Abstract
The orbital angular momentum (OAM) of light is used for increasing the optical communication capacity in the mode division multiplexing (MDM) technique. A novel and simple structure of ring-core photonic crystal fiber (RC-PCF) is proposed in this paper. The ring core is doped by the Schott sulfur difluoride material and the cladding region is composed of fused silica with one layer of well-patterned air-holes. The guiding of Terahertz (THz) OAM beams with 58 OAM modes over 0.70 THz (0.20 THz–0.90 THz) frequency is supported by this proposed RC-PCF. The OAM modes are well-separated for their large refractive index difference above 10−4. The dispersion profile of each mode is varied in the range of 0.23–7.77 ps/THz/cm. The ultra-low confinement loss around 10−9 dB/cm and better mode purity up to 0.932 is achieved by this RC-PCF. For these good properties, the proposed fiber is a promising candidate to be applied in the THz OAM transmission systems with high feasibility and high capacity.
Highlights
Increasing the receptivity of optical fiber transmission links is an exigent task due to the swiftly growing necessity for information transmission capacity
The physical wave of the light beam—the frequency, wavelength, amplitude, phase, and polarization—has been used to convey information. This is done by using multiplexing techniques, such as polarization division multiplexing (PDM), wavelength division multiplexing (WDM), mode-division multiplexing (MDM), space division multiplexing (SDM) and some advanced modulation techniques [1,2,3]
The radial orders with m > 1 are not considered because of their disturbance in multiplexing and demultiplexing of orbital angular momentum (OAM) modes [44], we considered only m equal to 1
Summary
Increasing the receptivity of optical fiber transmission links is an exigent task due to the swiftly growing necessity for information transmission capacity. OAM transmission with a large number of OAM states, low confinement loss, smooth dispersion variation, and better OAM quality are considered For developing those parameters of the PCF, some unique types of PCFs have been proposed and discussed before, such as the spiral PCF [37], circular PCF [38], chain PCF [39], quasi-crystal fiber [40], ring-based PCFs [41,42,43,44], and so forth. F. Israk et al [42] proposed, designed, and investigated a Schott sulfur Di-fluoride (SF2) doped ring based coil-shaped circular PCF supporting 56 OAM states with ultra-low confinement loss (1.7407 × 10−9 dB/cm) and smooth dispersion variation. Wang et al. In this paper, we designed a light-guiding Schott SF2 doped ring-based photonic crystal fiber for supporting Terahertz orbital angular momentum over a wide frequency range of 0.20–0.90 THz. The proposed circular PCF supported 58 OAM states.
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