ABSTRACT PbS/CdS core–shell colloidal quantum dots (CQDs) with average diameters of ∼5.6 ( CQDs 1 ) and ∼3.4 nm ( CQDs 2 ) are co‐doped to produce hybrid CQDs 3 , which are subsequently doped in polymethyl methacrylate (PMMA) to serve as a broadband optical gain medium. Optical amplification is observed across both O and C bands. Relative gains of 25.3 dB at 1550 nm and 21.3 dB at 1310 nm are achieved using a 3‐cm‐long SU‐8 polymer waveguide with a 2 × 3 µm 2 cross‐section. An ∼1.6‐µm‐thick CQDs 3 ‐doped PMMA upper cladding is utilized, and two low‐power ultraviolet light‐emitting diodes are employed as pump sources instead of a conventional 980 nm laser. For SU‐8 polymer, silicon nitride, and BK7 glass waveguides utilizing CQDs 3 as the gain medium, average relative gains in the C band (1528–1568 nm) are 12.1, 9.5, and 3.8 dB/cm, respectively. In the O band (1270–1370 nm), they are 10.8, 9.9, and 3.7 dB/cm, with a gain ripple maintained below 4 dB. This work presents a cost‐effective and broadband loss‐compensation strategy compatible with both organic and inorganic photonic platforms for planar integrated circuits. This strategy effectively mitigates the thermal quenching effects associated with high‐power laser pumping.
Lv et al. (Tue,) studied this question.