抄録
We designed a composite resonator VCSEL using a VCSEL chip and a concave external mirror for mode-locking to produce optical clock signals and demonstrated the operation experimentally. A very low threshold current was successfully realized by using a proper reflectivity of VCSEL and the external mirror and by achieving efficient feedback using a concave external mirror. Using a concave mirror with the curvature radius of 14.12mm, sub-harmonic active mode-locking was achieved at a repetition rate of 10.56GHz, which corresponded to the external cavity length.
