Switchable dual-polarization external cavity tunable laser.

ABSTRACT

An external cavity laser is demonstrated based on the hybrid integration of an InP-based gain element, a half-wave plate, and thermally drivable polymer waveguide circuits. The laser has one oscillation region but two outputs for TE and TM emissions. The central wavelength can be tuned 20 nm at 20 mW heater electrical power. The TM path undergoes a 1.4 dB power penalty due to the presence of the half-wave plate. However, the on-chip thermo-optic switch (TOS) can compensate for this imbalance and steer the laser into an equal TE and TM output power. The TOS can also be adjusted to prefer one polarization path over the other with ∼10 dB extinction ratio.