Non-Orthogonal-Polarized Optical Single-Sideband Modulation to Orthogonal Optical-Polarized Single-Sideband Modulation Conversion Using Semiconductor Lasers with Orthogonal Optical Injection
Yu-Han Hung1*, Sheng-Kwang Hwang1,2
1Department of Photonics, National Cheng Kung University, Tainan, Taiwan
2Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan
* Presenter:Yu-Han Hung,
For microwave photonic links, which desire high spectral efficiency, no inter-channel crosstalk, and high detection sensitivity, orthogonal-polarized optical single-sideband (OP-SSB) modulation signals with high optical modulation depth are highly preferred. This study investigates semiconductor laser dynamics in a semiconductor laser with orthogonal optical injection for conversion of non-OP-SSB signals into OP-SSB signals through OP-SSB modulation. When a single-mode semiconductor laser, which normally emits a TE lasing mode, is perturbed by a continuous-wave optical injection with a TM polarization, OP-SSB modulation can be activated. Since an optical frequency of the injection is not the same as that of the TE lasing mode of the laser, an output optical spectrum of the laser exhibits an optical component with a TE polarization and an optical component with a TM polarization, which are the TE lasing mode of the laser and the regeneration of the injection, respectively. Under a proper injection strength and frequency, the optical power of the two optical components can be comparable, which suggests a high optical modulation depth of up to 100%. Furthermore, a frequency spacing f₀ of the two optical components can be widely tuned from a few GHz to tens of GHz.

Keywords: Semiconductor lasers, Orthogonal-polarized optical single-sideband modulation, Orthogonal optical injection