Optical film and semiconductor laser

Abstract

The utility model relates to the technical field of semiconductor lasers, in particular to an optical film and a semiconductor laser, the optical film is arranged on the cavity surface of the semiconductor laser, and the optical film comprises a base layer, a functional layer and a protective layer which are laminated; the base layer is used for being plated on the cavity surface of the semiconductor laser, the functional layer is used for changing the refractive index of an optical signal emitted by the semiconductor laser, and the protective layer is arranged on the light emitting surface of the optical film. According to the optical film provided by the utility model, on one hand, the firmness of combination between the substrate material of the semiconductor laser and the optical film can be improved, and a film stripping phenomenon is prevented; and on the other hand, the protection layer can enable the semiconductor laser to have anti-oxidation and waterproof functions, and can further avoid heat energy accumulation on the end face caused by end face oxidation, thereby avoiding heat energy accumulation, improving the ESD capability and prolonging the service life of the semiconductor laser.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor lasers, in particular to an optical film and a semiconductor laser. Background Art

[0002] In the application of semiconductor lasers, it is hoped that most of the light can be emitted from a single side, which requires the anti-reflection film to be plated on the front cavity surface and the high-reflection film to be plated on the rear cavity surface to reduce the threshold gain. The front and rear end surfaces of the strip semiconductor laser are respectively plated with high-transmittance film and high-reflection film. On the one hand, it can protect the cavity surface, prevent air pollution and oxidation reaction, improve the light output performance of the semiconductor laser and extend the life of the semiconductor laser; on the other hand, it can reasonably adjust the reflectivity of the two end surfaces of the strip laser, optimize the laser threshold current and emission efficiency, and finally achieve the maximum laser power output on a single side.

[0003] The coating on the end face of the semiconductor laser is to form a multilayer dielectric film stack with alternating high and low refractive indexes on the surface of the plated component through physical vapor deposition to achieve anti-reflection film and high-reflection film. Therefore, the matching between the cavity surface and the film layer, the density of the film layer, the stability of the film layer, and the stable optical performance are all key to ensure the stable operation of the semiconductor laser. For example, the currently used coating film system TIO2 / AL203 / TIO2 / AL203 is a multilayer film system. The advantages of this film system are strong anti-reflection effect, high matching between AL203 film layer and TI02 film layer, and wide applicability. However, the combination of TIO2 and the substrate material InP of the semiconductor laser is relatively weak. On the one hand, the coating firmness is unstable after coating, and on the other hand, catastrophic optical mirror damage is prone to occur on the light-emitting surface of the coating.

[0004] In view of this, overcoming the defects of the prior art is an urgent problem to be solved in the field of this technology. Utility Model Content

[0005] The technical problem to be solved by the utility model is: how to solve the problem that the existing optical film is weakly bonded to the substrate of the semiconductor laser, resulting in the film being not firm after coating and easy to cause catastrophic optical mirror damage on the light-emitting surface.

[0006] The utility model adopts the following technical solutions:

[0007] In one aspect, an optical film is provided, wherein the optical film is arranged on a cavity surface of a semiconductor laser, and the optical film comprises: a base layer, a functional layer and a protective layer arranged in layers;

[0008] The base layer is used for coating on the cavity surface of the semiconductor laser, the functional layer is used for changing the refractive index of the optical signal emitted by the semiconductor laser, and the protective layer is arranged on the light emitting surface of the optical film.

[0009] Further, the functional layer is a transmission layer, and the transmission layer includes a Ti3O5 layer and a SiO2 layer stacked in sequence, wherein the Ti3O5 layer is arranged on the layer; the optical film is arranged on the front cavity surface of the semiconductor laser;

[0010] Alternatively, the functional layer is a reflective layer, and the reflective layer includes a TI3O5 layer, a SiO2 layer, a TI3O5 layer and a SiO2 layer stacked in sequence, wherein the TI3O5 layer is arranged on the base layer; and the optical film is arranged on the back cavity surface of the semiconductor laser.

[0011] Further, when the wavelength band of the semiconductor laser is 1270 nm, the thickness of the Ti3O5 layer is 69.44 nm to 70.44 nm, and the thickness of the SiO2 layer is 159.98 nm to 160.98 nm;

[0012] When the wavelength band of the semiconductor laser is 1310 nm, the thickness of the Ti3O5 layer is 74.44 nm to 75.44 nm, and the thickness of the SiO2 layer is 155.36 nm to 156.36 nm.

[0013] Furthermore, the base layer is an Al2O3 layer, and the protective layer is a diamond-like film layer.

[0014] Furthermore, the thickness of the Al2O3 layer is 15nm to 20nm, and the thickness of the diamond-like film layer is 10nm to 15nm.

[0015] Furthermore, when the wavelength band of the semiconductor laser is 1310 nm, the refractive index of the AL2O3 layer is 1.6 to 1.611, the refractive index of the TI3O5 layer is 2.294 to 2.3, and the refractive index of the SiO2 layer is 1.4 to 1.443.

[0016] Furthermore, the diamond-like film layer includes a hydrogen-free diamond-like carbon film and a hydrogenated diamond-like carbon film.

[0017] On the other hand, a semiconductor laser is provided, comprising a semiconductor laser body, wherein the optical film is coated on the cavity surface of the semiconductor laser body.

[0018] Furthermore, when the functional layer is a transmission layer, the optical film is arranged on the front cavity surface of the semiconductor laser; when the functional layer is a reflection layer, the optical film is arranged on the back cavity surface of the semiconductor laser;

[0019] Furthermore, the substrate material of the semiconductor laser is InP.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] The utility model improves the coating structure of the traditional semiconductor laser. The first layer adopts a base layer to better combine with the substrate material of the semiconductor laser. Secondly, a functional layer is set in the middle. Different film structures are selected to form the functional layer according to the coating position and function, so that the functional layer can better realize the transmission or reflection of the optical signal emitted by the semiconductor laser. Finally, a protective layer is plated on the outermost layer. The constituent material of the protective layer has excellent optical properties and stable physical properties. The optical film proposed by the utility model can, on the one hand, improve the firmness of the combination between the substrate material of the semiconductor laser and the optical film, and prevent the occurrence of film stripping; on the other hand, the protective layer can make the semiconductor laser have the functions of anti-oxidation and waterproofing, and can avoid the end face caused by end face oxidation. Heat energy accumulation, thereby avoiding heat energy accumulation, improving the electrostatic discharge test (Electro-Static discharge, abbreviated as ESD) capability, and increasing the life of the semiconductor laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the structure of an optical film provided by an embodiment of the utility model;

[0024] Figure 2 This is another structural schematic diagram of an optical film provided by an embodiment of the utility model;

[0025] Figure 3 It is a schematic structural diagram of a transmission film of an optical film provided by an embodiment of the utility model;

[0026] Figure 4 This is a schematic structural diagram of a high-reflective film of an optical film provided by an embodiment of the utility model;

[0027] Figure 5 It is a structural schematic diagram of a semiconductor laser provided by an embodiment of the utility model;

[0028] Figure 6 It is a structural schematic diagram of a coating device provided by an embodiment of the utility model;

[0029] Figure 7This is a schematic diagram of an ideal film thickness and spectral curve of a semiconductor laser simulated by software provided by an embodiment of the utility model;

[0030] Figure 8 It is a schematic diagram of an actual spectral curve of a semiconductor laser measured by a companion plate provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model. The terms "first", "second", etc. in the utility model are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the utility model, unless otherwise specified, "multiple" means two or more. In the utility model, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral one; it can be directly connected or indirectly connected through an intermediate medium.

[0032] In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Embodiment 1:

[0034] Semiconductor lasers are prone to catastrophic optical damage (COD) on the light-emitting surface, which is one of the main reasons that restrict the reliability and high-power light output of semiconductor lasers. Cavity surface light absorption and cavity surface oxidation will cause heat generation and accumulation, resulting in damage to the optical mirror surface and reliability problems. In actual application scenarios, the probability of COD can be reduced by reducing the light absorption of the light-emitting surface and preparing a cavity surface passivation protective layer. Therefore, reducing the introduction of impurities and cavity surface oxidation at each node in the coating process is very important for improving the damage threshold of the film. High-quality and high-performance cavity surface optical films can not only improve the slope efficiency of semiconductor lasers, prevent cavity surface oxidation, and protect the cavity surface, but more importantly, improve the reliability of semiconductor lasers, prevent the generation of cavity surface optical catastrophes and pollution of the active area, and extend the life of the laser.

[0035] However, the existing optical film is not firmly bonded to the end face of the semiconductor laser, and catastrophic optical mirror damage is easily caused on the light-emitting surface. To solve the problems of the prior art, this embodiment provides an optical film, which is arranged on the cavity surface of the semiconductor laser, such as Figure 1 As shown, the optical film includes: a stacked base layer, a functional layer and a protective layer; the base layer is used to be plated on the cavity surface of the semiconductor laser, the functional layer is used to change the refractive index of the optical signal emitted by the semiconductor laser, and the protective layer is arranged on the light output surface of the optical film.

[0036] The optical film described in this embodiment is designed to improve and protect the performance of semiconductor lasers. The optical film is designed to optimize the transmission efficiency of optical signals and protect the laser from the external environment by setting a specific hierarchical structure on the front and back surfaces of the laser. Among them, the base layer is the first layer of film directly coated on the front and back surfaces of the semiconductor laser. Its main function is to provide a uniform and smooth substrate for the upper film, thereby ensuring that the performance of the functional layer and the protective layer is maximized. At the same time, its material needs to match the substrate material of the semiconductor laser for better bonding and to prevent demolding after coating.

[0037] The functional layer is located on top of the base layer and is a key layer used to actively change the refractive index of the optical signal emitted by the semiconductor laser. By adjusting the refractive index of the optical signal, effective control of the light wave can be achieved, such as adjusting the direction of the light beam, improving the beam quality, or adjusting the phase and amplitude of the light wave. The design of the functional layer depends on the specific application requirements, such as a transmission film, a reflection film, or a phase control film. By selecting different materials and adjusting the thickness of the film layer, precise control of the optical signal characteristics can be achieved.

[0038] The protective layer is a thin film set on the outermost layer of the optical film. Its main function is to protect the underlying film layer from physical wear, chemical corrosion or other external factors, while ensuring the stability of optical performance. The protective layer needs to have good durability and light transmittance so as not to affect the transmission efficiency of the optical signal.

[0039] In one embodiment, Figure 2 As shown, the base layer is an Al2O3 layer, and the protective layer is a diamond-like film layer (DLC). The thickness of the Al2O3 layer is 15nm to 20nm, and the thickness of the diamond-like film layer is 10nm to 15nm. The thickness of the Al2O3 layer is designed based on the combination effect of the base layer with the front and back cavity surfaces of the semiconductor laser and the optical performance. The thickness of the diamond-like film layer is intended to protect the layer stack without excessively affecting the optical performance.

[0040] The diamond-like film layer includes a hydrogen-free diamond-like carbon film and a hydrogenated diamond-like carbon film. Both materials have extremely high hardness and chemical stability, but they may differ in optical properties and preparation processes. The hydrogen-free diamond-like carbon film generally has higher hardness and better wear resistance, while the hydrogenated diamond-like carbon film may perform better in reducing internal stress and improving film adhesion.

[0041] Diamond-like film is a new type of thin film material with similar properties to diamond film. It has high hardness, good thermal conductivity, extremely low friction coefficient, excellent electrical insulation, high chemical stability and infrared transmittance. Diamond-like film products have been widely used in various fields such as machinery, electronics, optics and medicine. There are two main methods for artificially synthesizing diamonds, high temperature and high pressure method and chemical vapor deposition method. High temperature and high pressure method technology is very mature and has formed an industry. Chemical vapor deposition method still mainly exists in laboratories. Under the conditions of static high pressure, high temperature and transition metal elements, the mechanism of graphite turning into diamond mainly changes with pressure. Under low pressure conditions, graphite is dissolved by metal and recrystallized into diamond, and the seed method of growing diamond belongs to this situation. With the increase of pressure, the proportion of graphite directly converted into diamond increases, until at 130,000 atmospheres and about 3000℃, graphite can be directly converted into all-corona without the help of metal.

[0042] In a preferred embodiment, the diamond-like film can also be prepared by sputtering deposition. Sputtering deposition mainly uses graphite target as carbon source. First, the cathode high voltage is used to ionize the inert gas Ar or He, and then the kinetic energy is obtained under the acceleration of the electric field and bombards the graphite target, sputtering carbon atoms or ions, and finally depositing on the substrate to form a diamond-like film. There are many methods of sputtering deposition technology, which can be mainly divided into magnetron sputtering, DC sputtering and radio frequency sputtering. The characteristics of this technology are: the deposited ion energy range is wide, the prepared diamond-like film is uniform and stable, etc. Therefore, sputtering deposition technology is the most commonly used method for preparing diamond-like films in industry. Magnetron sputtering has become the main technology for industrial production of diamond-like film coatings because it can provide good process control and is easy to adjust to meet the needs of processing and production. Its specific production process will not be explained in detail in this embodiment.

[0043] In this embodiment, according to the functional and structural differences of the functional layer, the optical film can be a reflective film or an anti-reflective film. The anti-reflective film is arranged on the front cavity surface of the semiconductor laser, and the reflective film is arranged on the back cavity surface of the semiconductor laser.

[0044] Specifically, Figure 3As shown, the functional layer can be a transmission layer, which includes a TI3O5 layer and a SiO2 layer stacked in sequence, wherein the TI3O5 layer is arranged on the layer; the optical film (ie, anti-reflection film) is arranged on the front cavity surface of the semiconductor laser.

[0045] like Figure 4 As shown, the functional layer can be a reflective layer, and the reflective layer includes a TI3O5 layer, a SiO2 layer, a TI3O5 layer and a SiO2 layer stacked in sequence, wherein the TI3O5 layer is arranged on the base layer; the optical film (i.e., the reflective film) is arranged on the back cavity surface of the semiconductor laser.

[0046] Reference Figure 3 , on the front cavity surface of the semiconductor laser, the first thing to be set is the base layer (i.e., the Al2O3 layer). The main function of this layer is to provide a smooth and uniform surface so that other film layers can be plated on it to ensure the overall performance of the optical film; at the same time, it can be stably combined with the substrate material of the semiconductor laser. The transmission layer is arranged on the base layer of the front cavity surface, including a Ti3O5 layer and a SiO2 layer stacked in sequence. The design purpose of the transmission layer is to improve the transmission performance of the optical signal emitted by the semiconductor laser, that is, to enhance the transmittance of light of a specific wavelength by adjusting the refractive index of the optical signal. Finally, a protective layer of diamond-like film is plated on the transmission layer to protect the entire optical film, that is, to complete the coating of the front cavity surface of the semiconductor laser.

[0047] Reference Figure 4 On the back cavity surface of the semiconductor laser, the first thing to be set is the base layer (i.e., the Al2O3 layer). The transmission layer is set on the base layer of the back cavity surface, including the Ti3O5 layer, the SiO2 layer, the Ti3O5 layer and the SiO2 layer arranged in sequence. The purpose of the reflection layer is to enhance the reflection performance of the optical signal, that is, to reflect the light of a specific wavelength through a specific stacked structure, thereby controlling the optical signal output by the laser. Finally, a protective layer of diamond-like film is coated on the transmission layer to protect the entire optical film, that is, to complete the coating of the back cavity surface of the semiconductor laser.

[0048] Through this design, the optical film set on the front cavity surface of the semiconductor laser mainly improves the transmittance of the optical signal, while the optical film set on the back cavity surface enhances the reflection performance of the optical signal. The different configurations of the transmission layer and the reflection layer, combined with the combined effects of the base layer and the protective layer, not only optimize the optical performance of the laser, but also improve its durability and stability. This design can effectively extend the service life of the laser while ensuring the efficient operation of the laser.

[0049] For semiconductor lasers of different wavelengths, the film thickness of the SiO2 layer and the Ti3O5 layer in the front and back cavity surfaces of the semiconductor laser needs to be precisely adjusted. This is because the propagation characteristics of light of different wavelengths in the medium (such as refractive index and reflectivity) will be different. By adjusting the film thickness, it can be ensured that the laser of a specific wavelength has the best transmittance. Specifically, the different wavelengths of the semiconductor laser correspond to different film thicknesses of the TI3O5 layer and the SIO2 layer; wherein, when the wavelength of the semiconductor laser is 1270nm, the thickness of the TI3O5 layer is 69.44nm~70.44nm, and the thickness of the SiO2 layer is 159.98nm~160.98nm; when the wavelength of the semiconductor laser is 1310nm, the thickness of the TI3O5 layer is 74.44nm~75.44nm, and the thickness of the SiO2 layer is 155.36nm~156.36nm.

[0050] For the 1270nm and 1310nm bands, the thickness of the Ti3O5 layer and the SiO2 layer are precisely adjusted respectively. When the wavelength bands of the semiconductor laser are 1290nm, 1330nm and 1350nm respectively, according to the invariance of the performance of the multi-layer optical characteristics system, the film thickness of the material of the corresponding wavelength can be known according to the proportion. These thickness adjustments are based on optical design principles, such as the quarter-wavelength principle, to maximize the transmittance of specific wavelengths. These adjustments reflect the design requirements of optical films at different wavelengths to ensure that the film structure has the best transmittance for light in a specific wavelength band. More specifically, no further explanation is given in this embodiment.

[0051] Refractive index values ​​are critical for designing optical film stacks because they determine the reflection and transmission behavior of light between film layers, thereby affecting the anti-reflection effect. In a preferred embodiment, when the wavelength of the semiconductor laser is 1310nm, the refractive index of the Al2O3 layer is 1.6 to 1.611, the refractive index of the Ti3O5 layer is 2.294 to 2.3, and the refractive index of the SiO2 layer is 1.4 to 1.443. More specifically, no further explanation is given in this embodiment.

[0052] This embodiment improves the coating structure of the traditional semiconductor laser. The first layer adopts a primer layer to better combine with the base material. Secondly, a functional layer is set in the middle. Different film layer structures are selected to form the functional layer according to the coating position and function, so that the functional layer can better realize the transmission or reflection of the optical signal emitted by the semiconductor laser. Finally, a protective layer is plated on the outermost layer. The constituent material of the protective layer has excellent optical properties and stable physical properties.

[0053] The optical film proposed by the utility model can, on the one hand, improve the mechanical properties of the surface of the semiconductor laser, and increase the firmness of the film layer to prevent the film peeling phenomenon; on the other hand, the provision of the protective layer can make the semiconductor laser have the functions of anti-oxidation and waterproofing, and can also avoid the accumulation of heat energy on the end face caused by end face oxidation, thereby avoiding the accumulation of heat energy, improving the electrostatic discharge test capability, and increasing the life of the semiconductor laser.

[0054] Embodiment 2:

[0055] In the first embodiment, an optical film is proposed. In the present embodiment, a semiconductor laser is proposed. Figure 5 As shown, it includes a semiconductor laser body, and the optical film described in Example 1 is coated on the cavity surface of the semiconductor laser body.

[0056] In this embodiment, an optical film with an anti-reflection function may be disposed on the front cavity surface of the semiconductor laser, and an optical film with a reflection function may also be disposed on the back cavity surface of the semiconductor laser.

[0057] Specifically, Figure 3 As shown, when the functional layer of the optical film is a transmission layer, the optical film (i.e., an anti-reflection film) is disposed on the front cavity surface of the semiconductor laser. When the functional layer of the optical film is a reflection layer, the optical film (i.e., a reflection film) is disposed on the back cavity surface of the semiconductor laser.

[0058] Through this design, the optical film set on the front cavity surface of the semiconductor laser mainly improves the transmittance of the optical signal, while the optical film set on the back cavity surface enhances the reflection performance of the optical signal. The different configurations of the transmission layer and the reflection layer, combined with the combined effects of the base layer and the protective layer, not only optimize the optical performance of the laser, but also improve its durability and stability. This design can effectively extend the service life of the laser while ensuring the efficient operation of the laser.

[0059] In a preferred embodiment, the light emitting region of the semiconductor laser body may be made of InGaAlAs material; the substrate material of the semiconductor laser may be InP; and the light emitting wavelength band of the semiconductor laser is 1270nm to 1370nm.

[0060] The light-emitting area of ​​the semiconductor laser body is made of InGaAlAs material. InGaAlAs is a quaternary compound semiconductor material that is a mixture of indium (In), gallium (Ga), aluminum (Al) and arsenic (As). It can provide a wide wavelength adjustment capability. By precisely controlling the proportion of the components, a specific light-emitting band can be achieved, which is suitable for wide band coverage from 1270nm to 1370nm.

[0061] InP (indium phosphide) is used as the substrate material, which not only provides a good crystal growth base, but also its electronic and optical properties are highly matched with the InGaAlAs light-emitting area material, which is conducive to the effective recombination of electron-hole pairs and the generation of light. The Al2O3 in the optical film can be better combined with the substrate material to prevent the entire optical film from falling off.

[0062] The specific structure of the optical film is shown in Example 1, and no further explanation is given in this example.

[0063] Embodiment 3:

[0064] In this embodiment, a semiconductor laser coating device is provided for coating the semiconductor laser as described in Embodiment 2. Figure 6 As shown, the coating device includes a coating machine and a filament-type Hall ion source for performing ion beam-assisted deposition on the end face of a semiconductor laser Bar.

[0065] The coating machine adopts an electron beam evaporation machine, which includes an electron gun, a film thickness monitor for monitoring the thickness of a single-layer SIO2 film, a crucible plate for placing film materials (including 8 holes or more), and a clamp for clamping semiconductor laser bar strips; the clamp is placed on the umbrella stand of the electron beam evaporation machine, and a monitoring device for monitoring the film thickness and evaporation coating rate is fixed on the top of the equipment and the umbrella stand. The electron beam evaporation machine includes a vacuuming device for evacuating the chamber and a heating device for heating the chamber.

[0066] Next, taking the optical film as an anti-reflection film as an example, the coating process of the coating device is introduced. It is worth noting that the present invention only protects the product structure, and the method level is all prior art.

[0067] The coating process of the coating device includes the following steps (taking the wavelength of the semiconductor laser as 1310nm as an example):

[0068] Step 1: First place the film material in the corresponding crucible, place the fixture loaded with the semiconductor laser bar on the umbrella stand of the coating machine, make the light-emitting surface of the semiconductor laser bar face down, close the coating machine chamber door, start vacuuming and heating. The vacuum of the machine needs to be between 3.0*10E-6Torr and 8.0*10E-7Torr, and the temperature inside the machine needs to be heated to 200℃~230℃ and maintained.

[0069] Step 2: After the environmental vacuum and temperature are reached, the ion source is turned on. After preheating for 30 seconds, the ion source baffle is opened. Pre-cleaning is performed first to pre-treat the end face of the semiconductor laser Bar. After the ion source is cleaned, the coating stage begins. First, the Bar end face needs to be surface treated, that is, ion source cleaning (ion cleaning of the Bar end face before coating can effectively remove surface dirt particles and oxides formed by oxidation along the Bar end face, thereby enhancing product reliability).

[0070] After the vacuum capacity and temperature are reached, the electron gun shutter is opened, and the evaporation material AL2O3 is started first. The set power is 22.3%, the current is 213mA, and the plating rate is 5.0 angstroms per second. When the monitored film thickness is 16.2nm, the electron gun shutter is closed, the electron gun is turned off, and while the film is being plated, the ion source is turned on synchronously for ion-assisted deposition. The anode voltage of the ion source is set to 120V, the current is 2.0A, the neutralization current is 200mA, and the gas is Ar. Because it is the first layer, the voltage should not be set too high, and O2 should not be introduced.

[0071] The crucible plate is further rotated to expose the material TI3O5, the electron gun is turned on, and the power is gradually increased. After the material is fully pre-melted, the electron gun baffle is opened to start evaporating the material. The power is set to 19.1%, the current is 188mA, and the plating rate is 2.0 angstroms per second. When the monitored film thickness is 74.94nm, the electron gun baffle is closed, the electron gun is turned off, and while the film is being plated, the ion source is turned on synchronously for ion-assisted deposition. The anode voltage of the ion source is set to 150V, the current is 2.0A, the neutralization current is 200mA, and the gas is O2.

[0072] The crucible plate is further rotated to expose the material SIO2, the electron gun is turned on, and the power is gradually increased. After the material is fully pre-melted, the electron gun baffle is opened to start evaporating the material. The power is set to 16.5%, the current is 158mA, and the plating rate is 5.0 angstroms per second. When the monitored film thickness is 155.86nm, the electron gun baffle is closed, the electron gun is turned off, and while the film is being plated, the ion source is synchronously turned on for ion-assisted deposition. The anode voltage of the ion source is set to 150V, the current is 2.0A, the neutralization current is 200mA, and the gas is Ar.

[0073] The crucible plate is further rotated to expose the material crystal diamond-like film, and the cavity is continued to be heated to 230 degrees. When the conditions are met, the electron gun is turned on to make the material surface temperature reach about 4000 degrees, and the molecular diamond-like film begins to evaporate. The anode voltage of the ion source is set to 200V, the current is 2.0A, the neutralization current is 200mA, and the gas is Ar. It is deposited on the product surface under the auxiliary bombardment of the ion source, and the power is set to 18.5%, the current is 180mA, and the plating rate is set to 1 angstrom per second. When the film thickness reaches 10nm, the electron gun baffle is closed and the coating is completed. After the coating is completed, the cavity temperature continues to maintain 230 degrees for more than 10 minutes before it can start to cool down naturally.

[0074] After the cavity temperature drops below 100°C, N2 is introduced to return the cavity to the atmosphere, and the bar fixture and companion film in the fan blade are taken out. The process capability is verified by testing the film thickness and reflectivity of the companion film.

[0075] Now we conduct an experiment for comparative analysis (taking the anti-reflection film on the front cavity surface as an example).

[0076] The experiment was conducted in 3 groups:

[0077] The first set of experimental conditions is to use the coating film system of TIO2 / AL203 / TIO2 / AL203 for coating experiments;

[0078] The second set of experimental conditions is to use the coating film system of AL203 / TI3O5 / SIO2 for coating experiments;

[0079] The third set of experimental conditions is to use the coating film system of AL203 / TI3O5 / SIO2 / diamond-like film for coating experiments;

[0080] After the three sets of experimental coating were completed:

[0081] Step 1: Take the InP co-plating film for spectroscopic detection and conduct baking, boiling and pulling experiments. By continuously increasing the tensile stress on the film layer, comparative analysis is conducted. The products of the third group of experiments are more tensile-resistant than those of the first two groups of experiments.

[0082] Step 2: Take 30 chips from each group for To packaging. Perform aging test on the packaged To at the same time. The aging conditions are as follows: aging parameter range unit temperature 100℃, current 100mA, time 72H. Every 24H, record the value of each chip threshold and optical power, and calculate its change rate (the change rate does not exceed 10% to be qualified). It can be seen from the experimental data that there is basically no change in the three groups of experiments.

[0083] Step 3: ESD test the To chips that have undergone aging tests in the three groups of experiments. During the test, the voltage of each group of experiments starts from 500V and increases in steps of 200V to simulate the electrostatic damage process of semiconductor lasers, and records the threshold and light output power of To at each voltage level. As the voltage increases, some To chips begin to fail (threshold current or power changes by more than 10% are unqualified). The realization ratio of the three groups of experiments at different voltages is statistically calculated. When the voltage reaches 1500V, the qualified ratio of the first two groups of conditions is almost 0, while the pass rate of Experiment 3 remains at a high level of 90%, indicating that under the conditions of Experiment 3, the product has good ESD capabilities.

[0084] in conclusion:

[0085] As a preferred embodiment, Figure 7 and Figure 8 The anti-reflection film can achieve a minimum reflection of 0.01% at a central wavelength of 1310nm, achieving an excellent anti-reflection effect. The film layer described in Example 1 has better firmness, better film strength, and better anti-static properties ESD; the stability and reliability of the semiconductor laser are improved.

[0086] The specific structures of the optical film and the semiconductor laser refer to Example 1 and Example 2, and will not be further described in this example.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical film, characterized in that: The optical film is arranged on the cavity surface of the semiconductor laser, and the optical film comprises: a base layer, a functional layer and a protective layer arranged in layers; The base layer is used for coating on the cavity surface of the semiconductor laser, the functional layer is used for changing the refractive index of the optical signal emitted by the semiconductor laser, and the protective layer is arranged on the light emitting surface of the optical film.

2. The optical film according to claim 1, characterized in that: The functional layer is a transmission layer, and the transmission layer includes a Ti3O5 layer and a SiO2 layer stacked in sequence, wherein the Ti3O5 layer is arranged on the base layer; the optical film is arranged on the front cavity surface of the semiconductor laser; Alternatively, the functional layer is a reflective layer, and the reflective layer includes a TI3O5 layer, a SiO2 layer, a TI3O5 layer and a SiO2 layer stacked in sequence, wherein the TI3O5 layer is arranged on the base layer; and the optical film is arranged on the back cavity surface of the semiconductor laser.

3. The optical film according to claim 2, characterized in that: When the wavelength of the semiconductor laser is 1270 nm, the thickness of the Ti3O5 layer is 69.44 nm to 70.44 nm, and the thickness of the SiO2 layer is 159.98 nm to 160.98 nm; When the wavelength band of the semiconductor laser is 1310 nm, the thickness of the Ti3O5 layer is 74.44 nm to 75.44 nm, and the thickness of the SiO2 layer is 155.36 nm to 156.36 nm.

4. The optical film according to claim 2, characterized in that: The base layer is an Al2O3 layer, and the protective layer is a diamond-like film layer.

5. The optical film according to claim 4, characterized in that: The thickness of the Al2O3 layer is 15nm-20nm, and the thickness of the diamond-like film layer is 10nm-15nm.

6. The optical film according to claim 4, characterized in that: When the wavelength band of the semiconductor laser is 1310 nm, the refractive index of the AL2O3 layer is 1.6-1.611, the refractive index of the TI3O5 layer is 2.294-2.3, and the refractive index of the SiO2 layer is 1.4-1.

443.

7. The optical film according to claim 4, characterized in that: The diamond-like film layer includes a hydrogen-free diamond-like carbon film and a hydrogenated diamond-like carbon film.

8. A semiconductor laser, characterized in that: It comprises a semiconductor laser body, wherein the optical film according to any one of claims 1 to 7 is plated on the cavity surface of the semiconductor laser body.

9. The semiconductor laser according to claim 8, characterized in that When the functional layer is a transmission layer, the optical film is arranged on the front cavity surface of the semiconductor laser; when the functional layer is a reflection layer, the optical film is arranged on the back cavity surface of the semiconductor laser.

10. The semiconductor laser according to claim 8, characterized in that The substrate material of the semiconductor laser is InP.

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