CN113009653A

CN113009653A - Light emitting assembly

Info

Publication number: CN113009653A
Application number: CN202110266599.3A
Authority: CN
Inventors: 宋小飞; 廖传武; 李志超; 王志文
Original assignee: Dalian Youxun Technology Co Ltd; Wuhan Qianxi Technology Co ltd
Current assignee: Dalian Youxinguang Technology Co ltd
Priority date: 2020-12-11
Filing date: 2020-12-11
Publication date: 2021-06-22
Anticipated expiration: 2040-12-11
Also published as: CN113009653B; CN112230354A; CN112230354B

Abstract

The present disclosure provides a light emitting assembly. The light emitting module includes: the laser component semiconductor laser chip is arranged at the focus position of the first lens and enables the semiconductor laser chip to deviate from the axis of the optical path by a first preset included angle, so that reflected light reflected by the first lens cannot reach a laser area of the semiconductor laser chip; a first lens having a first focal length greater than or equal to a predetermined focal length threshold configured to reduce a proportion of reflected light reflected via the first lens reaching the semiconductor laser chip; the optical isolator at least comprises a magnetic unit, a polarizer, a polaroid and an analyzer, wherein the polaroid is used for rotating the polarization direction of light input by the polarizer or emitted light reflected by the analyzer, and the included angle between the light passing axis of the polarizer and the light passing axis of the analyzer is a second preset included angle; and a second lens. The present disclosure can reduce relative intensity noise caused by reflected light.

Description

Light emitting assembly

The present application is a divisional application of the chinese patent application having an application date of 12/11/2020 and an application number of 202011436068.6 entitled "light emitting assembly and method for packaging a light emitting assembly".

Technical Field

Embodiments of the present disclosure relate generally to the field of fabrication of light emitting assemblies configured with semiconductor laser chips, and more particularly, to a light emitting assembly and method for packaging a light emitting assembly.

Background

With the increase in the speed of fifth generation communication systems, high speed communication devices formed of light emitting modules equipped with semiconductor laser chips are widely used.

The optical path of a conventional light emitting module employs, for example, a semiconductor laser chip combined with a single lens structure or a double lens structure. There is a certain proportion of light reflection phenomenon more or less during the packaging process of the above-mentioned conventional light emitting assembly. Spontaneous radiation is generated when the reflected light enters the semiconductor laser chip. In spontaneous emission, each atom is independent of each other in a spontaneous transition process, and spontaneous emission light generated by different atoms has certain randomness in frequency, phase, polarization direction and propagation direction, and the light is fatal to the performance degradation of a semiconductor laser chip. Therefore, how to reduce the influence of the reflected light is crucial to the packaging of high-speed lasers. Particularly, for high-power lasers, for example, according to the requirement of 5G high-power lasers, the relative intensity noise of the laser needs to be controlled to be-165 dB to-170 dB, and the reflected light causes the phenomenon of relative intensity noise increase.

In summary, the above-mentioned conventional packaging scheme for light emitting devices has a disadvantage of increasing relative intensity noise caused by reflected light.

Disclosure of Invention

The present disclosure provides a light emitting module capable of reducing relative intensity noise caused by reflected light.

According to a first aspect of the present invention, there is also provided a light emitting assembly, the apparatus comprising: the laser assembly comprises a semiconductor laser chip and a heat sink, wherein the semiconductor laser chip is arranged on the heat sink and is arranged at the focus position of the first lens, and the semiconductor laser chip deviates from the axis of the optical path by a first preset included angle, so that the reflected light reflected by the first lens cannot reach the laser area of the semiconductor laser chip; a first lens for converting a laser beam output by the semiconductor laser chip into parallel light, the first lens having a first focal length, the first focal length being greater than or equal to a predetermined focal length threshold, the predetermined focal length threshold being configured to reduce a proportion of reflected light reflected via the first lens reaching the semiconductor laser chip; the optical isolator is arranged between the first lens and the second lens and at least comprises a magnetic unit, a polarizer, a polaroid and an analyzer, wherein the magnetic unit is used for providing a magnetic field, the polaroid is used for rotating the polarization direction of light input by the polarizer or emitted light reflected by the analyzer, and the included angle between the light passing axis of the polarizer and the light passing axis of the analyzer is a second preset included angle; and a second lens for converging the parallel light output through the optical isolator; and an optical fiber for receiving the light condensed by the second lens, the optical fiber being disposed at a focal position of the second lens.

According to a second aspect of the present disclosure, there is provided a method of packaging a light emitting assembly, the method comprising: soldering a semiconductor laser chip over a heat sink in a housing to form a laser assembly; fixing the laser assembly on the backing plate; sucking a first lens having a first focal length via a suction device for disposing the semiconductor laser chip at a predetermined position on a first side of the first lens, the suction device being disposed on a six-axis displacement adjusting device, the first lens for converting a laser beam output from the semiconductor laser chip into parallel light, the first focal length being configured to be greater than or equal to a predetermined focal length threshold so as to reduce a proportion of reflected light reflected via the first lens reaching the semiconductor laser chip; acquiring a light spot image formed by parallel light output by the first lens through a light beam analysis device; based on the size of the light spot image, the position of the suction device is adjusted through a six-axis displacement adjusting device, so that the semiconductor laser chip is adjusted from a preset position to the focus position of the first lens, and the semiconductor laser chip deviates from the axis of the light path by a first preset included angle; the second side of the first lens is sequentially fixed with an optical isolator and a second lens, the optical isolator at least comprises a magnetic unit, a polarizer, a polaroid and an analyzer, the magnetic unit is used for providing a magnetic field, the polaroid is used for rotating the polarization direction of forward light path light output by the polarizer in the magnetic field and the polarization direction of reverse light path light reflected by the analyzer, the included angle between the light passing axis of the polarizer and the light passing axis of the analyzer is a second preset included angle, and the second lens is used for converging parallel light output by the optical isolator; and clamping the optical fiber via a clamp so as to adjust and fix a position of the optical fiber to a focal position of the second lens.

In some embodiments, the first predetermined included angle is 3 degrees such that the spot size variation measured by the beam analysis device at a first position from the first lens and a second position from the first lens, respectively, is less than a predetermined deviation threshold.

In some embodiments, the laser assembly includes a plurality of semiconductor laser chips, each of the plurality of semiconductor laser chips being disposed at a focal position of a corresponding one of the plurality of first lenses and offset from the corresponding optical path axis by the first predetermined angle, the light emitting assembly further including: an aggregator for aggregating the plurality of parallel lights converted by the plurality of first lenses into a bundle of parallel lights, the optical isolator being disposed between the aggregator and the second lens; and a thermistor attached at a predetermined detection position of the heat sink for detecting a temperature of the heat sink, the predetermined detection position being adjacent to the semiconductor laser chip.

In some embodiments, the polarizer is a faraday rotator that rotates linearly polarized light input via the polarizer or emitted light reflected via the analyzer by 45 degrees, and the second predetermined angle is 45 degrees.

In some embodiments, the predetermined focus threshold is 0.6 mm.

In some embodiments, the first predetermined angle is 3 degrees such that a change in spot size measured by the beam analysis device at a first location from the first lens and a second location from the first lens, respectively, is less than a predetermined deviation threshold, the polarizers comprise a first polarizer and a second polarizer, the analyzer comprises a first analyzer disposed between the first polarizer and the second polarizer, and a second analyzer disposed on the other side of the second polarizer.

In some embodiments, the faraday rotation in the first and second polarizers occurs in opposite directions.

In some embodiments, in the forward light path, forward incident light passes through a first analyzer via polarized light rotated 45 ° in a first polarizer, then the polarized light is rotated 45 ° by a second polarizer in a direction opposite to the direction of rotation produced by the first polarizer, and the rotated polarized light is output to an optical isolator via a second analyzer, the polarization direction of the outgoing light from the isolator being parallel to the polarization direction of the incident light.

In some embodiments, adjusting the position of the suction device via a six-axis displacement adjustment device for setting the semiconductor laser chip at the focal position of the first lens includes: extracting first light spot profile data and first center coordinate data of the first light spot image, and extracting second light spot profile data and second center coordinate data of the second light spot image; calculating size change data of the first light spot and the second light spot based on the first light spot profile data and the second light spot profile data; calculating coordinate change data of the first center coordinate data and the second center coordinate data; determining whether the change of the second light spot relative to the first light spot meets a predetermined condition based on the size change data and the coordinate change data; in response to determining that the change in the second spot relative to the first spot does not comply with a predetermined condition, outputting displacement data for adjusting the position of the extraction means via a six-axis displacement adjustment means; in response to determining that the change of the second light spot relative to the first light spot meets a predetermined condition, determining the position of the first lens corresponding to the current position of the suction device as the fixed position of the first lens; controlling the suction device to lift the first lens away from the fixed position so as to coat the UV glue at the fixed position; and controlling the suction device to lower the first lens so as to fix the first lens at a fixed position.

Drawings

The above and other objects, features and advantages of the embodiments of the present disclosure will become more readily understood through the following detailed description with reference to the accompanying drawings. In the drawings, various embodiments of the present disclosure will be described by way of example and not limitation.

Fig. 1 shows a schematic diagram of a system for implementing a method for packaging a light emitting assembly according to an embodiment of the present disclosure.

Fig. 2 shows a flow diagram of a method for packaging a light emitting assembly according to an embodiment of the present disclosure.

Fig. 3 shows a schematic diagram of the gaussian beam radius transmitted in free space.

FIG. 4 illustrates a functional diagram of an optical isolator according to an embodiment of the present disclosure.

FIG. 5 shows a schematic diagram of an optical isolator according to another embodiment of the present disclosure.

Fig. 6 shows a schematic diagram of an optical path model in the case where the semiconductor laser chip and the first lens are out of focus.

Fig. 7 shows a schematic diagram of an optical path model before and after a semiconductor laser chip is deviated from an optical path axis.

Fig. 8 shows a schematic diagram of an optical path model of a semiconductor laser chip at a focal position of a first lens of different focal lengths.

Fig. 9 illustrates a collimated spot image according to an embodiment of the disclosure.

Fig. 10 illustrates a relative intensity noise plot for a conventional approach for packaging light emitting assemblies.

Fig. 11 illustrates a relative noise diagram for a method for packaging a light emitting assembly according to an embodiment of the present disclosure.

Fig. 12 shows a flow chart of a method for setting a first lens position according to an embodiment of the present disclosure.

Fig. 13 illustrates a schematic structural view of a light emitting assembly according to an embodiment of the present disclosure.

Fig. 14 illustrates a schematic structural view of an array type light emitting assembly according to an embodiment of the present disclosure.

FIG. 15 schematically illustrates a block diagram of a computing device 1500 suitable for use to implement embodiments of the present disclosure.

Detailed Description

Preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The term "include" and variations thereof as used herein is meant to be inclusive in an open-ended manner, i.e., "including but not limited to". Unless specifically stated otherwise, the term "or" means "and/or". The term "based on" means "based at least in part on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first," "second," and the like may refer to different or the same object.

As described above, in the conventional packaging scheme of the light emitting module, the reflected light enters the semiconductor laser chip to generate spontaneous radiation. The deterioration of the performance of the semiconductor laser chip by the spontaneous emission is fatal, and the reflected light causes an increase in the relative intensity noise of the laser.

To address, at least in part, one or more of the above problems and other potential problems, example embodiments of the present disclosure propose a method for packaging a light emitting assembly. The scheme comprises the following steps: soldering a semiconductor laser chip over a heat sink in a housing to form a laser assembly; fixing the laser assembly on the backing plate; sucking a first lens having a first focal length via a suction device for disposing the semiconductor laser chip at a predetermined position on a first side of the first lens, the suction device being disposed on a six-axis displacement adjusting device, the first lens for converting a laser beam output from the semiconductor laser chip into parallel light, the first focal length being configured to be greater than or equal to a predetermined focal length threshold so as to reduce a proportion of reflected light reflected via the first lens reaching the semiconductor laser chip; acquiring a light spot image formed by parallel light output by the first lens through a light beam analysis device; based on the size of the light spot image, the position of the suction device is adjusted through a six-axis displacement adjusting device, so that the semiconductor laser chip is adjusted from a preset position to the focus position of the first lens, and the semiconductor laser chip deviates from the axis of the light path by a first preset included angle; the second side of the first lens is sequentially fixed with an optical isolator and a second lens, the optical isolator at least comprises a magnetic unit, a polarizer, a polaroid and an analyzer, the magnetic unit is used for providing a magnetic field, the polaroid is used for rotating the polarization direction of forward light path light output by the polarizer in the magnetic field and the polarization direction of reverse light path light reflected by the analyzer, the included angle between the light passing axis of the polarizer and the light passing axis of the analyzer is a second preset included angle, and the second lens is used for converging parallel light output by the optical isolator; and clamping the optical fiber via a clamp so as to adjust and fix a position of the optical fiber to a focal position of the second lens.

In the above scheme, through setting up the semiconductor laser chip in focus department that the focus is greater than or equal to the first lens of predetermined focus threshold value, this disclosure can make the light that reflects back through first lens less enter into the active area of semiconductor laser chip, and then avoid the interference that the reverberation caused to laser emission. In addition, through the size based on the parallel light facula that first lens exported, via the position of six displacement adjusting device regulation suction means, and then make the semiconductor laser chip adjusted to the focus position department of first lens and make the semiconductor laser chip deviate the first predetermined contained angle of light path axis, this disclosure can further make the light that reflects back through lens can not enter into the chip active area owing to the angle of the first predetermined contained angle of semiconductor laser chip, and then reduce the interference that causes the transmission, can not cause the reduction of coupling efficiency simultaneously. Moreover, the polaroid is used for rotating the polarization direction of the forward light path light output by the polarizer in the magnetic field and rotating the polarization direction of the reverse light path light reflected by the analyzer, so that the reflected and returned light beam can be isolated from the light path after being rotated by the polaroid, and the light passing through the optical isolator is prevented from returning to the chip to form spontaneous radiation to influence the quality of the light beam because of the original reflection path. Accordingly, the present disclosure can reduce relative intensity noise caused by reflected light.

Fig. 1 shows a schematic diagram of a system 100 for implementing a method for packaging a light emitting assembly according to an embodiment of the present disclosure. As shown in fig. 1, the system 100 includes: the semiconductor laser chip 110, the heat sink 112, the backing plate 114, the thermistor 116, the housing (not shown), the extracting device 120, the six-axis displacement adjusting device 122, the first lens 130, the beam analyzing device 140, the optical isolator 150 (the optical isolator 150 includes the magnetic unit 152, the polarizer 154, the polarizing plate 156, and the analyzer 158), the second lens 160, the clamp (not shown), and the optical fiber 170.

As for the semiconductor laser chip 110 for outputting a laser beam, the semiconductor laser chip is disposed over the heat sink 112. Since the threshold current increases exponentially with the increase in the temperature of the active region and the electro-optic conversion efficiency decreases exponentially with the increase in the temperature of the active region, temperature control of the active region of a semiconductor laser chip is an important issue for high-power lasers. Temperature control of the active region can be facilitated by reducing the thermal resistance between the active region and the cooling medium.

As for the heat sink 112, it is disposed inside a housing (not shown).

As for the thermistor 116, the thermistor 116 is attached at a predetermined detection position of the heat sink, which is adjacent to the semiconductor laser chip 110, by using silver epoxy glue. Based on the detection data of the thermistor 116, the temperature of the heat sink 112 is adjusted. For example, the computing device outputs a control instruction for lowering the refrigerator temperature if it is confirmed that the detection data of the thermistor 116 is greater than or equal to a predetermined temperature threshold.

As for the backing plate 114, a laser assembly composed of the semiconductor laser chip 110 and the heat sink 112 is fixed thereon.

With regard to the suction device 120, it is used to suck the first lens 130 having the first focal length for adjusting the semiconductor laser chip to a fixed position at the first side of the first lens 130. The suction device 120 is provided on a six-axis displacement adjustment device 122.

With respect to the six-axis displacement adjusting means 122, the suction means 120 is provided thereon. By adjusting the position of the suction device 120 of the six-axis displacement adjusting device 122, the first lens 130 sucked by the suction device 120 can be driven to move, for example, so that the semiconductor laser chip 110 is finally located at the focal position of the first lens 130 and the semiconductor laser chip deviates from the optical path axis by a first predetermined angle.

Regarding the first lens 130 for converting the laser beam output by the semiconductor laser chip into parallel light, the first lens has a first focal length, the first focal length is greater than or equal to a predetermined focal length threshold, and the predetermined focal length threshold is configured to reduce a proportion of reflected light reflected via the first lens reaching the semiconductor laser chip.

A beam analyzing device 140 for acquiring a first spot image formed at a first position by the parallel light output from the first lens 130; and acquiring a second spot image formed at a second position by the parallel light output by the first lens 130. And the distance between the second position and the first lens is greater than that between the first position and the first lens.

As the computing device, it is, for example, a computer shown in fig. 1. The computing device is used for generating displacement data based on the size change of the light spot (such as the change of the diameter of the light spot and/or the change of the center coordinate of the light spot) in the first light spot image and the second light spot image acquired by the light beam analysis device 140, and controlling the six-axis displacement adjusting device to adjust the position of the suction device so as to enable the size change of the second light spot relative to the first light spot to meet a preset condition. If the computing device is able to determine that the change in size of the second spot relative to the first spot meets a predetermined condition, the position of the extracted first lens 130 corresponding to the current position of the extraction means 120 is determined to be the fixed position of the first lens. In some embodiments, the computing device may have one or more processing units, including special purpose processing units such as GPUs, FPGAs, ASICs, and general purpose processing units such as CPUs. In addition, one or more virtual machines may be running on each management device.

With respect to the optical isolator 150, which is disposed between the first lens 130 and the second lens 160, the optical isolator 150 includes at least a magnetic element 152, a polarizer 154, a polarizing plate 156, and an analyzer 158. The magnetic unit 152 is configured to provide a magnetic field, and the polarizer 156 is configured to rotate a polarization direction of light input through the polarizer or the emitted light reflected by the analyzer, wherein an angle between a pass-light axis of the polarizer and a pass-light axis of the analyzer is a second predetermined angle.

As for the second lens 160, it serves to condense the parallel light output through the isolator.

As for the clamp, it is used for clamping the optical fiber so as to adjust and fix the position of the optical fiber to the focal position of the second lens so as to encapsulate the light emitting assembly.

Regarding the optical fiber 170 for receiving the light condensed via the second lens, the optical fiber is disposed at a focal position of the second lens.

A method 200 for packaging a light emitting assembly will be described below in conjunction with fig. 2. Fig. 2 shows a flow diagram of a method 200 for packaging a light emitting assembly according to an embodiment of the present disclosure. It should be understood that the method 200 may be performed, for example, at the system 100 depicted in fig. 1. It should be understood that method 200 may also include additional acts not shown and/or may omit acts shown, as the scope of the disclosure is not limited in this respect.

At step 202, a semiconductor laser chip is soldered over a heat sink in a housing to form a laser assembly. For example, prior to step 202, a refrigerator (TEC) is first mounted to the bottom of the tubular housing using silver epoxy glue; then, attaching the base plate to a refrigerator by using epoxy silver adhesive; and welding the semiconductor laser chip on the heat sink by using a chip eutectic device so as to form the laser assembly.

At step 204, the laser assembly is secured to the backing plate. The formed laser assembly is attached to a backing plate using, for example, silver epoxy glue. Then, the thermistor and other components can be attached to the corresponding position of the heat sink by using epoxy silver adhesive. Then, the elements and the bonding pads of the leads of the tubular shell are connected by gold wires by using gold wire bonding equipment.

In step 206, a first lens having a first focal length is suctioned via a suction device for disposing the semiconductor laser chip at a predetermined position on a first side of the first lens, the suction device being disposed on a six-axis displacement adjustment device, the first lens being for converting a laser beam output by the semiconductor laser chip into parallel light, the first focal length being configured to be greater than or equal to a predetermined focal length threshold so as to reduce a proportion of reflected light reflected via the first lens reaching the semiconductor laser chip.

For example, a special suction device is used to suck the first lens, and the position of the suction device is adjusted by a precise six-axis displacement adjusting table, so that the first lens is controlled to move in the directions of up and down, left and right, front and back, and the like.

With respect to the configuration of the first focal length of the first lens, it has been found through research that the use of the first lens with a proper focal length can ensure higher coupling efficiency and lower reflection of the laser area. The focal length of the conventionally used first lens is generally about 0.2mm, and if the first lens with longer focal length is used, the reflected light can be more difficult to enter the laser area of the semiconductor laser chip, however, the too long focal length of the first lens can cause the reduction of the coupling efficiency. The research shows that the first lens with the focal length of more than 0.2mm, especially about 0.6mm, can enable the light emitting component to have lower laser area reflection, and meanwhile, the coupling efficiency can reach more than 92%. Thus, the relative intensity noise caused by the reflected light can be reduced while obtaining a high coupling efficiency.

In step 208, a spot image formed by the parallel light output by the first lens is obtained through the beam analysis device. For example, a beam analysis device is disposed on a side of the first lens away from the semiconductor laser chip to collect a spot image formed by parallel light output by the first lens. For example, the optical power of the semiconductor laser chip is 100mW, and whether the spot quality after passing through the first lens (collimator lens) satisfies the predetermined condition may be determined based on the collected data of the beam analyzing apparatus. In some embodiments, the light beam analysis device is a light beam image acquisition device, such as a CMOS camera, or a CCD camera, which sends the acquired light spot image to the computing device, which analyzes the light spot image. In some embodiments, the beam analysis apparatus itself has a computing unit, and can analyze the acquired spot image to output data such as spot size and coordinates, and can send the data such as spot size and coordinates to a computing device for adjusting the position of the first lens.

The output light beam of the semiconductor laser chip is paraxial wave, the energy of the light beam gradually diverges along the direction of the axis Z, and the distribution is Gaussian light beam. Fig. 3 shows a schematic diagram of a gaussian beam radius 300 transmitted in free space. As shown in FIG. 3, W₀Representing the gaussian beam radius at the position where Z is 0, where the beam width is smallest, called the beam waist position. At a position where Z is Z0, the Gaussian beam radius W (Z) is

Multiple of W₀。

The following describes a case where the amplitude distribution characteristic of the light beam changes according to the gaussian function law with reference to equation (1). Equation (1) shows an expression of a gaussian beam.

In the above formula (1), r represents a radial coordinate with the optical axis center point as a reference. Z represents an axial coordinate with reference to the narrowest light wave (beam waist position) on the optical axis. W (z) represents the spot radius at which the amplitude drops to 1/e of the maximum. W₀The representation represents the gaussian beam radius at Z-0, i.e. the beam waist width of the laser. E₀Representing the intensity of the initial laser light.

For a Gaussian beam transmitted in free space, the radius of a spot at the position of the beam waist is larger than the width W of the beam waist in the optical axis direction₀. The distribution of the positions of the waist spots on the z-axis for a light wave with a wavelength λ is described below with reference to equation (2).

In the above formula (2), λ represents the wavelength of light waves. W₀Representing the beam waist width of the laser. W (z) represents the spot radius at which the amplitude drops to 1/e of the maximum. Z represents an axial coordinate with reference to the narrowest light wave (beam waist position) on the optical axis. z is a radical of_RRepresenting the rayleigh distance. The Rayleigh distance z is described below in conjunction with equation (3)_RThe calculation method of (1).

Therefore, the size of the spot of the free-space transmitted gaussian beam at different positions can be known by the above formula. In the method for packaging the light emitting component, the laser beam emitted by the semiconductor laser chip forms parallel light through the first lens, the beam analysis device collects a light spot image formed by the converted parallel light in the current actual light path (namely, the laser beam output by the semiconductor laser chip is converted into the parallel light through the first lens) through an actual measurement mode, and the light spot image is used for adjusting the light spot size of the collected light spot image in the subsequent stepThe relative position of the whole semiconductor laser chip and the first lens.

In step 210, the position of the suction device is adjusted via the six-axis displacement adjustment device based on the spot size of the spot image, so as to adjust the semiconductor laser chip from a predetermined position to a focus position of the first lens and to deviate the semiconductor laser chip from the optical path axis by a first predetermined angle.

With regard to the arrangement of the semiconductor laser chip deviating from the optical path axis by the first predetermined angle, it has been found through research that the defocusing phenomenon between the semiconductor laser chip and the first lens is unavoidable during the actual packaging process of the light emitting module. The light path model in the out-of-focus condition between the semiconductor laser chip and the first lens is illustrated below in conjunction with fig. 6. Fig. 6 shows a schematic diagram of an optical path model 600 with the semiconductor laser chip and the first lens out of focus. The upper and lower portions of fig. 6 exemplarily show two defocus cases, respectively. The optical path model 600 includes, for example, a semiconductor laser chip (not shown), a first lens 604, an optical isolator 606, a second lens 610, and an optical fiber 612. In the upper part of fig. 6, the position of the outgoing light from the semiconductor laser chip is shifted from the focal position 608 of the first lens 604, for example, at the position 602-1. The light emitted from the semiconductor laser chip is finally converged to a position shown by 614-1 through the first lens 604, the optical isolator 606 and the second lens 610. In the lower half of fig. 6, the position of the outgoing light from the semiconductor laser chip is shifted from the focal position of the first lens 604, for example, at the position 602-2. The emergent light of the semiconductor laser chip is finally converged to the position shown by 614-2 through the first lens, the optical isolator and the second lens. The occurrence of the defocusing condition can cause reflected light to enter a laser area of the semiconductor laser chip, and further the semiconductor laser chip is interfered to emit light to generate noise.

The manner in which the semiconductor laser chip is caused to deviate from the optical path axis by a first predetermined angle is described below in conjunction with fig. 7. Fig. 7 shows a schematic diagram of an optical path model 700 before and after a semiconductor laser chip is offset from an optical path axis. The upper part of fig. 7 shows the case where the semiconductor laser chip 702 and the first lens 710 are on the same optical path axis. The laser light 706 emitted from the semiconductor laser chip 702 passes through the first lens 710 and then forms parallel light. The reflected light 708-1 reflected by the first lens 710 reaches the laser region 704-1 of the semiconductor laser chip. It has been found that the diameter of the laser region 704-1 or 704-2 of a semiconductor laser chip is typically about 2 μm. Therefore, the first lens and the semiconductor laser chip form the first preset included angle on the basis of ensuring the sufficient coupling efficiency, so that the reflected light is prevented from entering the laser area of the semiconductor laser chip.

The lower half of fig. 7 shows the semiconductor laser chip 702 offset from the optical path axis 712 by a first predetermined angle. At this time, the reflected light 708-2 reflected by the first lens cannot reach the laser region 704-2 of the semiconductor laser chip. Thus, the relative intensity noise caused by the reflected light entering the laser region of the semiconductor laser chip is reduced. In some embodiments, the semiconductor laser chip at the focal position is adjusted to be deviated from the optical path axis by an angle of 3 °, which not only ensures high coupling efficiency, but also reduces relative intensity noise caused by the reflected light entering the laser region of the semiconductor laser chip.

For example, if the beam analysis apparatus is able to receive an elliptical spot of very good gaussian diameter. And calculating the change ratio of the light spots at different positions according to the characteristics of the Gaussian light beams transmitted in the free space and the principle thereof indicated by the formula and the light spot images formed at different positions by the converted parallel light in the current actual light path and actually acquired by the light beam analysis device. Methods related to calculating the spot variation ratio at different positions include, for example: the computing equipment extracts image characteristics of light spot images (actually acquired by the light beam analysis device) corresponding to different positions so as to determine light spot profile data and center coordinate data of the light spot images; then calculating the spot diameters of the spot images corresponding to different positions based on the spot profile data; then, a change ratio of the spot diameter between different positions is calculated based on the calculated spot diameter of the spot image. For example, the conventional image data processing method is adopted as a determination method of the spot profile data, and details thereof are not repeated here. By testing and calculating that the ratio of the change in spot diameter at 10cm (where the position 10cm from the first lens is determined to be related to the size of the light emitting element) to the change in spot diameter at 100cm (where the position 100cm from the first lens is determined by testing to better balance the collimation characteristics of the remotely transmitted parallel light) needs to be less than 0.005, a predetermined deviation threshold of 0.005 is determined, the spot sizes at the first position (e.g., at 10 cm) and at the second position 100cm can be measured by the beam analysis device, respectively, and then it is determined whether the spot center deviation is less than or equal to the predetermined deviation threshold based on the spot size, e.g., the measured spot diameter change ratio is 0.003 and less than the predetermined deviation threshold of 0.005 (e.g., the change ratio threshold). If less than the predetermined deviation threshold, it indicates that the position of the semiconductor laser chip is at the focal position of the first lens and that the collimating effect is good. The focal length of the first lens is configured to be greater than or equal to a predetermined focal length threshold so as to reduce a proportion of reflected light reflected via the first lens reaching the semiconductor laser chip.

The semiconductor laser chip at the focal position is then adjusted to be at an angle of 3 ° off the optical path axis and still have the spot size variation measured by the beam analysis device at the first position (e.g., 10 cm) and at the second position 100cm, respectively, less than a predetermined deviation threshold. The current position of the first lens can be determined to be a fixed position for the package. A method for setting the semiconductor laser chip at the focal position of the first lens will be described below with reference to fig. 12, and will not be described herein again.

Fig. 8 shows a schematic diagram of an optical path model 800 for a semiconductor laser chip off the optical path axis at a focal position of a first lens of different focal lengths. The upper half of fig. 8 shows a case where the semiconductor laser chip off the optical path axis is at the focal point of the first lens 810-1 having a smaller focal length. The lower half of fig. 8 shows a case where the semiconductor laser chip off the optical path axis is at the focal point of the first lens 810-2 having a larger focal length. The larger focal length is configured to be greater than or equal to a predetermined focal length threshold, for example, to make it more difficult for reflected light to enter the laser region of the semiconductor laser chip. As shown in fig. 8, a semiconductor laser chip with a longer focal length (e.g., about 0.6 mm) combined with a first lens 810-2 that is offset from the optical path axis can achieve lower laser area reflection. For example, the effect of reflected light 808-2 on laser region 804-2 of the semiconductor laser chip is significantly less than the effect of reflected light 808-1 on laser region 804-1 of the semiconductor laser chip.

After the semiconductor laser chip is adjusted to the focus position of the first lens from the preset position and deviates from the optical path axis by a first preset included angle, the position of the suction device is controlled by the six-axis displacement adjusting device to lift the first lens, then special UV glue is coated below the first lens, the suction device is controlled to lower the first lens to the focus position of the first lens, and then the UV light source is used for curing the glue.

In step 212, after the position of the first lens is fixed, an optical isolator and a second lens are sequentially fixed on the second side of the first lens, the optical isolator at least comprises a magnetic unit, a polarizer, a polaroid and an analyzer, the magnetic unit is used for providing a magnetic field, the polaroid is used for rotating the polarization direction of forward light path light output by the polarizer and the polarization direction of reverse light path light reflected by the analyzer in the magnetic field, the included angle between the light passing axis of the polarizer and the light passing axis of the analyzer is a second preset included angle, and the second lens is used for converging parallel light output by the optical isolator.

The optical isolator is fixed between the first lens and the second lens mainly for improving the beam quality and reducing the influence of the reflected light on the laser signal. The function of the optical isolator is explained below in conjunction with fig. 4 and 5.

The optical isolator is fixed between the first lens and the second lens, so that light passing through the optical isolator can be prevented from returning to the semiconductor laser chip due to reflection, spontaneous radiation is formed, and the quality of the light beam is prevented from being influenced.

FIG. 4 illustrates a functional diagram of an optical isolator according to an embodiment of the present disclosure. The left and right parts of fig. 4 illustrate the operation of the optical isolator 400 in the forward and reverse optical paths, respectively. As shown in fig. 4, the optical isolator 400 includes, for example, a magnetic cell 410, a polarizer 420, a polarizer plate 430, and an analyzer 440. The polarizer plate 430 is bonded between the polarizer 420 and the analyzer 440. The polarizing plate 430 is, for example and without limitation, a faraday rotator prepared from an yttrium iron garnet single crystal. The magnetic unit 410 is, for example, a magnetic ring. The polarizing plate 430 functions to rotate the polarization direction of forward path light output via the polarizer and to rotate the polarization direction of reverse path light reflected via the analyzer in the magnetic field. The rotation angle at which the polarizing plate 430 is rotated is described below with reference to formula (4).

θ＝VLB (4)

In the above formula (4), θ represents the rotation angle by which the polarizing plate 430 is rotated. V represents a verdet constant. The verdet constant is generally related to the properties of the medium, the frequency of the light wave and the temperature. L represents the thickness of the polarizing plate 430. B represents the magnetic field strength provided by the magnet unit 410. In some embodiments, the polarization direction of the polarizer 420 must be the same as the polarization direction of the output light of the semiconductor laser chip during the assembly of the optical isolator.

For example, in the forward path, see the left half of FIG. 4, the polarization direction of polarizer 420 is 0. Light 402 (the optical path direction of the emitted light is shown, for example, as 412-1) from the semiconductor laser chip passes through the polarizer 420 of 0 ° without loss, and the optical path direction when passing through the polarizer 420 is shown, for example, as 412-2. The rotation angle of the polarizing plate 430 is set to 45 °, for example, the polarizing plate 430 rotates the polarization direction of the output light of the semiconductor laser chip clockwise by 45 °, and the optical path direction when passing through the polarizing plate 430 is, for example, as shown by reference 412-3, the same as the polarization direction of the analyzer 440, and thus can pass through the analyzer 440 with low loss.

In the reverse optical path, see right half of fig. 4, the reflected light 406, after passing through the analyzer, is rotated 45 ° and after passing through the polarizer and rotated 45 °, the optical path direction of the reflected light becomes 90 ° vertical as shown by reference 412-4. The polarization direction of the polarizer is 0 °. The vertical 90-degree light path direction is perpendicular to the polarization direction of the 0-degree polarizer, so that reflected light is prevented from passing through, and performance degradation of the semiconductor laser chip caused by the reflected light can be avoided.

In some embodiments, the light emitting assembly is configured with a dual stage optical isolator. The two-stage optical isolator is, for example, a 4-chip two-stage optical isolator, or a 5-chip two-stage optical isolator. FIG. 5 shows a schematic diagram of an optical isolator according to another embodiment of the present disclosure. As shown in fig. 5, the 4-piece dual stage optical isolator includes a magnetic element 510, and a first polarizing plate 520 (e.g., a first faraday rotator), a first analyzer 530, a second polarizing plate 540 (e.g., a second faraday rotator), and a second analyzer 550, which are sequentially disposed. Wherein the magnetic element applies a magnetic field of the same direction to the first polarizer and the second polarizer, for example, and faraday rotation is generated in the opposite direction in the first polarizer 520 and the second polarizer 540. For example, in the forward optical path, forward incident light 502 passes through the first analyzer 530 via polarized light that is rotated by 45 ° in the first polarizer, and then is rotated by 45 ° by the second polarizer 540 in a direction opposite to the direction of rotation produced by the first polarizer 520. The rotated polarized light then outputs the optical isolator via the second analyzer 550. The polarization direction of the outgoing light 504 from the isolator is parallel to the polarization direction of the incoming light 502.

In the reverse path, the polarization direction of the reverse light becomes, for example, 90 ° vertical after the reflected light 506 passes through the second analyzer 550, and is rotated by 45 ° by the second polarizer 540. The vertically 90 ° polarized light cannot pass in the reverse direction and is perpendicular to the polarization direction of the incident light of the optical isolator 500. Therefore, the influence on the emitted laser light of the semiconductor laser chip can be reduced. By adopting the double-stage optical isolator, the noise caused by reflected light can be reduced better.

As for the manner of fixing the second lens, the second lens may be fixed using, for example, a special glue. For example, as shown in fig. 1, light emitted from the semiconductor laser chip of the present disclosure is changed into parallel light by a first lens (collimator lens), and then is converged into an optical fiber by a second lens (focus lens). By adopting the double-lens structure of the first lens and the second lens, the coupling efficiency of the light emitting component is high. For example, the simulated coupling efficiency of the double-lens structure can reach more than 95%, the coupling efficiency realized by the actual process can reach 80%, the simulated coupling efficiency of the single-lens structure is only 85%, and the coupling efficiency realized by the actual process is only 65%.

At step 214, the optical fiber is clamped via a clamp so that the position of the optical fiber is adjusted and fixed to the focal position of the second lens.

For example, the optical fiber can be clamped by using a clamp, the position of the optical fiber can be finely adjusted by the control of the equipment, the optimal position of the optical fiber, namely the focal position of the second lens, can be found, the light of the laser can enter the optical fiber to the maximum extent, and then the optical fiber is fixed by means of laser welding so as to package the light emitting component.

The technical effect of the present disclosure in reducing the relative intensity noise caused by reflected light is explained below in conjunction with fig. 10 and 11. Fig. 10 illustrates a relative intensity noise plot 1000 for a conventional approach for packaging light emitting assemblies. Fig. 10, for example, indicates a display interface of a measurement result of relative intensity noise of the noise measuring apparatus with respect to the light emitting module packaged by the conventional packaging method. Fig. 11, for example, indicates a display interface of a measurement result of relative intensity noise of a noise measuring device with respect to a light emitting module packaged by the packaging method of the present disclosure. As shown in FIG. 10, the peak 3.2GH is indicated at reference numeral 1002_ZThe relative noise RIN of a point is high. Fig. 11 illustrates a relative noise diagram 1100 of a method for packaging a light emitting assembly according to an embodiment of the disclosure. As shown in FIG. 11, the relative intensity noise of the packaged light emitting assembly is-169 dB/Hz, and the predetermined requirement of less than-165 dB/Hz is met. And the coupling efficiency can still meet more than 80%. Therefore, the present disclosure can not only reduce the technical effect in terms of relative intensity noise caused by reflected light, but also ensure higher coupling efficiency.

A method for bringing the semiconductor laser chip to the focal position of the first lens will be described below with reference to fig. 12. Fig. 12 shows a flow diagram of a method 1200 for setting a first lens position according to an embodiment of the present disclosure. It should be understood that the method 1200 may be performed, for example, at the system 100 depicted in fig. 1 (e.g., at a computing device included with the system 100). It should be understood that method 1200 may also include additional acts not shown and/or may omit acts shown, as the scope of the disclosure is not limited in this respect.

At step 1202, a first spot image formed at a first position by parallel light output by a first lens collected by a beam analysis device is acquired at a computing device.

In step 1204, the computing device obtains a second spot image formed by the parallel light output by the first lens at a second position collected by the beam analysis apparatus, wherein the second position is farther from the first lens than the first position.

In step 1206, first spot profile data and first center coordinate data of the first spot image are extracted, and second spot profile data and second center coordinate data of the second spot image are extracted.

In step 1208, the computing device calculates size change data for the first and second spots based on the first and second spot profile data.

In step 1210, the computing device calculates coordinate change data for the first center coordinate data and the second center coordinate data.

At step 1212, it is determined whether the variation of the second spot relative to the first spot meets a predetermined condition based on the dimensional variation data and the coordinate variation data.

If the computing means determines that the variation of the second spot relative to the first spot does not comply with the predetermined condition, displacement data is output to adjust the position of the extraction means via the six axis displacement adjustment means, step 1214.

If the change of the second light spot relative to the first light spot is determined to meet the predetermined condition, the position of the first lens corresponding to the current position of the suction device is determined as the fixed position of the first lens, step 1216.

After determining the fixed position of the first lens, the computing apparatus controls the suction device to lift the first lens from the fixed position to apply the UV glue at the fixed position, step 1218.

At step 1220, the computing device controls the suction device to lower the first lens to secure the first lens at a fixed position.

By adopting the above means, the present disclosure can automatically perform the collimation and fixation of the first lens.

Fig. 13 illustrates a schematic structural diagram of a light emitting assembly 1300 according to an embodiment of the present disclosure. As shown in fig. 13, the light emitting assembly 1300 includes, for example: a housing 1310, a semiconductor laser chip 1316, a heat sink 1304, a backing plate 1306, a first lens 1314, an optical isolator 1302, a second lens 1320, an optical fiber 1324. Transmission assembly 1300 also includes a refrigerator 1308, a thermistor 1318, a component 1312, and a metal piece 1322.

Regarding the first lens 1314 for converting the laser beam output by the semiconductor laser chip 1316 into parallel light, the first lens 1314 has a first focal length, which is greater than or equal to a predetermined focal length threshold configured to reduce a proportion of reflected light reflected via the first lens reaching the semiconductor laser chip 1316. In some embodiments, the first lens that is most reflective is placed on the refrigerator 1308 to prevent the film system from shifting due to temperature changes at high and low temperatures to cause high relative intensity noise.

With respect to the semiconductor laser chip 1316, it is disposed over the heat sink 1304, and the semiconductor laser chip 1316 is disposed at the focal position of the first lens 1314 and is such that the semiconductor laser chip is offset from the optical path axis by light of a first predetermined angle.

Regarding the optical isolator 1302, which is disposed 1320 between the first lens 1318 and the second lens, the optical isolator 1302 includes at least a magnetic unit for providing a magnetic field, a polarizer for rotating a polarization direction of light input via the polarizer or emitted light reflected via the analyzer, and an angle between an optical pass axis of the polarizer and an optical pass axis of the analyzer is a second predetermined angle.

As for the second lens 1320, it is used to condense the parallel light output through the isolator. Regarding the optical fiber 1324 for receiving the light condensed through the second lens 1320, the optical fiber 1324 is disposed at a focal position of the second lens 1320.

Fig. 14 illustrates a schematic structural view of an array type light emitting assembly 1400 according to an embodiment of the present disclosure. As shown in fig. 14, the array type light emitting assembly 1400 includes, for example: a housing 1410, a plurality of semiconductor laser chips 1412, a heat sink 1414, a backing plate 1416, a refrigerator 1418, a thermistor 1420, a plurality of first lenses 1422, an aggregator 1424, a displacement lens 1426, an optical isolator (not shown), a second lens (not shown), a metal piece 1428 and optical fibers 1430, and a flexible circuit board 1432. Only some of the components are shown in fig. 14. Each of the plurality of semiconductor laser chips is disposed at a focal position of a corresponding one of the plurality of first lenses and offset from the corresponding optical path axis by a first predetermined angle.

As for the aggregator 1424 for aggregating the plurality of parallel lights converted by the plurality of first lenses 1422 into one bundle of parallel lights, the optical isolator is disposed between the aggregator and the second lens.

With respect to the shift lens 1426, it is configured to translate a bundle of parallel light converged by the condenser 1424 so as to make the translated parallel light enter the optical fiber 1430 via an optical isolator (not shown) and a second lens (not shown). With the optical isolator and second lens disposed, for example, inside metal piece 1428. In some embodiments, the arrayed light emitting assembly 1400 may be provided with a plurality of optical isolators, and the plurality of optical isolators are respectively disposed between the plurality of first lenses 1422 and the aggregator 1424, in order to further reduce relative intensity noise caused by reflected light.

As for the thermistor 1420, it is attached at a predetermined detection position of the heat sink for detecting the temperature of the heat sink, the predetermined detection position being adjacent to the semiconductor laser chip.

With respect to the flexible circuit board 1432, it is used to provide power and signals to the plurality of semiconductor laser chips 1412.

FIG. 15 schematically illustrates a block diagram of a computing device 1500 suitable for use to implement embodiments of the present disclosure. Device 1500 may be a device for implementing the operations performed in method 1200 shown in FIG. 12. As shown in fig. 15, the device 1500 includes a Central Processing Unit (CPU)1501 that can perform various appropriate actions and processes in accordance with computer program instructions stored in a Read Only Memory (ROM)1502 or loaded from a storage unit 1508 into a Random Access Memory (RAM) 1503. In the RAM1503, various programs and data necessary for the operation of the device 1500 can also be stored. The CPU 1501, the ROM 1502, and the RAM1503 are connected to each other by a bus 1504. An input/output (I/O) interface 1505 is also connected to bus 1504.

Various components in device 1500 connect to I/O interface 1505, including: an input unit 1506, an output unit 1507, a storage unit 1508, and a processing unit 1501 execute the respective methods and processes described above, for example, the method 1200. For example, in some embodiments, the method 1200 may be implemented as a computer software program stored on a machine-readable medium, such as the storage unit 1208. In some embodiments, part or all of the computer program may be loaded and/or installed onto the device 1500 via the ROM 1502 and/or the communication unit 1509. When the computer program is loaded into RAM1503 and executed by CPU 1501, one or more of the operations of method 1200 described above may be performed. Alternatively, in other embodiments, CPU 1501 may be configured in any other suitable manner (e.g., by way of firmware) to perform one or more acts of method 1200.

The computer-readable program instructions described herein may be downloaded from a computer-readable storage medium to a respective computing/processing device, or to an external computer or external storage device via a network, such as the internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. The network adapter card or network interface in each computing/processing device receives computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in the respective computing/processing device.

The computer program instructions for carrying out operations of the present disclosure may be assembler instructions, Instruction Set Architecture (ISA) instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider). In some embodiments, the electronic circuitry that can execute the computer-readable program instructions implements aspects of the present disclosure by utilizing the state information of the computer-readable program instructions to personalize the electronic circuitry, such as a programmable logic circuit, a Field Programmable Gate Array (FPGA), or a Programmable Logic Array (PLA).

These computer-readable program instructions may be provided to a processor in a voice interaction device, a processing unit of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processing unit of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer-readable program instructions may also be stored in a computer-readable storage medium that can direct a computer, programmable data processing apparatus, and/or other devices to function in a particular manner.

Having described embodiments of the present disclosure, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

The above are merely alternative embodiments of the present disclosure and are not intended to limit the present disclosure, which may be modified and varied by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A light emitting assembly comprising:

a laser assembly including a semiconductor laser chip and a heat sink, the semiconductor laser chip being disposed over the heat sink and being disposed at a focal position of the first lens and being offset from the optical path axis by a first predetermined angle such that reflected light reflected by the first lens does not reach a lasing region of the semiconductor laser chip;

a first lens for converting a laser beam output by the semiconductor laser chip into parallel light, the first lens having a first focal length, the first focal length being greater than a predetermined focal length threshold configured to reduce a proportion of reflected light reflected via the first lens reaching the semiconductor laser chip;

the optical isolator is arranged between the first lens and the second lens and at least comprises a magnetic unit, a polarizer, a polaroid and an analyzer, wherein the magnetic unit is used for providing a magnetic field, the polaroid is used for rotating the polarization direction of light input by the polarizer or emitted light reflected by the analyzer, and the included angle between the light passing axis of the polarizer and the light passing axis of the analyzer is a second preset included angle; and

a second lens for condensing the parallel light output through the optical isolator;

an optical fiber for receiving the light condensed by the second lens, the optical fiber being disposed at a focal position of the second lens.

2. The light emitting assembly of claim 1, wherein the first predetermined included angle is 3 degrees such that a change in spot size measured by the light beam analyzing device at a first location from the first lens and at a second location from the first lens, respectively, is less than a predetermined deviation threshold.

3. A light emitting assembly as claimed in claim 1 wherein the laser assembly includes a plurality of semiconductor laser chips, each of the plurality of semiconductor laser chips being disposed at a focal position of a corresponding one of the plurality of first lenses and offset from the corresponding optical path axis by the first predetermined angle, the light emitting assembly further comprising: an aggregator for aggregating the plurality of parallel lights converted by the plurality of first lenses into a bundle of parallel lights, the optical isolator being disposed between the aggregator and the second lens; and

and the thermistor is attached at a preset detection position of the heat sink and used for detecting the temperature of the heat sink, and the preset detection position is close to the semiconductor laser chip.

4. The light emitting assembly of claim 3, wherein the light emitting assembly is an arrayed light emitting assembly, the light emitting assembly further comprising:

and the shifting lens is used for translating a beam of parallel light converged by the aggregator so as to enable the translated parallel light to enter the optical fiber through the optical isolator and the second lens, and the optical isolators are multiple and are respectively arranged between the first lenses and the aggregator.

5. The light emitting assembly of claim 1, wherein the polarizer is a faraday rotator that rotates linearly polarized light input via the polarizer or emitted light reflected via the analyzer by 45 degrees, and the second predetermined angle is 45 degrees.

6. The light emitting assembly of claim 1, wherein the predetermined focal length threshold is 0.6 mm.

7. The light-emitting assembly of claim 1, wherein the first predetermined angle is 3 degrees such that a change in spot size measured by the beam analysis device at a first location from the first lens and a second location from the first lens, respectively, is less than a predetermined deviation threshold, the polarizers comprise a first polarizer and a second polarizer, the analyzer comprises a first analyzer disposed between the first polarizer and the second polarizer, and a second analyzer disposed on an opposite side of the second polarizer.

8. The light emitting assembly of claim 7, wherein the faraday rotation in the first and second polarizers occurs in opposite directions.

9. The light emitting assembly of claim 8, wherein in the forward light path, forward incident light passes through a first analyzer via polarized light rotated 45 ° in a first polarizer, and then the polarized light is rotated 45 ° in a direction opposite to the direction of rotation produced by the first polarizer by a second polarizer, the rotated polarized light outputting an optical isolator via the second analyzer, the isolator having an exit light polarization direction parallel to the polarization direction of the incident light.

10. The light emitting assembly of claim 9, wherein in the reverse light path, after the reflected light passes through the second analyzer and is rotated by 45 ° by the second polarizer 540, the polarization direction of the reverse light is changed to 90 ° vertically, perpendicular to the polarization direction of the incident light from the optical isolator.