Patent Application
20120189323
Optoelectronic modules, such as optoelectronic transceiver or transponder modules, are increasingly used in electronic and optoelectronic communication. Some modules can be plugged into a variety of host networking equipment. Modules typically communicate with a printed circuit board of a host device by transmitting electrical signals to the printed circuit board and receiving electrical signals from the printed circuit board. These electrical signals can then be transmitted by the module outside the host device as optical signals.
Multi-source agreements (MSAs), such as the C Form-factor Pluggable (CFP) MSA and the Quad Small Form-factor Pluggable (QSFP) MSA, specify, among other things, housing dimensions for modules. Conformity with an MSA allows a module to be plugged into host equipment designed in compliance with the MSA.
Optical signals are typically generated within a transmitter optical subassembly (TOSA) of a module using a laser, such as a vertical cavity surface emitting laser (VCSEL) or a distributed feedback (DFB) laser. As data rates in modules increase, two or more lasers are often included in a single TOSA. However, as MSAs specify increasingly smaller module housing dimensions, there is less available space for multi-laser TOSAs within the module housing. In addition, multi-laser TOSAs are often relatively expensive and often suffer from relatively high optical loss.
In general, example embodiments of the invention relate to a multi-laser transmitter optical subassembly (TOSA) for an optoelectronic module. The example multi-laser TOSA disclosed herein exhibits a relatively small size, cost, and optical loss, thus enabling relatively improved overall performance of the optoelectronic module into which the multi-laser TOSA is integrated.
In one example embodiment, a multi-laser TOSA includes first, second, third, and fourth lasers configured to generate first, second, third, and fourth optical signals having first, second, third, and fourth wavelengths, respectively; first, second, and third mirrors not positioned in the same or parallel planes; first, second, and third filters having first, second, and third filter surfaces facing the first, second, and third minors, respectively; and a focusing lens. The first minor is configured to reflect the first optical signal toward the first filter. The first filter is configured to combine the first and second optical signals. The second mirror is configured to reflect the combined first and second optical signals toward the second filter. The second filter is configured to combine the first, second, and third optical signals. The third mirror is configured to reflect the combined first, second, and third optical signals toward the third filter. The third filter is configured to both combine the first, second, third, and fourth optical signals and transmit the combined first, second, third, and fourth optical signals toward the focusing lens.
In another example embodiment, an optoelectronic transceiver module includes a printed circuit board, a receiver optical subassembly (ROSA) in electrical communication with the printed circuit board, and a multi-laser TOSA in electrical communication with the printed circuit board. The multi-laser TOSA includes first, second, third, and fourth lasers configured to generate first, second, third, and fourth optical signals having first, second, third, and fourth wavelengths, respectively; first, second, and third mirrors not positioned in the same or parallel planes; first, second, and third filters having first, second, and third filter surfaces facing the first, second, and third minors, respectively; and a focusing lens. The first minor is configured to reflect the first optical signal toward the first filter. The first filter is configured to both transmit the second optical signal and reflect the first optical signal toward the second minor. The second mirror is configured to reflect the combined first and second optical signals toward the second filter. The second filter is configured to both transmit the third optical signal and reflect the combined first and second optical signals toward the third mirror. The third minor is configured to reflect the combined first, second, and third optical signals toward the third filter. The third filter is configured to both transmit the fourth optical signal and reflect the combined first, second, and third optical signals toward the focusing lens.
In yet another example embodiment, a method of fabricating a multi-laser TOSA includes various acts. First, first and second optical signals are transmitted from first and second lasers, respectively. Next, the angle of a first minor actively adjusted to reflect the first optical signal toward a first filter that reflects the first optical signal and transmits the second optical signal such that the first and second optical signals are aligned and combined.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
Additional features will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the teachings herein. Features of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.
To further clarify certain aspects of the present invention, a more particular description of the invention will be rendered by reference to example embodiments thereof which are disclosed in the appended drawings. It is appreciated that these drawings depict only example embodiments of the invention and are therefore not to be considered limiting of its scope. Aspects of the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
Example embodiments of the present invention relate to a multi-laser transmitter optical subassembly (TOSA) for an optoelectronic module. The example multi-laser TOSA disclosed herein exhibits a relatively small size, cost, and optical loss, thus enabling relatively improved overall performance of the optoelectronic module into which the multi-laser TOSA is integrated.
Reference will now be made to the drawings to describe various aspects of example embodiments of the invention. It is to be understood that the drawings are diagrammatic and schematic representations of such example embodiments, and are not limiting of the present invention, nor are they necessarily drawn to scale.
Reference is first made to
The module 100 can be configured for optical signal transmission and reception at a variety of data rates including, but not limited to, 40 Gb/s, 100 Gb/s, or higher. Furthermore, the module 100 can be configured for optical signal transmission and reception at various distinct wavelengths using wavelength division multiplexing (WDM) in which multiple optical signals having distinct wavelengths are multiplexed onto a single optical fiber. For example, the module 100 can be configured to operate using one of various WDM schemes, such as Coarse WDM (CWDM), Dense WDM (DWDM), Light WDM (LWDM), or Local Area Network WDM (LAN WDM). Further, the module 100 can be configured to support various communication protocols including, but not limited to, Fibre Channel and High Speed Ethernet. In addition, although the example module 100 is configured to have a form factor that is substantially compliant with the QSFP MSA, the module 100 can alternatively be configured in a variety of different form factors that are substantially compliant with other MSAs including, but not limited to, the CFP MSA.
With continued reference to
Having described a specific environment with respect to
With reference now to
As disclosed in
The first, second, and third filters 224-228 may be thin film filters, for example, and have first, second, and third filter surfaces 232-236 facing the first, second, and third minors 218-222, respectively. The first, second, and third minors 218-222 are each individually and precisely aligned with the first, second, and third filter surfaces 232-236, respectively. Being individually and precisely aligned, the first, second, and third minors 218-222 are not positioned in the same or parallel planes.
The first minor 218 is configured to reflect the first optical signal 210 toward the first filter surface 232 of the first filter 224. The first filter 224 is configured to both transmit the second optical signal 212 and reflect the first optical signal 210 toward the second minor 220. The second minor 220 is configured to reflect the combined first and second optical signals 238 toward the second filter surface 234 of the second filter 226. The second filter 226 is configured to both transmit the third optical signal 214 and reflect the combined first and second optical signals 238 toward the third mirror 222. The third minor 222 is configured to reflect the combined first, second, and third optical signals 240 toward the third filter 222. The third filter is configured to both transmit the fourth optical signal 216 and reflect the combined first, second, and third optical signals 242 toward the focusing lens 230.
As disclosed in
With continued reference to
At act 302, the first and second optical signals 210 and 212 are transmitted from the first and second lasers 202 and 204, respectively. For example, the first optical signal 210 may be transmitted through the collimating lens array 244, the beam splitter 246, and the WDM block 248 toward the first mirror 218. Simultaneously, the second optical signal 212 may be transmitted through the collimating lens array 244 and the beam splitter 246 toward the first filter 224.
At act 304, the angle of the first mirror 218 is actively adjusted to reflect the first optical signal 210 toward the first filter 224 such that the first and second optical signals 210 and 212 are aligned and combined. For example, the angle of the first minor 218 can be actively adjusted and then fixed in place. The first minor 218 may be fixed in place by affixing the first minor 218 to a substrate (not shown) with a high-viscosity low-shrinking ultraviolet epoxy and then curing the epoxy once the first minor has been actively adjusted. Alternatively, the first minor 218 may be part of a microelectromechanical system (MEMS) mirror array that is electronically tuned during active alignment.
At act 306, the third optical signal 214 is transmitted from the third laser 206. For example, the third optical signal 214 may be transmitted through the collimating lens array 244 and the beam splitter 246 toward the second filter 226.
At act 308, the angle of the second mirror 220 is actively adjusted to reflect the combined first and second optical signals 238 toward the second filter 226 such that the first, second, and third optical signals 210, 212, and 214 are aligned and combined. For example, the angle of the second minor 220 can be actively adjusted and then fixed in place in a manner similar to the active adjustment and fixing in place of the first minor 218. It is noted that since the first and second mirrors 218 and 220 are each individually and precisely aligned with the first and second filter surfaces 232 and 234 of the first and second filters 224 and 226, respectively, the first and second minors 218 and 220 may not be fixed in position in the same or parallel planes.
At act 310, the fourth optical signal 216 is transmitted from the fourth laser 208. For example, the fourth optical signal 216 may be transmitted through the collimating lens array 244 and the beam splitter 246 toward the third filter 228.
At act 312, the angle of the third minor 222 is actively adjusted to reflect the combined first, second, and third optical signals 240 toward the third filter 228 such that the first, second, third, and fourth optical signals 210-216 are aligned and combined. For example, the angle of the third mirror 222 can be actively adjusted and then fixed in place in a manner similar to the active adjustment and fixing in place of the first and second minors 218 and 220. It is noted that since the first, second, and third mirrors 218-222 are each individually and precisely aligned with the first, second, and third filter surfaces 232-236 of the first, second, and third filters 224-228, respectively, the first, second, and third mirrors 218-222 may not be fixed in position in the same or parallel planes.
In at least some example embodiments, the angles of the first, second, and third mirrors 218-222 are each actively adjusted such that the difference between the angle of incidence and the angle of reflection for each of the minors 218-222 is between about 4 degrees and about 16 degrees.
Although not shown in
It is also understood that TOSA 200 could be modified to have less than or greater than four lasers and three minors and still benefit from the individual and precise active adjustment of TOSA minors. For example, the TOSA 200 could have only two lasers and a single mirror that is actively adjusted. Alternatively, the TOSA 200 could have six lasers and five minors that at are each actively adjusted. The discussion of TOSAs herein is therefore not limited to TOSAs having four lasers and three minors.
The individual and precise active adjustment of each of the mirrors 218-222 in the example multi-laser TOSA 200 enables the combination of multiple optical signals with relatively low optical loss. The size and cost of the example multi-laser TOSA 200 are also relatively low compared to prior art multi-laser TOSAs. The individual and precise active adjustment of each of the mirrors 218-222 in the example multi-laser TOSA 200 thus enables the example multi-laser TOSA 200 to exhibit relatively small size, cost, and optical loss. Consequently, optoelectronic modules into which the example multi-laser TOSA 200 is integrated also exhibit relatively improved overall performance.
The example embodiments disclosed herein may be embodied in other specific forms. The example embodiments disclosed herein are to be considered in all respects only as illustrative and not restrictive.
