Patent Publication Number: US-11651787-B2

Title: VCSEL array for HAMR

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of co-pending U.S. patent application Ser. No. 16/908,270, filed Jun. 22, 2020, which is herein incorporated by reference. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     Embodiments of the present disclosure generally relate to a magnetic recording head for a magnetic media drive. 
     Description of the Related Art 
     The heart of the functioning and capability of a computer is the storing and writing of data to a data storage device, such as a magnetic media drive (e.g., hard disk drive (HDD)). The volume of data processed by a computer is increasing rapidly. There is a need for higher recording density of a magnetic recording medium to increase the function and the capability of a computer. 
     In order to achieve higher recording densities, such as recording densities exceeding 2 Tbit/in 2  for a magnetic recording medium, the width and pitch of write tracks are narrowed, and thus the corresponding magnetically recorded bits encoded in each write track is narrowed. One challenge in narrowing the width and pitch of write tracks is decreasing a surface area of a main pole of the magnetic recording write head at a media facing surface of the recording medium. As the main pole becomes smaller, the recording field becomes smaller as well, limiting the effectiveness of the magnetic recording write head. 
     Heat-assisted magnetic recording (HAMR) and microwave assisted magnetic recording (MAMR) are two types of energy-assisted recording technology to improve the recording density of a magnetic recording medium. In HAMR, a laser source is located next to or near the write element in order to produce heat, such as a laser source exciting a near-field transducer (NFT) to produce heat at a write location of a magnetic recording medium. 
     HAMR typically utilizes an edge emitting laser diode (EELD) as the light source. There are a number of issues with EELD such as the need to mount a sub-mount to a slider which increases cost, mode-hops that can suddenly change recording power and reduce HAMR HDD capacity, small diameter output beams such that there is little alignment tolerance, intense optical mode at the facet which can lower reliability, necessity for burn-in during manufacturing which increases costs, and a high profile on the slider which increases disk-to-disk spacing. 
     Therefore, there is a need in the art for an improved HAMR magnetic media drive. 
     SUMMARY OF THE DISCLOSURE 
     The present disclosure relates to pretreating a magnetic recording head for magnetic media drive. For a heat assisted magnetic recording (HAMR) head, a light source provides the necessary heat for the drive to operation. A vertical cavity surface emitting laser (VCSEL) is mounted to a top surface of a slider. A plurality of laser beams are emitted from the bottom surface of the VCSEL and directed to a corresponding number of waveguide structures within the HAMR head. The waveguide structures feed into a multimode interference (MMI) device that then directs the laser into a single waveguide for focusing on a near field transducer (NFT). The VCSEL lasers are phase coherent and have no mode hopping. 
     In one embodiment, a vertical cavity surface emitting laser (VCSEL) device comprises: a chip for mounting on a slider, wherein the chip has a first surface for facing the slider; and a plurality of laser apertures disposed in the first surface, wherein the plurality of laser apertures are spaced apart by a pitch of between 2 microns and 10 microns, wherein the VCSEL device is capable of emitting a plurality of lasers corresponding to the plurality of laser apertures, and wherein the plurality of lasers operate at the same frequency, and wherein the plurality of laser apertures are linearly arranged. 
     In another embodiment, a magnetic recording head assembly comprises: a leading shield; a main pole; a near field transducer (NFT) coupled between the leading shield and the main pole; a waveguide structure coupled to the NFT, wherein the waveguide structure comprises: a first waveguide coupled to the NFT; a multimodal interference (MMI) device coupled to the first waveguide at a first end; and a plurality of second waveguides coupled to a second end opposite the first end of the MMI device, wherein the plurality of second waveguides extend from the MMI device to a top surface of the head assembly, wherein the top surface of the head assembly is opposite a media facing surface; and a vertical cavity surface emitting laser (VCSEL) device coupled to the top surface. 
     In another embodiment, a magnetic media drive comprises: a magnetic recording head, wherein the magnetic recording head comprises: a near field transducer (NFT) at a media facing surface (MFS); a waveguide structure extending between the NFT and a first surface opposite the MFS; and a vertical cavity surface emitting laser (VCSEL) device coupled to the first surface, wherein the VCSEL includes a second surface facing the first surface, wherein the VCSEL is capable of emitting a plurality of lasers through the second surface; and a magnetic media facing the MFS. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
         FIG.  1    is a schematic illustration of certain embodiments of a magnetic media drive including a HAMR magnetic write head. 
         FIG.  2    is a schematic illustration of certain embodiments of a cross sectional side view of a HAMR write head facing a magnetic disk. 
         FIGS.  3 A and  3 B  are schematic illustrations of a slider having a VCSEL mounted thereto according to one embodiment. 
         FIGS.  4 A- 4 C  are schematic illustrations of a VCSEL according to one embodiment. 
         FIG.  5    is a schematic illustration of a waveguide structure of a HAMR head according to one embodiment. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
     DETAILED DESCRIPTION 
     In the following, reference is made to embodiments of the disclosure. However, it should be understood that the disclosure is not limited to specific described embodiments. Instead, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement and practice the disclosure. Furthermore, although embodiments of the disclosure may achieve advantages over other possible solutions and/or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the disclosure. Thus, the following aspects, features, embodiments and advantages are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, reference to “the disclosure” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s). 
     The present disclosure relates to pretreating a magnetic recording head for magnetic media drive. For a heat assisted magnetic recording (HAMR) head, a light source provides the necessary heat for the drive to operate. A vertical cavity surface emitting laser (VCSEL) is mounted to a top surface of a slider. A plurality of laser beams are emitted from the bottom surface of the VCSEL and directed to a corresponding number of waveguide structures within the HAMR head. The waveguide structures feed into a multimode interference (MMI) device that then directs the laser into a single waveguide for focusing on a near field transducer (NFT). The VCSEL lasers are phase coherent and have no mode hopping. 
       FIG.  1    is a schematic illustration of certain embodiments of a magnetic media drive including a HAMR magnetic write head. Such magnetic media drive may be a single drive/device or comprise multiple drives/devices. For the ease of illustration, a single disk drive  100  is shown according to one embodiment. The disk drive  100  includes at least one rotatable magnetic recording medium  112  (oftentimes referred to as magnetic disk  112 ) supported on a spindle  114  and rotated by a drive motor  118 . The magnetic recording on each magnetic disk  112  is in the form of any suitable patterns of data tracks, such as annular patterns of concentric data tracks (not shown) on the magnetic disk  112 . 
     At least one slider  113  is positioned near the magnetic disk  112 . Each slider  113  supports a head assembly  121  including one or more read heads and one or more write heads such as a HAMR write head. As the magnetic disk  112  rotates, the slider  113  moves radially in and out over the disk surface  122  so that the head assembly  121  may access different tracks of the magnetic disk  112  where desired data are written. Each slider  113  is attached to an actuator arm  119  by way of a suspension  115 . The suspension  115  provides a slight spring force which biases the slider  113  toward the disk surface  122 . Each actuator arm  119  is attached to an actuator  127 . The actuator  127  as shown in  FIG.  1    may be a voice coil motor (VCM). The VCM includes a coil movable within a fixed magnetic field, the direction and speed of the coil movements being controlled by the motor current signals supplied by control unit  129 . 
     During operation of the disk drive  100 , the rotation of the magnetic disk  112  generates an air bearing between the slider  113  and the disk surface  122  which exerts an upward force or lift on the slider  113 . The air bearing thus counter-balances the slight spring force of suspension  115  and supports slider  113  off and slightly above the disk surface  122  by a small, substantially constant spacing during normal operation. 
     The various components of the disk drive  100  are controlled in operation by control signals generated by control unit  129 , such as access control signals and internal clock signals. Typically, the control unit  129  comprises logic control circuits, storage means, and a microprocessor. The control unit  129  generates control signals to control various system operations such as drive motor control signals on line  123  and head position and seek control signals on line  128 . The control signals on line  128  provide the desired current profiles to optimally move and position slider  113  to the desired data track on magnetic disk  112 . Write and read signals are communicated to and from the head assembly  121  by way of recording channel  125 . Certain embodiments of a magnetic media drive of  FIG.  1    may further include a plurality of media, or disks, a plurality of actuators, and/or a plurality number of sliders. 
       FIG.  2    is a schematic illustration of certain embodiments of a cross sectional side view of a HAMR write head  230  facing a magnetic disk  112 . The HAMR write head  230  may correspond to part of the reading/recording head assembly  121  described in  FIG.  1    or a recording head used in other magnetic media drives. The HAMR write head  230  includes a media facing surface (MFS), such as an air bearing surface (ABS) or a gas bearing surface (GBS), facing the disk  112 . As shown in  FIG.  2   , the magnetic disk  112  and the HAMR write head  230  relatively moves in the direction indicated by the arrows  282  (need to change direction). 
     The HAMR write head  230  includes a main pole  236  disposed between a leading return pole  234  and a trailing return pole  238 . The main pole  236  can include a main pole tip  237  at the MFS. The main pole tip  237  can include or not include a leading taper and/or a trailing taper. A coil  260  around the main pole  236  excites the main pole tip  237  to produce a writing magnetic field for affecting a magnetic medium of the rotatable magnetic disk  112 . The coil  260  may be a helical structure or one or more sets of pancake structures. The leading shield  234  and/or the trailing shield  238  can act as the return pole for the main pole  236 . 
     The magnetic disk  112  is positioned adjacent to or under the HAMR write head  230 . A magnetic field produced by current in the coil  260  is used to control the direction of magnetization of bits in the magnetic disk  112 . 
     The HAMR write head  230  includes a structure for heating the magnetic disk  112  proximate to where the main pole tip  237  applies the magnetic write field to the storage media. A waveguide  242  is positioned between the main pole  236  and the leading shield  234 . The waveguide  242  can includes a core layer and a cladding layer surrounding the core layer. The waveguide  242  conducts light from a light source  278  of electromagnetic radiation, which may be, for example, ultraviolet, infrared, or visible light. The light source  278  may be, for example, a laser diode, or other suitable laser light source for directing a light beam toward the waveguide  242 . Various techniques that are known for coupling the light source  278  into the waveguide  242  may be used. For example, the light source  278  may work in combination with an optical fiber and external optics for directing a light beam to the waveguide  242 . Alternatively, the light source  278  may be mounted on the waveguide  242  and the light beam may be directly coupled into the waveguide  242  without the need for external optical configurations. Once the light beam is coupled into the waveguide  242 , the light propagates through the waveguide and heats a portion of the media, as the media moves relative to the HAMR write head  230  as shown by arrows  282 . 
     The HAMR write head  230  can include a near-field transducer (NFT)  284  to concentrate the heat in the vicinity of the end of the waveguide  242 . The NFT  284  is positioned in or adjacent to the waveguide  242  near or at the MFS. Light from the waveguide  242  is absorbed by the NFT  284  and excites surface plasmons which travel along the outside of the NFT  284  towards the MFS concentrating electric charge at the tip of the NFT  284  which in turn capacitively couples to the magnetic disk and heats a precise area of the magnetic disk  112  by Joule heating. One possible NFT  284  for the HAMR write head is a lollipop design with a disk portion and a peg extending between the disk and the MFS. The NFT  284  can be placed in close proximity to the main pole  236 . The NFT  284  is relatively thermally isolated and absorbs a significant portion of the laser power while it is in resonance. 
       FIGS.  3 A and  3 B  are schematic illustrations of a slider  302  having a VCSEL  304  mounted thereto according to one embodiment. The VCSEL  304  is mounted to the slider  302  via a first contact  308   a  and a second contact  308   b  in a first location as shown in  FIG.  3 B . In one embodiment, the VCSEL  304  is mounted on top of the slider  302 , unlike an edge emitting laser diode (EELD) which typically needs to be first mounted to a sub-mount because it is difficult to bond the edge-emitting facet face of the laser directly to the top of the slider. The VCSEL  304  may have a minimal design structure, such that the dimensions of the VCSEL  304  may reduce the overall size of the HAMR write head. The VCSEL  304  includes a mesa  306  on a bottom surface of the VCSEL  304  facing the slider  302 , where the mesa  306  is located between the VCSEL  304  and the slider  302 . In  FIG.  3 B , the VCSEL  304  is shown in phantom to provide better visibility to the electrodes  321  on the top surface of the slider  302 . The electrodes  321  provide the electrical connection, via an electrically conductive soldering material, to the electrodes of the VCSEL  304 . The electrodes  321 , the soldering material, and the electrodes of the VCSEL  304  collectively form the first contact  308   a  and the second contact  308   b . The electrodes  321  extend above the slider  302  by a distance of between about 1 micron and about 3 microns. 
     The VCSEL  304  is capable of emitting a plurality of lasers that correspond to plurality of laser apertures of the mesa  306 , where each of the plurality of lasers is aligned with the plurality of laser apertures (shown in  FIG.  4 C ) of the mesa  306 . Furthermore, the slider  302  includes a plurality of spot size converters  314   a - 314   n  that match the position and number of input lasers emitted by the VCSEL  304 . The spot size converters  314   a - 314   n  extend from the top surface of the slider  302  facing the VCSEL  304 . The mesa  306  is spaced from the top surface of the slider  302  by a first distance  318  of about 1 μm to about 20 μm. The mesa  306  includes a plurality of laser apertures, such as about 2 laser apertures to about 16 apertures. The previously listed values are not intended to be limiting, but to provide an example of an embodiment. The mesa is part of the VCSEL  304  chip and the apertures are on the surface of the mesa  306 . The mesa  306  is an optional relief structure on the surface of the VCSEL  304 . 
     The number of lasers mentioned above that the VCSEL  304  is capable of emitting matches the number of laser apertures of the mesa  306  as well as the number of spot size converters  314   a - 314   n . Each laser, and hence each spot size converter  314   a - 314   n  is spaced apart by a second distance. The second distance between each of the spot size converters  314   a - 314   n  is about 2 μm to about 10 μm. Furthermore, each of the plurality of lasers emitted by the VCSEL  304  operates at the same frequency and are phase coherent. For example, adjacent apertures may be in-phase or out-of-phase with each other. Each laser of the plurality of lasers emitted by the VCSEL  304  has a power level of between about 1 mW to about 10 mW. The previously listed value is not intended to be limiting, but to provide an example of an embodiment. The plurality of lasers each has an active region (e.g., an area where the laser excited electrons). These active regions are spaced close enough to enable coupling and phase coherence to occur. 
     The slider  302  includes a plurality of bonding pad studs  312   a - 312   n , such as about 2 bonding pad studs to about 32 bonding pad studs. The bonding pad studs  312   a - 312   n  have a first width  320  of about 25 μm, where the spacing  322  between adjacent bonding pad studs  312   a - 312   n  is about 32 μm. The previously listed values are not intended to be limiting, but to provide an example of an embodiment. The plurality of spot size converters  314   a - 314   n  are disposed at a location disposed between adjacent bonding pad studs  312   a - 312   n . In the embodiment shown in  FIG.  3 A , the spot size converters  314   a - 314   n  are disposed between bonding pad studs  312   c  and  312   d . Thus, in one example embodiment, all of the spot size converters  314   a - 314   n  need to fit within a linear distance of about 32 μm. Furthermore, the plurality of lasers, and hence, the plurality of spot size converters  314   a - 314   n  are linearly arranged. Each spot size converter  314   a - 314   n  is spaced about 2 μm to about 10 μm from the adjacent spot size converter  314   a - 314   n.    
     The plurality of spot size converters  314   a - 314   n  feed into a multimode interference (MMI) device  310  that is disposed within the slider  302 . The MMI device  310  combines the laser light fed from the output of the plurality of spot size converters  314   a - 314   n  at a first end, and emits a single laser through a single output waveguide  316 . The single waveguide  316  emits laser light from the MMI device  310  that includes the combined power of the plurality of input lasers from the plurality of spot size converters  314   a - 314   n  accepted by the MMI device  310 . The single output mode is needed to properly concentrate the optical power and couple to the NFT. Proper operation of the MMI typically requires stable phase coherence between the inputs. 
       FIG.  4 A  is a schematic illustration of the side view of the VCSEL  400 ,  FIG.  4 B  is a schematic illustration of the top view of the VCSEL  400 , and  FIG.  4 C  is a schematic illustration of the bottom view of the VCSEL  400  according to various embodiments. The side surface  402  of the VCSEL  400  includes a height (H) of about 75 μm to about 150 μm and a length (L) of about 100 μm to about 250 μm. The top surface  404  and the bottom surface  406  of the VCSEL  400  include the same dimensions. The dimensions of the top surface  404  and the bottom surface  406  include a width (W) of about 150 μm and a length of about 150 μm, where the length of the top surface  404 , the bottom surface  406 , and the side surface  402  are equal. The VCSEL  400  may have a plurality of electrodes  411  on the top surface  404  as shown in  FIG.  4 B , and they may be used to energize the VCSEL during active alignment before bonding. 
     In  FIG.  4 C , a plurality of laser apertures  408   a - 408   n  are disposed on the bottom surface  406  of the VCSEL  400 . The number of laser apertures  408   a - 408   n  matches the number of spot size converters of the slider, such as the spot size converters  314   a - 314   n  of  FIG.  3 A . Each laser aperture  408   a - 408   n  is spaced by a distance  412  of about 2 μm to about 10 μm from the adjacent laser aperture  408   a - 408   n . Furthermore, the laser apertures  408   a - 408   n  are aligned about a center line and each of the plurality laser apertures  408   a - 408   n  are aligned to a corresponding input laser. In addition to being aligned to each input laser, the laser apertures  408   a - 408   n  are aligned with a corresponding laser aperture of the mesa, such as the laser apertures of the mesa  306  of  FIG.  3   . 
     As shown in  FIG.  4 C , the bottom surface  406  of the VCSEL  400  has a plurality of electrodes  410  thereon to that function as anode and cathode, and mate with electrodes  321  of the slider  302  via soldering material. The electrodes  410  extend from the bottom surface  406  of the VCSEL  400  towards the slider for a distance of between about 1 micro and about 3 microns. Thus, in one embodiment, the gap between the VCSEL  400  and the slider  302  is between about 2 microns and about 6 microns. Additionally, the VCSEL  400  has a length  428  of between about 100 microns and about 200 microns. The VCSEL  400  also have a length  426  of between about 100 microns and about 200 microns. The apertures  408   a - 408   n  each have a diameter of between about 1.5 microns and about 8 microns and are on a 2 micron to 10 micron pitch. The center of the apertures  408   a - 408   n  are spaced from the side surface  402  by a distance  422  of between about 35 microns and about 50 microns. The center of the apertures  408   a - 408   n  are spaced from the electrodes  410  by a distance  424  of between about 75 microns and about 90 microns. 
       FIG.  5    is a schematic illustration of a waveguide structure  500  of a HAMR head according to one embodiment. The slider, such as the slider  302  of  FIG.  3   , includes the waveguide structure  500  that includes a first spot size converter  506  that extends from the NFT to the MMI device  502 . The waveguide structure  500  also includes a plurality of second spot size converters  504   a - 504   n , such as about 2 second spot size converters to about 8 second spot size converters. The number of second spot size converters  504   a - 504   n  matches the number of laser apertures  408   a - 408   n  of the VCSEL  400  described in  FIG.  4 C , the number of laser apertures of the mesa  306  described in  FIG.  3 A , and the number of spot size converters  314   a - 314   n  described in  FIG.  3 A . 
     The plurality of second spot size converters  504   a - 504   n  fit within the spacing between the bonding pad studs, such as the bonding pad studs  312   a - 312   n , such that the distance between the leftmost second spot size converter  504   a  and the rightmost second spot size converter  504   n  is less than the space of about 32 μm between the bonding pad studs. Furthermore, the plurality of laser apertures  408   a - 408   n  of the VCSEL described in  FIG.  4 C , the plurality of laser apertures of the mesa  306  described in  FIG.  3 A , and the plurality of emitted lasers, are each aligned with a corresponding second spot size converters  504   a - 504   n.    
     As noted above, the waveguide structure  500  further includes a MMI device  502 . The MMI device  502  may be the same as the MMI device  310  of  FIG.  3   . The first spot size converter  506  at a first end is coupled to the MMI device  502  at a first end and the plurality of second spot size converters  504   a - 504   n  at a second end are coupled to the MMI device  502  at a second end that is opposite of the first end of the MMI device  502 . The first spot size converter  506 , at a second end, is further coupled to a NFT, such as the NFT  284  of  FIG.  2   . 
     Furthermore, the core width of the second spot size converters  504   a - 504   n  gradually increases from about 150 nm to about 600 nm, along the direction towards the MMI device  502 . At 150 nm, the spot size is matched to the large VCSEL mode size of a few microns. At 600 nm, the waveguide mode is only a few hundred nanometers before going into the MMI device  502 . 
     VCSELs have a number of significant advantages for use as the light source in HAMR. The edge emitting laser diode (EELD) used today is typically mounted to a sub-mount because it is difficult to bond the edge-emitting facet face of the laser directly to the top of the slider. This sub-mount is then bonded to the slider. A VCSEL can easily have bonding electrodes on the surface-emitting face which match to corresponding electrodes on the top surface of the slider. These electrodes can be bonded together by laser-assisted solder reflow and can also serve as electrical connections for energizing the laser. By eliminating the need for a sub-mount, the light source cost can be significantly reduced. The VCSEL laser facet is made in a wafer level process which further lowers cost relative to EELDs. A VCSEL output beam is also larger and more circular than that of an EELD which increases the alignment tolerance and coupling efficiency to the slider spot size convertor. VCSELs are known to have higher reliability than EELDs due to larger, less intense optical mode and the wafer facet process. As a result, VCSELs do not require burn-in during manufacturing which further lowers cost. Since the VCSEL cavity length is shorter than EELDs, and because the laser is mounted on top of the slider, the lower overall height allows for a reduced disk-to-disk spacing, potentially more disks, and for higher HDD capacity. 
     Further, VCSELs have mode hop-free operation due to very short cavity length with one longitudinal mode and DBR mirror selectivity while EELDs suffer from mode hops. Mode hopping can cause a small (typically 1-2%) change in laser power to suddenly occur during the recording process. The possibility of a track width change and bit shift must be accounted for, which reduces the capacity of the HDD. 
     The primary technical issue with VCSELs is the relatively low output power relative to EELDs. Multimode VCSELs can have larger output power than single mode VCSELs but single mode operation is required by the waveguides and NFTs that are used to create the heat spot in the disk for HAMR. Single mode VCSELs typically have only about 2 mW of maximum output power, far short of the 10-20 mW needed for HAMR. The output cannot be efficiently increased by combining the outputs from multiple separate VCSELs because of decoherence between the wave fronts. If the active region of adjacent VCSELs are brought very close together, the wave functions will overlap enough to create coupling and phase coherence between their outputs. With the right VCSEL design and light delivery scheme, these outputs may be combined into a single waveguide with the necessary 5-10 mW of single mode power needed by the NFT for HAMR. 
     In one embodiment, a vertical cavity surface emitting laser (VCSEL) device comprises: a chip for mounting on a slider, wherein the chip has a first surface for facing the slider; and a plurality of laser apertures disposed in the first surface, wherein the plurality of laser apertures are spaced apart by a distance of between about 2 microns and about 10 microns, wherein the VCSEL device is capable of emitting a plurality of lasers corresponding to the plurality of laser apertures, wherein the plurality of lasers operate at the same frequency, and wherein the plurality of laser apertures are linearly arranged. The VCSEL device is capable of emitting a plurality of lasers that are phase coherent. The plurality of laser apertures includes 2-8 laser apertures. The VCSEL device is capable of emitting a plurality of lasers corresponding to the plurality of laser apertures, and wherein each laser of the plurality of lasers has a power level of between about 1 mW and about 10 mW. The first surface comprises a mesa and wherein the plurality of laser apertures are disposed in the mesa, wherein the plurality of laser apertures are spaced apart by a distance of between about 2 microns and about 10 microns. The VCSEL device further comprises a plurality of electrodes coupled to the first surface. The electrodes extend about 10 microns, and more preferably up to 2 microns from the first surface towards the slider. A magnetic media drive comprising the VCSEL device is also disclosed. 
     In another embodiment, a magnetic recording head assembly comprises: a leading shield; a main pole; a near field transducer (NFT) coupled between the leading shield and the main pole; a waveguide structure coupled to the NFT, wherein the waveguide structure comprises: a first waveguide coupled to the NFT; a multimodal interference (MMI) device coupled to the first waveguide at a first end; and a plurality of second waveguides coupled to a second end opposite the first end of the MMI device, wherein the plurality of second waveguides extend from the MMI device to a top surface of the head assembly, wherein the top surface of the head assembly is opposite a media facing surface; and a vertical cavity surface emitting laser (VCSEL) device coupled to the top surface. The VCSEL has a plurality of laser apertures that align with the plurality of second waveguides. The plurality of laser apertures are aligned with the plurality of second waveguides in a near field. The plurality of laser apertures are spaced from the top surface by a first distance of between about 1 microns to about 20 microns. The plurality of second waveguides comprises 2-16 second waveguides. A magnetic media drive comprising the magnetic recording head assembly is also disclosed. 
     In another embodiment, a magnetic media drive comprises: a magnetic recording head, wherein the magnetic recording head comprises: a near field transducer (NFT) at a media facing surface (MFS); a waveguide structure extending between the NFT and a first surface opposite the MFS; and a vertical cavity surface emitting laser (VCSEL) device coupled to the first surface, wherein the VCSEL includes a second surface facing the first surface, wherein the VCSEL is capable of emitting a plurality of lasers through the second surface; and a magnetic media facing the MFS. The second surface is spaced between about 1 microns and about 20 microns from the first surface. The waveguide structure has a width that is less than a width between adjacent electrodes of a slider upon which the magnetic recording head is disposed. The VCSEL is capable of emitting a plurality of lasers that are phase coherent. The waveguide structure comprises a multimodal interference (MMI) device that is disposed between the NFT and the first surface. The VCSEL is capable of emitting a plurality of lasers and wherein the plurality of lasers have active regions that at least partially overlap. 
     While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.