| Title |
A Study on Input-Polarization-Controlled Switching of Channel Spacings in Fiber Multiwavelength Filter Based on Polarization-Diversified Loop |
| Authors |
Seul-Lee Lee ; Yong Wook Lee |
| DOI |
http://doi.org/10.5207/JIEIE.2020.34.2.052 |
| Keywords |
Optical Fiber Multiwavelength Filter; Polarization-Diversified Loop; Polarization-Maintaining Fiber |
| Abstract |
In this paper, we propose an optical fiber multiwavelength filter based on a polarization-diversified loop (PDL), whose channel spacings (CSs) can be controlled by its input state of polarization (SOP). The PDL-based filter consists of a polarization beam splitter, three half-wave plates (HWPs), a Faraday rotator (FR), and two polarization-maintaining fiber (PMF) segments with equal birefringence and different lengths. At proper orientation angle sets (θh1, θh2, θh3) of the three HWPs, the proposed filter can have its polarization-dependent transmittance, offering the CS-switchable operation realized by switching between two orthogonal input SOPs of linear horizontal polarization (LHP) and linear vertical polarization (LVP). In particular, at a fixed input SOP, a half-period wavelength switching operation, i.e., an interleaving operation, can also be implemented by controlling only one HWP angle (θh1 or θh3). Theoretical prediction was verified by experiments. For orthogonal input SOPs of LHP and LVP, the fabricated PDL-based filter could provide transmission spectra with CSs of ∼0.9 and ∼0.3nm or vice versa at appropriate sets of (θh1, θh2, θh3), respectively, and each of the transmission spectra could be interleaved by adjusting only θh1 or θh3. |