Fabrication and characterization of InAs quantum dot semiconductor optical amplifiers on InP operating at 1.5 μm

摘要

Round and dome-shaped InAs/InGaAsP QDs on InP (100) substrate were used for semiconductor optical amplifier. The diameter, height and density of QDs were 32 nm, 3.4 nm and 1.1 × l0~(11) cm~(-2), respectively. The PL peak was controlled from 1.43 to 1.57 μm and the room temperature PL yield was quite high, about 25% of the low temperature value. We have fabricated SOAs with 2 ～ 4 μm ridge width using the above mentioned QDs. The QDSOAs had a barrier of 1.1 μm emitting InGaAsP and a simple separate confinement hetero-structure with InP cladding layer. The spacing between adjacent QD layers was 40 nm to ensure no vertical electronic coupling, confirmed by time resolved PL measurements. The small signal gain was about 20 dB and the typical gain peak was around 1.54 μm, which matches well with the optical communication band. We have also measured 3-dB gain bandwidth by using a broadband light source with 200 nm flat band and found that it was around 40 nm.