Bridge coupling to surface emitters
Techniques are provided for reducing crosstalk between bond wires coupling high frequency signals to multiple transducers in an integrated circuit (IC) chip. At least some of the techniques employ a bridge element configured to be bottom mounted to a printed circuit board next to a surface emitter chip. The bridge element may include: device contacts to each be bond wire connected to a respective anode contact of the surface emitter chip; board contacts to each be bond wire connected to a respective signal trace of the printed circuit board; and a signal path for each of the device contacts, the signal path connecting that device contact to a respective one of the board contacts without active amplification.
1 . A printed circuit board assembly that comprises:
a printed circuit board having signal traces;
a surface emitter chip bottom-mounted to the printed circuit board and having an array of photoemitter devices with associated anode contacts; and
a passive bridge element bottom-mounted to the printed circuit board next to the surface emitter chip, the passive bridge element having:
device contacts each bond wire connected to a respective one of the anode contacts;
board contacts each bond wire connected to a respective one of the printed circuit board signal traces; and
for each device contact, a signal path connecting that device contact to a respective one of the board contacts without active amplification.
2 . The printed circuit board assembly of claim 1 , wherein each of the device contacts is aligned with the respective one of the anode contacts to minimize a length of the bond wire connection to the respective one of the anode contacts.
3 . The printed circuit board assembly of claim 2 , wherein each of the board contacts is aligned with the respective one of the signal traces to minimize a length of the bond wire connection to the respective one of the signal traces.
4 . The printed circuit board assembly of claim 2 , wherein the board contacts have a pitch at least twice a pitch of the device contacts.
5 . The printed circuit board assembly of claim 1 , wherein at least one of the signal paths couples to at least one passive component from a set consisting of: a shunt resistor, a shunt capacitor, and a shunt inductor.
6 . The printed circuit board assembly of claim 1 , wherein at least one of the signal paths includes at least one passive component from a set consisting of: a series resistor, a series capacitor, and a series inductor.
7 . The printed circuit board assembly of claim 1 , wherein the passive bridge element further includes additional device contacts each bond wire connected to a respective cathode contact for the array of photoemitter devices, each additional device contact connected to a respective board contact by a signal path without active amplification.
8 . The printed circuit board assembly of claim 1 further comprising a data recovery and remodulation device mounted to the printed circuit board in a flip-chip configuration, the data recovery and remodulation device having integrated drivers coupled to the signal traces to drive the array of photoemitter devices.
9 . A bridge element configured to be bottom mounted to a printed circuit board next to a surface emitter chip, the bridge element comprising:
device contacts to each be bond wire connected to a respective anode contact of the surface emitter chip;
board contacts to each be bond wire connected to a respective signal trace of the printed circuit board; and
a signal path for each of the device contacts, the signal path connecting that device contact to a respective one of the board contacts without active amplification.
10 . The bridge element of claim 9 , wherein each of the device contacts is positioned to align with the respective anode contact to minimize a length of the bond wire connected to the device contact.
11 . The bridge element of claim 10 , wherein each of the board contacts is positioned to align with the respective signal trace to minimize a length of the bond wire connected to the board contact.
12 . The bridge element of claim 10 , wherein the board contacts have a pitch at least twice a pitch of the device contacts.
13 . The bridge element of claim 9 , wherein at least one of the signal paths couples to at least one passive component from a set consisting of: a shunt resistor, a shunt capacitor, and a shunt inductor.
14 . The bridge element of claim 9 , wherein at least one of the signal paths includes at least one passive component from a set consisting of: a series resistor, a series capacitor, and a series inductor.
15 . The bridge element of claim 9 , further comprising additional device contacts each positioned to align a respective cathode contact of the surface emitter chip, each additional device contact connected to a respective board contact by a signal path without active amplification.
16 . A cable connector that comprises:
an optical coupling module that optically couples optical fibers to an array of photoemitters on a surface emitter chip bottom-mounted to a printed circuit board, the surface emitter chip having anode contacts for the photoemitters in the array; and
a passive bridge element bottom-mounted to the printed circuit board next to the surface emitter chip, the passive bridge element having:
device contacts each bond wire connected to a respective one of the anode contacts;
board contacts each bond wire connected to a respective signal trace on the printed circuit board; and
for each device contact, a signal path connecting that device contact to a respective one of the board contacts without active amplification.
17 . The cable connector of claim 16 , wherein the bridge element includes a semiconductor substrate having a same thickness as the surface emitter chip, and wherein each of the device contacts is aligned with the respective one of the anode contacts to minimize a length of the bond wire connection to the respective one of the anode contacts.
18 . The cable connector of claim 17 , wherein each of the board contacts is aligned with the respective one of the signal traces to minimize a length of the bond wire connection to the respective one of the signal traces.
19 . The cable connector of claim 17 , wherein the board contacts have a pitch at least twice a pitch of the device contacts.
20 . The cable connector of claim 19 , further comprising a data recovery and remodulation device mounted to the printed circuit board in a flip-chip configuration, the data recovery and remodulation device having integrated drivers coupled to the signal traces to drive the array of photoemitter devices.