Methods and apparatus for improving reliability of an optical device using auxiliary lasers in a photonic integrated circuit

A photonic integrated circuit (“PIC”) operable to transmit and receive optical signals, comprising:

• a laser array capable of generating a plurality of optical signals, wherein the laser array includes a set of fixed-wavelength lasers (“FWLs”) configured to generate a first set of optical wavelengths representing the plurality of optical signals;
• a standby laser array coupled to the laser array and capable of being optionally activated to replace one or more defective FWLs in the laser array when one or more defective wavelengths are detected;
• a spare laser array coupled to the laser array and configured to include at least one tunable-wavelength auxiliary laser (“TWAL”) configured to generate an optical signal having a wavelength based on a wavelength setting signal;
• and
• an optical switch coupled to the laser array and capable of replacing a defective FWL in the laser array with a TWAL in the spare laser array after output wavelength of the TWAL is adjusted in response to the defective wavelength produced by the defective FWL.

A method of replacing a defective laser in a photonic integrated circuit (“PIC”) having a laser array, a standby laser array, and a spare laser array, comprising:

• detecting, by an optical diode, a defective wavelength associated to a defective laser;
• activating a standby laser in the standby laser array to replace the defective laser if the defective laser is not an auxiliary laser in the spare laser array;
• tuning, by a tuner, output wavelength of a tunable-wavelength auxiliary laser (“TWAL”) in the spare laser array to have similar wavelength as the defective wavelength when the standby laser is not available;
• and
• replacing, by the optical switch, output wavelength of the defective laser in the laser array with the output wavelength of the TWAL in the spare array.