CN211123362U - A Novel High Extinction Ratio Uniaxial Working Isolator - Google Patents

Abstract

The utility model relates to the technical field of the structure of communication accessories, and in particular discloses a novel high extinction ratio uniaxial working isolator, which comprises a first refraction crystal, a second refraction crystal, and is disposed between the first refraction crystal and the second refraction crystal. The Faraday rotator FR; the Faraday rotator FR is a 45° Faraday rotator; the first refractive crystal and the second refractive crystal are wedge-shaped structures with an optical axis angle of 45 degrees; and the first refractive crystal and The second refracting crystals are arranged upside down to each other; a magnetic tube is arranged around the outer side of the Faraday rotator FR, and the magnetic tube forms a magnetic field. The isolator of the utility model utilizes the optical crystal characteristics of the isolator itself to invert the original magnetic field direction, and the polarization state of the two beams of the output light is enlarged to separate the angle so as to prevent them from being effectively parallel; A single-polarization crystal is installed after the parallel light to accurately receive the light of one of the polarization states, which can greatly improve the extinction ratio.

Description

A Novel High Extinction Ratio Uniaxial Working Isolator

technical field

The utility model relates to the technical field of the structure of communication accessories, in particular to a novel high extinction ratio uniaxial working isolator.

Background technique

With the rapid development of high-speed, ultra-high-speed, and ultra-broadband optical networks, the performance indicators of optical devices used in optical fiber communication networks are more stringent, and the performance parameters are required to be higher. The polarization-maintaining isolator is an indispensable basic component of the optical fiber sensing system. The polarization-maintaining device is facing huge market potential. Due to its structural reasons, the parameters of the traditional polarization-maintaining device are generally relatively common, especially in its general extinction parameter, which is usually only about 20dB, which has great defects and cannot be used at all. Meet special application areas.

Utility model content

The purpose of the utility model is to provide a novel structure design, by setting a single polarized crystal or increasing the angle between two polarized beams, and then using a polarization-maintaining collimator to accurately receive one of the polarized light rays, so as to achieve a single polarized light beam. For the purpose of shaft work, it can also achieve high extinction ratio, low insertion loss and high standard polarization-maintaining devices.

The technical scheme adopted by the utility model is: a novel high extinction ratio uniaxial working isolator, the isolator comprises a first refraction crystal, a second refraction crystal, and is arranged between the first refraction crystal and the second refraction crystal The Faraday rotator FR; the Faraday rotator FR is a 45° Faraday rotator; the first refractive crystal and the second refractive crystal are wedge-shaped structures with an optical axis angle of 45 degrees; and the first refractive crystal and The second refracting crystals are arranged upside down to each other; a magnetic tube is arranged around the outer side of the Faraday rotator FR, and the magnetic tube forms a magnetic field.

Further, when the light beam is transmitted in the forward direction, after the light beam enters the first refracting crystal, the light beam is divided into O light and e light, and the polarization directions of the O light and the e light are perpendicular to each other, and their propagation directions are in the shape of a clamp. When the O light and the e light pass through the 45° Faraday rotator, the polarization planes of the outgoing O light and the e light are rotated 45° clockwise respectively, because the optical axis of the second refracting crystal is just in the direction of the first refracting crystal. At an included angle of 45°, after the O light and the e light are refracted by the second refracting crystal, two parallel light beams with a small distance are formed.

Further, when the light beam is transmitted in reverse, the light beam first passes through the second refracting crystal, and the light beam is divided into O light and e light, and the polarization plane of the O light forms an angle of 45° with the optical axis of the first refracting crystal. ;

At this time, the rotation direction of the vibration surface of the O light and the vibration surface of the e light is determined by the magnetic induction intensity B, the vibration surface rotates 45° clockwise, and rotates 90° relative to the optical axis of the first refracting crystal. The road is equivalent to passing through a Wollaston prism, which increases the angle between the two linearly polarized lights that emerge.

Further, a polarization-maintaining collimator is arranged at the front end of the isolator, and a polarization-maintaining collimator is arranged at the rear end, and the polarization-maintaining collimator is arranged.

The beam from the polarization-maintaining collimator is irradiated into the isolator, and the direction of the beam is the same as the direction of the magnetic field of the isolator, that is, forward transmission; the beam passes through the isolator to form two parallel beams, so The single-polarization crystal allows only one polarized light to pass through and filters other polarized light;

The light beam passing through the single polarization crystal is transmitted into the polarization maintaining collimator.

Further, a polarization-maintaining collimator is arranged at the front end of the isolator, and a polarization-maintaining collimator is arranged at the rear end;

The beam from the polarization-maintaining collimator is irradiated into the isolator, and the direction of the beam is opposite to the direction of the magnetic field of the isolator, that is, the direction of transmission is reversed; Since the two beams have a large angle and different transmission directions, the polarization-maintaining collimator is arranged behind the beam to be received.

The isolator of the utility model utilizes the optical crystal characteristics of the isolator itself, through the principle of non-reciprocity of the magnetic optical rotatory crystal, inverts the original magnetic field direction, and widens the separation angle of the two beam polarization states of the output light , do not allow it to be effectively paralleled; or set a single-polarization crystal after the two parallel beams, and then use a polarization-maintaining collimator to accurately receive one of the polarized lights. To achieve the purpose of single-axis operation, the extinction ratio can be greatly improved.

Description of drawings

The present utility model will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Fig. 1 is the structural representation of a novel high extinction ratio uniaxial working isolator of the present invention;

2 is a schematic structural diagram of a novel high extinction ratio uniaxial working isolator of the present utility model when the light beam is transmitted in the forward direction;

3 is a schematic structural diagram of a novel high extinction ratio uniaxial working isolator of the present invention when the light beam is transmitted in reverse.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the implementations. example. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

In the following description, many specific details are set forth in order to fully understand the present utility model, but the present utility model can also be implemented in other ways different from those described herein, and those skilled in the art can do so without departing from the connotation of the present utility model. Therefore, the present invention is not limited by the specific embodiments disclosed below.

As shown in Figure 1, it is a schematic structural diagram of a novel high extinction ratio uniaxial working isolator of the present invention; the optical isolator is a passive device for optical non-reciprocal transmission, which is used to eliminate or suppress the fiber channel Due to the existence of this kind of reverse light, the self-coupling effect will occur between the optical path systems, which will make the laser work unstable and generate system reflection noise, which will change the optical amplifier on the fiber link. and self-excitation, causing the entire optical fiber communication system to fail to work properly. If an optical isolator is connected to the output end of the semiconductor laser and the input or output end of the optical amplifier, the influence of the reflected light on the LD can be reduced.

The isolator in the present application includes a first refracting crystal P1, a second refracting crystal P2, and a Faraday rotator FR disposed between the first refracting crystal and the second refracting crystal P2; the Faraday rotator FR is a 45° Faraday a rotator; the first refraction crystal P1 and the second refraction crystal P2 are wedge-shaped structures with an optical axis angle of 45 degrees; and the first refraction crystal P1 and the second refraction crystal P2 are set upside down with each other; in the Faraday A magnetic tube C is arranged around the outer side of the rotator FR, and the magnetic tube C forms a magnetic field.

As shown in FIG. 2, it is a schematic structural diagram of a novel high extinction ratio uniaxial working isolator of the present invention when the light beam is transmitted in the forward direction; when the light beam is transmitted in the forward direction, after the light beam enters the first refracting crystal P1, The light beam is divided into O light and e light, the polarization directions of the O light and the e light are perpendicular to each other, and their propagation directions are at an included angle; when the O light and the e light pass through the 45° Faraday rotator, the emitted O light and The polarization planes of the e light are rotated clockwise by 45°. Since the optical axis of the second refracting crystal P2 is at an angle of 45° with respect to the first refracting crystal P1, the O light and the e light are refracted by the second refracting crystal P2. After that, two parallel beams with a small distance are formed.

A polarization-maintaining collimator Z1 is arranged at the front end of the isolator, a polarization-maintaining collimator Z2 is arranged at the rear end, and a single-polarization crystal P3 is also arranged before the polarization-maintaining collimator Z2 and the isolator;

The beam from the polarization-maintaining collimator Z1 is irradiated into the isolator, and the direction of the beam is the same as the direction of the magnetic field of the isolator, that is, forward transmission; the beam passes through the isolator to form two parallel beams, The single-polarization crystal P3 only allows one kind of polarized light to pass through, and filters other polarized light;

The light beam passing through the single-polarization crystal P3 is transmitted into the polarization-maintaining collimator Z2.

Therefore, when the light beam is transmitted in the forward direction, through the setting of the single-polarization crystal P3, when the two parallel beams pass through the single-polarization crystal P3, only one beam of light is retained, other beams are filtered out, and the extinction ratio is higher.

As shown in FIG. 3, it is a structural schematic diagram of a novel high extinction ratio uniaxial working isolator of the present invention when the beam is transmitted in reverse; when the beam is transmitted in reverse, the beam first passes through the second refracting crystal P2, The light beam is divided into O light and e light, and the polarization plane of the O light forms an angle of 45° with the optical axis of the first refracting crystal P1;

At this time, the rotation direction of the vibration surface of the O light and the vibration surface of the e light is determined by the magnetic induction intensity B, the vibration surface rotates 45° clockwise, and rotates 90° relative to the optical axis of the first refracting crystal P1, the entire The reverse light path is equivalent to passing through a Worcestershire prism, which increases the angle between the two linearly polarized light beams.

A polarization-maintaining collimator Z1' is arranged at the front end of the isolator, and a polarization-maintaining collimator Z2' is arranged at the rear end;

The beam from the polarization-maintaining collimator Z1' is irradiated into the isolator, and the direction of the beam is opposite to the direction of the magnetic field of the isolator, that is, it is transmitted in the opposite direction; the beams pass through the isolator to form a larger angle with each other Since the two beams of light have a large angle and different transmission directions, the polarization-maintaining collimator Z2' is arranged behind the beam to be received.

Because the O light and the E light basically overlap when the light is output by the traditional solution device, it is difficult to separate, so only one kind of polarized light can be obtained by depolarizing the back end. However, this method requires additional raw material components, which increases the difficulty of production, and increases the alignment requirements of the optical fiber cat's eye position, making it difficult to increase the extinction ratio (the more places where the cat's eye is aligned, the easier it is to cause positional deviation, reduce the extinction ratio of the device), and the device loss is also too large.

In the isolator of the present invention, the polarization states of the two beams of the output light are widened and separated by an angle, so that they cannot be effectively paralleled. In this way, the polarization-maintaining collimator is used to accurately receive the light of one of the polarization states. It can achieve the purpose of single-axis work. In addition, there is only one spot in the optical path to adjust the alignment of the cat's eye, and it is easy to perform high-quality accurate alignment at the position of the cat's eye, thus achieving the purpose of high extinction ratio. This makes the reliability and performance of the device better. In addition, the group material of the device is reduced, the operation is simple, and the production cost and production efficiency are also greatly improved.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still understand the foregoing. The technical solutions recorded in each embodiment are modified, or some technical features thereof are equivalently replaced. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included in the present utility model. within the scope of the new protection.

Claims (5)

1. a novel high extinction ratio uniaxial working isolator is characterized in that: The isolator includes a first refracting crystal, a second refracting crystal, and a Faraday rotator FR disposed between the first refracting crystal and the second refracting crystal; the Faraday rotator FR is a 45° Faraday rotator; A refracting crystal and a second refracting crystal are wedge-shaped structures with an optical axis angle of 45 degrees; the first refracting crystal and the second refracting crystal are set upside down with each other; a magnetic tube is arranged around the outside of the Faraday rotator FR , the magnetic tube forms a magnetic field. 2. The isolator according to claim 1, wherein: When the light beam is transmitted in the forward direction, after the light beam enters the first refracting crystal, the light beam is divided into O light and e light, the polarization directions of the O light and the e light are perpendicular to each other, and their propagation directions form an included angle; When the light and e light pass through the 45° Faraday rotator, the polarization planes of the outgoing O light and e light are rotated 45° clockwise respectively, because the optical axis of the second refracting crystal is exactly 45° with respect to the first refracting crystal. , after the O light and the e light are refracted by the second refracting crystal, two parallel light beams with a small distance are formed. 3. The isolator according to claim 1, wherein: When the light beam is transmitted in reverse, the light beam first passes through the second refracting crystal, the light beam is divided into O light and e light, and the polarization plane of the O light forms an angle of 45° with the optical axis of the first refracting crystal; At this time, the rotation direction of the vibration surface of the O light and the vibration surface of the e light is determined by the magnetic induction intensity B, the vibration surface rotates 45° clockwise, and rotates 90° relative to the optical axis of the first refracting crystal. The path is equivalent to passing through a Worcestershire prism, which increases the angle between the two linearly polarized lights that emerge. 4. The isolator according to claim 2, wherein: A polarization-maintaining collimator is arranged at the front end of the isolator, a polarization-maintaining collimator is arranged at the rear end, and a single-polarization crystal is also arranged before the polarization-maintaining collimator and the isolator; The beam from the polarization-maintaining collimator is irradiated into the isolator, and the direction of the beam is the same as the direction of the magnetic field of the isolator, that is, forward transmission; the beam passes through the isolator to form two parallel beams, so The single-polarization crystal allows only one polarized light to pass through and filters other polarized light; The light beam passing through the single polarization crystal is transmitted into the polarization maintaining collimator. 5. The isolator according to claim 3, wherein: A polarization-maintaining collimator is arranged at the front end of the isolator, and a polarization-maintaining collimator is arranged at the rear end; The beam from the polarization-maintaining collimator is irradiated into the isolator, and the direction of the beam is opposite to the direction of the magnetic field of the isolator, that is, the direction of transmission is reversed; Since the two beams have a large angle and different transmission directions, the polarization-maintaining collimator is arranged behind the beam to be received.

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