Narrow-linewidth thermally tuned multi-channel interference widely tunable semiconductor laser with thermal tuning power below 50 mW
Quanan Chen, Chun Jiang, Kuankuan Wang, Miao Zhang, Xiang Ma, Ye Liu, Qiaoyin Lu, Weihua Guo
Abstract
A thermally tuned multi-channel interference widely tunable semiconductor laser is designed and demonstrated, for the first time to our knowledge, that realizes a tuning range of more than 45 nm, side-mode suppression ratios up to 56 dB, and Lorentzian linewidth below 160 kHz. AlGaInAs multiple quantum wells (MQWs) were used to reduce linewidth, which have a lower linewidth enhancement factor compared with InGaAsP MQWs. To decrease the power consumption of micro-heaters, air gaps were fabricated below the arm phase sections. For a 75 μm long suspended thermal tuning waveguide, about 6.3 mW micro-heater tuning power is needed for a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:mn>2</mml:mn> <mml:mi>π</mml:mi> </mml:mrow> </mml:math> round-trip phase change. Total micro-heater tuning power required is less than 50 mW across the whole tuning range, which is lower than that of the reported thermally tuned tunable semiconductor lasers.