HIGH-LANE COUNT OPTICAL TRANSCEIVER WITH BUILT-IN SELF TEST
An optical device such as an optical transceiver can include a cascaded built-in self-test structure that can be configured in testing mode using an active power mode and can sufficiently attenuate light away from a loopback path in an inactive power mode. The optical device can include a wafer top emitter that can be used to tune a light source for testing and calibration of optical components while the built-in self-test structure is in active mode.
1 . A method for testing an optical transceiver comprising a transmitter and a receiver, the method comprising:
activating one or more filters to an active power mode to propagate light from the transmitter to the receiver along a loopback path in the optical transceiver;
testing one or more optical components in the optical transceiver using the light propagated along the loopback path by the one or more filters in the active power mode;
setting the optical transceiver in mission mode by setting the one or more filters to an inactive power mode such that the one or more filters passively direct light away from the loopback path while in the inactive power mode; and
transmitting, by the transmitter, output light while the optical transceiver is in the mission mode and the one or more filters are in the inactive power mode.
2 . The method of claim 1 , wherein activating the one or more filters to the active power mode comprises providing electrical power to the one or more filters.
3 . The method claim 2 , wherein the one or more filters are set to the inactive power mode by not providing the electrical power to the one or more filters.
4 . The method claim 2 , wherein setting the one or more filters to the inactive power mode comprises providing less electrical power to the one or more filters.
5 . The method of claim 1 , wherein the optical transceiver is a multilane optical transceiver comprising a plurality of transmitter and receiver pairs.
6 . The method of claim 5 , wherein each transmitter and receiver pair is coupled by an individual loopback path down which light is directed using an individual integrated loopback switch that is operating in the active power mode.
7 . The method of claim 1 , wherein the one or more filters comprise one or more power splitters that are configured to passively direct light away from the loopback path in the inactive power mode and actively direct light towards the loopback path in the active power mode.
8 . The method of claim 7 , wherein at least one of the one or more power splitters is a multimode coupler.
9 . The method of claim 8 , wherein at least one of the one or more power splitters is a direct coupler.
10 . The method of claim 7 , wherein at least one of the one or more filters comprises a tuner that changes a phase of light to direct light to a propagate port of the one or more filters.
11 . The method of claim 10 , wherein a drop port of the one or more filters propagates light away from the loopback path and wherein a propagate port of each filter propagates light towards the loopback path.
12 . The method of claim 1 , wherein the one or more filters comprises a plurality of filters, and each of the plurality of filters are in a sequence to increasingly attenuate light in the inactive power mode.
13 . The method of claim 1 , further comprising:
generating the light using a light source; and
tuning the light source to a preconfigured wavelength using a wafer emitter in the optical transceiver.
14 . The method of claim 13 , wherein the one or more optical components are tested after tuning the light source to the preconfigured wavelength.
15 . The method of claim 13 , wherein the light source is a tunable laser, and wherein the one or more optical components that are tested include the light source.
16 . The method of claim 13 , wherein an optical spectrum analyzer is coupled to the wafer emitter and wherein the light source is tuned to the preconfigured wavelength according to the light received by the optical spectrum analyzer from the wafer emitter.
17 . The method of claim 13 , wherein the optical transceiver is included in a wafer, and the one or more optical components are tested using wafer-level testing using light emitted from the wafer emitter.
18 . An optical transceiver comprising:
an optical transmitter configured to generate modulated light;
an optical receiver to receive light; and
one or more filters that propagate light from the optical transmitter to the optical receiver along a loopback path while the one or more filters are in an active power mode, the one or more filters passively directing light away from the loopback path while in an inactive power mode.
19 . The optical transceiver of claim 18 , wherein the one or more filters are set to the active power mode by providing electrical power to the one or more filters, and wherein the one or more filters are set to the inactive power mode by providing less electrical power to the one or more filters.
20 . The optical transceiver of claim 19 , wherein providing the electrical power to set the one or more filters in the active power mode comprises providing the electrical power to an electrically controlled tuner in the one or more filters to change a phase of the light to direct the light along the loopback path.