Hybrid Integrated External Cavity Diode Laser with Flexible Feedback at 1-μm Band

We have developed an advanced hybrid integrated external cavity diode laser (ECDL) with flexible feedback that operates in the 1-μm spectral region. The ECDL utilizes a III-V gain chip and a Si
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external cavity chip. Within the Si
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external cavity chip, in addition to the spot size converter, phase shifter and cascaded dual micro-ring resonant cavity, we also designed an adjustable mirror composed of symmetric Mach-Zehnder interferometer (MZI) and Sagnac loop. By changing the power in the micro-heater on the one arm of the MZI, the feedback ratio of the external cavity can be flexibly adjusted. We investigated the output power of the ECDL at different feedback ratio. The output power can achieve its maximum value when the reflectivity is 28% The tuning range of the ECDL is 40 nm and the SMSR higher than 58 dB.