Limits...
Diffractive optics for combined spatial- and mode- division demultiplexing of optical vortices: design, fabrication and optical characterization.

Ruffato G, Massari M, Romanato F - Sci Rep (2016)

Bottom Line: During the last decade, the orbital angular momentum (OAM) of light has attracted growing interest as a new degree of freedom for signal channel multiplexing in order to increase the information transmission capacity in today's optical networks.Here we present the design, fabrication and characterization of phase-only diffractive optical elements (DOE) performing mode-division (de)multiplexing (MDM) and spatial-division (de)multiplexing (SDM) at the same time.These novel DOE designs appear promising for telecom applications both in free-space and in multi-core fibers propagation.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Astronomy 'G. Galilei', University of Padova, via Marzolo 8, 35131 Padova, Italy.

ABSTRACT
During the last decade, the orbital angular momentum (OAM) of light has attracted growing interest as a new degree of freedom for signal channel multiplexing in order to increase the information transmission capacity in today's optical networks. Here we present the design, fabrication and characterization of phase-only diffractive optical elements (DOE) performing mode-division (de)multiplexing (MDM) and spatial-division (de)multiplexing (SDM) at the same time. Samples have been fabricated with high-resolution electron-beam lithography patterning a polymethylmethacrylate (PMMA) resist layer spun over a glass substrate. Different DOE designs are presented for the sorting of optical vortices differing in either OAM content or beam size in the optical regime, with different steering geometries in far-field. These novel DOE designs appear promising for telecom applications both in free-space and in multi-core fibers propagation.

No MeSH data available.


Related in: MedlinePlus

(a) Measured intensity of the incident perfect vortex, in the specific case with ℓ = −2, on a plane perpendicular to the propagation direction. (b.1–5) Experimental far-field on the CCD camera of a DOE performing OAM-MDM in the range {−2, −1, 0, +1, +2}, according to the scheme in Fig. 2. The far-field exhibits a bright spot in correspondence of the corresponding input OAM (c), otherwise no peak is present (d).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4837364&req=5

f8: (a) Measured intensity of the incident perfect vortex, in the specific case with ℓ = −2, on a plane perpendicular to the propagation direction. (b.1–5) Experimental far-field on the CCD camera of a DOE performing OAM-MDM in the range {−2, −1, 0, +1, +2}, according to the scheme in Fig. 2. The far-field exhibits a bright spot in correspondence of the corresponding input OAM (c), otherwise no peak is present (d).

Mentions: Depending on the designed phase pattern, the final output consists of an array of spots, whose brightness is proportional to the corresponding OAM contribution to the input beam. For each input OAM signal, energy is collected in far-field over a well-defined matrix of detectors by measuring light intensity at specific points on the CCD image, in correspondence of the different diffraction orders specified by equation (6). In Fig. 8 normalized intensities are reported for a DOE performing OAM-MDM in the range {−2, −1, 0, +1, +2}. The plot exhibits a well-defined channel response, with efficiencies between 77% and 86% (Fig. 9). The cross-talk XT of the channel corresponding to a selected value ℓ = ℓ* is defined as:


Diffractive optics for combined spatial- and mode- division demultiplexing of optical vortices: design, fabrication and optical characterization.

Ruffato G, Massari M, Romanato F - Sci Rep (2016)

(a) Measured intensity of the incident perfect vortex, in the specific case with ℓ = −2, on a plane perpendicular to the propagation direction. (b.1–5) Experimental far-field on the CCD camera of a DOE performing OAM-MDM in the range {−2, −1, 0, +1, +2}, according to the scheme in Fig. 2. The far-field exhibits a bright spot in correspondence of the corresponding input OAM (c), otherwise no peak is present (d).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837364&req=5

f8: (a) Measured intensity of the incident perfect vortex, in the specific case with ℓ = −2, on a plane perpendicular to the propagation direction. (b.1–5) Experimental far-field on the CCD camera of a DOE performing OAM-MDM in the range {−2, −1, 0, +1, +2}, according to the scheme in Fig. 2. The far-field exhibits a bright spot in correspondence of the corresponding input OAM (c), otherwise no peak is present (d).
Mentions: Depending on the designed phase pattern, the final output consists of an array of spots, whose brightness is proportional to the corresponding OAM contribution to the input beam. For each input OAM signal, energy is collected in far-field over a well-defined matrix of detectors by measuring light intensity at specific points on the CCD image, in correspondence of the different diffraction orders specified by equation (6). In Fig. 8 normalized intensities are reported for a DOE performing OAM-MDM in the range {−2, −1, 0, +1, +2}. The plot exhibits a well-defined channel response, with efficiencies between 77% and 86% (Fig. 9). The cross-talk XT of the channel corresponding to a selected value ℓ = ℓ* is defined as:

Bottom Line: During the last decade, the orbital angular momentum (OAM) of light has attracted growing interest as a new degree of freedom for signal channel multiplexing in order to increase the information transmission capacity in today's optical networks.Here we present the design, fabrication and characterization of phase-only diffractive optical elements (DOE) performing mode-division (de)multiplexing (MDM) and spatial-division (de)multiplexing (SDM) at the same time.These novel DOE designs appear promising for telecom applications both in free-space and in multi-core fibers propagation.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Astronomy 'G. Galilei', University of Padova, via Marzolo 8, 35131 Padova, Italy.

ABSTRACT
During the last decade, the orbital angular momentum (OAM) of light has attracted growing interest as a new degree of freedom for signal channel multiplexing in order to increase the information transmission capacity in today's optical networks. Here we present the design, fabrication and characterization of phase-only diffractive optical elements (DOE) performing mode-division (de)multiplexing (MDM) and spatial-division (de)multiplexing (SDM) at the same time. Samples have been fabricated with high-resolution electron-beam lithography patterning a polymethylmethacrylate (PMMA) resist layer spun over a glass substrate. Different DOE designs are presented for the sorting of optical vortices differing in either OAM content or beam size in the optical regime, with different steering geometries in far-field. These novel DOE designs appear promising for telecom applications both in free-space and in multi-core fibers propagation.

No MeSH data available.


Related in: MedlinePlus