CN211123362U - Novel single-shaft working isolator with high extinction ratio - Google Patents

Abstract

The utility model relates to the technical field of the structure of communication accessories, in particular to a novel single-shaft working isolator with high extinction ratio; the device comprises a first refraction crystal, a second refraction crystal and a Faraday rotator FR arranged between the first refraction crystal and the second refraction crystal; the Faraday rotator FR is a 45-degree Faraday rotator; the first refraction crystal and the second refraction crystal are of wedge-shaped structures, and the included angle of optical axes is 45 degrees; the first refraction crystal and the second refraction crystal are arranged in an inverted mode; and a magnetic tube is arranged around the outer side of the Faraday rotator FR and forms a magnetic field. The isolator of the utility model utilizes the optical crystal characteristic of the isolator to invert the original magnetic field direction, and enlarges the two polarization states of the output light by a separation angle, so that the two polarization states are not effectively parallel; or a single polarization crystal is arranged behind the two parallel beams, so that one path of polarized light is accurately received, and the extinction ratio can be greatly improved.

Description

Novel single-shaft working isolator with high extinction ratio

Technical Field

The utility model relates to a technical field of communication accessory's structure especially relates to a novel high extinction ratio unipolar work isolator.

Background

With the rapid development of high-speed, ultra-high-speed and ultra-wideband optical networks, the performance indexes of optical devices applied to optical fiber communication networks are more strict, and the requirements on performance parameters are higher. The polarization-maintaining isolator is an essential component of the optical fiber sensing system. Polarization maintaining devices face huge market potential, parameters of the polarization maintaining devices in the traditional process are generally common due to the structure of the polarization maintaining devices, especially extinction parameters of the polarization maintaining devices are generally only about 20dB, and the polarization maintaining devices have great defects and can not meet the requirements of special application fields.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a structural design is novel, through setting up single polarization crystal or drawing two bunches of polarized light beam's contained angles big, reuse polarization maintaining collimator carries out the accurate light of receiving polarization state wherein all the way, makes its purpose that reaches unipolar work, can realize high extinction ratio again, low insertion loss's polarization maintaining device of high standard requirement.

The utility model adopts the technical proposal that: a novel single-axis working isolator with high extinction ratio comprises a first refraction crystal, a second refraction crystal and a Faraday rotator FR arranged between the first refraction crystal and the second refraction crystal; the Faraday rotator FR is a 45-degree Faraday rotator; the first refraction crystal and the second refraction crystal are of wedge-shaped structures, and the included angle of optical axes is 45 degrees; the first refraction crystal and the second refraction crystal are arranged in an inverted mode; and a magnetic tube is arranged around the outer side of the Faraday rotator FR and forms a magnetic field.

Further, when the light beam is transmitted in the forward direction, after the light beam enters the first refraction crystal, the light beam is divided into O light and e light, the polarization directions of the O light and the e light are mutually vertical, and the transmission directions of the O light and the e light form an included angle; when O light and e light pass through a 45-degree Faraday rotator, the polarization surfaces of the emergent O light and the emergent e light respectively rotate 45 degrees clockwise, and because the optical axis of the second refraction crystal just forms a 45-degree included angle relative to the first refraction crystal, the O light and the e light are refracted by the second refraction crystal to form two parallel light beams with small space.

Further, when the light beam is transmitted reversely, the light beam firstly passes through the second refraction crystal, the light beam is divided into O light and e light, and the polarization plane of the O light and the optical axis of the first refraction crystal form an angle of 45 degrees;

at the moment, the rotation directions of the vibration surface of the O light and the vibration surface of the e light are determined by the magnetic induction intensity B, the vibration surfaces rotate clockwise by 45 degrees and rotate together by 90 degrees relative to the optical axis of the first refraction crystal, the whole reverse optical path equivalently passes through a Wollaston prism, and the included angle of two emergent linearly polarized light beams is increased.

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 of the isolator.

The light beam from the polarization-maintaining collimator irradiates into the isolator, and the direction of the light beam is the same as the direction of the magnetic field of the isolator, namely the light beam is transmitted in the positive direction; the light beams form two parallel beams after passing through the isolator, and the single-polarization crystal only allows one polarized light to pass through and filters other polarized lights;

and the light beam passing through the single polarization crystal is transmitted into a 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 of the isolator;

the light beam from the polarization-maintaining collimator irradiates into the isolator, and the direction of the light beam is opposite to the direction of the magnetic field of the isolator, namely the light beam is transmitted reversely; the light beam forms two beams of light with a large mutual included angle after passing through the isolator, and the polarization maintaining collimator is arranged behind the light beam to be received due to the fact that the included angle of the two beams of light is large and the transmission directions are different.

The isolator of the utility model utilizes the optical crystal characteristic of the isolator, inverts the original magnetic field direction through the non-reciprocity principle of the magneto-optical crystal, enlarges and separates the two polarization states of the output light, and does not effectively parallel the two polarization states; or a single polarization crystal is arranged behind the two beams of parallel light, and then a polarization-maintaining collimator is used for accurately receiving one path of light in a polarization state. The purpose of uniaxial work is achieved, and the extinction ratio can be greatly improved.

Drawings

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

FIG. 1 is a schematic structural diagram of a novel high extinction ratio single-axis isolator of the present invention;

FIG. 2 is a schematic structural diagram of the novel single-axis isolator with high extinction ratio for forward transmission of light beam;

fig. 3 is a schematic structural diagram of the novel high extinction ratio single-axis isolator during reverse transmission of light beams.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be implemented in other ways different from the specific details set forth herein, and one skilled in the art may similarly generalize the present invention without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

As shown in FIG. 1, the optical isolator is a passive device of optical nonreciprocal transmission, which is used to eliminate or suppress the reverse light generated in the optical fiber channel, and due to the existence of such reverse light, the self-coupling effect will be generated between the optical path systems, which makes the laser work unstable and generate the system reflection noise, and makes the optical amplifier on the optical fiber link change and generate self-excitation, which causes the whole optical fiber communication system to work abnormally.

The isolator in the utility model comprises a first refraction crystal P1, a second refraction crystal P2 and a Faraday rotator FR arranged between the first refraction crystal and the second refraction crystal P2; the Faraday rotator FR is a 45-degree Faraday rotator; the first refraction crystal P1 and the second refraction crystal P2 are wedge-shaped structures with the included angle of the optical axes being 45 degrees; the first refraction crystal P1 and the second refraction crystal P2 are arranged in an inverted mode; a magnetic tube C is arranged around the outer side of the faraday rotator FR, and forms a magnetic field.

As shown in fig. 2, it is a schematic structural diagram of the novel single-axis working isolator with high extinction ratio during forward transmission of light beam; when the light beam is transmitted in the forward direction, after the light beam enters the first refraction 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 mutually vertical, and the transmission directions of the O light and the e light form an included angle; when the O light and the e light pass through the 45-degree Faraday rotator, the polarization surfaces of the emergent O light and the e light rotate 45 degrees clockwise respectively, and because the optical axis of the second refraction crystal P2 just forms an included angle of 45 degrees relative to the first refraction crystal P1, the O light and the e light form two parallel light beams with small space after being refracted by the second refraction crystal P2.

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 of the isolator, and a single-polarization crystal P3 is further arranged in front of the polarization-maintaining collimator Z2 and the isolator;

the beam from the polarization-maintaining collimator Z1 enters the isolator, and the direction of the beam is the same as the direction of the magnetic field of the isolator, namely the beam is transmitted in the positive direction; the light beams form two parallel beams after passing through the isolator, and the single-polarization crystal P3 only allows one polarization light to pass through and filters other polarization light;

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

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

Fig. 3 is a schematic structural diagram of the novel single-axis working isolator with high extinction ratio when light beams are reversely transmitted; when the light beam reversely transmits, the light beam firstly passes through the second refraction 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 degrees with the optical axis of the first refraction crystal P1;

at this time, the rotation directions of the vibration plane of the O light and the vibration plane of the e light are determined by the magnetic induction B, the vibration plane rotates clockwise by 45 degrees, and rotates by 90 degrees together relative to the optical axis of the first refraction crystal P1, the whole reverse optical path is equivalent to pass through one woolly prism, and the included angle of the two outgoing linearly polarized light beams is increased.

The front end of the isolator is provided with a polarization-maintaining collimator Z1 ', and the rear end of the isolator is provided with a polarization-maintaining collimator Z2';

the beam from the polarization-maintaining collimator Z1' irradiates into the isolator, and the direction of the beam is opposite to the direction of the magnetic field of the isolator, namely, the beam is transmitted reversely; the light beams form two beams of light with a large mutual included angle after passing through the isolator, and the polarization maintaining collimator Z2' is arranged behind the beams to be received due to the large included angle and different transmission directions of the two beams of light.

Because the O light and the E light are basically overlapped and are difficult to separate when the traditional scheme device outputs light, only a polarized light can be obtained by utilizing a rear-end depolarization mode. In the mode, raw material components are additionally added, production difficulty is increased, the alignment requirement of the cat eye position of the optical fiber is increased, the extinction ratio is difficult to increase (the more positions aligned by the cat eye, the more position deviation is easily caused, the extinction ratio of a device is reduced), and the loss of the device is larger.

In the isolator of the utility model, two bundles of polarization states of outputting light are enlarged to separate the angle, and are not allowed to be effectively parallel. Thus, the polarization-maintaining collimator is used for accurately receiving one path of light in the polarization state. So that the single-shaft working purpose is achieved. And only one position in the optical path is used for aligning and debugging the cat eye, and the cat eye position is easy to perform high-quality accurate alignment, so that the aim of high extinction ratio is fulfilled. So that the device has better reliability and performance indexes. In addition, the grouped materials of the device are reduced, the operation is simple, and the production cost and the production efficiency are also greatly improved.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications and variations can be made in the embodiments or in part of the technical features of the embodiments without departing from the spirit and the scope of the invention.

Claims (5)

1. A novel single-shaft working isolator with high extinction ratio is characterized in that:

the isolator comprises a first refraction crystal, a second refraction crystal and a Faraday rotator FR arranged between the first refraction crystal and the second refraction crystal; the Faraday rotator FR is a 45-degree Faraday rotator; the first refraction crystal and the second refraction crystal are of wedge-shaped structures, and the included angle of optical axes is 45 degrees; the first refraction crystal and the second refraction crystal are arranged in an inverted mode; and a magnetic tube is arranged around the outer side of the Faraday rotator FR and forms a magnetic field.

2. The isolator as in claim 1, wherein:

when the light beam is transmitted in the forward direction, after the light beam enters the first refraction crystal, the light beam is divided into O light and e light, the polarization directions of the O light and the e light are mutually vertical, and the transmission directions of the O light and the e light form an included angle; when O light and e light pass through a 45-degree Faraday rotator, the polarization surfaces of the emergent O light and the emergent e light respectively rotate 45 degrees clockwise, and because the optical axis of the second refraction crystal just forms a 45-degree included angle relative to the first refraction crystal, the O light and the e light are refracted by the second refraction crystal to form two parallel light beams with small space.

3. The isolator as in claim 1, wherein:

when the light beam reversely transmits, the light beam firstly passes through the second refraction crystal, the light beam is divided into O light and e light, and the polarization plane of the O light and the optical axis of the first refraction crystal form an angle of 45 degrees;

at the moment, the rotation directions of the vibration surface of the O light and the vibration surface of the e light are determined by the magnetic induction intensity B, the vibration surfaces rotate clockwise by 45 degrees and rotate together by 90 degrees relative to the optical axis of the first refraction crystal, the whole reverse light path equivalently passes through a Wollow prism, and the included angle of two emergent linearly polarized light beams is increased.

4. The isolator as in claim 2, wherein:

the front end of the isolator is provided with a polarization-maintaining collimator, the rear end of the isolator is provided with a polarization-maintaining collimator, and a single polarization crystal is arranged in front of the polarization-maintaining collimator and the isolator;

the light beam from the polarization-maintaining collimator irradiates into the isolator, and the direction of the light beam is the same as the direction of the magnetic field of the isolator, namely the light beam is transmitted in the positive direction; the light beams form two parallel beams after passing through the isolator, and the single-polarization crystal only allows one polarized light to pass through and filters other polarized lights;

and the light beam passing through the single polarization crystal is transmitted into a polarization-maintaining collimator.

5. The isolator as in claim 3, wherein:

the front end of the isolator is provided with a polarization-maintaining collimator, and the rear end of the isolator is provided with a polarization-maintaining collimator;

the light beam from the polarization-maintaining collimator irradiates into the isolator, and the direction of the light beam is opposite to the direction of the magnetic field of the isolator, namely the light beam is transmitted reversely; the light beam forms two beams of light with a large mutual included angle after passing through the isolator, and the polarization maintaining collimator is arranged behind the light beam to be received due to the fact that the included angle of the two beams of light is large and the transmission directions are different.

Images