Search

We propose a silicon polarization-diversity coherent receiver for wavelength-multiplexing transmission without using the large-footprint arrayed waveguide grating (AWG). We have integrated our proposed coherent receiver on the silicon-on-insulator (SOI) platform for high-capacity transmission. In the proposed coherent receiver, high-frequency photocurrent signals from other wavelengths are suppressed by electrical low-pass filters. Moreover, the signal-signal beat interference (SSBI) generated from each wavelength is eliminated by the balanced detection. These two features lend to the proposed coherent receiver being free of the mm-scale AWG. We have demonstrated our proposed coherent receiver to detect a 1.12-Tb/s wavelength-division-multiplexed and polarization-division-multiplexed 16-ary quadrature amplitude modulation (PDM-16-QAM) signal. The compact footprint of the silicon chip promises small-form-factor receivers for future ultra-high-capacity coherent communication systems that require a high integration level and low fabrication cost. [ABSTRACT FROM AUTHOR]

In this study, a symmetric polarization-division-multiplexing (PDM) wavelength-division-multiplexing passive optical network (WDM-PON) with fiber to the extension (FTTE) architecture is presented and investigated. The proposed PON can also avoid the Rayleigh backscattering (RB) interference noise. Here, each WDM wavelength can produce 25 Gbit/s on-off keying (OOK) and 10 Gbit/s OOK modulation channels simultaneously in x- and y-polarizations (Polx and Poly) through PDM method for 25 and 105 km single-mode fiber (SMF) transmissions without dispersion compensation. The measured minimal power budget of 25 and 10 Gbit/s downstream and upstream signals are 29 and 35.1 dB and 29.8 and 31.5 dB, respectively, at the forward error correction (FEC) target. Therefore, the proposed PDM WDM-PON architecture can not only offer symmetric 35 Gbit/s downstream and upstream connections by the dual-polarized wavelength, but also can avoid the RB-induced interference noise. In addition, the presented dual-polarized downstream signal also can provide information security in physical layer, when the unauthorized user occupies unlawfully.

In this study, a symmetric polarization-division-multiplexing (PDM) wavelength-division-multiplexing passive optical network (WDM-PON) with fiber to the extension (FTTE) architecture is presented and investigated. The proposed PON can also avoid the Rayleigh backscattering (RB) interference noise. Here, each WDM wavelength can produce 25 Gbit/s on-off keying (OOK) and 10 Gbit/s OOK modulation channels simultaneously in x- and y-polarizations (Polx and Poly) through PDM method for 25 and 105 km single-mode fiber (SMF) transmissions without dispersion compensation. The measured minimal power budget of 25 and 10 Gbit/s downstream and upstream signals are 29 and 35.1 dB and 29.8 and 31.5 dB, respectively, at the forward error correction (FEC) target. Therefore, the proposed PDM WDM-PON architecture can not only offer symmetric 35 Gbit/s downstream and upstream connections by the dual-polarized wavelength, but also can avoid the RB-induced interference noise. In addition, the presented dual-polarized downstream signal also can provide information security in physical layer, when the unauthorized user occupies unlawfully. [ABSTRACT FROM AUTHOR]

For high-speed optical transmission, polarization-division-multiplexing (PDM) is a promising technic to double the link capacity. However, most of on-chip PDM systems include a polarization beam splitter, a polarization rotator, and two modulators, which are costly and complex for integration. In this study, a novel dual-polarization electro-optic intensity modulator is proposed that is based on a single silicon waveguide with indium tin oxide (ITO) cladding. The design is validated by numerical simulation with commercial software Lumerical Solution. Based on the epsilon-near-zero effect of ITO, the device, on a single waveguide, manages to modulate simultaneously transverse electric (TE) and transverse magnetic (TM) modes with independent electrical driving signals. With a 75 μ m-long silicon rib waveguide, the extinction ratios (ERs) of both TE and TM modes can be around 15 dB, and the nonuniformity is around 0.5 dB. The 3 dB modulation bandwidths are 57.8 GHz and 65.9 GHz for TE and TM modulation, respectively. Within 1 dB ER nonuniformity, the device can operate at E-, S-, and C-band, which distinguishes itself by achieving wavelength-division-multiplexing compatible PDM and with only one single waveguide. To our best knowledge, the concept of independent and simultaneous dual-polarization modulation on a single waveguide is proposed for the first time. The modulator offers various merits including ultracompact size, high speed, and complementary metal oxide semiconductor (CMOS) compatibility. [ABSTRACT FROM AUTHOR]

Over the past several decades, the data-carrying capacity of a single optical fiber have been increased significantly by fully exploring and optimizing physical dimensions of the light. Generally there are five major candidates of dimensions, including time, wavelength, polarization, space and quadrature (phase and amplitude). Multi-dimension, utilizing more than two dimensions of the light simultaneously, is one of the essential characteristics of next generation optical communication systems. We review recent advances in transmission of multi-dimensional signals, and highlight innovative ways of exploring the polarization dimension to further increase the capacity or spectral efficiency of a single optical fiber, a so-called pseudo-polarization-division-multiplexing (PPDM) technique. Related demonstrations include non-orthogonal PDM, PPDM of three and four states (PPDM-3 and PPDM-4). Brief discussions on trends of multi-dimensional signal transmission technologies are also presented. [ABSTRACT FROM AUTHOR]

Schemes of all-optical regeneration in polarization-division-multiplexing (PDM) systems are proposed and demonstrated with 2 × 10-Gb/s return-to-zero on-off-keying (RZ-OOK) transmission. Regeneration is achieved based on self-phase-modulation (SPM) effect and detuned filtering in highly nonlinear fiber (HNLF) with a polarization-diversified loop configuration. Furthermore, the ability of mitigating polarization-mode-dispersion (PMD) effects in PDM systems is evaluated. More than 3.7-dB eye-diagram-based signal-to-noise-ratio (SNR) improvement is achieved in the presence of 6.3-ps PMD as the pulsewidth of the PDM signal is about 18 ps.