Fig. 4 The comparison results of the normalized electrical rectification data of a conventional QCL and a π-shape electrode QCL.
Conclusion: We have demonstrated a CW high-speed QCL with emitting wavelength of 8.5μ m and output optical power about 141 mW at 20 ℃. By monolithic integrating a π-shape metal contact electrode, the parasitic capacitance of the device is effectively reduced from 36.6 pF to 7.1 pF and the -3 dB modulation bandwidth is increased from 870 MHz to 4.5 GHz compared with the conventional electrode configuration. The device shows a high application potential in FSOC, active mode locking, etc.
Acknowledgments: This work was supported in part by the National Natural Science Foundation of China under Grant Nos. 61835011, 61991430, and the Key Program of the Chinese Academy of Sciences under Grant Nos. XDB43000000.
 2022 The Authors. Electronics Letters published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology
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