Polymer-Based External Cavity Lasers: Tuning Efficiency, Reliability, and Polarization Diversity

Abstract

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 °C and 45 °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).