Abstract:
Apparatus is disclosed for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising a selected optical component having a periphery forming at least one flat surface; a holding block having at least one attachment region corresponding to the at least one flat surface of the selected optical component; a positioning mechanism having a first portion and a second portion, the first portion configured to position the selected optical component relative to another opto-electronic component, and the second portion configured to position the holding block relative to the selected optical component and in contact with a platform in attachment with the another opto-electronic component; and an attachment component disposed between the selected optical component and the holding block, and the attachment component disposed between the holding block and the platform so as to fix the selected optical component in position relative to the another opto-electronic component. A method of precision alignment and assembly of opto-electronic components relative to one another is disclosed, the method comprising: positioning the selected optical component relative to the another optical component using the first portion of the positioning mechanism; positioning the holding block relative to the selected optical component and in contact with the platform; and securing the selected optical component and the holding block, and the holding block and the platform, with the attachment component.

Description:
REFERENCE TO PENDING PRIOR PATENT APPLICATION 
   This patent application claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 60/465,144, filed Apr. 24, 2003 by Masud Azimi et al. for ATTACHMENT CONFIGURATIONS FOR OPTOELECTRONIC COMPONENTS AND ASSEMBLIES (Attorney&#39;s Docket No. AHURA-12 PROV), which patent application is hereby incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention related to methods and apparatus for the alignment and assembly of optoelectronic components in general, and more particularly to methods and apparatus for precision alignment and assembly of optoelectronic components without a correction process subsequent to attachment of the opto-electronic components. 
   BACKGROUND OF THE INVENTION 
   In order to facilitate large volume production of sophisticated opto-electronic assemblies, it is important to develop high productivity apparatus and methods for manufacturing precision opto-electronic assemblies. This includes avoiding the need to reposition opto-electronic components subsequent to attachment to a common platform or the use of any other post-attachment correction process. 
   The basic building blocks of sophisticated opto-electronic assemblies include optical components such as optical lenses, optical fibers, optical filters, optical beam splitters, optical reflectors, and wavelength selective elements, which need to be precisely positioned with respect to each other and then attached to a common platform. The alignment and attachment of these optical elements should maintain the relative position of these elements with respect to each other and to other components on the common platform at micrometer to sub-micrometer accuracy over life of the device. The development of high productivity methods and apparatus for manufacturing precision opto-electronic assemblies should also include attachment techniques which have three dimensional (3-D) freedom of movement on a common platform with micrometer to sub-micrometer accuracy for free space optical connectivity during alignment and prior to fixation of the optical elements. This should also include attachment techniques as one time alignment-attachment processes which do not require further correction or fine realignment of an optical component after attachment as opposed to the common practice at present time of implementing a post attachment correction process. These methods and apparatus should also be low cost, easy to implement, and useful for large volume manufacturing and prototype fabrication. 
   SUMMARY OF THE INVENTION 
   An object of the invention is to provide a method for alignment and assembly of optoelectronic components. 
   Another object of the invention is to provide a method for alignment and assembly of optoelectronic compounds without a post-attachment correction process. 
   A further object of the invention is to provide apparatus for precision alignment and assembly of optoelectronic components. 
   A still further object is to provide apparatus for alignment and assembly of optoelectronic components without a correction process subsequent to attachment of the opto-electronic components. 
   With the above and other objects in view, as will hereinafter appear, there is provided apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising: 
   a selected optical component having a periphery forming at least one flat surface; 
   a holding block having at least one attachment region corresponding to the at least one flat surface of the selected optical component; 
   a positioning mechanism having a first portion and a second portion, the first portion configured to position the selected optical component relative to another opto-electronic component, and the second portion configured to position the holding block relative to the selected optical component and in contact with a platform in attachment with the another opto-electronic component; and 
   an attachment component disposed between the selected optical component and the holding block, and the attachment component disposed between the holding block and the platform so as to fix the selected optical component in position relative to the another opto-electronic component. 
   In accordance with a further feature of the invention there is provided apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising: 
   a selected optical component having a periphery forming at least one flat surface; 
   a holding block having at least one attachment region corresponding to the at least one flat surface of the selected optical component; 
   a positioning mechanism having a flexible finger mechanism and a pressing mechanism, the flexible finger portion configured to position the selected optical component relative to another opto-electronic component, and the pressing mechanism configured to position the holding block relative to the selected optical component and in contact with a platform in attachment with the another opto-electronic component; and 
   an attachment component disposed between the selected optical component and the holding block, and the attachment component disposed between the holding block and the platform so as to fix the selected optical component in position relative to the another opto-electronic component; 
   wherein the at least one attachment region of the holding block is substantially vertical so as to permit vertical adjustment of the selected optical component with respect to the platform; 
   wherein the holding block comprises a substantially horizontal attachment region configured to permit horizontal adjustment of the selected optical component with respect to the platform prior to fixation of the holding block to the platform; and 
   wherein the positioning mechanism comprises a main body configured for attachment to an XYZ motion system, a gripper arm having a first end and a second end, the first end of the gripper arm connected to a flexture to the main body, the second end of the gripper arm connected to the flexible finger mechanism, and the pressing mechanism comprises a sliding rail system and a spring, a first portion of the sliding rail system mounted vertically to the main body, a second portion of the sliding rail system mounted vertically to the pressing mechanism, and ball bearings between the first portion and the second portion to allow vertical motion, and restrict horizontal motion, of the pressing mechanism with respect to the main body, and the spring extending between the main body and the pressing mechanism to compress the holding block disposed between the platform and the pressing mechanism. 
   In accordance with a further feature of the invention there is provided apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising: 
   a selected optical component having a periphery forming at least one flat surface; 
   a holding block having at least one attachment region corresponding to the at least one flat surface of the selected optical component; 
   a positioning mechanism having a first portion and a second portion, the first portion configured to position the selected optical component relative to another opto-electronic component, and the second portion configured to position the holding block relative to the selected optical component and in contact with a laser submount in attachment with the another opto-electronic component; and 
   an attachment component disposed between the selected optical component and the holding block, and the attachment component disposed between the holding block and the laser submount so as to fix the selected optical component in position relative to the another opto-electronic component; 
   wherein the holding block comprises a substantially vertical attachment region configured to permit vertical adjustment of the holding block along the laser submount prior to fixation of the selected optical component thereon; 
   wherein the at least one attachment region of the holding block is substantially horizontal so as to permit attachment to a substantially horizontally disposed portion of the at least one flat surface of the selected optical component; and 
   wherein the first portion of the positioning mechanism comprises a parallel gripper having a first end and a second end, the first end configured for releasably securing the selected optical component and the second end configured for attachment to an XYZ motion system, and the second portion of the positioning mechanism comprises a holding elevator configured for selectively positioning the holding block in a vertical direction while maintaining contact with the laser submount as contact is made between the at least one attachment region of the holding block and the at least one flat surface of the selected optical component. 
   In accordance with a still further feature of the invention there is provided apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising: 
   a selected optical component having a periphery forming at least two flat surfaces; 
   a first holding block having at least one attachment region corresponding to a first one of the at least two flat surfaces of the selected optical component, and a second holding block having at least one attachment region corresponding to a second one of the at least two flat surfaces of the selected optical component; 
   a positioning mechanism having a first portion and a second portion, the first portion configured to position the selected optical component relative to another opto-electronic component, and the second portion configured to position the first holding block and the second holding block relative to the selected optical component and in contact with a platform in attachment with the another opto-electronic component; and 
   an attachment component disposed between the selected optical component and the holding block, and the attachment component disposed between the holding block and the platform so as to fix the selected optical component in position relative to the another optical component; 
   wherein the second one of the at least two flat surfaces of the selected optical component is disposed in opposition to the first one so as to permit positioning of the holding block and the second holding block in parallel with one another; and 
   wherein the first portion of the positioning mechanism comprises a pair of gripper arms having a first end and a second end, respectively, the first end configured for releasably securing the selected optical component and the second end configured for attachment to an XYZ motion system, and the second potion of the positioning mechanism comprises a pair of push rods selectively extending from the pair of gripper arms, respectively, further wherein the gripper arms and the XYZ motion system are configured to align the selected optical component with the another opto-electronic component, and the push rods are configured to push the first holding block and the second holding block against the platform, respectively. 
   In accordance with another further feature of the invention there is provided apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising: 
   a selected optical component having a periphery forming at least one flat surface; 
   a holding block having at least one attachment region corresponding to the at least one flat surface of the selected optical component; 
   a positioning mechanism having a first portion and a second portion, the first portion configured to position the selected optical component relative to another opto-electronic component, and the second portion configured to position the holding block relative to the selected optical component and in contact with a platform in attachment with the another opto-electronic component; and 
   an attachment component disposed between the selected optical component and the holding block, and disposed between the holding block and the platform so as to fix the selected optical component in position relative to the another opto-electronic component; 
   wherein the holding block has a top surface and a bottom surface, and the top surface and the bottom surface are configured at a non-parallel angle with respect to one another; 
   wherein the at least one flat surface of the optical component is disposed at the non-parallel angle of the holding block when positioned by the first portion of the positioning mechanism so as to mate with the top surface of the holding block when the holding block is wedged between the platform; and 
   wherein the first portion of the positioning mechanism comprises a first pair of gripping mechanisms having a first end and a second end, the first end configured for releasably securing the selected optical component and the second end configured for attachment to an XYZ motion system, and the second portion of the positioning mechanism comprises a second pair of gripping mechanisms configured to slide the holding block over the platform to the selected optical component so as to wedge the holding block between the platform and the selected optical component. 
   In accordance with a still another further feature of the invention there is provided apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising: 
   a selected optical component having a periphery forming at least one flat surface; 
   a holding block having at least one attachment region corresponding to the at least one flat surface of the selected optical component; and 
   an attachment component disposed between the selected optical component and the holding block, and the attachment component disposed between the holding block and the platform so as to fix the selected optical component in position relative to another opto-electronic component. 
   In accordance with a yet still another further feature of the invention there is provided a method of precision alignment and assembly of opto-electronic components relative to one another, the method comprising: 
   providing apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising:
         a selected optical component having a periphery forming at least one flat surface;   a holding block having at least one attachment region corresponding to the at least one flat surface of the selected optical component;   a positioning mechanism having a first portion and a second portion, the first portion configured to position the selected optical component relative to another opto-electronic component, and the second portion configured to position the holding block relative to the selected optical component and in contact with a platform in attachment with the another opto-electronic component; and   an attachment component disposed between the selected optical component and the holding block, and the attachment component disposed between the holding block and the platform so as to fix the selected optical component in position relative to the another opto-electronic component;       

   positioning the selected optical component relative to the another optical component using the first portion of the positioning mechanism; 
   positioning the holding block relative to the selected optical component and in contact with the platform; and 
   securing the selected optical component and the holding block, and the holding block and the platform, with the attachment component. 
   In accordance with another further feature of the invention there is provided a method of precision alignment and assembly of opto-electronic components relative to one another, the method comprising: 
   providing apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising:
         a selected optical component having a periphery forming at least one flat surface;   a holding block having at least one attachment region corresponding to the at least one flat surface of the selected optical component;   a positioning mechanism having a flexible finger mechanism and a pressing mechanism, the flexible finger portion configured to position the selected optical component relative to another opto-electronic component, and the pressing mechanism configured to position the holding block relative to the selected optical component and in contact with a platform in attachment with the another opto-electronic component; and   an attachment component disposed between the selected optical component and the holding block, and the attachment component disposed between the holding block and the platform so as to fix the selected optical component in position relative to the another opto-electronic component;   wherein the at least one attachment region of the holding block is substantially vertical so as to permit vertical adjustment of the selected optical component with respect to the platform;   wherein the holding block comprises a substantially horizontal attachment region configured to permit horizontal adjustment of the selected optical component with respect to the platform prior to fixation of the holding block to the platform; and   wherein the positioning mechanism comprises a main body configured for attachment to an XYZ motion system, a gripper arm having a first end and a second end, the first end of the gripper arm connected to a flexture to the main body, the second end of the gripper arm connected to the flexible finger mechanism, and the pressing mechanism comprises a sliding rail system and a spring, a first portion of the sliding rail system mounted vertically to the main body, a second portion of the sliding rail system mounted vertically to the pressing mechanism, and ball bearings between the first portion and the second portion to allow vertical motion, and restrict horizontal motion, of the pressing mechanism with respect to the main body, and the spring extending between the main body and the pressing mechanism to compress the holding block disposed between the platform and the pressing mechanism;       

   positioning the selected optical component relative to the another optical component using the first portion of the positioning mechanism; 
   positioning the holding block relative to the selected optical component and in contact with the platform; and 
   securing the selected optical component and the holding block, and the holding block and the platform, with the attachment component. 
   In accordance with a still further feature of the invention there is provided a method of precision alignment and assembly of opto-electronic components relative to one another, the method comprising:
         providing apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising:   a selected optical component having a periphery forming at least one flat surface;   a holding block having at least one attachment region corresponding to the at least one flat surface of the selected optical component;   a positioning mechanism having a first portion and a second portion, the first portion configured to position the selected optical component relative to another opto-electronic component, and the second portion configured to position the holding block relative to the selected optical component and in contact with a laser submount in attachment with the another opto-electronic component; and   an attachment component disposed between the selected optical component and the holding block, and the attachment component disposed between the holding block and the laser submount so as to fix the selected optical component in position relative to the another opto-electonic component;   wherein the holding block comprises a substantially vertical attachment region configured to permit vertical adjustment of the holding block along the laser submount prior to fixation of the selected optical component thereon;   wherein the at least one attachment region of the holding block is substantially horizontal so as to permit attachment to a substantially horizontally disposed portion of the at least one flat surface of the selected optical component; and   wherein the first portion of the positioning mechanism comprises a parallel gripper having a first end and a second end, the first end configured for releasably securing the selected optical component and the second end configured for attachment to an XYZ motion system, and the second portion of the positioning mechanism comprises a holding elevator configured for selectively positioning the holding block in a vertical direction while maintaining contact with the laser submount as contact is made between the at least one attachment region of the holding block and the at least one flat surface of the selected optical component;       

   positioning the selected optical component relative to the another optical component using the first portion of the positioning mechanism; 
   positioning the holding block relative to the selected optical component and in contact with the platform; and 
   securing the selected optical component and the holding block, and the holding block and the platform, with the attachment component. 
   In accordance with a yet still further feature of the invention there is provided a method of precision alignment and assembly of opto-electronic components relative to one another, the method comprising: 
   providing apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising:
         a selected optical component having a periphery forming at least two flat surfaces;   a first holding block having at least one attachment region corresponding to a first one of the at least two flat surfaces of the selected optical component, and a second holding block having at least one attachment region corresponding to a second one of the at least two flat surfaces of the selected optical component;   a positioning mechanism having a first portion and a second portion, the first portion configured to position the selected optical component relative to another opto-electronic component, and the second portion configured to position the first holding block and the second holding block relative to the selected optical component and in contact with a platform in attachment with the another opto-electronic component; and   an attachment component disposed between the selected optical component and the holding block, and the attachment component disposed between the holding block and the platform so as to fix the selected optical component in position relative to the another opto-electronic component;   wherein the second one of the at least two flat surfaces of the selected optical component is disposed in opposition to the first one so as to permit positioning of the holding block and the second holding block in parallel with one another; and   wherein the first portion of the positioning mechanism comprises a pair of gripper arms having a first end and a second end, respectively, the first end configured for releasably securing the selected optical component and the second end configured for attachment to an XYZ motion system, and the second potion of the positioning mechanism comprises a pair of push rods selectively extending from the pair of gripper arms, respectively, further wherein the gripper arms and the XYZ motion system are configured to align the selected optical component with the another opto-electronic component, and the push rods are configured to push the first holding block and the second holding block against the platform, respectively;       

   positioning the selected optical component relative to the another optical component using the first portion of the positioning mechanism; 
   positioning the first holding block and the second holding block relative to the selected optical component and in contact with the platform, respectively; and 
   securing the selected optical component with the holding block, and the first holding block and the second holding block with the platform, using the attachment component. 
   In accordance with a still further feature of the invention there is provided a method of precision alignment and assembly of opto-electronic components relative to one another, the method comprising: 
   providing apparatus for precision alignment and assembly of opto-electronic components relative to one another, the apparatus comprising:
         a selected optical component having a periphery forming at least one flat surface;   a holding block having at least one attachment region corresponding to the at least one flat surface of the selected optical component;   a positioning mechanism having a first portion and a second portion, the first portion configured to position the selected optical component relative to another opto-electronic component, and the second portion configured to position the holding block relative to the selected optical component and in contact with a platform in attachment with the another opto-electronic component; and   an attachment component disposed between the selected optical component and the holding block, and disposed between the holding block and the platform so as to fix the selected optical component in position relative to the another opto-electronic component;   wherein the holding block has a top surface and a bottom surface, and the top surface and the bottom surface are configured at a non-parallel angle with respect to one another;   wherein the at least one flat surface of the optical component is disposed at the non-parallel angle of the holding block when positioned by the first portion of the positioning mechanism so as to mate with the top surface of the holding block when the holding block is wedged between the platform; and   wherein the first portion of the positioning mechanism comprises a first pair of gripping mechanisms having a first end and a second end, the first end configured for releasably securing the selected optical component and the second end configured for attachment to an XYZ motion system, and the second portion of the positioning mechanism comprises a second pair of gripping mechanisms configured to slide the holding block over the platform to the selected optical component so as to wedge the holding block between the platform and the selected optical component;       

   positioning the selected optical component relative to the another optical component using the first portion of the positioning mechanism; 
   positioning the holding block relative to the selected optical component and in contact with the platform; and 
   securing the selected optical component and the holding block, and the holding block and the platform, with the attachment component. 
   The above and other features of the invention, including various novel details of construction and combinations of parts and method steps will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular devices and method steps embodying the invention are shown by way of illustration only and not as limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which are to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein: 
       FIG. 1  is a schematic diagram of one form of a novel gripper mechanism configured for side-mount attachment of an optical component to a common platform, which is illustrative of a preferred embodiment of the invention; 
       FIG. 2  is a schematic diagram of the optical component, holding block, and common platform shown aligned and assembled together by the novel gripper mechanism of  FIG. 1 ; 
       FIG. 3  is a schematic diagram of another formed of a novel gripper mechanism configured for front-mount attachment of optical components to a laser submount; 
       FIG. 4  is a schematic diagram of the optical component, holding block, and laser submount shown aligned and assembled together by the novel gripper mechanism of  FIG. 3 ; 
       FIG. 5  is a schematic diagram of a preferred embodiment of the present invention in which there is shown a novel gripper mechanism configured for sandwich-mount attachment of an optical component to a common platform; 
       FIG. 6  is a schematic diagram of the optical component, holding blocks, and common platform as aligned and assembled together by the novel gripper mechanism of  FIG. 5 ; 
       FIG. 7  is a schematic diagram of a preferred embodiment of the present invention in which there is shown a novel system of a wedge attachment block and two pairs of grippers configured for attachment of an optical component to a common platform in optical alignment with another optical component; 
       FIG. 8  is a schematic diagram of the optical component, wedge holding block, and common platform as aligned and assembled together by the two pairs of grippers shown in  FIG. 7 ; and 
       FIG. 9  is a schematic diagram of a novel assembly of a single mode fiber and lens configured in attachment to one another for coupling of light into the fiber. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1–9 , there are shown several attachment, alignment procedure, mechanical holding mechanism and gripping apparatus which are used to align and attach optical components such as optical lenses, optical fibers, optical beam splitters, optical reflectors, wavelength selective elements, and other optical elements to a common platform with sub-micrometer accuracy and high long term reliability and stability. These provide three dimensional (3-D) freedom of movement on a common platform for these elements. The novel apparatus and methods are described hereinbelow for the alignment and attachment of optical lenses made of glass. However, the methods and apparatus are configured to attach lenses made of other materials and other type of elements such as lenses with metal or plastic housing, optical fibers or any other optical element with a similar or corresponding geometry. 
   Referring now to  FIGS. 1 and 2 , and in a preferred embodiment of the present invention, there is shown an optical lens  5  which has a flat side  10  on its periphery. A side-mount gripper mechanism  20  is used to selectively position lens  5  with respect to holding block  15 , and is also used to selectively position both lens  5  and holding block  15  with respect to a common platform  25 . A block of proper material  15 , which here after is referred to as holding block  15  is configured for selective mating and attachment with lens  5 . A gripper mechanism  20  is used to selectively position lens  5  with respect to holding block  15 , and is also used to selectively position both lens  5  and holding block  15  with respect to a common platform  25 . Using this gripper mechanism  20  optical element  5  is aligned and attached in front of a laser  30  or optical fiber (not shown) for collimation or focusing of the light. The attachment of holding block  15  to platform  25  and optical element  5  to holding block  15  can be achieved using an attachment component such as adhesives, solders, laser welding or low melting temperature glasses. For example, adhesives may include UV curable resins or thermally curable resins. The attachment process must be optimized to eliminate or minimize any possible shift of optical component  5  after alignment and attachment. 
   Optical element  5  such as lens  5  with flat side  10  on its periphery is pressed against a block of material  15  using gripper mechanism  20  while block  15  is in contact with common platform ( FIG. 2 ). A main body  35  of gripper mechanism  20  is attached to a 3-D (XYZ) motion or translation system. Main body  35  is moved by this system in the three X,Y and Z directions independently. A gripper arm  40  is attached by a flexure  45  to main body  35  and is configured to press lens  5  against holding block  15 . Between lens  5  and holding block  15  there is disposed an adhesive or solder  50 . Holding block  15  is placed on common platform  25  and an attachment component  50 , such as, adhesive or solder, is disposed between holding block  15  and common platform  25 . Holding block  15  is pressed against common platform  25  using a pressing mechanism  55  together with a compression spring  60  and pressing mechanism  55  is attached to main body using a sliding rail system  65 . Pressing mechanism  55  is therefore configured for movement only along Y axis, i.e. up and down, with respect to main body  35 . Gripper mechanism  20  is configured to press holding block  15  downward in the Y direction against platform  25  and freely move in X and Z direction independent of the downward pressure in the Y direction. If the XYZ motion system is moved in X-Z plane then both holding block  15  and lens  5  are dragged and moved in X-Z plane, respectively. In addition, gripper mechanism  20  has a flexible finger mechanism  70  which is independent from the motion of holding block  15  and can move lens  5  along the Y direction (up and down) independent from the holding block which only can move in X-Z plane. This mechanism  70  enables positioning of optical element  5  (i.e., lens  5 ) with sub-micrometer accuracy in 3-D space while motion in each translation axis X, Y and Z are decoupled and independent from each other. Also, each of these three independent motions have been achieved only with one translation stage with three degrees of freedom. Using this gripper system  20  optical element  5  is attached in front of laser  30  for collimation of the light ( FIG. 2 ). In addition, optical gripper system  20  may be used to attach optical elements in front of an optical fiber for focusing of light (not shown). The attachment of holding block  15  to platform  25  and optical element  5  to holding block  15  can be achieved using attachment component  50 , such as adhesives, solders, laser welding or low melting temperature glasses. These adhesives may include, for example, ultraviolet curable resins or thermally curable resins. The attachment process is preferably optimized to eliminate or minimize any possible shift the optical component  5  after attachment to block  15  and release by gripper mechanism  20 . 
   Front-Mount Attachment 
   Referring now to  FIGS. 3 and 4 , there is shown an optical element  105 , such as a lens  105 , attached at the front of another optical element  110 , such as a laser  110 . A front-mount attachment mechanism  115  is configured to align lens  105  with laser  110  and then a holding block  120  to a laser submount  125 , and attach lens  105  to holding block  120  attached to submount  125 . Submount  125  of semiconductor laser chip  110  is used to attach holding block  120  which in turn holds lens  105  in front of laser chip  110  at a proper distance, height, and lateral position from the emission aperture of laser  110 . 
   To align lens  105  with laser  110 , attachment mechanism  115  uses a parallel gripping structure  130  which is preferably actuated pneumatically to hold lens  105  in front of laser  110 . Gripper  130  is attached to an XYZ motion and translation stage which freely moves lens  105  in all three axes independently. In a first step of the process, lens  105  is free to move in X, Y, and Z direction and has no contact with holding block  120  from its flat side. Next, after lens  105  is aligned with laser  110 , a holding block elevator  135  moves holding block  120  upward to contact lens  105  on a bottom portion  140  while pressing holding block  120  against laser sub-mount  125  with an attachment component  142  therebetween. Preferably, bottom portion  140  of lens  105  is flat so as to correspond to a flat upper portion of holding block  120 . However, other complimentary configurations may be provided. 
   Once lens  105  is in contact with holding block  120 , attachment component  142  between lens  105  and holding block  120  and submount  125  is cured and, as a result, holding block  120  is attached to laser submount  125  and lens  105  is attached to holding block  120  at a proper distance and position from laser emission facet (not shown). To achieve this arrangement attachment component  142  may include adhesive, solder, laser welding, or low melting temperature glass for attachment of lens  105 , holding block  120  and laser sub-mount  125 . 
   Sandwich-Mount Attachment 
   Referring now to  FIGS. 5 and 6 , there is shown an optical glass lens  205  which has two flat sides  210 ,  215  on its periphery. Optical glass lens  205  is mated and attached to two blocks of proper material  220 ,  225  which here after are called holding blocks  220 ,  225 . Optical element  205  is attached in front of a laser  230  for collimation of light ( FIG. 6 ). Alternatively, an optical element may be attached in front of an optical fiber for focusing of light (not shown). The attachment of holding blocks  220 ,  225  to a platform  235  and optical element  205  to holding blocks  220 ,  225  can be achieved using an attachment component  238  such as, for example, an adhesive, solders, laser welding or low melting temperature glasses. The adhesives may include, but are not limited to, ultraviolet curable resins or thermally curable resins. To achieve this arrangement, a sandwich mount gripper mechanism  240  with parallel gripper arms  245 A,  245 B configured to press two flat sides  210 ,  215  of lens  205  against two blocks  220 ,  225  while blocks  220 ,  225  are not in contact with common platform  235 . A main body (not shown) of gripper structure  240  is attached to a 3-D (XYZ) motion or translation system (not shown) which moves main body of gripper mechanism in three X,Y and Z directions independently. Gripper arms  245 A,  245 B are actuated pneumatically and contain two small push rods  250 A,  250 B which are also actuated pneumatically. 
   In first step of the process, lens  205  is aligned at proper position with respect to the facet of laser  230  and then two push rods  250 A,  250 B are activated and as a result these push rods  250 A,  250 B exert force on two holding blocks  220 ,  225  so as to push these blocks  220 ,  225  down against platform  235 . Once the contact between holding blocks  220 ,  225  and platform  235  is achieved, adhesives  238  are cured and parallel gripper arms  245 A,  245 B are opened and lens is released therefrom. 
   Wedge Attachment 
   Referring now to  FIGS. 7 and 8 , there is shown an optical glass lens  305  which has one flat side  310  on its periphery and is configured to mate and attach to a block of material  315  which has a small wedge angle α. A wedge alignment system  320  is provided to attach lens  305  or other optical elements in front of a laser  325  ( FIG. 8 ) for collimation of light. Additionally, wedge alignment system  320  may be used to attach optical components in front of an optical fiber for focusing of light (not shown). The attachment of wedge block  315  to a platform  330  and optical element  305  to wedge block  315  can be achieved using an attaching component  332  such as adhesives, solders, laser welding or low melting temperature glasses. Adhesives may include ultraviolet curable resins or thermally curable resins. 
   To achieve this arrangement, a pair of gripper mechanisms  335 ,  340  are used to hold and manipulate the position of wedge  315  and lens  305  relative to each other. First gripper mechanism  335  has a pair of parallel gripper mechanisms  345 A,  345 B, which can hold and move lens  305  in X-Y-Z directions independent from the second gripper mechanism  340 . Second gripper mechanism  340  has a simple holding structure  350 A,  350 B, which is capable of freely sliding wedge  315  over surface of optical platform  330 , while pushing wedge  315  down against platform  330 . 
   Initially, wedge  315  is completely moved away from lens  305  such that lens  305  is moved and aligned freely in 3D space. Once lens  305  is properly aligned with laser  325  edge block is pushed under lens  305  such that it comes in contact with lens  305 . At this time, attaching component  332  is activated and bonding is completed. 
   Single-Mode Fiber Attachment 
   Coupling of light from a light source to a single mode optical fiber is a difficult process which requires sub-micron positioning accuracy of optical components such as, for example, lenses between the light source and fiber. Further difficulty arises when the position of these optical components is incorrect relative to a fiber and a light source and must be corrected after attachment. Since known attachment processes for aligning and fixing these elements relative to one another is not perfect, a post attachment shift is typically inherent. At visible wavelengths, the core of single mode optical fiber is about 3–4 micron and post attachment shifts have more adverse effect on final coupling efficiency between the source and the fiber. An optical design method is provided hereinbelow which reduces the sensitivity of the coupling efficiency to misalignment of optical elements between the fiber and the light source. 
   Referring now to  FIG. 9 , there is shown a fiber-lens assembly  405  having a single mode fiber  410  mounted to a platform  415  and a lens  420  mounted to platform  415  so as to provide an optical axis  425  which is in alignment for lens  420  and fiber  410 . 
   In this arrangement in which a collimated or semi-collimated beam of light  430  is incident on lens  420  and is then focused on the core of single mode optical fiber  410 . The relative position of fiber  410  and lens  420  can be fixed with respect to one another such that lens  420  and fiber  410  can be moved together as assembly  405  and aligned relative to incident light beam  430 . In order to maximize coupling of light  430  into fiber  410  the conditions should be satisfied: (1) optical axis  425  of fiber-lens assembly  405  and optical axis  435  of incident beam  430  should be collinear and coaxial; (2) the relative position of lens  420  to fiber  410  in fiber-lens assembly is configured such that divergence angle of the incident beam  430  is the same as optical divergence angle of fiber-lens assembly  405 . Optical divergence of the fiber-lens assembly  405  is defined by coupling light into fiber  410 , from other end opposite of lens  420 , and then measuring the divergence of the light exiting lens in the reverse direction relative to incident beam  430 ; and (3) the relative position of lens  420  to fiber in fiber-lens assembly  405  is configured such that diameter of the incident beam  430  be the same as beam diameter of fiber-lens assembly  405 . Beam diameter of fiber-lens assembly  405  is defined by coupling light into fiber  410 , from other end opposite of lens  420 , and then measuring the beam diameter of the light exiting lens  420  in the reverse direction relative to incident beam  430 . 
   From the above-identified conditions it is noted that (1) lateral misalignment of incident beam  430  relative to fiber-lens assembly  405  is less important as the diameter of beam  430  increases, which is referred to as non-coaxial misalignment, and (2) angular misalignment of incident beam  430  and fiber-less assembly  405  is less important as the divergence angle of beam  430  increases. 
   Due to nature of Gaussian beam optics, which is a good approximation for optical mode of single mode fibers, optical beam diameter and divergence angle are inversely proportional. A beam with larger diameter has smaller divergence angle. Thus, in order to minimize the misalignment effect on coupling efficiency of light  430  into fiber  410 , an optimal beam diameter, or optimal divergence angle is selected, such that both above conditions can be satisfied. As one example, a single mode fibers in visible wavelengths with a core diameter of 3–5 microns and a beam diameter between 390–450 microns is an optimal beam diameter and provides minimum dependence of coupling efficiency on lateral and angular misalignment.