講演情報
[10p-C212-4]Fast and wide wavelength tuning of a Si-photonics external-cavity
laser via two-step pulsed heating
〇(DC)Cong Wang1,2, Fuyi Cao1, Yihan Qi1, Masataka Kobayashi1, To-Fan Pan1, Shaoqiang Chen1,2, Hidefumi Akiyama1 (1.ISSP, The University of Tokyo, 2.SCEE, East China Normal University)
キーワード：
tunable laser、fast wavelength switching、ring resonators
Fast and wide wavelength tuning is important for optical communication systems, wavelength-division multiplexed transceivers, and other frequency-agile photonic applications. However, thermo-optically tuned integrated lasers are generally limited by slow thermal response, which restricts their switching speed. In this work, we demonstrate a hybrid-integrated III-V/Si3N4 external-cavity laser incorporating two microring resonators configured as a Vernier filter, as shown in Fig. 1(a). Figure 1(b) shows the static tuning characteristics of the laser, where stable single-mode operation is maintained over a wavelength range from 1486 to 1614 nm, with an output power exceeding 10 mW and a side-mode suppression ratio reaching up to 60 dB. To accelerate wavelength switching, impulsive thermal pumping was applied to the on-chip microheaters using short-duration, high-amplitude voltage pulses. Figure 1(c) shows that the measured thermo-optic response is well fitted by a simple first-order thermal model, confirming the predictability and controllability of the wavelength-switching dynamics. Based on this response, we introduced a two-step pulsed thermal pumping scheme, in which the initial fast, quasi-linear heating transient is used for rapid wavelength displacement, followed by a holding pulse to maintain the target wavelength. As a result, a 101 nm red-shift within 11.33 us and a 104 nm blue-shift within 10.74 us were achieved, corresponding to quasi-linear tuning rates of 8.91 and 9.68 nm/us, respectively. These results show that waveform-engineered thermal pumping can overcome the conventional speed limitation of thermo-optic tuning without requiring major structural modifications. The proposed approach provides a practical route toward fast and wide-range wavelength switching in integrated external-cavity lasers for frequency-agile photonic systems.