Encapsulation for self-heating using multi-channel laser

Abstract

Aspects described herein include a method of manufacturing an optical assembly. The method includes electrically coupling different laser channels of a laser die to different electrical leads, testing a respective optical coupling of each of the different laser channels, optically aligning an optical fiber with a first laser channel of the different laser channels, the first laser channel having a maximum optical coupling, and designating a second laser channel of the different laser channels as a heater element for the first laser channel. A method is also described including transmitting light from a first laser channel of a laser die into an optical fiber and operating a second laser channel of the laser die as a heater element for the first laser channel.

Description

Technical Field

[0001] The embodiments presented in this disclosure generally relate to optical devices, and more specifically, to techniques for manufacturing and operating optical devices capable of self-heating using multichannel lasers. Background Technology

[0002] The optimal performance of semiconductor-based lasers occurs within a limited temperature range. For example, above this range, laser efficiency (e.g., emitted light power for an electrically biased power) may decrease, while below this range, spectral performance may degrade due to the appearance of out-of-band parasitic laser emission modes. Attached Figure Description

[0003] To gain a more detailed understanding of the features described above in this disclosure, a more specific description of the briefly summarized disclosure can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate typical embodiments and should not be considered limiting; other equally effective embodiments may be contemplated.

[0004] Figure 1 This is an illustration showing a perspective view of an exemplary multichannel laser die according to one or more embodiments.

[0005] Figure 2 This is an exemplary method of manufacturing an optical device according to one or more embodiments.

[0006] Figure 3 This is an exemplary method of operating an optical device according to one or more embodiments.

[0007] Figures 4A-4F An exemplary sequence for manufacturing an optical device according to one or more embodiments is shown.

[0008] Figure 5 This is an illustration showing an exemplary alignment of an optical fiber, lens, and multichannel laser die according to one or more embodiments.

[0009] For ease of understanding, the same reference numerals are used where possible to indicate common elements in the figures. Elements disclosed in one embodiment may be advantageously used in other embodiments without specific description. Detailed Implementation

[0010] Overview

[0011] One embodiment presented in this disclosure is a method of manufacturing an optical component. The method includes: electrically coupling different laser channels of a laser die to different electrical leads; testing the corresponding optical coupling of each of the different laser channels; optically aligning an optical fiber to a first laser channel of the different laser channels, the first laser channel having maximum optical coupling; and designating a second laser channel of the different laser channels as a heater element for the first laser channel.

[0012] Another embodiment presented in this disclosure is an optical assembly comprising a laser die and a housing assembly attached to the laser die. Different laser channels of the laser die are electrically coupled to different electrical leads of the housing assembly. The optical assembly also includes an optical fiber optically aligned with a first laser channel of the different laser channels. A second laser channel of the different laser channels is designated as a heater element for the first laser channel.

[0013] Another embodiment presented in this disclosure is a method comprising: transmitting light from a first laser channel of a laser die into an optical fiber; and operating a second laser channel of the laser die as a heater element for the first laser channel.

[0014] Exemplary embodiments

[0015] Semiconductor-based lasers (e.g., distributed feedback (DFB) lasers) can use high reflectivity (HR) backfaces and antireflectivity (AR) frontfaces. The phase of the backface is often defined by the dicing or etching process, which results in a random phase relationship between the light reflected at the backface and the grating. In some cases, this random phase can correspond to an inappropriately low side-mode rejection ratio (SMSR), indicating a significant parasitic effect affecting the propagation of the modulated signal. These inappropriately low SMSR values ​​can lead to a considerable proportion of laser die failures. To improve laser die yield, multiple laser channels can be formed in each laser die. Therefore, even if one laser channel is determined to be faulty or out of specification during the laser die burn-in process, the other (one or more) laser channels may still be within specifications, and the laser die can remain usable.

[0016] The optimal performance of semiconductor-based lasers occurs within a limited temperature range. For example, above this range, the laser's efficiency (e.g., emitted optical power at electrical bias power) may decrease, while below this range, spectral performance may degrade due to the emergence of out-of-band parasitic laser emission modes. Techniques for laser temperature control may include thermoelectric coolers (TECs) combined with a temperature feedback loop (e.g., a thermistor), or alternatively, heater circuitry (e.g., surface mount technology (SMT) or thin-film resistors) located close to the laser die combined with a temperature feedback loop (e.g., a thermistor).

[0017] According to the embodiments described herein, the optical assembly includes a laser die and a housing assembly attached to the laser die. Different laser channels of the laser die are electrically coupled to different electrical leads of the housing assembly. The optical assembly also includes an optical fiber optically aligned with a first laser channel of the laser channels. A second laser channel of the laser channels is designated as a heater element for the first laser channel.

[0018] Advantageously, including multiple laser stripes on the laser die provides redundancy, thereby significantly improving the yield of the laser die. These laser stripes are arranged close to each other, allowing the use of standard packaging techniques. In some embodiments, the multiple laser stripes share a lens and are spaced apart so that light energy from a first laser channel is coupled to the fiber core, while light energy from a second laser channel (e.g., a heater element) is not coupled to the fiber core. In some embodiments, the maximum optical coupling of the laser channels is determined during testing, and the laser channel with the maximum optical coupling is identified as the first laser channel.

[0019] Figure 1 Illustration 100 is a perspective view of an exemplary multichannel laser die 105 according to one or more embodiments.

[0020] A multichannel laser die 105 (also referred to as laser die 105) includes a substrate 110 and a plurality of laser channels 115-1, 115-2. The substrate 110 may be formed of one or more suitable semiconductor materials (one or more). As shown, the substrate 110 includes an optical waveguide layer 135 disposed above a cladding layer 140, which is disposed above a conductive contact layer 145. The laser channels 115-1, 115-2 are spaced (e.g., pitched) by a distance d and each includes an optically active layer 130-1, 130-2. The multichannel laser die 105 also includes cladding layers 125-1, 125-2 disposed above the optically active layers 130-1, 130-2, and conductive contact layers 120-1, 120-2 disposed above the cladding layers 125-1, 125-2.

[0021] In one example, cladding layers 140, 125-1, and 125-2 comprise indium phosphide (InP) semiconductor material, and the optical waveguide layer 135 may be formed of indium gallium arsenide phosphide (GaInAsP), indium aluminum gallium arsenide (AlGaInAs), or other suitable quaternary compound semiconductor materials. In another example, cladding layers 140, 125-1, and 125-2 comprise aluminum gallium arsenide (AlGaAs) semiconductor material, and the optical waveguide layer 135 may be formed of gallium arsenide (GaAs), AlGaAs (with a lower proportion of aluminum), etc. Optically active layers 130-1 and 130-2 may comprise regions of any suitable optically active material(s), such as quantum wells, quantum dots, and quantum wires. Furthermore, the optically active material(s) may be electrically pumped and / or optically pumped.

[0022] The multichannel laser die 105 includes a front section 150 with an anti-reflective film or coating and a back section 155 with a high-reflectivity film or coating. Each of the laser channels 115-1, 115-2 extends between the front section 150 and the back section 155.

[0023] In some embodiments, laser channels 115-1 and 115-2 have the same phase at the back slit 155. In other embodiments, laser channels 115-1 and 115-2 have a predetermined phase difference at the back slit 155 to remove any unwanted phase of the associated laser channels 115-1 and 115-2.

[0024] Typically, the production of the multichannel laser die 105 requires only one of the laser channels 115-1 and 115-2 to function. Assuming both laser channels 115-1 and 115-2 are functional, "non-preferred" laser channels 115-1 and 115-2 (e.g., having lower optical coupling and / or degraded spectral performance and / or showing signs of early failure (burn-in failure)) can be designated and operated as heater elements for the "preferred" laser channels 115-1 and 115-2, which are operated as laser elements. The heater elements can be operated to increase the operating temperature of the laser and extend the operating range of the laser elements. Furthermore, using one of the laser channels 115-1 and 115-2 as the heater element provides a simpler implementation because additional components such as TEC are not required.

[0025] Figure 2 This is an exemplary method 200 for manufacturing an optical device according to one or more embodiments. Method 200 may be combined with other embodiments (e.g., Figure 1 The multi-channel laser die 105 is used.

[0026] Method 200 begins at block 205, where different channels of the laser die are electrically coupled to different electrical leads. The electrical leads may be included in a package of the optical device. In some embodiments, the header of the package includes the electrical leads, and electrically coupling the different channels to the different electrical leads includes attaching the laser die to the header. In some embodiments, the different channels of the laser die may be electrically coupled to the same electrical lead (e.g., a common cathode shared by the different channels), provided that each channel is also electrically coupled to a different electrical lead (e.g., each of the different channels is electrically coupled to a different anode).

[0027] In block 215, the optical coupling of each of the laser channels is tested. In some embodiments, a monitoring photodiode (e.g., a large-area monitoring photodiode) shared by the laser channels is used to perform the test on the respective optical coupling. In some embodiments, the monitoring photodiode is included in a package (e.g., included in a header).

[0028] In other embodiments, the monitoring photodiode may be external to the optical component package. In some embodiments, testing the corresponding optical coupling includes placing a lens between the laser die and the monitoring photodiode. For example, method 200 may also include contacting a cap of the package with a head, wherein the lens is arranged at an opening in the cap.

[0029] In block 225, the optical fiber is optically aligned with a first laser channel in the laser channels, the first laser channel having maximum optical coupling. In some embodiments, optical alignment of the optical fiber includes moving a cap relative to the head. In this way, optical alignment of the optical fiber is performed via a lens. The method may also include rigidly attaching the cap to the head.

[0030] In some embodiments, fiber optic alignment includes positioning the fiber at a first distance from the lens. The first distance is based on the lens's magnification and is selected to match the mode size of the laser channel with the mode size of the fiber.

[0031] In box 235, the second laser channel in the laser channels is designated as the heater element for the first laser channel. Method 200 ends after box 235 is completed.

[0032] Figure 3 This is an exemplary method 300 for operating an optical device according to one or more embodiments. Method 300 can be used in conjunction with other embodiments, such as operating... Figure 2 The optical device formed by method 200.

[0033] Method 300 begins at block 305, where light is transmitted from a first laser channel of the laser die into an optical fiber. In some embodiments, the light is transmitted into the core of the optical fiber via a lens. At block 315, a temperature measurement is obtained. In some embodiments, a thermistor coupled to the laser die is used to obtain the temperature measurement. In some embodiments, the laser die is disposed within a package, and the temperature measurement is obtained outside the package.

[0034] In block 325, the second laser channel of the laser die is operated as a heater element against the first laser channel. In some embodiments, the second laser channel is operated based on temperature measurements. In some embodiments, light from the second laser channel is transmitted through a lens without coupling into the fiber core. For example, the spacing between the laser die, the lens, and the fiber can be determined such that the light from the second laser channel is offset from the light from the first laser channel at the fiber by a predetermined amount (e.g., a few micrometers) to minimize coupling from the second laser channel into the fiber core. This spacing can also be based on the spacing between the first and second laser channels and the magnification of the lens. Method 300 ends after block 325 is completed.

[0035] Figures 4A-4F An exemplary sequence for manufacturing an optical device according to one or more embodiments is shown. Figures 4A-4E The order shown can be used in combination with other embodiments, for example, Figure 2 One possible implementation of method 200.

[0036] Figure 4A Figure 400 shows a top view of a multi-channel laser die 105. Laser channels 115-1 and 115-2 are disposed on a substrate 110. Laser channels 115-1 and 115-2 extend parallel to each other and are spaced apart by a distance d (e.g., pitch). Figure 400 thus represents the bartesting stage of a pre-bonded chip or multi-channel laser die 105.

[0037] exist Figure 4B In the middle, the multi-channel laser die 105 is bonded to the substrate 410 to form the accessory 405. Figure 4B Therefore, this represents the die bonding, testing, and / or programming stages of the multichannel laser die 105.

[0038] exist Figure 4C and Figure 4DIn this embodiment, accessory 405 is attached to base 425 of head 420 to form accessories 415 and 432, respectively. Head 420 can be formed of any suitable material, such as metal. Head 420 also includes multiple electrical leads 430-1, 430-2, and 430-3. In some embodiments, electrical lead 430-1 is the anode for laser channel 115-1, electrical lead 430-3 is the anode for laser channel 115-2, and electrical lead 430-2 is the common cathode for laser channels 115-1 and 115-2. In other embodiments, laser channels 115-1 and 115-2 can be electrically coupled to different cathodes.

[0039] In some embodiments, testing is performed on the multi-channel laser die 105 to determine the optical and spectral performance and reliability of each of the laser channels 115-1, 115-2. For example, a large-area monitoring photodiode may be shared by the laser channels 115-1, 115-2. In some embodiments, the testing is performed before the accessory 405 is attached to the base 425. In other embodiments, the testing is performed after the accessory 405 is attached to the base 425.

[0040] In some embodiments, a first laser channel 115-1 exhibiting superior performance is designated as a laser element of accessory 405, while a second laser channel 115-2 is designated as a heater element for laser channel 115-1. In some embodiments, such as Figure 4D As shown, attaching accessory 405 to base 425 includes aligning the first laser channel 115-1 with the central axis C of head 420, which in some cases corresponds to the optical axis of the optics. This may occur if the multichannel laser die 105 has been tested and programmed before being attached to head 420. In other embodiments, the optical axis of the optics may not correspond to the central axis C, and the first laser channel 115-1 may be aligned with the optical axis.

[0041] In some embodiments, such as Figure 4C As shown, the first laser channel 115-1 and the second laser channel 115-2 are offset from the central axis C of the head 420 (which in some cases corresponds to the optical axis of the lens of the optical device). However, the offset distance of the laser channels 115-1, 115-2 from the central axis C is relatively small compared to the distance between the laser die and the lens, and the distance between the optical fiber and the lens, such that the offset distance causes only negligible aberrations compared to on-axis optical systems, without reducing optical coupling. This can occur when the multi-channel laser die 105 is attached to the head 420 (e.g., a transistor profile (TO) head) and then tested and programmed.

[0042] exist Figure 4EIn this assembly, the encapsulated cap 440 contacts the head 420 to form an accessory 435, wherein the laser die is disposed within the internal space formed by the cap 440 and the head 420. The cap 440 can be formed of any suitable material, such as metal. A lens 445 is disposed at the opening of the cap 440. In some embodiments, the lens 445 can have a positive magnification, imaging the mode size of the optical signal exiting the laser die onto the mode size of the fiber core. By translating the cap 440 relative to the head 420, the lens 445 can be aligned with the first laser channel 115-1 in two spatial dimensions. Once the lens 445 is aligned with the cut surface, the cap 440 can be rigidly attached to the head 420 (e.g., by welding).

[0043] In some embodiments, the test is performed on the multichannel laser die 105 via lens 445. In these embodiments, the large-area monitoring photodiode 455-1 is external to the optical component package and is shared by laser channels 115-1 and 115-2. In other words, light energy from laser channels 115-1 and 115-2 is directed to the large-area monitoring photodiode 455-1 via lens 445. In other embodiments, the large-area monitoring photodiode 455-2 is included in the package (e.g., included in the header 420) and is shared by laser channels 115-1 and 115-2.

[0044] exist Figure 4F In this configuration, optical connector 465 contacts cap 440 at interface 470 to form accessory 460. Optical connector 465 can have any suitable implementation, such as a fiber optic pigtail or receptacle. Fiber optic cable 480 is rigidly attached to optical connector 465. In some embodiments, sleeve 475 surrounds fiber optic cable 480 and ensures alignment of fiber optic cable 480 during connector mating. Sleeve 475 can be formed of any material with suitable rigidity, such as ceramic, stainless steel, plastic, or tungsten carbide. Any suitable technique (e.g., adhesive or crimping) can be used to rigidly attach sleeve 475 and fiber optic cable 480 to each other. In some cases, one end of sleeve 475 may be polished after rigid attachment of fiber optic cable 480, for example, to provide an improved optical interface.

[0045] The sleeve 475 and the optical fiber 480 are inserted into the internal space of the optical connector 465 and held by the optical connector 465 using any suitable means (e.g., adhesive, friction fit, etc.). In some embodiments, the optical isolator 485 is arranged in the internal space and aligned with the optical fiber 480 upon insertion. By translating the optical connector 465 relative to the cap 440, the optical fiber 480 can be aligned with the first laser channel 115-1 in three spatial dimensions via the optical isolator 485 and the lens 445. Once the optical fiber 480 is aligned with the first laser channel 115-1, the optical connector 465 can be rigidly attached to the cap 440 (e.g., by soldering). Thus, aligning the optical fiber 480 with the laser die involves attaching the optical connector 465 to the housing assembly (e.g., attaching it to the head 420 via the cap 440).

[0046] In some embodiments, operation of the second laser channel 115-2 is based on temperature measurements obtained using a thermistor 490 coupled to the multichannel laser die 105. The thermistor 490 supports an active feedback loop for operating the second laser channel 115-2 as a heater element.

[0047] In other embodiments, operation of the second laser channel 115-2 is based on temperature measurements obtained outside the package (e.g., outside accessory 460). During calibration, the performance of the laser element (i.e., the first laser channel 115-1) can be determined relative to the current and temperature measurements supplied to the second laser channel 115-2. Calibration data can be stored in memory (e.g., in a lookup table), and during operation, the current supplied to the second laser channel 115-2 can be selected based on the temperature measurements to achieve optimal performance of the first laser channel 115-1.

[0048] Figure 5 Figure 500 illustrates an exemplary alignment of an optical fiber, lens, and multichannel laser die according to one or more embodiments. The features shown in Figure 500 can be used in conjunction with other embodiments. For example, Figure 500 represents... Figure 4E One possible implementation of the optical device shown.

[0049] In Figure 500, the inset portion 505 shows optical signals 450-1 and 450-2 exiting the laser channels 115-1 and 115-2 at a cross-section 515 of the laser die 105. Optical signals 450-1 and 450-2 are incident on a lens 445 and directed towards the end face 520 of the optical fiber 480. The inset portion 510 shows the optical signals 450-1 and 450-2 received at the end face 520. Although not shown here, an optical isolator can be arranged between the lens 445 and the end face 520.

[0050] Optical signals 450-1 and 450-2 exit along a segment of the cross-section 515 (distance d1), and are received along a segment of the end face 520 (distance d2). In some embodiments, the end face 520 of the optical fiber 480 and the cross-section 515 of the laser die 105 are parallel, and adjacent optical signals 450-1 and 450-2 are equidistant at the end face 520 and the cross-section 515.

[0051] Lens 445 provides a given magnification to image the mode sizes of optical signals 450-1, 450-2 exiting from the cross-section 515 of the laser die 105 onto the mode size of the fiber core at the end face 520. In some embodiments, the magnification of lens 445 is positive.

[0052] The magnification of lens 445 also affects the spacing between optical signals 450-1 and 450-2 at end face 520. In some embodiments, the spacing between optical signals 450-1 and 450-2 (i.e., distance d2) is greater than about 10 micrometers to minimize crosstalk from optical signal 450-2 to optical signal 450-1 received at the core of optical fiber 480. For example, the spacing between laser channels 115-1 and 115-2 (i.e., distance d1) can be between about 20 micrometers and about 70 micrometers, and the distance d2 can be between about 50 micrometers and 150 micrometers. Other values ​​and ratios of distances d1 and d2 may also be considered.

[0053] The size of lens 445, the spacing between lens 445 and optical fiber 480, and the spacing between lens 445 and cut surface 515 can be selected based on distances d1 and d2. In some embodiments, aligning optical fiber 480 with laser die 105 via lens 445 includes positioning optical fiber 480 at a distance d4 from lens 445. Distance d4 is based on the magnification of lens 445 and is selected to (i) match the mode dimensions of laser channels 115-1, 115-2 with the mode dimensions of the fiber core of optical fiber 480.

[0054] In some embodiments, the distance d4 between lens 445 and optical fiber 480 (i.e., end face 520) is approximately two (2) to five (5) times the distance d3 between lens 445 and cut surface 515. In a non-limiting example, distance d4 is approximately 3000 micrometers, while the second distance is approximately 1000 micrometers. With this combination of distances d3 and d4, the relatively large aperture of lens 445 can support multiple channels. Compared to distances d3 and d4, the offset of optical signals 450-1 and 450-2 relative to the optical axis of lens 445 is relatively small, causing only negligible aberrations compared to on-axis optics without reducing optical coupling.

[0055] Various techniques have been described for manufacturing and operating optical devices capable of self-heating using multi-channel lasers. In some embodiments, the laser die can be bonded to a base and encapsulated on a TO head before optical alignment with the fiber. In some embodiments, each laser channel is tested to identify the superior laser channel for operation as a laser element. In the case of multiple laser channels, the partially encapsulated assembly can be divided into four (4) bins, where only one bin is eliminated when two laser channels fail programming, electrical, power, and spectral screening. Another laser channel can operate as a heating element within the laser die and provides higher efficiency due to its proximity to the laser element, offering extended power handling capabilities for the laser and reducing component costs (e.g., eliminating the need for external heaters or TECs).

[0056] Multiple laser channels are arranged close to each other, allowing the lasers to be implemented within the same mechanical package as a single-channel package. Optical alignment of the fiber with the selected laser channel can be performed without modifying the design, as the fiber offset required for any laser channel falls within the tolerances of the standard fittings.

[0057] Regardless of which laser channel is chosen, the design of the optical system can remain the same because the offset between the laser channel and the lens optical axis is likely to be relatively small compared to the distance between the laser die and the lens, and between the fiber and the lens. This means that the offset distance causes only negligible aberrations and does not reduce optical coupling compared to on-axis optical systems.

[0058] During the manufacturing process, each laser channel can be switched independently for testing, and both laser channels can use the same large-area monitoring photodiode. Once the laser channels are designated as laser and heater elements, optical alignment can be performed with the laser elements on and the heater elements off. Aside from testing each laser channel, the optical assembly can be manufactured without significant changes to the process flow, equipment, or testing schedule.

[0059] Although the laser channels share the same coupling lens, the laser channel designated as the heater element will not couple light into the optical fiber as long as the laser channel is at least a few micrometers away from the laser channel designated as the laser element. In some embodiments, light from the heater element is focused outside the main package cavity (e.g., outside the optical isolator), thus preventing stray light from entering the main package cavity that could interfere with the operation of the laser element.

[0060] In the foregoing, reference has been made to the embodiments presented in this disclosure. However, the scope of this disclosure is not limited to the specifically described embodiments. Rather, any combination of features and elements described, whether or not associated with different embodiments, is considered for implementation and practice of the embodiments contemplated. Furthermore, while the embodiments disclosed herein may achieve advantages over other possible solutions or prior art, whether a given embodiment achieves a particular advantage does not limit the scope of this disclosure. Therefore, the foregoing aspects, features, embodiments, and advantages are merely illustrative and should not be considered as elements or limitations of the appended claims unless expressly recited in claim(s).

[0061] Various aspects of this disclosure are described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments presented in this disclosure. It should be understood that each block in the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to generate a machine, thereby creating, via the processor of the computer or other programmable data processing apparatus, modules for implementing the functions / actions specified in one or more blocks of the flowcharts and / or block diagrams.

[0062] These computer program instructions may also be stored in a computer-readable medium that can direct a computer, other programmable data processing apparatus or other device to operate in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture (including instructions that implement the functions / actions specified in one or more boxes of a flowchart and / or block diagram).

[0063] Computer program instructions may also be loaded onto a computer, other programmable data processing apparatus or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable device, provide a process for implementing the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0064] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments. In this regard, each box in a flowchart or block diagram may represent a module, code segment, or portion of code, comprising one or more executable instructions for implementing one or more specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the boxes may not appear in the order indicated in the figures. For example, two boxes shown consecutively may actually be executed substantially simultaneously, or these boxes may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each box in the block diagrams and / or flowcharts, and combinations of boxes in the block diagrams and / or flowcharts, may be implemented by a system based on dedicated hardware or a combination of dedicated hardware and computer instructions that performs a specific function or action.

[0065] In view of the foregoing, the scope of this disclosure is defined by the appended claims.

Claims

1. A method of manufacturing an optical assembly, the method comprising: electrically coupling different laser channels of a laser die to different electrical leads; testing respective optical couplings between a monitor photodiode and each of the different laser channels; optically aligning an optical fiber to a first laser channel of the different laser channels, of which the first laser channel has a greatest optical coupling to the monitor photodiode; and designating, based on the first laser channel having the greatest optical coupling to the monitor photodiode, a second laser channel of the different laser channels as a heater element for the first laser channel. The electrically coupling of the different laser channels comprises:

2. The method of claim 1, wherein, attaching the laser die to a head of a package of the optical assembly, wherein the head comprises the different electrical leads.

3. The method of claim 2, further comprising: contacting a cap of the package to the head, wherein a lens is disposed at an opening of the cap, and wherein the testing of the respective optical couplings and the optically aligning of the optical fiber are performed through the lens. The optically aligning of the optical fiber comprises moving the cap relative to the head, the method further comprising:

4. The method of claim 3, wherein, rigidly attaching the cap to the head. The optically aligning of the optical fiber comprises:

5. The method of claim 3, wherein, disposing the optical fiber at a first distance from the lens, wherein the first distance is based on a magnification of the lens and is selected to match a mode size of the different laser channels to a mode size of the optical fiber. The monitor photodiode is included in a head of a package of the optical assembly.

6. The method of claim 1, wherein, The monitor photodiode is external to a package of the optical assembly.

7. The method of claim 1, wherein, 8. An optical assembly comprising: a laser die; a housing assembly attached to the laser die, wherein different laser channels of the laser die are electrically coupled to different electrical leads of the housing assembly; a monitor photodiode; and an optical fiber optically aligned to a first laser channel of the different laser channels, of which the first laser channel has a greatest optical coupling to the monitor photodiode, wherein, based on the first laser channel having the greatest optical coupling to the monitor photodiode, a second laser channel of the different laser channels is designated as a heater element for the first laser channel. The housing assembly is a first housing assembly, the optical assembly further comprising:

9. The optical assembly of claim 8, wherein, a second housing assembly in contact with the first housing assembly; and a lens disposed at an opening of the second housing assembly, wherein the optical fiber is optically aligned through the lens. The optical fiber is disposed at a first distance from the lens, the first distance being based on a magnification of the lens and selected to match a mode size of the different laser channels to a mode size of the optical fiber.

10. The optical assembly of claim 9, wherein, 11. The optical assembly of claim 8, wherein the monitor photodiode is included in the housing assembly.

12. A method comprising: ​ a first laser channel of a plurality of laser channels of a laser die has a maximum optical coupling to a monitor photodiode, transmitting light from the first laser channel into an optical fiber; and operating a second laser channel of the plurality of laser channels of the laser die as a heater element for the first laser channel based on the first laser channel having the maximum optical coupling to the monitor photodiode.

13. The method of claim 12, wherein, The first laser channel is selected due to having a greater optical coupling than the second laser channel during testing.

14. The method of claim 12, wherein the laser die is attached to a head of a package, and wherein the monitor photodiode is included in the head.

15. The method of any one of claims 12 to 14, wherein, The operation of the second laser channel is based on temperature measurements taken using a thermistor coupled with the laser die.

16. The method of any of claims 12 to 14, wherein the laser die is disposed within a package, and wherein the operation of the second laser channel is based on temperature measurements taken outside of the package.

17. The method of any of claims 12 to 14, wherein the laser die is attached to a head of a package, wherein the head includes electrical leads, and wherein the first laser channel and the second laser channel are electrically coupled to different electrical leads.

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