≤0.10(mm).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical isolator used in, for example, optical communications and optical measurement, and a method for manufacturing the optical isolator. [Background technology]

[0002] In optical communications and optical measurement, if the light emitted from a laser is reflected from the surface of a component placed along the transmission path and returns to the laser light source, the laser oscillation becomes unstable. To block this reflected light, an optical isolator is used that uses a Faraday rotator, which rotates the polarization plane non-reciprocally. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-36594 Summary of the Invention [Problem to be solved by the invention]

[0004] An optical isolator is used in a laser module for optical communication. The inclination angle of the incident surface is set to 2 to 6 degrees (deg) with respect to the incident optical axis. To set the incident angle, the optical isolator chip 30 is processed so that the incident surface 6 is perpendicular to the axis of the optical isolator chip 30 as shown in Figure 5, and is then tilted at the desired angle θ A θ = 2 to 6° (deg) (FIG. 6), or the incident surface 6 is inclined in advance relative to the axis of the optical isolator chip 40. B The side of the isolator chip 40, which has been beveled at an angle of 2 to 6 degrees, is placed on a base 12 including a magnet (FIG. 7), thereby setting the inclination angle of the incident surface 6 with respect to the optical axis 10 of the incident light 8. However, these methods have problems such as increasing the size. This will be explained in more detail below.

[0005] FIG. 5 is a diagram illustrating an optical isolator according to a first conventional example, showing an optical isolator chip 30 in which the incident surface 6 is perpendicular to the central axis 5 of the light traveling direction of the optical isolator chip. This optical isolator chip 30 is an example of a rectangular parallelepiped shape. FIG. 6 shows the optical isolator chip 30 as shown in FIG. 5, which is rotated at an angle θ A 6 shows a first conventional optical isolator 200 obtained by arranging the incident light 8 at a tilt of 2 to 6 degrees (deg). In the optical isolator 200 shown in FIG. 6, when incident light 8 is centered at the incident surface 6 of the optical isolator chip, an optical axis shift (corresponding to a shift length ΔT) occurs in the optical axis 11 of the output light 9, causing the center position of the output light 9 on the output surface 7 to be located downward. When viewed from the optical axis, if the chip height is CH as shown in FIG. 6, the distance from the position of the optical axis 11 (beam center) on the output surface 7 to the upper chip edge is CH / 2+ΔT, and the distance to the lower chip edge is CH / 2-ΔT. In this case, in order to ensure the required effective diameter corresponding to the transmitted beam diameter, a method is used in which CH is increased or the center of the optical axis of the incident light is shifted upward to displace the center of the optical axis of the output light upward, thereby ensuring the effective diameter.

[0006] In addition, in the optical isolator 300 according to the second conventional example shown in FIG. 7, the incident surface 6 of the isolator chip 40 is beveled in advance, allowing the side of the isolator chip to be supported on the base 12 during assembly. When incident light 8 is centered on the chip's incident surface 6, a shift (equivalent to a shift length ΔT) occurs in the optical axis 11 of the output light 9, causing the output light 9 to be positioned above the center of the output surface 7. When viewed from the optical axis, the distance from the optical axis 11 (beam center) to the upper chip edge is CH / 2-ΔT, and the distance from the lower chip edge is CH / 2+ΔT. In this case, to ensure the required effective diameter corresponding to the transmitted beam diameter, methods have been used to increase CH or shift the center of the optical axis of the input light downward to shift the center of the output optical axis downward, thereby ensuring the effective diameter.

[0007] When a rectangular parallelepiped optical isolator chip 30 (FIG. 5) is used and is installed at an angle (FIG. 6), if the incident surface 6 is tilted significantly, the chip length L is tilted, and the height direction is changed by L×sinθ. A The height of the optical isolator chip 30 increases by an amount corresponding to (=ΔC). ΔC is called the "slope offset length." Furthermore, in both the shapes of Figures 6 and 7, taking into account the incident surface 6, the exit surface 7, and the effective beam diameter, it is necessary to increase the chip height (height direction length) CH. In this case, costs increase due to the increased area of ​​the expensive optical element. Furthermore, even if the area of ​​the optical element is increased, the light beam transmission area becomes relatively small, resulting in a large amount of wasted material.

[0008] Furthermore, in recent years, high-density packaging has become common in optical communications, and attempts have been made to insert components for adjusting the optical axis within a module (see, for example, Patent Document 1).

[0009] However, when further space saving is considered, it is becoming difficult to incorporate components for adjusting the optical axis as described in Patent Document 1. There is a demand for an optical isolator with a small optical element size that can obtain a large beam shift amount without impairing the optical characteristics of the optical isolator.

[0010] The present invention has been made to solve the above problems, and aims to provide an optical isolator with a small optical element size that can obtain a large beam shift (optical axis shift) amount without impairing the optical characteristics of the optical isolator, and a method for manufacturing such an optical isolator. [Means for solving the problem]

[0011] The present invention has been made to achieve the above object, and provides an optical axis shift type optical isolator having one or more polarizers and one or more Faraday rotators in a light propagation direction, and including an optical isolator chip formed by bonding the polarizer and the Faraday rotator together, wherein the incident surface of the optical isolator chip in the optical isolator is a surface inclined at an angle of 40° (deg) or less with respect to the optical axis of light incident on the optical isolator, the incident surface of the optical isolator chip is a surface inclined with respect to the central axis of the optical isolator chip in the light propagation direction, and the central axis of the optical isolator chip in the light propagation direction is inclined with respect to the optical axis of the light incident on the optical isolator, and a shift length ΔT (mm) of the optical axis of light emitted from the optical isolator with respect to the optical axis of the light incident on the optical isolator, and a tilt deviation length ΔC (mm) of the output surface side of the optical isolator chip with respect to the input surface side due to the tilt of the central axis of the optical isolator chip in the light propagation direction are | ΔT - ΔC | ≦ 0.10(mm) The present invention provides an optical axis shift type optical isolator that satisfies the above requirements.

[0012] Such an optical isolator can obtain a large beam shift (optical axis shift) amount without impairing the optical characteristics of the optical isolator, while having a small optical element size and ensuring the maximum effective diameter.

[0013] In this case, the incident surface of the optical isolator chip in the optical isolator can be an optical axis shift type optical isolator, which is a surface inclined at an angle of 8° (deg) or more with respect to the optical axis of the light incident on the optical isolator.

[0014] This results in an optical axis shift type optical isolator that can obtain a larger beam shift amount.

[0015] In this case, the optical isolator chip may be an optical axis shift type optical isolator in which one side surface of the optical isolator chip is inclined and disposed on a flat base including a magnet.

[0016] This results in a simpler structure.

[0017] The present invention has been made to achieve the above object, and provides a method for manufacturing an optical axis shift type optical isolator having one or more polarizers and one or more Faraday rotators in the light propagation direction, and including an optical isolator chip in which the polarizer and the Faraday rotator are bonded together, the method comprising: making an incident surface of the optical isolator chip a surface inclined with respect to a central axis of the optical isolator chip in the light propagation direction; installing the optical isolator chip such that the central axis of the optical isolator chip in the light propagation direction is inclined with respect to the optical axis of the light incident on the optical isolator; making the incident surface of the optical isolator chip a surface inclined at an angle of 40° (deg) or less with respect to the optical axis of the light incident on the optical isolator; and determining whether a shift length ΔT (mm) of the optical axis of the light emitted from the optical isolator with respect to the optical axis of the light incident on the optical isolator and an inclination deviation length ΔC (mm) of the output surface side of the optical isolator chip with respect to the input surface side due to the inclination of the central axis of the optical isolator chip in the light propagation direction are | ΔT - ΔC | ≦ 0.10(mm) The present invention provides a method for manufacturing an optical axis shift type optical isolator that satisfies the above requirements.

[0018] According to this method for manufacturing an optical isolator, it is possible to manufacture an optical isolator that can obtain a large beam shift (optical axis shift) amount without impairing the optical characteristics of the optical isolator, while having a small optical element size and ensuring the maximum effective diameter.

[0019] In this case, the method for manufacturing an optical axis shift type optical isolator can be such that the incident surface of the optical isolator chip is a surface inclined at an angle of 8° (deg) or more with respect to the optical axis of the light incident on the optical isolator.

[0020] This makes it possible to manufacture an optical axis shift type optical isolator that can obtain a larger beam shift amount.

[0021] In this case, by placing one side of the optical isolator chip at an angle on a planar base including a magnet, a method for manufacturing an optical axis shift type optical isolator can be achieved in which the central axis of the optical isolator chip in the direction of light propagation is angled with respect to the optical axis of the light incident on the optical isolator.

[0022] This makes it possible to more easily manufacture an optical axis shift type optical isolator. [Effects of the Invention]

[0023] As described above, the optical isolator of the present invention can obtain a large beam shift (optical axis shift) amount without impairing the optical characteristics of the optical isolator, while having a small optical element size and ensuring the maximum effective diameter. The method for manufacturing an optical isolator of the present invention makes it possible to manufacture the optical isolator described above. [Brief explanation of the drawings]

[0024] [Figure 1] 1 shows an optical isolator according to the present invention. [Figure 2] 1 shows an optical isolator chip in an optical isolator according to the present invention. [Figure 3] An example of the configuration of a single-stage optical isolator is shown. [Figure 4] An example of the configuration of a 1.5-stage optical isolator is shown. [Figure 5] 1 is a diagram illustrating an optical isolator according to a first conventional example. [Figure 6] 1 is a diagram illustrating an optical isolator according to a first conventional example. [Figure 7] 10 is a diagram illustrating an optical isolator according to a second conventional example. [Figure 8]This shows the incidence surface angle dependence of the forward insertion loss (dB) of an optical isolator. [Figure 9] This shows the incidence surface angle dependence of the reverse insertion loss (dB) of an optical isolator. [Figure 10] 1 shows the dependence of the extinction ratio of a glass polarizer on the angle of incidence. [Figure 11] 1 shows the incidence surface angle dependence of the insertion loss of a glass polarizer. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention will be described in detail below, but the present invention is not limited thereto.

[0026] As described above, there has been a demand for an optical isolator with a small optical element size while achieving a large beam shift (optical axis shift) amount without impairing the optical characteristics of the optical isolator, and a method for manufacturing such an optical isolator.

[0027] As a result of extensive research into the above-mentioned problems, the present inventors have found an optical axis shift type optical isolator having one or more polarizers and one or more Faraday rotators in the light propagation direction, and including an optical isolator chip in which the polarizer and the Faraday rotator are bonded together, wherein the incident surface of the optical isolator chip in the optical isolator is a surface inclined at an angle of 40° (deg) or less with respect to the optical axis of the light incident on the optical isolator, the incident surface of the optical isolator chip is a surface inclined with respect to the central axis of the optical isolator chip in the light propagation direction, and the central axis of the optical isolator chip in the light propagation direction is inclined with respect to the optical axis of the light incident on the optical isolator, and a shift length ΔT (mm) of the optical axis of the light emitted from the optical isolator with respect to the optical axis of the light incident on the optical isolator, and a tilt deviation length ΔC (mm) of the output surface side of the optical isolator chip with respect to the input surface side due to the tilt of the central axis of the optical isolator chip in the light propagation direction are | ΔT - ΔC | ≦ 0.10(mm) The inventors have found that an optical axis shift type optical isolator that satisfies the above requirement can provide a large beam shift amount (optical axis shift) without impairing the optical characteristics of the optical isolator, while having a small optical element size and ensuring the maximum effective diameter, and have completed the present invention.

[0028] Furthermore, there is provided a method for manufacturing an optical axis shift type optical isolator having one or more polarizers and one or more Faraday rotators in the light propagation direction, and an optical isolator chip in which the polarizer and the Faraday rotator are bonded together, the method comprising: making an incident surface of the optical isolator chip a surface inclined with respect to a central axis of the optical isolator chip in the light propagation direction; installing the optical isolator chip so that the central axis of the optical isolator chip in the light propagation direction is inclined with respect to the optical axis of the incident light into the optical isolator; making the incident surface of the optical isolator chip a surface inclined at an angle of 40° (deg) or less with respect to the optical axis of the incident light into the optical isolator; and determining whether a shift length ΔT (mm) of the optical axis of the output light from the optical isolator with respect to the optical axis of the incident light into the optical isolator and an inclination deviation length ΔC (mm) of the output surface side with respect to the input surface side of the optical isolator chip due to the inclination of the central axis of the optical isolator chip in the light propagation direction are | ΔT - ΔC | ≦ 0.10(mm) The present inventors have found that a method for manufacturing an optical axis shift type optical isolator that satisfies the above requirement can provide an optical isolator that has a large beam shift (optical axis shift) amount without impairing the optical characteristics of the optical isolator, while having a small optical element size and ensuring the maximum effective diameter, and have completed the present invention.

[0029] The following description will be made with reference to the drawings.

[0030] First, we checked the condition of increasing the incident surface angle of the optical isolator, which is different from normal use. The optical characteristics of an optical isolator depend on the incident surface angle of the incident light, and it was found that when the incident angle was changed from 0 to 50 degrees, the reverse insertion loss and forward insertion loss of the optical isolator changed as shown in Figures 8 and 9, respectively. It was also found that the glass polarizer alone exhibited the characteristics shown in Figures 10 and 11.

[0031] As shown in Figure 8, when the tilt angle of the incident surface of the optical isolator is increased, the forward insertion loss gradually increases once the incident surface angle reaches 15 degrees (deg), and as shown in Figure 9, the reverse insertion loss gradually decreases once the incident surface angle reaches 10 degrees (deg). Generally, in a single-stage configuration (two polarizers and one Faraday rotator) as shown in Figure 3, a forward insertion loss of 0.3 dB or less and a reverse insertion loss of 30 dB or more are required. From the perspective of these optical characteristics, it was found that the tilt angle of the incident surface must be 40 degrees or less.

[0032] The inventor then inclined the incident surface 6 of the optical isolator chip 20 (angle θ C ), and then the optical isolator chip 20 is tilted (at an angle θ A The optical isolator chip 20 is arranged at an inclination angle (tilt angle: θ A °) and the length of the bottom surface (= tip length L) to calculate the tilt deviation length ΔC = L × sinθ A (mm) and shift length ΔT (mm), | ΔT - ΔC | ≦ 0.1mm By doing so, it has been found that the chip height CH of the optical isolator chip 20 is not made larger (longer) than necessary, and that the balance of the transmission areas of the incident surface 6 and the exit surface 7 is not impaired while providing a large beam shift function, and further, by setting the inclination angle of the incident surface 6 with respect to the incident light 8 to 40° (deg) or less, the optical characteristics required of an optical isolator can be satisfied.

[0033] That is, the optical axis shift type optical isolator according to the present invention has one or more polarizers and one or more Faraday rotators in the direction of light propagation, and is equipped with an optical isolator chip (e.g., Figures 3 and 4) in which the polarizers and Faraday rotators are bonded together.

[0034] 2, the incident surface 6 of the optical isolator chip 20 is inclined (inclination angle: θ C 1, the optical isolator chip 20 is disposed so that the central axis 5 of the light traveling direction is inclined with respect to the optical axis 10 of the incident light 8 to the optical isolator 100 (inclination angle: θ A The optical axis shift type optical isolator 100 according to the present invention is formed by inclining the incident surface 6 of the optical isolator chip 20 (inclination angle: θ C °) and the tilted arrangement of the optical isolator chip 20 (tilt angle: θ A By adjusting the angle (angle) of the incident surface 6 of the optical isolator chip 20 in the optical isolator 100, the incident surface 6 is set to be a surface inclined at an angle of 40 degrees (deg) or less with respect to the optical axis 10 of the light 8 incident on the optical isolator 100. Note that the angle of inclination of the incident surface 6 of the optical isolator chip 20 with respect to the optical axis 10 of the light 8 incident on the optical isolator 100 may be greater than 0 degrees (deg).

[0035] Furthermore, the shift length ΔT (mm) of the optical axis 11 of the output light 9 from the optical isolator 100 relative to the optical axis 10 of the input light 8 to the optical isolator 100, and the tilt shift length ΔC (mm) of the output surface 7 side of the optical isolator chip 20 relative to the input surface 6 side due to the tilt of the central axis 5 of the optical isolator chip 20 in the light propagation direction are | ΔT - ΔC | ≦ 0.10(mm) It satisfies the following.

[0036] In this optical axis shift type optical isolator 100, the light 9 emitted from the exit surface 7 is emitted from a position closer to the center of the exit surface 7, so that a large beam shift (optical axis shift) can be obtained while the optical element size is small and the maximum effective diameter can be secured, without impairing the optical characteristics of the optical isolator.

[0037] The incident surface 6 of the optical isolator chip 20 in the optical isolator 100 is preferably a surface inclined at an angle of 8° (deg) or more with respect to the optical axis 10 of the incident light 8 to the optical isolator 100. This results in an optical isolator 100 that can obtain a larger beam shift amount.

[0038] Furthermore, as shown in FIG. 1, it is preferable to arrange one side of the optical isolator chip 20 at an angle on a flat base 12 including a magnet, as this results in a simpler structure.

[0039] Next, a method for manufacturing the optical isolator according to the present invention will be described.

[0040] First, an optical isolator chip (e.g., FIGS. 3 and 4) is prepared, which has one or more polarizers and one or more Faraday rotators in the light propagation direction, and the polarizers and the Faraday rotators are bonded together. Then, as shown in FIG. 2, the incident surface 6 of the optical isolator chip 20 is inclined (at an angle θ C The surface is then beveled by cutting, grinding, etc. to create a beveled surface.

[0041] Next, the optical isolator chip 20 is tilted such that the central axis 5 of the optical isolator chip 20 in the light propagation direction is tilted (angle θ A Install it so that it is oriented in the same direction as the camera.

[0042] Furthermore, the incident surface 6 of the optical isolator chip 20 is a surface inclined at an angle of 40° (deg) or less with respect to the optical axis 10 of the incident light 8 to the optical isolator 100, and the shift length ΔT (mm) of the optical axis 11 of the output light 9 from the optical isolator 100 with respect to the optical axis 10 of the incident light 8 to the optical isolator 100 and the tilt deviation length ΔC (mm) of the output surface 7 side with respect to the incident surface 6 side of the optical isolator chip 20 caused by tilting the central axis 5 of the optical isolator chip 100 in the light propagation direction are | ΔT - ΔC | ≦ 0.10(mm) The optical isolator chip 20 is positioned so that the above-mentioned angle θ C °, angle θ A This can be set by adjusting the angle.

[0043] There is no particular limitation on the method for arranging the optical isolator chip 20 in this manner, but for example, it can be placed on a planar base 12 including a magnet using adhesive or the like, and the tilt angle can be adjusted by adjusting the angle at which the chip is attached (this can be achieved by holding it at a specific angle using a jig or the like before the adhesive hardens and then hardening the adhesive).

[0044] Furthermore, the lower limit of the angle of inclination of the incident surface of the optical isolator chip with respect to the optical axis of the light incident on the optical isolator is not particularly limited, but it can be set to, for example, 8 degrees or more, which makes it possible to manufacture an optical axis shift type optical isolator that can obtain a larger beam shift amount. [Example]

[0045] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0046] (Example 1, Comparative Examples 1-1 and 1-2) 3 shows an example of the configuration of the single-stage optical isolator used in Example 1. The first polarizer 1 and the second polarizer 2 are flat glass polarizers (Polarcor: Corning) in which Ag particles are dispersed and aligned, and the Faraday rotator (first Faraday rotator 13) is made of (TbEuBi)3(FeGa)5O 12 and (GdBi)3(FeGa)5O 12 was used.

[0047] The surfaces of the first polarizer 1 and second polarizer 2 (11 mm square, 0.2 mm thick, 52 dB extinction) were coated with an air-resistant coating at 1550 nm. A 45.0° Faraday rotator (first Faraday rotator 13) (11 mm square, 0.54 mm thick) at 1550 nm was coated with an epoxy coating on both sides and bonded to the non-AR-coated surface of the polarizer using epoxy adhesive. The first polarizer 1 and second polarizer 2 were bonded and fixed so that the relative angle was 45.0°. The optical isolator chip was then cut to a 1 mm square so that the incident surface was at the desired angle, and bonded and fixed to a permanent magnet (1.4 mm high, 0.8 mm wide, 1.5 mm long in the optical axis direction) as the base 12 (similarly bonded and positioned at each tilt angle). The thickness of the epoxy adhesive layer was approximately 0.005 to 0.008 mm.

[0048] Table 1 lists the results for each incident surface inclination angle, optical axis shift length ΔT (beam shift amount), effective diameter, etc. It can be seen that the optical isolator of Example 1 can secure the maximum effective diameter while obtaining a large beam optical axis shift length without impairing the optical characteristics of the optical isolator (incident surface inclination angle of 40° or less). It should be noted that when processing the chip, the influence of chipping during cutting must be taken into consideration, and the vicinity of the cut edge (for example, 0.02 mm from the chip cut edge) must be excluded from the effective diameter.

[0049] [Table 1]

[0050] As shown in Table 1, compared to the case where the inclined processing angle of the chip incident surface is simply set to the inclination angle with respect to the optical axis of the incident light (inclination angle of the incident surface) as shown in Figure 7, as shown as [Reference] in Table 1, or the case where the rectangular chip is tilted and the inclined arrangement angle is set to the inclination angle with respect to the optical axis of the incident light (inclination angle of the incident surface) as shown in Figure 6, it can be seen that in Example 1, a large effective diameter (φ0.85 mm) close to the chip area can be stably secured.

[0051] (Example 2, Comparative Examples 2-1 and 2-2) The evaluation was carried out using the same configuration as in Example 1, except that the thickness of the first polarizer 1 and the second polarizer 2 was set to 0.12 mm. The results are shown in Table 2.

[0052] [Table 2]

[0053] (Example 3, Comparative Examples 3-1 and 3-2) 4 shows an example of the configuration of the 1.5-stage optical isolator used in Example 3. The first polarizer 1, second polarizer 2, and third polarizer 3 are flat glass polarizers in which Ag particles are dispersed and aligned, and the first Faraday rotator 13 and second Faraday rotator 14 are (TbEuBi)3(FeGa)5O 12 and (GdBi)3(FeGa)5O 12 was used.

[0054] The surfaces of the first polarizer 1 and third polarizer 3 (11 mm square, 0.12 mm thick, 52 dB extinction) were coated with an air-resistant coating at 1550 nm. A 45.0° Faraday rotator (11 mm square, 0.54 mm thick) at 1550 nm was epoxy-coated on both sides and bonded to the uncoated surface of the polarizer using epoxy adhesive. The first, second, and third polarizers were bonded so that the relative angles between the first and second polarizers and between the second and third polarizers were 45.0°. The chips were then cut to 1 mm square so that the incident surfaces were at the desired angles, and bonded to permanent magnets (1.4 mm high, 0.8 mm wide, and 2.0 mm long in the optical axis direction) (similarly bonded to each tilt angle). The results are shown in Table 3.

[0055] [Table 3]

[0056] As shown in Tables 2 and 3, the optical isolators of Examples 2 and 3 can also secure the maximum effective diameter while obtaining a large shift length of the beam optical axis without impairing the optical characteristics of the optical isolator (incident surface inclination angle of 40° or less). Furthermore, even when the vicinity of the cut end is excluded from the effective diameter, it can be seen that a large effective diameter (φ0.85 mm) close to the chip area can be stably secured, as in Example 1.

[0057] As described above, according to the embodiment of the present invention, an optical isolator can be obtained that can obtain a large beam shift amount without impairing the optical characteristics of the optical isolator, while having a small optical element size and ensuring the maximum effective diameter.

[0058] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0059] 1...first polarizer, 2...second polarizer, 3...third polarizer, 5...Central axis, 6...Incidence surface, 7...Output surface, 8...Incoming light, 9...Outgoing light, 10...Optical axis (incident light), 11...Optical axis (outgoing light), 12...Base, 13...first Faraday rotator, 14...second Faraday rotator, 20, 30, 40... optical isolator chip, 100, 200, 300...optical isolators. L...chip length, CH...chip height, ΔT...shift length, ΔC...inclination deviation length.

Claims

1. An optical axis shift type optical isolator having one or more polarizers and one or more Faraday rotators in the light propagation direction, and including an optical isolator chip in which the polarizers and the Faraday rotators are bonded together, an incident surface of the optical isolator chip in the optical isolator is a surface inclined at an angle of 40° (deg) or less with respect to an optical axis of light incident on the optical isolator; an incident surface of the optical isolator chip is a surface inclined with respect to a central axis of the optical isolator chip in the direction of propagation of the light, a central axis of the optical isolator chip in the light propagation direction is inclined with respect to an optical axis of the light incident on the optical isolator; a shift length ΔT (mm) of the optical axis of the output light from the optical isolator relative to the optical axis of the input light to the optical isolator, and a tilt deviation length ΔC (mm) of the output surface side of the optical isolator chip relative to the input surface side due to the tilt of the central axis of the optical isolator chip in the light propagation direction, | ΔT - ΔC | ≦ 0.10 (mm) and The angle between the optical axis of the incident light to the optical isolator and the central axis of the optical isolator is θ Ａ (°), The inclination angle of the incident surface of the optical isolator chip with respect to the plane perpendicular to the central axis of the light propagation direction of the optical isolator chip is θ Ｃ (°), The inclination angle of the incident surface of the optical isolator chip in the optical isolator with respect to the plane perpendicular to the optical axis of the incident light to the optical isolator is θ Ａ +θ Ｃ (°).

2. 2. The optical axis shift type optical isolator according to claim 1, wherein the incident surface of the optical isolator chip in the optical isolator is a surface inclined at an angle of 8° (deg) or more with respect to the optical axis of the light incident on the optical isolator.

3. 3. The optical axis shift type optical isolator according to claim 1, wherein one side of the optical isolator chip is disposed at an angle on a flat base including a magnet.

4. A method for manufacturing an optical axis shift type optical isolator having one or more polarizers and one or more Faraday rotators in the light propagation direction, and including an optical isolator chip in which the polarizers and the Faraday rotators are bonded together, comprising: an incident surface of the optical isolator chip is inclined with respect to a central axis of the optical isolator chip in the direction of propagation of the light; the optical isolator chip is installed so that a central axis of the optical isolator chip in the light propagation direction is inclined with respect to an optical axis of light incident on the optical isolator; The incident surface of the optical isolator chip is a surface inclined at an angle of 40° (deg) or less with respect to the optical axis of the incident light to the optical isolator, and a shift length ΔT (mm) of the optical axis of the output light from the optical isolator with respect to the optical axis of the incident light to the optical isolator, and a tilt deviation length ΔC (mm) of the output surface side of the optical isolator chip with respect to the incident surface side due to a tilt of the central axis of the optical isolator chip in the traveling direction of the light are | ΔT - ΔC | ≦ 0.10 (mm) and The angle between the optical axis of the incident light to the optical isolator and the central axis of the optical isolator is θ Ａ (°), The inclination angle of the incident surface of the optical isolator chip with respect to the plane perpendicular to the central axis of the light propagation direction of the optical isolator chip is θ Ｃ (°), The inclination angle of the incident surface of the optical isolator chip in the optical isolator with respect to the plane perpendicular to the optical axis of the incident light to the optical isolator is defined as θ Ａ +θ Ｃ (°) is a manufacturing method of an optical axis shift type optical isolator.

5. 5. The method for manufacturing an optical axis shift type optical isolator according to claim 4, wherein the incident surface of the optical isolator chip is a surface inclined at an angle of 8 degrees or more with respect to the optical axis of the light incident on the optical isolator.

6. 6. A method for manufacturing an optical axis shift type optical isolator according to claim 4 or 5, characterized in that one side of the optical isolator chip is tilted on a planar base including a magnet, so that the central axis of the optical isolator chip in the direction of light propagation is tilted with respect to the optical axis of the light incident on the optical isolator.

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