JP4812342B2 - Optical connector - Google Patents

Description

  The present invention relates to an optical connector, and more particularly to an optical connector incorporating a polarization-independent optical isolator used between optical fibers in optical fiber communication or the like.

  With the advance of optical communication using a semiconductor laser as a signal light source, high-speed and high-density signal transmission exceeding several gigahertz has been put into practical use. One of optical components used for high-speed and high-density signal transmission is an optical isolator used for the purpose of preventing reflected return light to a semiconductor laser. There are two types of optical isolators: polarization-dependent optical isolators that transmit only light in a specific polarization direction, and polarization-independent optical isolators that transmit all light in any polarization direction. Of these, the latter polarization-independent optical isolator is used in signal transmission repeaters, terminations, optical amplifiers, and the like, and is expected to be in great demand in the future.

  FIG. 5 shows a configuration of a conventional typical polarization-independent optical isolator 20, which uses a single Faraday rotator and three birefringent crystal plates.

  In FIG. 5, the first to third birefringent crystal plates are 11, 12, and 13, respectively, and the Faraday rotator placed between 11 and 12 is 14. A magnetic field parallel to the Z direction is applied to the Faraday rotator. 11, 12, and 13 are cut from a uniaxial crystal so that the C-axis is inclined with respect to the surface and polished to a parallel plate, and splits the light incident perpendicularly to the parallel plate into two lights whose polarization directions are orthogonal to each other. To do. 11, 12, and 13 have thicknesses in the light transmission direction of 1: 1 / √2: 1 / √2, and the 13 C-axis is rotated 90 ° around the Z-axis with respect to 12 C-axis It is. Reference numeral 14 denotes a Faraday rotator formed of bismuth-substituted garnet or the like, which rotates the polarization direction of light by 45 °. Light emitted from the optical fiber 15 passes through the lens 16, the birefringent crystal plate 11, the Faraday rotator 14, and the birefringent crystal plates 12 and 13, and enters the optical fiber 18 through the lens 17.

  Here, a case where light is incident from the birefringent crystal plate 11 is defined as a forward direction, a case where light is incident from the birefringent crystal plate 13 is defined as a reverse direction, a forward incident light beam is 10f, and a reverse incident light beam is 10b. The light beams separated into two are respectively represented by f1 and f2 in the forward direction and b1 and b2 in the reverse direction, and are indicated by arrows in the drawing.

  The forward incident light beam 10 f is separated into light beams f 1 and f 2, but is combined by the birefringent crystal plates 12 and 13 and enters the optical fiber 18. Since the reverse incident light beam 10b is emitted to a position different from the optical fiber 15 while being separated into the light beams b1 and b2, the return light is not coupled to the optical fiber 15 and functions as an optical isolator.

  FIG. 6 shows a conventional product in which the function of the polarization-independent optical isolator shown in FIG. 5 is incorporated in an optical connector.

  The optical connector shown in FIG. 6 has a polarization-independent optical isolator composed of an optical isolator element 23 in which a Faraday rotator 14, a birefringent crystal plate, and a half-wave plate are integrated in a cylindrical magnet 24. is doing. The optical fibers 15 and 18 are held by holding members 25a and 25b, respectively, while core expansion fibers 21a and 21b having a lens function are bonded to one ends of the optical fibers 15 and 18, respectively. The above-described optical isolator element 23 is disposed at a substantially central portion of the inner hole of the cylindrical sleeve, and holding members 25a and 25b for holding the optical fiber are inserted into the inner hole of the sleeve 26 and fixed. Further, by holding the holding member 25a with the flange 27 that is press-fitted into and brought into contact with the outer periphery of the holding member 25a, the conventional optical connector having the function of a polarization-independent optical isolator shown in FIG. 6 is configured. ing.

  The plug-type optical isolator constituting such an optical connector has a polarization-independent optical isolator function, has a simple structure, is easy to assemble and adjust, is small, and is easy to optically adjust each optical component. It has excellent stability and high versatility for incorporation into measuring instruments and communication devices.

In addition, when it is arranged near the laser diode, a polarization-dependent isolator may be used as the optical isolator. Polarization independent optical isolator includes a first polarizer having optical transmission axis, and a Faraday rotator, a second polarizer Toka Rannahli having an optical transmission axis, the magnetic field parallel to the Z direction in the Faraday rotator Has been added. The Faraday rotator rotates the polarization direction of light by 45 degrees, and the tilt angle of the light transmission axis of the first polarizer and the second polarizer is adjusted to approximately 45 degrees. Such a polarization-dependent optical isolator cuts off a part of the incident light in the first polarizer and the polarized light orthogonal to the light transmission axis, so that the light transmission axis of the first polarizer in advance. And the direction of polarization of incident light must be aligned.

  However, in the optical connector incorporating the conventional polarization-independent optical isolator, the reverse incident light beam 10b is separated into the light beams b1 and b2, but this is incident on the cladding portion and the coating portion of the optical fiber 15, There is a problem of leaking from the opposite end of the optical fiber 15 (referred to as a clad mode). This clad mode usually diverges and disappears in the optical fiber, but in the case of an optical connector, the length of the propagating optical fiber is shortened, so the reflected return light is output without leaking and is connected. This causes instability of the semiconductor laser.

Further, in the conventional polarization-dependent optical isolator, since light orthogonal to the light transmission axis of the first polarizer is blocked, the polarization direction of the light incident on the first polarizer varies. As a result, there is a problem that the power of the emitted light varies with the variation. Further, in order to prevent the blocking of light at the surface of the first polarizer, positioning a first polarizer to align the polarization direction of the incident light and the direction of the light transmission axis of the first polarizer It was difficult.

The present invention has been made in view of the above problems, a first optical fiber, the light derived from the first optical fiber is introduced, a second optical fiber optically coupled , An optical isolator provided between the first optical fiber and the second optical fiber, the optical isolator having a light transmission axis and 1 of incident light A first polarizer and a second polarizer having a function of transmitting a polarization component of a direction and absorbing light of a component orthogonal thereto, and between the first polarizer and the second polarizer A Faraday rotator is provided , and the incident light is linearly polarized between the first optical fiber and the first polarizer, and the light transmission axis of the first polarizer. distribution quarter wave plate 45 having a C-axis that are ± 5 degrees inclined with respect to Characterized in that it was.

  Furthermore, the first optical fiber includes a first holding member that holds the first optical fiber with an inner hole, and a second holding member that holds the second optical fiber with an inner hole.

According to the configuration of the present invention, between the first optical fiber and the first polarizer, a linearly polarized light incident Isa is and 45 ± with respect to the optical transmission axis of the first polarizer by disposing the quarter-wave plate 5 degrees having a C-axis that inclined, it is possible to maintain a constant output value without depending on the polarization direction of the incident light.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of the optical connector of the present invention.

  As shown in FIG. 1, the optical connector 1 includes a holding member 2 (first holding member 2a and second holding member 2b), an optical fiber 3 (first optical fiber 3a and second optical fiber 3b), Sleeve 4, magnet 5, lens function unit 6 (first lens function unit 6a, second lens function unit 6b), birefringent member 7, and first polarizer 8a on the first optical fiber side, Faraday rotation An isolator portion 8 including a second polarizer 8c and a second polarizer 8c on the second optical fiber side is provided.

  The holding member 2 has a through hole, and holds the first optical fiber 3a or the second optical fiber 3b in the through hole. The holding member 2 is made of ceramic or resin such as alumina or zirconia, The outer shape can be various shapes such as a prismatic shape or a cylindrical shape. Here, the first optical fiber 3a is held by the first holding member 2a, and the second optical fiber 3b is held by the second holding member 2b.

  The optical fiber 3 has a function of transmitting light, emits light incident from one end of the first optical fiber 3a from the other end of the first optical fiber 3a, and emits the emitted light to the second light. Light can be transmitted by being incident on one end of the fiber. The optical fiber 3 is a quartz cylindrical body having an outer diameter of 100 to 150 μm, and a core portion of about 10 μm through which light propagates is formed.

  The sleeve 4 has a slit in the longitudinal direction and has a through hole, and holds the first holding member 2a and the second holding member 2b in the through hole. The sleeve 4 is made of ceramic such as zirconia or metal such as phosphor bronze.

  The magnet 5 is arranged to apply a magnetic field in a certain direction to the Faraday rotator, and the shape of the magnet 5 surrounds the Faraday rotator. For example, a prismatic shape having a through hole or a cylindrical shape is used. be able to. A material such as samarium cobalt is preferable because of its small size and strong magnetic field strength.

  The lens function unit 6 has a shape or an internal refractive index distribution so that light emitted from the optical fiber 3a is efficiently collected on the optical fiber 3b. For example, a graded index fiber such as a gradient index lens having a refractive index distribution toward the cylindrical cross section can be suitably used.

  In general, the birefringent member 7 is divided into two linearly polarized beams whose vibration directions are perpendicular to each other when a wavefront traveling direction is given, but their phase velocities, that is, refractive indexes are different. Here, the traveling direction of the wave front in which the phase velocities of the two linearly polarized lights are equal is referred to as the C axis. Such a birefringent member 7 is made of, for example, a birefringent crystal such as quartz or calcite, or a stretched resin, and a polycarbonate resin or a polysulfone resin excellent in transparency and wavelength dispersion of light is particularly preferable.

  The first polarizer 8a and the second polarizer 8c constituting the isolator unit 8 have a function of transmitting a polarized light component in one direction of incident light and absorbing a light component orthogonal thereto. The child is made of a polarizing glass having a structure in which ellipsoidal metal particles are dispersed in the glass. This polarizing glass is a glass having polarization characteristics by arranging long stretched metal particles in one direction in the glass itself, light having a polarization plane perpendicular to the stretch direction of the metal particles is transmitted, Light with a parallel polarization plane is absorbed. This polarization characteristic is because the metal fine particles embedded in the dielectric exhibit light-plasma resonance.

The Faraday rotator 8b constituting the isolator unit 8 is, for example, a bismuth-substituted garnet crystal, and the thickness thereof is set so that the polarization plane of incident light having a predetermined wavelength rotates 45 degrees. In order to rotate the plane of polarization, it is necessary to apply a sufficient magnetic field H in the direction of the optical axis Z of the incident light, and generally a permanent magnet (not shown) is often used. Further, if the Faraday rotator 8b has a very large magnetic hysteresis and does not have a magnet, a magnetic force-holding material that retains its own magnetic force, such as (TbBi) ₃ (FeAlGa) ₅ O ₁₂ or the like, can apply a magnetic field. It becomes unnecessary.

  Below, the preparation methods of the optical connector 1 of this invention are explained in full detail.

  First, the isolator part 8 is produced by bonding and integrating the first polarizer 8a, the Faraday rotator 8b, and the second polarizer 8c in this order using a light-transmitting resin. At this time, the first polarizer 8a and the second polarizer 8b are positioned so that the light transmission axis of the first polarizer 8a and the light transmission axis of the second polarizer 8c have an angle of 45 degrees. And glued.

  Next, the birefringent member 7 is bonded and integrated with a translucent resin on the side surface of the first polarizer 8a not bonded to the Faraday rotator 8b. Further, the adhesive member composed of the birefringent member 7 and the isolator portion 8 produced as described above is bonded and fixed in the inner hole of the cylindrical magnet 5. In addition, as said translucent resin, a fluorine resin, an epoxy resin, an acrylic resin, etc. can be used, for example.

  Then, the adhesive member composed of the birefringent member 7 and the isolator portion 8 produced as described above is used as one of the first holding members 2a for holding the first optical fiber 3a and the first lens function portion 6a in the through holes. Adhere to the end face with translucent resin. At this time, the first holding member 2a and the adhesive member bond the birefringent member 7 to the end portion of the first holding member 2a on the first lens function unit 6a side.

  Next, the first holding member 2a provided with the adhesive member composed of the birefringent member 7 and the isolator portion 8 manufactured as described above is inserted from the opening on one end side of the sleeve 4 having the through hole, while the second A second holding member 2b for holding the optical fiber 3b and the second lens function portion 6b in the through hole is inserted from an opening on the other end side of the sleeve 4, and the sleeve 4 holds the first holding member 2a, The optical connector 1 is configured by sandwiching the second holding member 2b.

  Next, the function of the optical connector 1 will be described. The light incident from the first optical fiber 3a which is the incident side optical fiber is converted into a condensed beam or a parallel beam by the first lens function unit 6a and is transmitted through the isolator unit 8. Thereafter, the beam is condensed on the emission side optical fiber 3b by the second lens function unit 6b on the emission side, and transmitted to the end of the emission side optical fiber 3b. As will be described in detail below, the optical connector of the present invention has a polarization-independent configuration in which the loss does not change depending on the direction of polarization incident on the first polarizer 8a. It has a characteristic that light reaches the end of the emission side optical fiber 3b.

  Here, the arrangement of the birefringent member 7 and the isolator portion 8 included in the optical connector of the present invention will be described with reference to FIG. FIG. 2 is a perspective view showing the arrangement of the birefringent member 7 and the isolator portion 8 included in the optical connector.

  The birefringent member 7 is arranged so that the C axis of the birefringent member 7 is in the k direction shown in FIG. The birefringent member 7 is adjusted in thickness so that when light (linearly polarized light) is incident on the birefringent member 7, a phase delay is generated between the polarization parallel to k and the polarization perpendicular to k. is there. On the other hand, the polarizer 8a is disposed such that the light transmission axis is located in the j direction.

  According to the configuration of the present invention, the birefringent member 7 is disposed by inclining the C axis of the birefringent member 7 with respect to the light transmission axis of the first polarizer 8a. Since the transmitted light becomes light having a certain component with respect to the transmission axis direction of the polarizer 8a, it is possible to suppress variations in power output from the second optical fiber 3b. Here, inclining the C axis of the birefringent member 7 with respect to the light transmission axis of the first polarizer 8a means that the k direction indicating the direction of the C axis and the light transmission axis are The birefringent member 7 and the first polarizer 8a are arranged with a predetermined inclination angle θ in the j direction indicating the direction. In addition, after the arrangement, the birefringent member 7 and the polarizer 8a may be bonded and fixed to each other.

  In the optical connector of the present invention, a quarter wave plate is used for the birefringent member 7, and the inclination angle of the light transmission axis of the first polarizer 8a with respect to the C axis of the quarter wave plate is 45 ± 5. It is preferable to be within the range of degrees. The inclination angle θ is an angle formed by a k direction indicating the direction of the C axis of the quarter-wave plate and a j direction indicating the direction of the light transmission axis of the first polarizer 8a. Is the smaller angle (0 ° ≦ θ ≦ 90 °).

  Here, the quarter wavelength plate is a birefringent member that has different refractive indexes in the k direction and the component orthogonal thereto, and accordingly, the propagation speed of the light wave in each direction is different. This is a part that has been processed and polished to such a thickness that the deviation of the optical distance is a quarter of the wavelength (the phase is shifted by π / 2).

  Therefore, the linearly polarized light incident on the ¼ wavelength plate is transmitted through the ¼ wavelength plate and is emitted as circularly polarized light or an ellipse whose major axis or minor axis is the C-axis direction. It becomes polarized light or linearly polarized light in the C-axis direction.

  Then, when the first polarizer 8a is arranged so that the light transmission axis of the first polarizer 8a is at an inclination angle θ = 45 degrees with respect to the C-axis of the quarter-wave plate, the incident light Regardless of whether circularly polarized light, elliptically polarized light, or linearly polarized light in the C-axis direction, which is emitted depending on the polarization direction, is incident on the first polarizer 8a, it passes through the first polarizer 8a. Since the light power is output at a light power that is substantially half the light power incident on the first polarizer 8a, a constant output value is maintained without depending on the polarization direction of the incident light. Can do.

  Here, when the inclination angle θ exceeds 50 degrees or less than 40 degrees, the polarization dependence in the polarization direction of the incident light affects the output light power, and the output light power. There is a possibility that the variation is likely to occur. Therefore, when using as an optical connector having a desired constant light output power, it is preferable to set the inclination angle θ within a range of 45 ± 5 degrees, thereby stabilizing the light output power. This is preferable.

  Furthermore, in the present invention, as shown in FIGS. 1 and 2, a Faraday rotator 8b is provided between the first polarizer 8a and the second optical fiber 3a, and the Faraday rotator 8b and the second optical fiber 3a are provided. A second polarizer 8c is preferably provided between the optical fiber 3a. Here, the positional relationship among the first polarizer 8a, the Faraday rotator 8b, and the second polarizer 8c is such that the light transmission axis of the first polarizer 31 is arranged in the j direction as shown in FIG. In this case, the light transmission axis of the second polarizer 33 is positioned in the m direction, which is a direction that forms an angle of approximately 45 degrees with the light transmission axis of the first polarizer 31.

  Then, the Faraday rotation angle of the Faraday rotator 8b is set in advance so that the Faraday rotation angle is about 45 degrees, and a magnetic field in the H direction is applied to the isolator portion 8 by the magnet 5, whereby the second light Since the return light from the fiber 3b can be blocked by the isolator unit 8, the light returning to the core or the clad of the first optical fiber 3a can be suppressed, and the light source can be prevented from becoming unstable.

  In the optical connector of the present invention, it is preferable to hold the optical fiber 3 in the inner hole of the holding member 2. By holding the optical fiber 3 in the inner hole of the holding member 2, the loss of light transmitted through the optical fiber 3 is reduced, and the pair of optical fibers 3, that is, the first optical fiber 3 a and the second light. Since the fiber 3b can be positioned with high accuracy, it is possible to suppress the loss of light that occurs during optical coupling between the first optical fiber 3a and the second optical fiber 3b.

  Next, another embodiment of the present invention will be described with reference to FIG. As shown in FIG. 3, the optical fiber on the incident side including the first optical fiber 3a and the first lens function unit 6a bonded to one end thereof, the second optical fiber 3b, and the one bonded to one end thereof. A groove is formed in a part of one holding member 2 that holds both the optical fiber on the emission side including the second lens function unit 6b, and the birefringent member 7, the isolator unit 8, and A magnet 5 that gives a Faraday effect to the isolator 8 is inserted and fixed. Further, the emission end side of the sleeve 4 is configured such that another plug holding member can be inserted. By using the optical connector in which the holding member 2 is configured in this manner, the optical connector can be manufactured more easily.

  Also, these optical connectors can be used in FC-type, SC-type, and LC-type housings. In this case, as compared with the conventional optical isolator in which the fiber is connected to both ends, the optical fiber routing is not complicated, and the space can be saved significantly. In addition, since the insertion loss has no output fluctuation due to incident polarization, and the isolation characteristic is that the return light is absorbed by the polarizer 8a, there is no fear of leakage light, and an optical connector having a good isolation characteristic has been realized.

  In the following, compared with the optical connector A which is an example of the present invention and the optical connector B which is a comparative example, the normalized transmission power of light in incident light at various angles was verified.

  A manufacturing method of the optical connector A which is an embodiment of the present invention will be described below.

  As the first polarizer 8a and the second polarizer 8c constituting the isolator unit 8, polarizers made of Corning glass having a thickness of 0.2 mm were used. The Faraday rotator 8b was made of a terbium bismuth-substituted garnet film having a thickness of 0.35 mm. Then, the first polarizer 8a and the second polarizer 8c are arranged so that the angle between the light transmission axis of the first polarizer 8a and the light transmission axis of the second polarizer 8c is 45 degrees, and the first polarizer 8a and the second polarizer 8c. The Faraday rotator 8b was sandwiched between them, and these were bonded and integrated with an adhesive made of a translucent epoxy resin.

  Next, a quarter-wave plate made of a quartz plate having a thickness of 50 μm used as the birefringent member 7 is set to the C-axis of the quarter-wave plate (birefringent member 7) and the light transmission axis of the first polarizer 8a. The inclination angle θ was adjusted to 45 degrees, and the polarizer 8a was bonded with a light-transmitting epoxy resin. The inclination angle θ after bonding was 45.7 degrees. Here, the element size in which the quarter-wave plate (birefringent member 7) and the isolator portion 8 are bonded and integrated is 11 mm square, and chip processing is performed to 0.5 mm square with a dicing apparatus.

  The adhesive member composed of the birefringent member 7 and the isolator portion 8 produced in this way was bonded and fixed in the inner hole of the cylindrical magnet 5 with a translucent epoxy resin. The cylindrical magnet is a magnet made of samarium cobalt, designed to have an inner diameter of Φ0.8 mm, an outer diameter of Φ1.2 mm, smaller than the inner diameter of the sleeve, and a length of 0.6 mm, which is shorter than the adhesive member.

  On the other hand, an optical fiber in which a graded index fiber corresponding to the first lens function unit 6a is bonded to one end of a first optical fiber 3a made of quartz is a zirconia having an outer diameter of Φ1.25 mm and an inner diameter of 126 μm. It mounted in the through-hole of the cylindrical 1st holding member 2a which consists of. Further, a second holding member 2b having the above-described material and size and having an optical fiber mounted in the through hole was produced.

  Next, a quarter-wave plate and an isolator portion produced by chip processing at the center of the end of the graded index fiber (first lens function portion 6a) held by the first holding member 2a. These adhesive members were joined and inserted into the inner hole from the opening on one end side of the cylindrical zirconia sleeve 4. Further, the second holding member 2b is inserted from the other end side of the sleeve 4, and the end portion of the second holding member 2b and the above-mentioned adhesive member located at the longitudinal center portion of the sleeve 4 are bonded and fixed. The optical connector A was manufactured by sandwiching the first holding member 2 a and the second holding member 2 b with the sleeve 4.

  Moreover, the optical connector B which is a comparative example of the present invention is obtained by removing the quarter wavelength plate from the optical connector A which is an embodiment of the present invention, and the material and size of other members are the same as those of the optical connector A. A thing was used.

  In order to measure the incident polarization dependency of light with respect to the optical connectors A and B produced above, the light emitted from the semiconductor laser is converted into an arbitrary linearly polarized light by a polarization rotator composed of a half-wave plate. The polarization angle is changed in the range of 0 to 360 degrees and introduced into the first optical fiber, the light output from the second optical fiber 2b is measured with an optical power meter, and the power of the incident light is measured. The ratio (Pout / Pin) of the power of the emitted light, that is, the normalized transmission power P was measured, and the result is shown in FIG. In FIG. 4, the horizontal axis represents the incident light polarization angle α, and the vertical axis represents the normalized transmission power P.

  As shown in FIG. 4, since the optical connector B which is a comparative example of the present invention does not include the quarter wavelength plate (birefringent member 7), it is incident on a portion other than the light transmission axis of the polarizer 8a. While the linearly polarized light is blocked by the surface of the polarizer 8a and the normalized transmission power P varies from 0 to 1 depending on the polarization angle α of the incident light, the optical connector A of the present invention has the incident light polarization angle. Regardless of α, the normalized transmission power was almost constant.

  Furthermore, an optical connector C incorporating the conventional independent optical isolator shown in FIG. 6 was produced. The birefringent crystal plate used for the isolator part was a 1 mm square rutile crystal, and the components other than the isolator part were the same as those of the optical connector A of the present invention. Then, 10 optical connectors A and 10 optical connectors C were produced respectively, and the isolation characteristics were measured. As a result, all the samples of the optical connector A exhibited high isolation characteristics of 40 dB or more, whereas the conventional optical connector C varies in the range of 20 dB to 30 dB due to the influence of the return light in the cladding mode. The optical connector A of the invention was superior to the conventional optical connector incorporating the independent optical isolator in the isolation characteristics.

It is sectional drawing which shows embodiment of the optical connector of this invention. It is a perspective view which shows the structure of an isolator part. It is sectional drawing which shows other embodiment of this invention. It is the figure which measured the polarization dependence of the optical connector. It is a schematic diagram which shows the structure of the conventional polarization independent type optical isolator. It is sectional drawing which shows the conventional optical connector which incorporated the function of the polarization independent type optical isolator in the optical connector.

Explanation of symbols

1: optical connector 2: holding member 2a: first holding member 2b: second holding member 3: optical fiber 3a: first optical fiber 3b: second optical fiber 4: sleeve 5: magnet 6: lens function Part 6a: First lens function part 6b: Second lens function part 7: Birefringent member 8: Isolator part 10: Light beams 11, 12, 13: Birefringent crystal plate 14: Faraday rotator 15, 18: Optical fiber 16, 17: Lens 21: Core expansion fiber 23: Optical isolator element 24: Magnet 25: Holding member 26: Sleeve 27: Flange

Claims (3)

A first optical fiber, is introduced light derived from the first optical fiber, a second optical fiber optically coupled, and the first optical fiber and said second optical fiber An optical connector including an optical isolator provided therebetween, wherein the optical isolator has a light transmission axis, transmits a polarization component in one direction of incident light, and transmits light having a component orthogonal thereto. A first polarizer and a second polarizer having a function of absorbing, and a Faraday rotator provided between the first polarizer and the second polarizer. between the the fiber first polarizer, the light is incident is linearly polarized light, and having a C-axis that inclined 45 ± 5 degrees to the optical transmission axis of said first polarizer An optical connector comprising a quarter-wave plate . The optical connector according to claim 1, wherein the quarter-wave plate is formed integrally with the first polarizer. A first holding member for holding the inner bore of the first optical fiber, to claim 1 or 2, characterized in that it comprises a second holding member for holding the inner bore of the second optical fiber The optical connector described.

Images