Semiconductor Optical Amplifier and Gain Chip Used in Wavelength Tunable Lasers
SATO Kenji1, 2, ZHANG Xiaobo1
(1. ZTE Photonics, Nanjing 210000, China;
2. Southeast University, Nanjing 211189, China)
The design concept of semiconductor optical amplifier (SOA) and gain chip used in wavelength tunable lasers (TL) is discussed in this paper. The design concept is similar to that of a conventional SOA or a laser; however, there are a few different points. An SOA in front of the tunable laser should be polarization dependent and has low optical confinement factor. To obtain wide gain bandwidth at the threshold current, the gain chip used in the tunable laser cavity should be something between SOA and fixed-wavelength laser design, while the fixed-wavelength laser has high optical confinement factor. Detailed discussion is given with basic equations and some simulation results on saturation power of the SOA and gain bandwidth of gain chip are shown.
external cavity; gain chip; saturation power; semiconductor optical amplifier; tunable laser