High-reliability tunable laser and coupling method thereof

Abstract

The invention belongs to the technical field of laser coupling, and particularly relates to a high-reliability tunable laser and a coupling method thereof.The tunable laser comprises a shell, a light-emitting chip is arranged in the shell, light emitted by the light-emitting chip sequentially passes through a collimating lens, an isolator and a spectroscope, the spectroscope divides the light into two paths of primary light, and the two paths of primary light are coupled through the collimating lens; wherein one path of primary light enters an optical fiber through a coupling lens, the other path of primary light enters a beam splitter prism and is divided into two paths of secondary light, one path of secondary light enters a backlight detector I, and the other path of secondary light enters a backlight detector II through an etalon; when the etalon is coupled, a total reflection mirror for totally reflecting secondary light passing through the etalon to the coupling lens is arranged in the shell, and after the position of the etalon is determined, the total reflection mirror is removed. According to the invention, the light passing through the etalon can be coupled to the optical fiber through the holophote for detection, only a conventional intracavity coupling process is needed, extra operations such as out-of-cavity coupling are not needed, and the coupling difficulty is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser coupling, and particularly relates to a highly reliable tunable laser and a coupling method thereof. Background Art

[0002] Tunable lasers can be used in the fields of optical fiber communication and optical fiber sensing. Dense wavelength division multiplexing (DWDM) is considered to be the most promising technology for solving the increasing network bandwidth. Using wavelength tunable lasers in DWDM systems can reduce system complexity, reduce the amount of spare parts, and enable dynamic reconfiguration, thus effectively reducing installation and maintenance costs. An optical fiber sensing system using a tunable laser can achieve multi-point distributed sensing through wavelength scanning, and has great advantages in the demand for large-area detection.

[0003] To improve the production yield and reliability of devices, it is urgent to break through the design of the internal structure and simplify the coupling process.

[0004] At present, there are various technical routes for tunable laser devices, including DFB array monolithic integration, DBR monolithic integration, ECL external cavity and other technical routes. The packaging of DFB array monolithic integration and DBR monolithic integration tunable lasers is relatively simple, but limited by the existing chip preparation process and chip size, there are problems of wide linewidth and poor spectral characteristics. The ECL external cavity tunable laser has the characteristics of narrow linewidth, high power and high side mode suppression ratio, and has a broad market space. However, since the ECL external cavity tunable laser needs to couple and package the gain chip with the external cavity, there are many components to be packaged, resulting in high packaging difficulty and poor reliability, which restricts the development and application of related products.

[0005] A highly reliable tunable laser needs to have the ability of wavelength monitoring, which is usually achieved by comparing the optical energy directly entering the backlight detector and the optical energy entering the backlight detector after passing through the etalon. The coupling of the etalon needs to be detected in real time using a spectrometer. However, since the detection beam does not directly enter the optical fiber, it is difficult to monitor. To solve this problem, two methods are used in the production process. One is external cavity coupling, which results in a complex process flow, increases the coupling process and reduces the yield. The other is internal cavity coupling. By opening a window on the side wall of the package, inserting an optical fiber collimator to detect the spectrum, and then closing the package by laser welding after coupling, this method increases the welding step and will reduce the reliability and yield.

[0006] In summary, the ECL external cavity tunable laser has problems of high packaging difficulty and high coupling difficulty, which affect the reliability and production yield of the tunable laser. To reduce the packaging difficulty of the ECL external cavity tunable laser and improve the production yield and reliability of the device, it is urgent to break through the design of the internal structure and simplify the coupling process. Summary of the Invention

[0007] To solve the above technical problems, the present invention provides a highly reliable tunable laser and its coupling method.

[0008] The object of the present invention is achieved by the following technical solutions. A highly reliable tunable laser according to the present invention includes a housing, in which a light-emitting chip is provided. The light emitted by the light-emitting chip sequentially passes through a collimating lens, an isolator, and a beam splitter. The beam splitter divides the light into two primary light beams. One of the primary light beams enters an optical fiber through a coupling lens, and the other primary light beam enters a beam splitting prism and is divided into two secondary light beams. One of the secondary light beams enters a backlight detector I, and the other secondary light beam enters a backlight detector II through an etalon; when coupling the etalon, a total reflection mirror that totally reflects the secondary light passing through the etalon to the coupling lens is provided in the housing. After the position of the etalon is determined, the total reflection mirror is removed.

[0009] Further, the gain chip, the thermistor, and the gain chip thin-film circuit are die-bonded and pasted on a heat sink substrate; the heat sink substrate is pasted on a semiconductor refrigerator, and the semiconductor refrigerator is sintered on the housing; the gain chip and the thermistor are wire-bonded, and the semiconductor refrigerator is welded to the pins of the housing.

[0010] Further, the positions of the isolator, the beam splitter, and the beam splitting prism are determined and fixed by passive coupling.

[0011] Further, the beam splitting prism is provided with a total reflection surface and a beam splitting surface, and the ratio of reflection to transmission of the beam splitting surface is 50∶50 to 70∶30.

[0012] Further, the collimating lens, the coupling lens, and the optical fiber are adjusted and coupled to the maximum output power and an acceptable side mode suppression ratio and then fixed.

[0013] Further, when coupling the etalon, after the center wavelength of the longitudinal mode of the light received by the spectrometer connected to the optical fiber is the required wavelength, the position of the etalon is fixed and the total reflection mirror is removed.

[0014] Further, the external cavity chip is fixed after being coupled to the maximum output power.

[0015] Further, the external cavity chip, the backlight detector I, and the backlight detector II are electrically connected to the pins of the housing by wire bonding.

[0016] A coupling method for a highly reliable tunable laser includes the following steps:

[0017] Die-bond and paste the gain chip, the thermistor, and the gain chip thin-film circuit on a heat sink substrate; paste the heat sink substrate on a semiconductor refrigerator, and sinter the semiconductor refrigerator on the housing; wire-bond the gain chip and the thermistor, and weld the semiconductor refrigerator to the pins of the housing;

[0018] Passively couple and fix the isolator, beam splitter, and beam splitting prism;

[0019] Power on the laser so that the gain chip can emit light normally;

[0020] Clamp the collimating lens, coupling lens, and optical fiber. The output end of the optical fiber is connected to a power meter and a spectrometer through an optical splitter for detection. Adjust the displacement and angle of the collimating lens, coupling lens, and optical fiber to couple to the maximum output power and an acceptable side mode suppression ratio, and fix the optical fiber, collimating lens, and coupling lens;

[0021] Clamp the total reflection mirror and the etalon. Make the light split by the beam splitting surface on the beam splitting prism pass through the etalon, total reflection mirror, and coupling lens in sequence and then enter the optical fiber. Adjust the displacement and angle of the etalon so that the center wavelength of the longitudinal mode of the light received by the spectrometer is the required wavelength;

[0022] Fix the etalon and remove the total reflection mirror;

[0023] Clamp the external cavity chip, adjust the displacement and angle of the external cavity chip to couple to the maximum output power and fix it;

[0024] Fix the backlight detector I and backlight detector II;

[0025] Wire the backlight detector I and backlight detector II; wire the external cavity chip; cover.

[0026] Furthermore, when coupling the collimating lens, coupling lens, and optical fiber, clamp the collimating lens, adjust the collimating lens, and perform stray light coupling of the collimating lens to increase the power; then clamp the coupling lens and adjust the coupling lens to continue increasing the power; then finely adjust the collimating lens to further increase the power. When the maximum power is reached, fix the collimating lens and coupling lens.

[0027] Furthermore, after the laser is coupled, bake it. If the power change after baking is less than 10%, it is qualified; then perform gold wire bonding on the external cavity chip, and gold wire bonding on the backlight detector I and backlight detector II to form an electrical connection with the pins on the housing; then perform a temperature cycle test. If the power change after the temperature cycle is less than 10%, it is qualified.

[0028] Compared with the prior art, the advantages of the present invention are as follows:

[0029] (1) The laser uses an ECL external cavity design. The special optical path design improves the space utilization rate, reduces the product size, and can realize a tunable laser with narrow linewidth, high side mode suppression ratio, and wavelength detection function in a narrow space.

[0030] (2) The special optical path design and coupling process design of this laser can couple the light passing through the etalon 114 to the optical fiber 106 for detection through the total reflection mirror 121. This can be achieved only by using the conventional in-cavity coupling process, without additional operations such as out-of-cavity coupling, reducing the coupling difficulty.

[0031] (3) The special optical path design and coupling process design of this laser only require the use of a conventional package, without the need for additional openings on the sidewall of the package (using the optical signal output from the optical fiber 106 of the laser for detection and coupling, without the need to open holes on the housing to output the optical signal) or the use of an out-of-cavity coupling process, improving the product reliability.

[0032] The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the content of the specification. And in order to make the purpose, features and advantages of the present invention more obvious and understandable, the following preferred embodiments are specifically given and described in detail in conjunction with the accompanying drawings. Description of the Drawings

[0033] Figure 1 It is a schematic diagram of an embodiment of a highly reliable tunable laser of the present invention;

[0034] Figure 2 It is a schematic diagram of the steps of an embodiment of a coupling method for a highly reliable tunable laser of the present invention.

[0035] Reference Numerals:

[0036] 100 - Housing;

[0037] 101 - External cavity chip;

[0038] 102 - Gain chip;

[0039] 103 - Collimating lens;

[0040] 104 - Isolator;

[0041] 105 - Coupling lens;

[0042] 106 - Optical fiber;

[0043] 111 - Beam splitter;

[0044] 112 - Beam splitting prism;

[0045] 113 - Backlight detector I;

[0046] 114 - Etalon;

[0047] 116 - Backlight detector II;

[0048] 121 - Total reflection mirror;

[0049] 201 - Total reflection surface;

[0050] 202 - Beam splitting surface. Specific embodiments

[0051] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0052] A highly reliable tunable laser according to the present invention is as Figure 1 shown.

[0053] Currently, ECL external cavity tunable lasers have narrow linewidth, high power, and high side mode suppression ratio, but they have the disadvantages of difficult packaging and large coupling difficulty, which restricts the application of tunable lasers. The present invention designs the internal structure and supporting coupling process, which can simplify the coupling process, reduce the coupling difficulty, and improve the product reliability.

[0054] The tunable laser provided by the present invention includes a housing 100, an external cavity chip 101, a gain chip 102, a collimating lens 103, an isolator 104, a coupling lens 105, an optical fiber 106, a beam splitter 111, a beam splitting prism 112, a backlight detector I 113, a Fabry - Perot etalon 114, a backlight detector I 116, and a total reflection mirror 121.

[0055] Necessary components such as a semiconductor cooler and a thin - film circuit are also provided inside the housing 100.

[0056] Preferably, the beam splitting prism 112 is provided with a total reflection surface 201 and a beam splitting surface 202, and the ratio of reflection to transmission of the beam splitting surface 202 is 50:50 to 70:30.

[0057] The coupling method of the tunable laser provided by the present invention is as Figure 2 shown, and includes the following steps:

[0058] Step 1: Incoming material cleaning; The gain chip 102, the thermistor and the gain chip thin - film circuit are die - bonded to form a COC; The COC is pasted on the heat sink substrate; The heat sink substrate carrying the COC is pasted on the TEC (semiconductor cooler), and the TEC is sintered on the housing 100; The gain chip 102 and the thermistor are wire - bonded, and the TEC is welded to the pins of the housing 100. This step is a pre - step.

[0059] Preferably, the mounting in this step must be flat, and the parallelism deviation from the housing 100 is less than 0.1°, otherwise the subsequent coupling cannot be carried out.

[0060] Step 2: Fix the passive coupling isolator 104, beam splitter 111, and beam splitting prism 112 at the positions as shown in accordance with the designed angles. Figure 1 to the position.

[0061] Preferably, the mounting angles in this step need to be strictly controlled, with a deviation from the theoretical value of less than 0.1°.

[0062] Step 3: Power on the laser so that the gain chip 102 can emit light normally.

[0063] Step 4: Clamp the collimating lens 103, coupling lens 105, and optical fiber 106. The output end of the optical fiber 106 has been connected to a power meter and a spectrometer through an optical splitter for detection. Adjust the displacement and angle of the collimating lens 103, coupling lens 105, and optical fiber 106 to couple to the maximum output power and acceptable side mode suppression ratio, and fix the optical fiber 106 and the lenses (including the collimating lens 103 and coupling lens 105) at the positions as shown. Figure 1 to the position.

[0064] Step 5: Clamp the total reflection mirror 121 and the etalon 114, and make the light split by the beam splitting surface 202 pass through the etalon 114, total reflection mirror 121, and coupling lens 105 in sequence and then enter the optical fiber 106. Adjust the displacement and angle of the etalon 114 so that the central wavelength of the longitudinal mode of the light received by the spectrometer is the required wavelength. When coupling the etalon 114, the light passing through the etalon 114 is reflected to the coupling lens 105 and the optical fiber 106 through the total reflection mirror 121, and the etalon 114 is detected and adjusted in real time through the spectrometer. The total reflection mirror 121 can block the light split by the beam splitter 111 and reflect all the light passing through the etalon 114.

[0065] Preferably, the required wavelength includes multiple wavelengths that need to be tuned to reach.

[0066] Step 6: Fix the etalon 114 and remove the total reflection mirror 121.

[0067] Step 7: Clamp the external cavity chip 101, and adjust the displacement and angle of the external cavity chip 101 to couple to the maximum output power and fix it.

[0068] Preferably, the fixing angle in this step needs to be strictly controlled, with a deviation from the theoretical value of less than 0.1° and 5 μm, otherwise the subsequent steps cannot be carried out.

[0069] Step 8: Fix the backlight detector I 113 and the backlight detector II 116.

[0070] Step 9: Wire the backlight detectors (including the backlight detector I 113 and the backlight detector II 11); wire the external cavity chip 101; and cover the lid.

[0071] The beneficial effects of the present invention are summarized as follows:

[0072] (1) The laser uses an ECL external cavity design. The special optical path design improves the space utilization rate, reduces the product size, and can realize a tunable laser with narrow linewidth, high side mode suppression ratio, and wavelength detection function in a narrow space.

[0073] (2) The special optical path design and coupling process design of this laser can couple the light passing through the etalon 114 to the optical fiber 106 through the total reflection mirror 121 for detection. It can be achieved only by using a conventional in-cavity coupling process, without additional operations such as out-of-cavity coupling, reducing the coupling difficulty;

[0074] (3) The special optical path design and coupling process design of this laser only require the use of a conventional package, without additional openings on the side wall of the package (using the optical fiber 106 of the laser to output the optical signal for detection, without opening the shell to output the optical signal for detection) or using an out-of-cavity coupling process, improving the product reliability.

[0075] An embodiment of the tunable laser is as Figure 1 shown. The light emitted by the gain chip 102 passes through the collimating lens 103 and the isolator 104, and then enters the beam splitter 111 for the first beam splitting, splitting into two primary light beams. One of the primary light beams enters the optical fiber 106 through the coupling lens 105, and the other primary light beam enters the beam splitting prism 112. The total reflection surface 201 and the beam splitting surface 202 are arranged in the beam splitting prism 112. The primary light beam entering the beam splitting prism 112 first undergoes total reflection through the total reflection surface 201, and then undergoes the second beam splitting through the beam splitting surface 202. One of the two secondary light beams after the second beam splitting directly enters the backlight detector I 113, and the other secondary light beam needs to pass through the etalon 114 and then enter the backlight detector II 116. By comparing the optical energy entering the two backlight detectors, the wavelength monitoring ability required for a highly reliable tunable laser is realized. The coupling of the etalon 114 needs to be detected in real time using a spectrometer. When coupling the etalon 114, the total reflection mirror 121 is set, and the secondary light beam that needs to pass through the etalon 114 and enter the backlight detector II 116 is reflected by the total reflection mirror 121 and enters the coupling lens 105 and the optical fiber 106. The displacement and angle of the etalon 114 are adjusted so that the center wavelength of the longitudinal mode of the light received by the spectrometer is the required wavelength. Then, the position of the etalon 114 is determined and fixed. After removing the total reflection mirror 121, the two secondary beam splittings entering the corresponding backlight detectors are compared to realize the wavelength monitoring ability.

[0076] An embodiment of the coupling process of the tunable laser is as Figure 2 shown, and the steps are as follows:

[0077] Step 1: Coupling pre-step.

[0078] Step 1.1: Incoming material cleaning.

[0079] Step 1.2: Die-bond the gain chip 102 to form a COC, weld the thermistor, and perform COC screening.

[0080] Step 1.3: The COC that passes the screening is welded to the heat sink substrate, then welded to the semiconductor cooler, and finally sintered to the housing 100.

[0081] Step 1.4: Wire bond the gain chip 102 and the thermistor with gold wires, weld the TEC to the pins on the housing 100 to form an electrical connection with the pins on the housing 100.

[0082] Step 2: Mount the isolator 104 in the direction perpendicular to the long side of the housing 100, mount the beam splitter 111 in the direction at 45° to the long side of the housing 100, and mount the beam splitting prism 112 in parallel in the direction parallel to the long side of the housing 100 according to the designed angle, and fix them with UV glue.

[0083] Step 3: Fix the device in the previous step on the coupling platform, connect the TEC, thermistor, and gain chip 102 with the laser diode power supply device to power them on. At the same time, connect the optical fiber 106 to the spectrometer and power meter through the optical splitter.

[0084] Step 4: Clamp the collimating lens 103 (fiber collimator), adjust the collimating lens 103, and perform stray light coupling of the collimating lens 103 until the power is greater than 100 μW. Clamp the coupling lens 105 and adjust the coupling lens 105 until the coupling power is greater than 320 μW. Fine-tune the collimating lens 103, the power further increases, and when the maximum power is reached, fix the collimating lens 103 and the coupling lens 105 with UV glue.

[0085] Step 5: Clamp the total reflection mirror 121 and move it to the predetermined position. Make one of the secondary lights couple into the optical fiber 106 by adjusting the total reflection mirror 121. At this time, the spontaneous emission spectrum of the gain chip 102 can be observed on the spectrometer. Clamp the etalon 114 to the predetermined position, the spectrogram becomes multi-longitudinal mode, and fine-tune the displacement and angle so that the wavelength at the center of each longitudinal mode corresponds to the required wavelength, with a deviation less than 0.02 nm.

[0086] Step 6: Fix the etalon 114 with UV glue and remove the total reflection mirror 121.

[0087] Step 7: Clamp the external cavity chip 101, adjust the displacement (distance from the gain chip 102) from far to near and adjust the angle until the spectrum shows a single longitudinal mode, the side mode suppression ratio is greater than 40 dB, and the power is greater than 24 mW. Fix the external cavity chip 101 with UV glue.

[0088] Step 8: Fix the backlight detectors (including backlight detector I113 and backlight detector II 116).

[0089] Step 9: Couple the subsequent steps.

[0090] Step 9.1: Bake. It is qualified if the power change after baking is less than 10%.

[0091] Step 9.2: Bond the gold wires of the external cavity chip 101 and the gold wires of the backlight detector to form an electrical connection with the pins on the housing 100.

[0092] Step 9.3: Temperature cycle test. It is qualified if the power change after temperature cycling is less than 10%.

[0093] Step 9.4: Parallel seam welding.

[0094] In other embodiments of the present invention, the external cavity chip 101 and the gain chip 102 can also be replaced with other forms of light-emitting chips.

[0095] In other embodiments of the present invention, the coupling lens 105 and the optical fiber 106 can also be replaced with an optical fiber collimator.

[0096] In other embodiments of the present invention, the total reflection mirror 121 is a coupling auxiliary material, which can reflect all the incident light and must be removed after coupling is completed.

[0097] In other embodiments of the present invention, the clamping of the device includes various methods such as suction and clamping.

[0098] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made in these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A highly reliable tunable laser, comprising a housing (100), characterized in that: A light-emitting chip is disposed inside the housing (100). The light emitted by the light-emitting chip sequentially passes through a collimating lens (103), an isolator (104), and a beam splitter (111). The beam splitter (111) divides the light into two paths of primary light. One path of the primary light enters an optical fiber (106) through a coupling lens (105), and the other path of the primary light enters a beam splitting prism (112) and is divided into two paths of secondary light. One path of the secondary light enters a backlight detector I (113), and the other path of the secondary light enters a backlight detector II (116) through an etalon (114); when the etalon (114) is coupled, a total reflection mirror (121) is disposed inside the housing (100) to totally reflect the secondary light passing through the etalon (114) to the coupling lens (105). After the position of the etalon (114) is determined, the total reflection mirror (121) is removed.

2. The tunable laser with high reliability according to claim 1, characterized in that: The gain chip (102), the thermistor, and the gain chip thin-film circuit are die-bonded and pasted on a heat sink substrate; the heat sink substrate is pasted on a semiconductor refrigerator, and the semiconductor refrigerator is sintered on the housing (100); the gain chip (102) and the thermistor are wire-bonded, and the semiconductor refrigerator is welded to the pins of the housing (100).

3. The tunable laser with high reliability according to claim 1, wherein: The isolator (104), the beam splitter (111), and the beam splitting prism (112) are positioned and fixed through passive coupling.

4. A highly reliable tunable laser according to claim 1, characterized in that: The beam splitting prism (112) is provided with a total reflection surface (201) and a beam splitting surface (202), and the ratio of reflection to transmission of the beam splitting surface (202) is 50:50 to 70:

30.

5. A highly reliable tunable laser according to claim 1, characterized in that: The collimating lens (103), the coupling lens (105), and the optical fiber (106) are adjusted and coupled to the maximum output power and an acceptable side mode suppression ratio and then fixed.

6. The tunable laser with high reliability according to claim 1, characterized in that: When the etalon (114) is coupled, after the center wavelength of the longitudinal mode of the light received by the spectrometer connected to the optical fiber (106) is the required wavelength, the position of the etalon (114) is fixed and the total reflection mirror (121) is removed.

7. The tunable laser with high reliability according to claim 1, characterized in that: The external cavity chip (101) is coupled to the maximum output power and then fixed.

8. The tunable laser with high reliability according to claim 1, wherein: The external cavity chip (101), the backlight detector I (113), and the backlight detector II (116) are electrically connected to the pins of the housing (100) through wire bonding.

9. A coupling method for a highly reliable tunable laser, characterized in that: Including the following steps: Die-bond and paste the gain chip (102), the thermistor, and the gain chip thin-film circuit on a heat sink substrate; paste the heat sink substrate on a semiconductor refrigerator and sinter the semiconductor refrigerator on the housing (100); wire-bond the gain chip (102) and the thermistor, and weld the semiconductor refrigerator to the pins of the housing (100); Passively couple and fix the isolator (104), the beam splitter (111), and the beam splitting prism (112); Power on the laser to enable the gain chip (102) to emit light normally; Clamp the collimating lens (103), coupling lens (105), and optical fiber (106). The output end of the optical fiber (106) is connected to a power meter and a spectrometer through an optical splitter for detection. Adjust the displacements and angles of the collimating lens (103), coupling lens (105), and optical fiber (106) to couple to the maximum output power and an acceptable side mode suppression ratio, and fix the optical fiber (106), collimating lens (103), and coupling lens (105). Clamp the total reflection mirror (121) and the etalon (114). Make the light split by the splitting surface (202) on the beam splitting prism (112) pass through the etalon (114), total reflection mirror (121), and coupling lens (105) in sequence and then enter the optical fiber (106). Adjust the displacement and angle of the etalon (114) so that the central wavelength of the longitudinal mode of the light received by the spectrometer is the required wavelength. Fix the etalon (114) and remove the total reflection mirror (121). Clamp the external cavity chip (101). Adjust the displacement and angle of the external cavity chip (101) to couple to the maximum output power and fix it. Fix the backlight detector I (113) and backlight detector II (116). Wire the backlight detector I (113) and backlight detector II (116); wire the external cavity chip (101); cover.

10. A coupling method for a highly reliable tunable laser according to claim 9, characterized in that: When coupling the collimating lens (103), coupling lens (105), and optical fiber (106), clamp the collimating lens (103), adjust the collimating lens (103), and perform stray light coupling of the collimating lens (103) to increase the power. Then clamp the coupling lens (105) and adjust the coupling lens (105) to continue increasing the power. Then finely adjust the collimating lens (103), and the power further increases. When the maximum power is reached, fix the collimating lens (103) and coupling lens (105).

11. The coupling method of a highly reliable tunable laser according to claim 9, characterized in that: After laser coupling, perform baking. If the power change after baking is less than 10%, it is qualified. Then perform gold wire bonding on the external cavity chip (101) and the backlight detector I (113) and backlight detector II (116) to form an electrical connection with the pins on the housing (100). Then perform a temperature cycle test. If the power change after the temperature cycle is less than 10%, it is qualified.

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