CN206788411U - Optical circulator - Google Patents

Abstract

The utility model relates to an optical circulator belongs to the optical fiber communication field. The optical circulator includes: the optical fiber collimator comprises a first optical fiber collimator, a second optical fiber collimator and an optical element arranged between the first optical fiber collimator and the second optical fiber collimator, wherein the optical element sequentially comprises a first birefringent crystal, a first wave plate, a first Faraday optical rotation sheet, a YVO4 wedge angle pair, a second Faraday optical rotation sheet, a second wave plate and a second birefringent crystal according to the placing sequence, the optical element is placed on a magnet base and used for providing a permanent magnetic field for the first Faraday optical rotation sheet and the second Faraday optical rotation sheet, the permanent magnetic field required by the first Faraday optical rotation sheet and the second Faraday optical rotation sheet can be directly provided through the magnet base by using the magnet base to replace a metal base, light spots of the first optical fiber collimator and the second optical fiber collimator are modulated to be 0.2mm, the sizes of the first birefringent crystal and the second birefringent crystal are correspondingly adjusted to be 1mm 5mm, and the production cost of the optical circulator is reduced, it is beneficial to the miniaturization and integration of the optical circulator.

Description

optical circulator

technical field

The utility model relates to the field of optical fiber communication, in particular to an optical circulator.

Background technique

Optical circulator is a multi-port (minimum three-port) irreversible passive device, its function is to transmit the light beam from one port to the adjacent port with the maximum intensity, while preventing the light beam from transmitting from one port to the previous port . The working principle of the optical circulator is based on the polarization-independent Faraday rotation effect.

Optical circulators enable optical signals to be transmitted only along specified port sequences. With the continuous development of optical fiber communication technology, it has become one of the important devices in the present and future optical fiber communication system. A three-port circulator is shown in FIG. 1 , wherein L1 is a first port, L2 is a second port, and L3 is a third port. When the optical signal is input from the specified port, it can only propagate in the specified order in the device. For example, when the optical signal is input from the first port L1, the propagation order of the optical signal is: L1→L2→L3; when the optical signal When the transmission sequence is changed, for example, when the optical signal is transmitted from the second port L2 to the first port L1, or when the optical signal is transmitted from the third port L3 to the second port L2, the loss of the optical signal will be very large, which can realize Isolation of optical signals. The non-reciprocal characteristic of the optical circulator is realized by using the Faraday effect of the magneto-optical material, and its principle is similar to that of the optical isolator. The Faraday effect refers to the phenomenon that the polarization plane of the electromagnetic wave (light wave) in the dielectric material rotates under the action of a magnetic field parallel to the direction of light propagation, and its rotation direction has nothing to do with the direction of light propagation, that is, polarization is independent. After the light wave passes through the first polarizer, it becomes polarized light. After the polarized light passes through the Faraday rotator, the polarization direction is rotated by 45°, parallel to the light passing direction of the second polarizer, and allowed to pass through; when the light transmits in the opposite direction, it passes through the Faraday rotator. Finally, the polarization direction of the light is perpendicular to the light passing direction of the first polarizer and cannot pass through. The optical circulator structure of the prior art usually consists of fiber collimators A1 and A2, birefringent crystals B1 and B2, YVO4 wedge angle pair C, wave plate D1 and wave plate D2 and Faraday optical plates E1 and E2, magnetic ring F1 and F2 composition, as shown in Figure 2.

When a beam of single incident light is refracted at the interface of isotropic media, there is only one beam of refracted light, thus obeying the law of refraction. However, when a single beam of light is refracted at the interface of an anisotropic crystal, two beams of refracted light can generally be produced, which is the phenomenon of birefringence. However, one of the two separated refracted rays always obeys the law of refraction. Regardless of the orientation of the incident beam, this refracted ray is always in the incident plane and the ratio of the sine of the angle of refraction to the sine of the angle of incidence is constant. The refracted light is called o-ray, and the other beam of refracted light is often not in the incident plane and does not obey the law of refraction even if the incident angle is zero. It is called extraordinary light, e-ray.

In addition, there is a specific direction in the crystal, and when light travels along this direction in the crystal, no birefringence occurs. This particular direction within the crystal is called the optical axis of the crystal.

If an analyzer is used to verify the polarization states of o-light and e-light produced by birefringence, it will be found that both o-light and e-light are linearly polarized light, and the electric vector of o-light is perpendicular to the main plane of o-light, therefore, Always perpendicular to the optical axis, the electric vector of e light is in the main plane of e, so the angle between it and the optical axis will change with the different propagation directions.

Due to the birefringence and displacement of the light passing through the birefringent crystal, and the two or three beam spots in the optical path of the optical circulator propagate together, and the most important thing is that the optical fiber collimator used in the conventional circulator has a large spot diameter , around 0.36mm, so that the effective light-passing area of the birefringent crystal is required to be larger. The crystal size of the conventionally used birefringent crystal is 2mm*2mm*7mm, which requires the size of other optical components in the entire optical circulator All increase accordingly, so that the outer seal size of the entire optical circulator is larger, and its conventional size is (￠5.5X50mm). Since the price of the crystal material for producing the optical circulator is relatively expensive, the production cost of the optical circulator is very high, and it is not conducive to the development of miniaturization and integration of optical communication system equipment.

Utility model content

In order to solve the related problems in the prior art, the utility model provides an optical circulator.

According to an aspect of an embodiment of the present invention, an optical circulator is provided, including a first fiber collimator, a second fiber collimator, and an optical element arranged between them, and the optical elements are placed in the order From left to right are the first birefringent crystal, the first wave plate, the first Faraday optical rotation plate, the YVO4 wedge angle pair, the second Faraday optical rotation plate, the second wave plate, and the second birefringent crystal. The optical elements are placed On the base, the base is a magnet base for providing a permanent magnetic field to the first Faraday optical rotator and the second Faraday optical rotator.

Optionally, the spot modulation of the first fiber collimator and the second fiber collimator is 0.2mm, and the size of the first birefringent crystal and the second birefringent crystal is 1mm*1mm* 5mm.

Optionally, the first birefringent crystal is integrated with the first wave plate, and the second birefringent crystal and the second wave plate are respectively deepened with optical glue.

Optionally, the first Faraday optical rotator and the YVO4 wedge angle pair, the second Faraday optical rotator and the YVO4 wedge angle pair are respectively deepened into one optical glue.

Optionally, the optical circulator is further provided with a sealing tube, and the sealing tube is used to encapsulate the optical element.

Optionally, the size of the optical circulator is ￠3.5X38mm.

The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

By using the magnet base instead of the metal base, the permanent magnetic field required for the first Faraday rotator and the second Faraday rotator can be provided directly through the magnet base, which reduces the optical components in the optical circulator. The processing steps of the optical circulator are reduced; in addition, the utility model modulates the light spots of the first optical fiber collimator and the second optical fiber collimator used in the optical circulator to 0.2mm, and the first birefringent crystal and the second optical fiber collimator The size of the two birefringent crystals is correspondingly adjusted to 1mm*1mm*5mm, which can reduce the effective area requirements for the birefringent crystal material in the optical circulator, save the production cost of the optical circulator, reduce the volume of the optical circulator, and improve the production process. Simplification is conducive to the miniaturization and integration of optical communication system equipment.

It should be understood that the foregoing general description and the following detailed description are exemplary only, and are not restrictive of the present invention.

Description of drawings

The accompanying drawings, which are incorporated in the specification and constitute a part of the specification, illustrate embodiments consistent with the present utility model, and are used together with the specification to explain the principle of the utility model.

Figure 1 is a schematic diagram of a three-port circulator.

Fig. 2 is a schematic diagram of an optical circulator in the prior art.

Fig. 3 is a schematic structural diagram of an optical circulator provided by an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

As shown in Figure 3, the embodiment of the present utility model provides an optical circulator, comprising a first optical fiber collimator 10, a second optical fiber collimator 20, and an optical element arranged between the two, said The optical components are placed in order from left to right as the first birefringent crystal 30, the first wave plate 40, the first Faraday optical rotation plate 50, the YVO4 wedge angle pair 60, the second Faraday optical rotation plate 70, the second wave plate 80, The second birefringent crystal 90, the optical element is placed on the pedestal 100, the pedestal is a magnet pedestal for providing permanent magnetic fields to the first Faraday optical rotator 50 and the second Faraday optical rotator 70 .

The Faradian optical rotator in the optical circulator needs a permanent magnetic field to work normally. The optical circulator provided by the prior art usually has a rectangular hole processed on the metal base, and the rectangular hole is used to place the magnetic ring. Through the magnetic ring, the Provide the permanent magnetic field required for the work of the Faraday optical rotator; the optical circulator provided by the utility model saves the design of the magnetic ring on the basis of the existing optical circulator, and uses a magnet base to replace the metal base and provides Faraday The permanent magnetic field required for the work of the optical rotator can save the processing of the rectangular hole on the base and the processing of the magnetic ring, and at the same time save the installation space of the optical components required inside the optical circulator.

In an embodiment of an optical circulator of the present utility model, the spot modulation of the first fiber collimator 10 and the second fiber collimator 20 is 0.2mm, and the first birefringent crystal 30 and the The size of the second birefringent crystal 90 is 1mm*1mm*5mm.

The spot diameter of the optical fiber collimator used in the circulator provided by the prior art is relatively large, about 0.36mm, so that the effective light-passing area of the birefringent crystal is required to be larger, and the crystal size of the conventionally used birefringent crystal is 2mm. *2mm*7mm, which requires the size of other optical components in the entire optical circulator to be increased accordingly, so that the outer seal size of the entire optical circulator is larger, and its conventional size is (￠5.5X50mm).

The light spot diameters of the first optical fiber collimator and the second optical fiber collimator provided by the utility model are significantly smaller than the light spot diameters of the optical fiber collimator in the circulator provided by the prior art, so that the optical signal travels through the birefringent crystal. The cross section is also smaller, which can reduce the size of the first birefringent crystal and the second birefringent crystal correspondingly, reduces the requirement of the optical circulator on the effective area of the birefringent crystal material, and saves the production cost of the optical circulator.

In an embodiment of an optical circulator of the present invention, the first birefringent crystal 30 and the first wave plate 40, the second birefringent crystal 90 and the second wave plate 80 are respectively deepened Light glue as a whole.

In an embodiment of an optical circulator of the present utility model, the first Faraday optical rotator 50 and the YVO4 wedge angle pair 60, the second Faraday optical rotator 70 and the YVO4 wedge angle pair 60 are respectively deepened Light glue as a whole.

In an embodiment of the optical circulator of the present invention, the optical circulator is further provided with a sealing tube, and the sealing tube is used to encapsulate the optical element.

It should be noted that the sealing tube can be made of a ceramic tube or a glass tube.

In an embodiment of the optical circulator of the present utility model, the size of the optical circulator is ￠3.5X38mm.

To sum up, the optical circulator provided by the utility model can directly provide the permanent magnetic field required by the first Faraday optical rotator and the second Faraday optical rotator through the magnet base instead of the metal base. , which reduces the occupied space of the optical elements in the optical circulator, and reduces the processing steps of the optical circulator; in addition, the utility model uses the light spots of the first optical fiber collimator and the second optical fiber collimator used in the optical circulator The modulation is 0.2mm, and the size of the first birefringent crystal and the second birefringent crystal is adjusted to 1mm*1mm*5mm, which can reduce the effective area requirement of the birefringent crystal material in the optical circulator and save the optical circulator The production cost of the optical ring device is reduced, and the production process is simplified, which is conducive to the miniaturization and integration of optical communication system equipment.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (6)

1. An optical circulator, characterized in that: comprising a first fiber collimator, a second fiber collimator, and optical elements arranged between the two, said optical elements are placed in order from left to right It is the first birefringent crystal, the first wave plate, the first Faraday optical rotation plate, the YVO4 wedge angle pair, the second Faraday optical rotation plate, the second wave plate, and the second birefringent crystal, and the optical element is placed on the base, The base is a magnet base for providing a permanent magnetic field to the first Faraday optical rotator and the second Faraday optical rotator. 2. The optical circulator according to claim 1, wherein the spot modulation of the first fiber collimator and the second fiber collimator is 0.2mm, and the first birefringent crystal and the The size of the second birefringent crystal is 1mm*1mm*5mm. 3. The optical circulator according to claim 1, wherein the first birefringent crystal and the first wave plate, the second birefringent crystal and the second wave plate respectively deepen the optical glue as one. 4. The optical circulator according to claim 1, wherein the first Faraday optical rotator and the YVO4 wedge angle pair, the second Faraday optical rotator and the YVO4 wedge angle pair respectively deepen the optical glue as one. 5. The optical circulator according to claim 1, characterized in that, the optical circulator is further provided with a sealing tube, and the sealing tube is used to encapsulate the optical element. 6. The optical circulator according to claim 1, wherein the size of the optical circulator is ￠3.5X38mm.