Optical alignment systems and methods

A system for optically aligning an integrated photonics die to a fiber array, the fiber array comprising a first and a second fiber channels, the system comprising:

• the integrated photonics die having:
• a first and a second optical channels;
• a first and a second wavelength division multiplexing (WDM) couplers each comprising a bar port, a cross port, and a common port, the first and the second WDM couplers being optically connected to the first and the second optical channels, respectively, via the bar ports and the common ports;
• and
• a waveguide crossing optically connecting the cross ports of the first and the second WDM couplers;
• the system being adapted to couple a first optical signal received from the first fiber channel and having a first wavelength into the cross port of the first WDM coupler and thus into the waveguide crossing, the first optical signal being propagated from the waveguide crossing into the cross port of the second WDM coupler, and thus being coupled into the second optical channel, the first optical signal being subsequently coupled into the fiber array via the second fiber channel.

A method of optically aligning an integrated photonics die to a fiber array, the fiber array comprising a first and a second fiber channels, the method comprising the steps of:

• receiving the integrated photonics die, the integrated photonics die comprising:
• a first and a second optical channels, the first optical channel comprising a first bidirectional port, and the second optical channel comprising a second bidirectional port;
• a first and a second wavelength division multiplexing (WDM) couplers each comprising a bar port, a cross port, and a common port, the first and the second WDM couplers being optically connected to the first and the second optical channels, respectively, via the bar ports and the common ports;
• and
• a waveguide crossing optically connecting the cross ports of the first and the second WDM couplers;
• aligning an end of the fiber array to an edge of the integrated photonics die, such that the first and the second fiber channels at least partially align with the first and the second bidirectional ports;
• launching an optical signal from the first fiber channel into the first optical channel via the first bidirectional port;
• and
• detecting at least a portion of the optical signal at the second fiber channel, the at least a portion of the optical signal being coupled from the first optical channel to the second optical channel via the first and the second WDM couplers and the waveguide crossing, the at least a portion of the optical signal subsequently being coupled from the second optical channel into the second fiber channel via the second bidirectional port.