OPTICAL DEVICES AND METHODS TO CONSTRUCT THE SAME
Optical devices and methods for constructing the same are disclosed. An example optical device includes an optical transmitter, a photodetector and a waveguide optically coupling the optical transmitter and the photodetector. It also includes a substrate having a first cavity to receive the optical transmitter and a second cavity to receive the second transmitter. The first and second cavities are located and dimensioned to passively align the optical transmitter, the waveguide and the photodetector when the transmitter is inserted into the first cavity and the photodetector is inserted into the second cavity.
This patent arises from a divisional of U.S. patent application Ser. No. 10/397,580, which was filed on Mar. 26, 2003 and is hereby incorporated by reference in its entirety.
FIELD OF THE DISCLOSUREThis disclosure relates generally to optical devices, and, more particularly, to optical devices and methods to construct the same.
BACKGROUNDThe coherent light generated by edge emitting laser diodes is emitted in one or more planes that are substantially parallel to the boundaries between the semiconductor layers that form the laser. More recently, vertical cavity surface emitting lasers (VCSEL) have been developed. Unlike edge emitting laser diodes, VCSELs are laser diodes that are fabricated to emit light in one or more planes that are substantially perpendicular to the boundaries formed between their semiconductor layers. VCSELs appear to be advantageous over edge emitting laser diodes in several respects. For example, VCSELs generally require lower power and are less expensive to manufacture than their edge emitting counterparts.
An example prior art optical device 10 is shown in
This complicated mechanism for directing the light generated by the VCSEL 12 to the photodetector 14 is expensive and difficult to manufacture. For example, to manufacture a device 10 such as that shown in
The tolerances associated with the die-substrate height standoff requirements and the VCSEL-to-waveguide and waveguide-to-photodetector alignment requirements dictate that the placement/bonding of the VCSEL 12, the photodetector 14, and sometimes the waveguide 16 be carried out through an active alignment technique. An active alignment technique is a feedback technique in which a laser (e.g., the VCSEL) associated with the component(s) being placed is energized, and the position(s) of the component(s) being placed are adjusted to maximize an output of the energized laser at an output of those component(s). When the output is maximized, the component(s) are aligned and bonded in place. Unfortunately, active alignment processes such as that described above are slow and do not lend themselves to mass production.
Additionally, prior art optical devices 10 such as that shown in
An example optical element 40 is schematically illustrated in
The optical element 40 of
As illustrated in the example of
In the illustrated example, in addition to or instead of bonding the optical element 40 in the cavity 32, 34 with a conventional bonding agent, the optical element 40 is secured in the corresponding cavity 32, 34 via the solder bumps 44. For instance, in the illustrated example the substrate 30 includes a plurality of electrically conductive contacts 48 located either in or adjacent the top surface of the substrate 30. The contacts 48 of the substrate 30 are positioned adjacent the cavities 32, 34 in locations to engage the solder bumps 44 of the optical elements 40 when the optical elements 40 are positioned within their corresponding cavities 32, 34. Thus, when the optical elements 40 are positioned within the cavities 32, 34, the solder bump(s) of the optical element 40 are reflowed to form solder joints 50 (see
As mentioned above, the waveguide 36 carried by the substrate 30 may be positioned above a top surface of the substrate 30 (see
If the waveguide(s) 36 are positioned below the top surface of the substrate 30 (see
As shown in
To construct an optical device such as the devices shown in
The optical transmitter 40 is then positioned in the first cavity 32 such that solder bump(s) 44 formed on a side (e.g., the active side) of the transmitter are located adjacent and/or in engagement with contact(s) 48 formed on or in the substrate 30. The photodetector is positioned within the second cavity 34 such that solder bump(s) 44 formed on a side (e.g., the active side) of the photodetector are located adjacent and/or in engagement with contact(s) 48 formed on or in the substrate 30. The solder bumps 44 are then melted to wet the metal contact pads 48 of the substrate 30 to thereby form solder joints 50 that mechanically and electrically couple the optical elements 40 to the substrate 30. The close tolerances of the cavities 32, 34 and the optical transmitter 40 and the photodetector 40 ensure that placing the optical elements 40 in their corresponding cavities achieves passive alignment with the waveguide channel(s) 54 and that active alignment is not necessary.
Although the examples described above employed a single substrate 30 defining two cavities 32, 34 dimensioned to receive two optical elements 40 such that a single substrate 30 carried at least two optical elements 40 and a waveguide 36, persons of ordinary skill in the art will appreciate that other numbers of substrates, waveguides, and/or optical elements may alternatively be employed. For example, as shown in
In the example of
As shown in
To optically couple the first and second substrates 130A, 130B, the illustrated optical device is further provided with a flying waveguide 137 as shown in
Although only two pins 145 and two bores 147A, 147B are shown in
Although in the examples discussed above, the optical elements 40 include pre-deposited solder bumps 44, persons of ordinary skill in the art will appreciate that these pre-formed solder bumps 44 are optional. Alternatively, one or both of the optical elements 240 may exclude the preformed solder bumps as shown in the example of
From the foregoing, persons of ordinary skill in the art will readily appreciate that optical devices and methods of manufacturing the same have been disclosed. Such persons will further appreciate that the disclosed optical devices and methods of manufacture are advantageous in several respects. For example, because the optical devices illustrated in
Also, because the illustrated optical devices employ cavities 32, 34 to mechanically pre-align their optical elements 40 with their waveguides 36, the illustrated devices can be assembled without employing an active alignment process and without requiring die-substrate standoff height control. As a result, the illustrated optical devices may be more susceptible to mass production and, thus, less costly to manufacture than their prior art counterparts. Furthermore, the illustrated devices may employ stacked waveguide arrays 36 to thereby increase the number of optical channels and, thus, the operational bandwidth of the devices.
Although certain example methods and apparatus have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods and apparatus fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.
Claims
1. A substrate for an optical module comprising:
- a substrate;
- a first cavity defined in the substrate, the first cavity being dimensioned to receive an optical transmitter; and
- a second cavity defined in the substrate, the second cavity being dimensioned to receive a photodetector, the first cavity and second cavity being located and dimensioned to passively align the optical transmitter and the photodetector when the optical transmitter is positioned in the first cavity and the photodetector is located in the second cavity.
2. A substrate as defined in claim 1 further comprising a waveguide secured to a surface of the substrate between the first and second cavities.
3. A substrate as defined in claim 2 wherein the waveguide comprises a waveguide array.
4. A substrate as defined in claim 3 wherein the waveguide array comprises a first waveguide channel and a second waveguide channel.
5. A substrate as defined in claim 4 wherein the first waveguide channel is vertically displaced from the second waveguide channel.
6. A substrate as defined in claim 4 wherein the first and second waveguide channels are in a common plane.
7. A substrate as defined in claim 1 further comprising a waveguide integrated with the substrate between the first and second cavities.
8. A substrate as defined in claim 7 wherein the waveguide comprises a waveguide array.
9. A substrate as defined in claim 8 wherein the waveguide array comprises a first waveguide channel and a second waveguide channel.
10. A substrate as defined in claim 9 wherein the first waveguide channel is vertically displaced from the second waveguide channel.
11. A substrate as defined in claim 9 wherein the first and second waveguide channels are in a common plane.
12. An optical device comprising:
- a first optical element;
- a first waveguide;
- a first substrate having a first cavity to receive the first optical element, the first cavity being located and dimensioned to passively align the first optical element and the first waveguide;
- a second optical element;
- a second waveguide;
- a second substrate having a second cavity to receive the second optical element, the second cavity being located and dimensioned to passively align the second optical element and the second waveguide; and
- a flying waveguide optically coupling the first and second waveguides.
13. An optical device as defined in claim 12 wherein the flying waveguide is coupled to the first substrate and the second substrate.
14. An optical device as defined in claim 13 wherein the first waveguide, the second waveguide and the flying waveguide are passively aligned.
15. An optical device as defined in claim 14 wherein the flying waveguide includes a first connector and a second connector, and further comprising a first aligning pin and a first mating bore positioned to connect the first connector and the first waveguide, and a second aligning pin and a second mating bore positioned to connect the second connector and the second waveguide.
Type: Application
Filed: Feb 6, 2007
Publication Date: Jun 7, 2007
Inventors: Daoqiang Lu (Chandler, AZ), Gilroy Vandentop (Tempe, AZ)
Application Number: 11/671,775
International Classification: G02B 6/12 (20060101);