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     

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     

Integrated optics 4*4 switch matrix with digital optical switches

Reports on the first 4*4 switch matrix with digital optical switches as switch elements. The matrix is arranged in a tree structure, and comprises 24 switch elements and is pigtailed and packaged.<>     

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     

4×4 OEIC switch module using GaAs substrate

A compact 4×4 optical switch module consisting of a monolithic 4-channel OEIC receiver chip, a 4×4 GaAs IC chip, and a 4-channel OEIC transmitter chip has been developed for the first time. The module offers good performance, without an optical loss, a bandwidth of more than 600 MHz, and a crosstalk between neighboring channels of less than -20 dB. It has a good switching and distributive performance for high speed optical input signals of 560 Mbit/s. The switch module is attractive for use in high data-rate optical communication systems, particularly in local area networks, CATV systems, and intra-office links     

Polarization-insensitive, monolithic 4×4 InGaAsP-InP laseramplifier gate switch matrix

Monolithically integrated 4×4 semiconductor laser amplifier gate switch arrays comprising twenty-four integrated laser amplifiers have been designed, fabricated, and evaluated. Low fiber-to-fiber loss, low polarization dependence, high extinction ratio, and low crosstalk are reported     

Polarisation-independent LiNbO3 4×4 matrix switch

The first polarisation independent LiNbO₃ strictly non-blocking 4×4 matrix switch has been developed. This matrix switch has a 4-6 dB insertion loss at any incident polarisation with 1.3 μm wavelength and about 30 V switching voltage     

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     

Architecture of crosstalk-reduced digital optical 2×2 switch(CRDOS)

Coherent crosstalk of optical space switch matrices is a key problem of optical transparent networks. An analysis of the crosstalk sources of electrooptical digital switches (DOS) is given and a new crosstalk compensating technique based on the integration of a general mode converter as correcting device into a 3×2 DOS is proposed and theoretically investigated. It can be shown, that a -20 dB crosstalk 2×2 DOS device can be enhanced to -40 dB. This architecture leads to an increase of the device length by only a few percent. It opens up the possibility to realize short optical switches for larger matrices     

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     

Linear crosstalk in 4×4 semiconductor optical amplifier gateswitch matrix

We report a comprehensive crosstalk investigation of a packaged InGaAsP/InP 4×4 semiconductor optical amplifier gate switch matrix, experimentally as well as theoretically. For a fully loaded switch with the same wavelength on all four inputs, all possible switching combinations are analyzed, thus yielding realistic crosstalk figures. Coherent and incoherent crosstalk phenomena are identified, and a switch crosstalk less than -40 dB has been measured     

Hybrid optical switch using passive polymer waveguides andsemiconductor optical amplifiers

Optical switching can be performed by using optical amplifiers combined with a passive waveguiding network. Recently, most of the effort in optical amplifier switch modules have been focused on monolithic switches in which the entire device is fabricated on an InP substrate together with the semiconductor optical amplifiers (SOA's). In this paper, we investigate the use of SOA's with passive polymer waveguides to make hybrid switches of varying sizes. The optical amplifiers serve dual purposes, gating the signal and amplifying the signal. Amplification is needed in order to offset the losses associated with the passive waveguide elements as well as the losses from component misalignments in the switch module. Our analysis finds the largest switch module size that can be made with the architecture used. We also calculate the maximum number of switch modules which can be cascaded in order to retain a bit-error rate (BER) under 10^-9     

Tree-structured polarisation independent 4×4 switch matrix inLiNbO3

Reports on the performance of a 4×4 polarisation-independent LiNbO₃ switch matrix with a `tree-structure', permitting strictly nonblocking communicative as well as distributive switching     

1 × 2 MOEMS switch based on silicon-on-insulator andpolymeric waveguides

A new planar optical switch concept based on a silicon-on-insulator microelectromechanical system (MEMS) structure with post-processed polymeric waveguides is reported. The actuation voltage is 20 to 50 V, and the switching time as low as 30 μs. A crosstalk of -32 dB has been measured     

Integrated optical high-voltage sensor based on a polymeric Y-branch digital optical switch

An integrated optical high-voltage sensor is realized by fabricating a Y-branch digital optical switch in an electrooptic polymer. The measurement of ac high voltage is accomplished by using the linear transfer characteristics of the switch at zero bias voltage. Furthermore, the logarithmic ratio between the optical powers of two output ports may be used to remove the noise caused by the power fluctuations of a light source. The polymeric high-voltage sensor requires no electrical dc biases and no voltage dividers. It is also wavelength insensitive and fabrication-tolerant due to its use of mode evolution effects instead of interference. The measured sensing voltage range is as large as ac 500-V peak-to-peak.     

Silica-based 8×8 optical matrix switch integrating newswitching units with large fabrication tolerance

An 8×8 optical matrix switch consisting of asymmetric Mach-Zehnder (MZ) interferometer switching units with a waveguide intersection was fabricated using silica-based planar lightwave circuits (PLC's) on a silicon substrate. This switching unit can realize a high extinction ratio and a wide operation wavelength range even if the coupling ratios of the directional couplers (DC's) consisting the switching unit, deviate greatly from the ideal value of 50%. A matrix switch with a DC-coupling ratio of 30% was fabricated to test the validity of the proposed geometry. The average insertion loss was 7.3 dB in the transverse electric (TE) mode and 7.5 dB in the transverse magnetic (TM) mode. The average extinction ratio was 31.2 dB in the TE mode and 31.3 dB in the TM mode. The wavelength range with an extinction ratio greater than 20 dB was over 100 nm     

Optimization of silicon-on-insulator based optical switch using tapered waveguides

Optimized 2×2 switches based on silicon-on-insulator (SOI) were demonstrated. In the design, single mode rib waveguidesand multimode interferences (MMIs) are connected by tapered waveguides to reduce the mode coupling loss between thetwo types of waveguides. The average insertion loss of the switches is about -16.9 dB and the excess loss of one is measuredof -1.3 dB. The worst crosstalk is larger than 25 dB. Experimental results indicate that some of the main characteristics ofoptical switches are improved in the modified design, which is according with theoretic analysis. The novel design can beused to improve the characteristics of optical switch matrixes based on 2×2 switch units.     

First digital optical switch based on InP/GaInAsP double heterostructure waveguides

A Y-junction digital optical switch based on InP/GaInAsP has been realised and operated using either carrier injection or carrier depletion. the switch functions with both TE and TM polarised light. In the case of current injection, 30 mA is enough to obtain a crosstalk up to 20 dB for TM polarisation and 10 dB for TE polarisation.<>     

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     

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