2×2 optical fibre polarisation switch and polarisationcontroller

A liquid crystal based optical fibre polarisation switch is demonstrated. Switching voltages of about 3 V were used and switching speeds of a few Hz obtained. In addition, the device may be used as the basis for a polarisation controller in coherent optical detection schemes     

4×4 digital optical matrix switch using polymeric oversizedrib waveguides

For the first time the concept of oversized rib waveguides has been employed in a complex integrated optical device. Using commercially available polymers, a strictly nonblocking 4×4 digital optical matrix switch with full functionality has been realized. The matrix consists of 24 1×2 switching elements and showed a polarization independent average crosstalk of -28.8 dB     

1×2 optical switch for WDM transmission systems

A 1×2 optical switch, which also functions as wavelength demultiplexer, is designed and experimentally fabricated utilising a phase plate and a twisted nematic liquid crystal. Measured insertion loss, crosstalk attenuation, and transit time are <1.5 dB, >17.6 dB, and <80 ms, respectively     

A high-speed low-voltage stress-induced micromachined 2×2optical switch

A low-voltage electrostatically actuated 2×2 fiber optic switch is achieved using a stress-induced curved polysilicon actuator. The curved polysilicon beam substantially lowers the electrostatic operating voltage of the switch. Large mirror displacement (300 μm) and low operating voltage (20 V) are obtained simultaneously. Sub-millisecond switching time (<600 μs), low optical insertion loss (0.7 dB), and small polarization-dependent loss (0.09 dB) have been achieved     

Prototype 32×32 optical switch matrix

A 32×32 optical switch matrix with a banyan network architecture is demonstrated using a Ti:LiNbO₃ waveguide. The switching voltage was 24 V and extinction ratio averaged -18 dB. The prototype device showed path dependent insertion loss deviation of 10 dB. The device can be used as a building block for many functional optical switch matrices     

Reflective digital optical switch (RDOS) for DWDM optical networkapplications

A novel, high-performance, reflective digital optical switch for use in dense wavelength-division-multiplexed (WDM) network applications is presented. Highly reliable Ti-LiNbO₃ devices show high-speed polarization-independent reflection modulation with 30-dB ON-OFF ratios over a wavelength range from 1520 to 1570 nm     

Lossless 1×4 laser diode optical gate switch

The fabrication of a compact 1×4 laser diode (LD) optical gate switch for the 1.3 μm band, comprising five LD optical gate submodules and a 1×4 planar lightwave circuit, is described. The switch exhibited a lossless switching function and polarization sensitivities of 0.5-1.1 dB, with operation currents of 45 to 55 mA. At operation currents of 120 mA, the switch exhibited positive gains of 9.0 to 10.2 dB. No power penalty was detected for nonreturn-to-zero (NRZ) transmissions of up to 2 Gb/s at -10 dBm input levels, when a narrowband optical filter for spontaneous emission reduction was used     

Rearrangeably nonblocking 8×8 guided wave optical switch

The design and construction of a lithium niobate 8×8 optical switch with a rearrangeably nonblocking architecture is described. The design is compared with the more familiar strictly nonblocking architecture. The switch has 28 elements, a switching voltage of 26 V and a loss of 5.5 dB at 1.3 μm wavelength     

Pigtailed tree-structured 8×8 LiNbO3 switch matrixwith 112 digital optical switches

We report on integrated optics Ti:LiNbO₃-based 8×8 switch matrices. The matrix design uses a tree structure with 112 digital optical switches as switch elements. The matrix, which has been pigtailed and packaged in an open package for convenient system demonstrator use, exhibits a worst case insertion loss of less than 15 dB     

Advanced architecture for a one-chip 16×16 digital switch

A one-chip 16×16 digital switch (SWEL) is presented which is designed for use in a wide variety of applications, ranging from digital mobile radio and satellite applications, to PCM switching systems (integrated services digital network). It provides a compact, low-power solution to perform in channel-controlled switching of 64-kb/s or 2-Mb/s channels. Both architecture and design issues are discussed in detail; a 1.2 μm double metal CMOS technology was employed in the design. The multiplexed architecture allows for easy implementation of new application-specific requirements, making this circuit the cornerstone for new telecommunication switching products     

A 2×2 crosspoint switch fabricated on the passive activeresonant coupler (PARC) platform

We demonstrate the fabrication of a 2×2 crosspoint switch monolithically fabricated on the passive active resonant coupler (PARC) platform by utilizing vertical resonant coupling over a taper between an active and a passive waveguide. The coupling taper was 100 μm long with less than 0.15 dB coupling loss. By pushing the mode up and down as and when required, we are able to integrate passive waveguides and electroabsorption modulators on one chip. The static performance of the switch has been tested, and a modulation depth of 30 dB has been achieved at the wavelength of 1.57 μm for an applied bias of 2.5 V     

An 8 mm length nonblocking 4×4 optical switch array

A novel single-mode-single-slip-structure S³ optical switch using carrier-induced refractive index change is proposed as a unit cell for a small polarization-independent nonblocking N×N optical switch array. Sixteen S³ optical switches have been integrated into a nonblocking 4×4 optical switch array on an InP substrate. The 8-mm-length InGaAsP/InP 4×4 optical array has shown satisfactory switching characteristics and is suitable for larger scale integration of optical switch arrays and also for integration with other active optical devices such as laser diodes     

非对称电极数字光开关

提出了一种新型的数字光开关电极结构.用两组不对称的电极作用于Z切割LiNbO3Y分叉波导上,其中一组电极从Y分叉波导的顶端就开始对波导进行作用,由于开关电极加强了对Y分叉强耦合区的作用,因此开关的串扰有了很大的降低.用光束传输法(BPM)软件模拟了该结构的性能,与对称电极结构相比,开关电压在6V左右时串扰降低了约6dB,开关电压在6～9V之间时开关串扰<-20dB.     

Design and fabrication of silicon-based 8×8 MEMS optical switch array

Silicon-based torsion-beam 8×8 optical switch array are designed and fabricated with bulk silicon micromachining technology. Torsion beams and cantilever beams with reflective micromirror situated on the same wafer are fabricated on (1 1 0) silicon. During fabricating the torsion beam actuating structure, the etched hillocks on (1 1 0) plane are obstacles to achieve smooth torsion beam. It is put forward the reasonable ratios mixtures of HF, HNO₃ and CH₃COOH to improve the processes of fabricating torsion beam actuating structure. The slanted under electrodes that can reduce the actuating voltage are designed and fabricated on tilting (1 1 1) plane by wet chemical etching. According to the etching characteristics of (1 1 1) silicon in KOH solution, two designed photomask patterns are proposed in this paper. According to the experimental results, for the 180 μm displacement of mirrors, the device presents the switching time less than 6 ms and the actuating voltage about 65 V. It shows that this optical switch array can make the meet of the optical communication network.     

Fabrication of 128×128 element optical switch array by micromachining technology

Polycrystalline VO₂ thin films were obtained on Si substrates by ion beam sputtering deposition and annealing in flowing Ar gas. SEM images indicate that VO₂ thin films were grown into compact surfaces. Four-probe measurements indicated that the VO₂ thin films own good electrical homogeneity. After the films' production, micromachining technology including lithography, reaction ion etching and metallization connection processes was used to produce the optical switch array. As a result, the 128×128 element optical switch array was achieved.     

2×2 optical waveguide switch with bow-tie electrode based oncarrier-injection total internal reflection in SiGe alloy

Based on the total internal reflection and the plasma dispersion effect of SiGe alloy, a 2×2 intersectional rib optical waveguide switch with bow-tie electrode has been proposed and fabricated for the wavelength of 1.3-μm operation. The thickness of the SiGe layer is 2.6 μm and the width is 9 μm. The branch angle of the switch is 2° and the bow-tie angle is 1.5°. The on-state crosstalk is -19.6 dB, the off-state extinction ratio is 38.5 dB and the off-state insertion loss is less than 1.70 dB. The switching time is about 180 ns     

Improved 8×8 integrated optical matrix switch usingsilica-based planar lightwave circuits

An improved 8×8 optical matrix switch was fabricated using silica-based planar lightwave circuits (PLCs) on a silicon substrate. Three improvements were made. First, the waveguide material was changed from titanium-doped silica (SiO₂₂-TiO₂) to germanium-doped silica (SiO₂₂-GeO₂) to reduce propagation loss. Second, offset driving powers were supplied to every switch unit to realize high extinction ratios. Third, the dummy switch units were modified to suppress the crosstalk through these units. The average insertion loss of the fabricated device was 3.81 db in the TE mode and 3.82 dB in the TM mode. The average extinction ratio of the switch units was 25.3 dB in the TE mode and 22.3 dB in the TM mode. The accumulated crosstalk was estimated to be less than -14 dB in the TE mode and -11 dB in the TM mode. The average driving power of the phase shifter in the on-state was 0.54 W in the TE mode and 0.52 W in the TM mode. The switching response time was 1.3 ms. The packaged 8×8 matrix switch with additional fiber-waveguide coupling loss of 2.7 dB was successfully employed in photonic multimedia switching and photonic inter-module connector system experiments     

Hybrid-integrated 4×4 optical gate matrix switch usingsilica-based optical waveguides and LD array chips

The fabrication and characteristics of a hybrid-integrated optical gate matrix switch were studied. The switch was composed of a silica-based single-mode guided-wave circuit and two InGaAsP gate array chips, each of which comprised eight laser diode optical gates. The gate array chips were assembled on the guided-wave circuit using a hybrid integration technique. The insertion loss of the fabricated 4×4 matrix switch was scattered among switching paths and ranged from 26 to 33 dB. The switch was applicable to a 400 Mb/s signal system with a bit error rate of 10^-9. The numerical analysis shows that the residual reflectivity at the LD gate and waveguide facets caused the loss scattering among the paths and that reduction of the residual reflectivity is essential for improving the switch characteristics     

Polarization-insensitive InP-based MQW digital optical switch

A polarization-insensitive InP-based p-i-n multiple-quantum-well switch is demonstrated for the first time. Polarization-insensitive switching and loss are achieved. Crosstalk and loss measurements across a wavelength range of 20 nm centered at 1.55 μm are reported. A crosstalk of better than -13 dB is achieved for both TE and TM polarizations across the 1.54-1.56-μm wavelength range with a switching voltage of -7 V. A low on-chip loss of less than 3 dB is achieved for both TE and TM across the above wavelength range, with a compact switch structure which is 3 mm long     

Silicon 1*2 digital optical switch using plasma dispersion

The first silicon 1*2 digital optical waveguide switch which relies on free-carrier plasma dispersion and the waveguide-vanishing effect is demonstrated. Operation is demonstrated at a wavelength of 1.3 mu m.<>