Polymer-based external cavity lasers: Tuning efficiency, reliability, and polarization diversity

Three aspects of polymer-based external cavity tunable lasers are investigated. First, the tuning efficiency is increased from 0.29 nm/mW to a record 0.52 nm/mW by improving the microheater thermal design. Second, the long-term reliability of such tunable laser modules is investigated through two batches of stress tests at 25 degrees C and 45 degrees C, respectively. No degradation effect is observed in terms of output power drop and wavelength drifting after thousands of hours of continuous operation at tuned wavelength of 20 nm. Finally, a novel TM-emitting tunable laser is demonstrated by inserting a half-wave plate into the polymer output waveguide. Index-matching techniques and the intrinsic curved waveguide design guarantee robust single mode operation. The TM laser exhibits excellent side mode suppression ratio (>40 dB), large tuning range (>20 nm), and high output power (>5 mW at 100-mA drive current).