Multi-channel transmitter optical subassembly (tosa) with opposing placement of transistor outline (to) can laser packages

Abstract

A multi-channel transmitter optical subassembly (TOSA) including staggered transistor outline (TO) can laser package placement to provide enhanced coupling and optical power is disclosed, and may be used in an optical transceiver for transmitting an optical signal. The TOSA comprises a housing that includes plurality of sidewall openings with each sidewall opening configured to couple to a TO can laser package to provide coarse wavelength division multiplexing. The housing includes at least first and second sidewall openings on a first sidewall, and a third sidewall opening disposed on a sidewall opposing the first sidewall and being positioned at generally a mid-point between the first and second sidewall openings. This staggered and opposing sidewall opening arrangement allows an increased distance between adjacent sidewall openings, and thus, the TOSA may increase optical power and yield by providing additional space for performing post-attachment alignment of TO can laser packages.

1 . A transmitter optical subassembly (TOSA) including a plurality of transistor outline (TO) can laser packages, the TOSA comprising:
 a housing including at least a first and second sidewall on opposite sides of the housing and extending along a first major axis from a first end to a second end, and forming a compartment defined by an inner surface therein, the first sidewall including at least first and second sidewall openings, the second sidewall including at least a third sidewall opening being positioned generally at a midpoint between the first and second sidewall openings;   at least first and second TO can laser packages coupled to the first and second sidewall opening of the first sidewall, respectively, and a third TO can laser package coupled to the third sidewall opening and opposing the first and second TO can laser packages;   at least a first filter holder coupled to the first sidewall between the first and second sidewall openings of the first and second TO can laser packages, respectively, and wherein the first filter holder provides a substantially flat surface along an outer edge of the housing between the first and second TO can laser packages; and   a first filter coupled to the first filter holder.   
     
     
         2 . The TOSA of  claim 1 , further comprising a third sidewall at the first end and adjoining the first and second sidewall, the third sidewall including a fourth sidewall opening and a fourth TO can laser package coupled thereto. 
     
     
         3 . The TOSA of  claim 1 , further comprising a plurality of welding rings, wherein the plurality of TO can laser packages are coupled to respective sidewalls of the housing by the plurality of welding rings via laser welds. 
     
     
         4 . The TOSA of  claim 1 , wherein the compartment defines a light path, the light path extending from the first end to at least the second end. 
     
     
         5 . The TOSA of  claim 4 , wherein each of the plurality of TO can laser packages includes a laser diode optically aligned to direct light into the compartment. 
     
     
         6 . The TOSA of  claim 1 , further comprising:
 a second and third filter holder coupled to the third sidewall on opposite sides of the third TO can laser packages relative to each other; and   a second and a third filter coupled to the second and third filter holders, respectively, wherein each of the first, second and third filters are configured to align with an associated TO can laser package to pass and reflect laser light at associated channel wavelengths.   
     
     
         7 . The TOSA of  claim 6 , wherein each of the second and third filter holders provide a substantially flat surface along an outer edge of the housing. 
     
     
         8 . The TOSA of  claim 1 , wherein the compartment includes a focusing lens aligned with a light path at the second end of the housing. 
     
     
         9 . The TOSA of  claim 1 , wherein the first and second TO can laser packages are greater than  1  mm apart. 
     
     
         10 . The TOSA of  claim 1 , wherein the second end includes an optical coupling receptacle configured to optically couple a signal having multiple different channel wavelengths to a transmit optical fiber. 
     
     
         11 . An optical transceiver module comprising:
 a transceiver housing;   a transmitter optical subassembly (TOSA) having a plurality of transistor outline (TO) can laser packages coupled thereto and located in the transceiver housing for transmitting optical signals at different channel wavelengths, the TOSA comprising:
 a housing including at least a first and second sidewall on opposite sides of the housing and extending along a first major axis from a first end to a second end, and forming a compartment defined by an inner surface therein, the first sidewall including at least first and second sidewall openings, the second sidewall including at least a third sidewall opening being positioned generally at a midpoint between the first and second sidewall openings; and 
 at least first and second transistor outline TO can laser packages coupled to the first and second sidewall opening of the first sidewall, respectively, and a third TO can laser package coupled to the third sidewall opening and opposing the first and second TO can laser packages; 
   a multi-channel receiver optical assembly (ROSA) located in the transceiver housing for receiving optical signals at different channel wavelengths; and   wherein the third TO can laser package of the TOSA directly contacts a surface of the multi-channel ROSA.   
     
     
         12 . The optical transceiver of  claim 11 , further comprising a transmit connecting circuit electrically connected to the TOSA, and a receive connecting circuit electrically connected to the ROSA. 
     
     
         13 . The optical transceiver of  claim 11 , wherein the TOSA further comprises a plurality of filters within the compartment configured to provide a multiplexed optical signal having multiple different wavelengths. 
     
     
         14 . The optical transceiver of  claim 11 , wherein the TOSA further comprises a third sidewall at the first end and adjoining the first and second sidewall, the third sidewall including a fourth sidewall opening and a fourth TO can laser package coupled thereto. 
     
     
         15 . The optical transceiver of  claim 14 , wherein each of the first, second, third and fourth TO can laser packages are associated with a channel wavelength of 1290 nm, 1330 nm, 1310 nm, and 1270 nm, respectively. 
     
     
         16 . The optical transceiver of  claim 11 , the TOSA further comprises a plurality of welding rings, wherein each of the plurality of TO can laser packages are coupled to respective sidewalls of the TOSA housing by the plurality of welding rings via laser welds. 
     
     
         17 . The optical transceiver of  claim 11 , wherein the transceiver is a Quad Small Form-factor Pluggable (QSFP) transceiver module and the TOSA is configured to transmit at four different channel wavelengths at transmission rates of at least about 10 Gbps per channel and transmission distances of 2 km to at least about 10 km. 
     
     
         18 . (canceled) 
     
     
         19 . The optical transceiver of  claim 11 , wherein the first and second TO can laser packages of the TOSA are greater than 1 mm apart. 
     
     
         20 . The optical transceiver of  claim 11 , wherein the second end of the TOSA includes an optical coupling receptacle configured to optically couple a signal having multiple different channel wavelengths to a transmit optical fiber. 
     
     
         21 . The TOSA of  claim 1 , wherein the first sidewall includes a first step portion adjacent the first end of the housing that defines at least one surface, and wherein the substantially flat surface provided by the first filter holder along an outer edge of the housing is offset relative to the at least one surface defined by the first step portion. 
     
     
         22 . The TOSA of  claim 21 , wherein the third sidewall includes a second step portion adjacent the first end of the housing, the first and second step portions defining a tapered region that extends between the first and second ends of the housing.