Novel polarization beam splitter based on p-i-n structure for an indium phosphide platform

Alignment-free characterization of polarizing beamsplitters

“…Table I shows the measurement results for both methods. The so-called literature method is the one described in [5], [7]. According to Table I,the proposed and literature methods provide similar extinction ratio results which prove the efficacy of the proposed method.…”

“…Two 3-port and one 4-port PBS's were characterized with the proposed method, and the results are presented in Table I. Even though all extinction ratios measured comply with those described in the devices' data sheets (¿ 20 dB), for a more accurate comparison, the extinction ratios were also measured with the conventional method described in literature [4], [5], [6], [7]. For this, a polarized light source comprised of a laser was used and had its polarization aligned with one axis of the tested PBS.…”

“…The reader may have noticed that all equations (3)(4)(5)(6)(7)(8) could also be written for a generic 3-port device, such as a regular beamsplitter. However, as discussed in Section IV-A, there is an uncertainty in the measurement introduced by the PDL of the circulator and the optical switch, which are unavoidable.…”

“…Traditionally, this measurement is performed using a highly coherent light source, such as a laser [4], [5], [6], [7], [8], [9], [10], [11]. The polarization state of a test light signal is matched with both axes -horizontal and vertical polarizations -of the device under test (DUT), using birefringent elements such as half-waveplates or fiber polarization controllers, depending on whether the DUT is a bulk or fiber-optical PBS, respectively.…”

“…By a clever arrangement of a Faraday Mirror, a 2x2 optical switch, two power meters and an optical circulator, it is possible to obtain the insertion losses and extinction ratios in a single-sweep, three-step measurement. The method is validated, a fully automated characterization unit is assembled and the results are compared to the literature method [4], [5], [6], [7] with good correspondence.…”