Channeled spectropolarimetry measures the spectral dependence of the polarization states of light. This technique is marked by its snapshot feature, in that the complete polarization states can be determined simultaneously from a single
intensity spectrum. However, without athermalization, it suffers from high sensitivity to temperature, which in turn, degrades the polarimetric reconstruction accuracy. In this paper, we present a calibration technique for a fiber-based channeled spectropolarimetry that leverages phase-shifting interferometry to accurately demodulate the retarders' phase, thereby improving the accuracy of the acquired Stokes parameters. Additionally, it enables robust spectropolarimetric performance that is insensitive to environmental perturbations. Experimental results demonstrate that calibrations using phase-shifting interferometry improve the Stokes reconstruction results by approximately a factor of 3 when compared to
the reference beam calibration method.
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Single-shot phase calibration of a spatial light modulator using geometric phase interferometry
A vibration-insensitive, single-shot phase-calibration method for phase-only spatial light modulators (SLM) is
reported. The proposed technique uses a geometric phase lens to forma phase-shifting radial shearing interferometer
to enable common-path measurements. This configuration has several advantages: (a) unlike diffraction-based
SLM calibration techniques, this technique is robust against intensity errors due to misalignment; (b) unlike twobeam
interferometers, this technique offers a high environmental stability; and (c) unlike intensity-based methods,
the phase-shifting capability provides a phase uncertainty routinely in the order of 2=100. The experimental
results show a significantly higher accuracy when compared to the diffraction-based approaches. © 2020 Optical
Society of America
https://doi.org/10.1364/AO.383610
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- NSF-PAR ID:
- 10161242
- Date Published:
- Journal Name:
- Applied optics
- Volume:
- 59
- Issue:
- 13
- ISSN:
- 1559-128X
- Page Range / eLocation ID:
- D125-D130
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Orthogonal frequency division multiplexing (OFDM) is a candidate technique to provide high-speed data transmissions for optical communication systems. For intensity modulation and direct detection (IM/DD) optical communication systems, only real and non-negative valued signals can be transmitted due to the natural properties of the transmitters and receivers. This paper proposes a technique called magnitude-phase optical OFDM (MPO-OFDM) that transmits the magnitude and phase of the conventional complex valued OFDM signal successively, similar to polar-based OFDM. Unlike polar-based OFDM, however, the proposed MPO-OFDM quantizes, encodes, and transmits the phase information using pulse amplitude modulation (PAM) to reduce the interference introduced by the additive noise on the phase. Considering the peak radiation power constraint of optical devices, the magnitude component of the MPO-OFDM signal experiences clipping distortion. In this paper, we optimally adjust the modulation index to control the scale of the magnitude component and achieve the highest signal to noise ratio (SNR). For the same transmitted data rate, the proposed MPO-OFDM can achieve a lower bit error rate than previously proposed techniques. For a similar BER performance, MPO-OFDM can support a higher throughput than the other techniques tested.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1364/AO.383610
