OPTICS 2017 Abstracts

Full Papers
Paper Nr: 1

Intrusion Location with Breaking-the-Pulse-Width-Limit Spatial Resolution and High Robustness based on φ-OTDR and Spatial Frequency Analysis


Zhou Sha, Hao Feng, Yi Shi and Zhoumo Zeng

Abstract: This paper proposes a vibration location method based on spatial-frequency analysis, which can help achieve better location performance in the application of φ-OTDR. The method is proven to be able to separately locate coupled vibration events to some extent, achieve break-the-pulse-width-limit spatial resolution in the case of single event detection with higher robustness, and provide more comprehensive information about the vibration situation to better identify vibration events, noise and disturbance. Different experiments including indoor and outdoor tests are conducted to practically validate the effectiveness of the method and its advantages over the conventional moving differential method. Experiment results show that the proposed method exhibits several useful merits.

Paper Nr: 2

Optical MIMO Multi-mode Fiber Transmission using Photonic Lanterns


Andreas Ahrens, André Sandmann and Steffen Lochmann

Abstract: Within the last years the multiple-input multiple-output (MIMO) technology has attracted increasing interest in the optical fiber community. Theoretically, the concept of MIMO is well-understood and shows some similarities to wireless MIMO systems. However, practical implementations of optical components are in the focus of interest. Optical couplers have long been used as passive optical components being able to combine or split single-input single-output (SISO) data transmissions. They have been proven to be well-suited for the optical MIMO transmission despite their insertion losses and asymmetries. Nowadays, next to optical couplers, photonic lanterns (PLs) have attracted a lot of attention in the research community as they offer the benefit of a low loss transition from the input fibers to the modes supported by the waveguide at its output. In this contribution the properties of a six-port PL are evaluated by measurements with regards to their respective MIMO suitability. Based on the obtained results, a simplified time-domain MIMO simulation model, including PLs for mode combining at the transmitter-side as well as for mode splitting at the receiver-side, is elaborated. Our results obtained by the simulated bit-error rate (BER) performance as well as by measurements show that PLs are well-suited for the optical MIMO transmission.

Short Papers
Paper Nr: 5

High Frequency Stability External Cavity Diode Laser with Narrow Linewidth for Cs Atomic Clock


Baolu Guan, Guanzhong Pan, Weiling Guo, YiYang Xie and Chen Xu

Abstract: A robust external cavity diode laser (ECDL) based on wide bandwidth filter is fabricated and tested. The ECDL demonstrates a narrow Lorentzian fitted linewidth of 95kHz and a spectral purity of 2.9MHz. A simple saturation absorption spectrum setup is constructed to lock the ECDL. Long term frequency stability of the ECDL reaches 5.59×10-12. The 852nm Fabry-Perot diode laser used in the ECDL is also fabricated and tested. The lateral mode of the laser diode is analyzed based on finite difference method. The diode laser demonstrates a full width at half maximum (FWHM) spectrum as low as 0.31nm and a slope efficiency as high as 0.66mW/mA. Low threshold and single lateral mode operation of the diode laser have been achieved attributed to a special dual-grooves structure. Good characteristics of the diode laser ensure the performance of the ECDL. A detailed description and discussion of techniques used to characterize the frequency stability is provided.

Paper Nr: 8

Suppressing the Effect of Dispersion Fluctuation on Broadband Optical Parametric Amplification using Highly Nonlinear Tellurite Microstructured Optical Fibers


Tong Hoang Tuan, Kawamura Harukata, Takenobu Suzuki and Yasutake Ohishi

Abstract: The contribution of fiber nonlinearity to the signal gain spectrum of a fiber-optical parametric amplifier (FOPA) in presence of fiber transverse geometry variation is numerically studied in this work. This is the first time to demonstrate that the degradation of FOPA signal gain performance which is caused by fiber diameter fluctuation and zero-dispersion wavelength (ZDW) variation can be suppressed by using highly nonlinear optical fibers with short fiber length. By increasing the fiber nonlinear coefficient, the fiber length which is required to have similar value of signal gain is reduced, the signal gain bandwidth can be broadened and the spectral shape can be maintained. A tellurite microstructured optical fiber was fabricated by using a developed tellurite glass 78TeO2–5ZnO-12Li2O-5Bi2O3 mol%. The fiber outer-diameter fluctuation is less than ±0.53 % and the corresponding ZDW varies less than ±2 nm over a 1-m-long section of the fabricated fiber. The fiber nonlinear coefficient is calculated to be 676 W-1km-1 which is 23 times larger than those values of highly nonlinear silica fibers. When the pump source is 5 W at 1557 nm, the influence of ZDW fluctuation on signal gain spectra is almost suppressed.

Paper Nr: 4

Nonlinearity Mitigation using Optical Phase Conjugation for Discrete Multi-tone based Optical Transmission System


Raman Jee and Somnath Chandra

Abstract: Discrete Multi-tone modulation has recently emerged as one of the preferred modulation format for high bit rate intensity modulated–direct detection (IM-DD) optical transmission, this paper, we have investigated analytically the performance of Discrete-Multi-Tone signal with spectral inversion techniques using mid-span optical phase conjugation. Our analysis shows that, the use of optical phase conjugation can increase the non-linearity tolerance of the multi-subcarrier DMT transmission system for medium range transmission, used for inter-data center link. The results show that at FEC threshold of 3.8×10-3, the use of OPC can provide a system gain of 1.6dB in comparison to the case where no OPC is used.

Paper Nr: 6

Phased Beam Steering and Mode Switching in Coupled Vertical Cavity Surface Emitting Laser Arrays


Xie Yiyang, Xu Chen, Guan Baolu, Guo Weiling, Xun Meng and Liu Jie

Abstract: High quality light source can be achieved in coupled vertical cavity surface emitting laser arrays. Electrically controlled beam steering is easily achieved via tuning resonance between elements. In the experiment, the beam steering in 1×2 arrays is continuous and controlled. The maximum deflection angle is 1.4 degrees. The power concentrated in the central lobe is 34.7%~43.9%. The divergence in the far-field profile of the in-phase mode is 3.66 degrees. The properties of near-field profiles and far-field profiles under different currents are analyzed. The mode switching between out-of-phase and in-phase mode was obtained.