Extinction ratio and resonant wavelength tuning using three dimensions of silica microresonators

In this paper, a multidimensional tuning method of the silica microcapillary resonator(MCR) is proposed and demonstrated whereby the extinction ratio(ER) as well as the resonant wavelength can be individually controlled.An ER tuning range of up to 17 d B and a maximum tuning sensitivity of 0.3 d B/μm are realized due to the tapered profile of the silica optical microfiber(MF) when the MF is adjusted along its axial direction. Compared to direct tuning of the coupling gap, this method could lower the requirement for the resolution of displacement stage to micrometers. When the MF is adjusted along the axial direction of the silica microcapillary, a resonance shift of 3.06 nm and maximum tuning sensitivity of 0.01 nm/μm are achieved. This method avoids the use of an applied external field to control the silica microresonators. Moreover, when air is replaced by ethanol and water in the core of the silica microcapillary, a maximum resonance shift of 5.22 nm is also achieved to further enlarge the resonance tuning range. Finally, a microbubble resonator with a higher Q factor is also fabricated to achieve an ER tuning range of 8.5 d B. Our method fully takes advantage of the unique structure of the MCR to separately and easily tune its key parameters, and may broaden its applications in optical signal processing and sensing.

Additional Sensitivity Penalty of Burst Mode Receivers in Ethernet PON due to Extinction Ratio

An additional sensitivity penalty of burst mode receivers due to the extinction ratio is analyzed considering the specific transmitter control in Ethernet PON. For an extinction ratio of 6dB, a penalty of 8dB occurs additionally.

Design of a photonic crystal fiber polarization beam splitter with simple structure and ultra-wide bandwidth

A novel polarization beam splitter(PBS)based on dual-core photonic crystal fiber(DC-PCF)is proposed in this work.The proposed DC-PCF PBS contains two kinds of lattices and three kinds of air holes to form the asymmetrical elliptic dual-core structure.By using the full-vector finite element method,the propagation characteristics of the proposed DC-PCF PBS are investigated.The simulation results show that the bandwidth of the proposed DC-PCF PBS can reach to 340 nm,which covers the S+C+L+U communication bands,the shortest splitting length is 1.97 mm,and the maximum extinction ratio appears near wavelength 1550 nm.Moreover,the insertion loss of the proposed DC-PCF PBS is very low.It is believed that the proposed DC-PCF PBS has important applications in the field of all-optical communication and network.

Design of a polarization splitter for an ultra-broadband dual-core photonic crystal fiber

A novel ultra-broadband polarization splitter based on a dual-core photonic crystal fiber(DC-PCF)is designed.The full-vector finite element method and coupled-mode theory are employed to investigate the characteristics of the polarization splitter.According to the numerical results,a graphene-filled layer not only broadens the working bandwidth but also reduces the size of the polarization splitter.Furthermore,the fluorine-doped region and the germanium-doped region can broaden the bandwidth.Also,the 4.78 mm long polarization splitter can achieve an extinction ratio of-98.6 d B at a wavelength of 1550 nm.When extinction ratio is less than-20 d B,the range of the wavelength is 1027 nm-1723 nm with a bandwidth of 696 nm.Overall,the polarization splitter can be applied to all-optical network communication systems in the infrared and near-infrared wavelength range.

Novel configuration for wavelength conversion based on cross-gain modulation in semiconductor optical amplifiers

Novel configuration for cross-gain modulation (XGM) wavelength conversion based on the single-port-coupled semiconductor optical amplifier (SOA), in which the input and the output share one port, has been demonstrated with the output extinction ratio as high as 15 dB, even in the 2.5 Gbit/s wavelength up conversion with a 12.8 nm span. Owing to the existence of double-pass gain and the transmission loss of the rear facet, the novel scheme can be achieved with simpler implementation and higher output extinction ratio, compared with the conventional schemes based on double-port-coupled SOA either with identical long chip or double long chip.

A Novel Polarization Maintaining Fiber

It introduces a novel elliptical jacket polarization maintaining fiber, whose SAP is like numeral "1". One preform can be drawn over 8km. Fiber's performances show that it is fit for fiber gyroscope and other sensors.

Silicon photonics integrated dynamic polarization controller

We designed and demonstrated experimentally a silicon photonics integrated dynamic polarization controller.The overall size of the dynamic polarization controller on chip is 2.830 mm × 0.210 mm × 1 mm.The modulation bandwidth is 30 kHz.By using a variable step simulated annealing approach,we achieve a dynamic polarization extinction ratio greater than 25 dB.A numerical simulation method was used to optimize the relevant parameters of the dynamic polarization controller.It is expected that the dynamic polarization controller can be utilized in fiber communication systems or silicon photonics integrated quantum communication systems to minimize the size and decrease the cost further.