product focus: MEMS components
Dynamic channel equaliser
Lightconnect has introduced the first diffractive MEMS-based dynamic channel equaliser, for use in DWDM optical add/drop multiplexers, wavelength drop modules and switching applications, designed to equalise or block individual channels across the C band (1527-1570nm) on a 50GHz grid.
Control of the power of 100-plus wavelengths in one compact module eliminates the need for a discrete component per channel. Lightconnect says it is the first high-channel-count device to provide seamless attenuation control, a wide dynamic range for blocking, as well as four-fold reduction in size and power compared to existing discrete architectures.
In July 2001 Lightconnect introduced its fast variable optical attenuator and 40nm-range dynamic gain equaliser, designed to control and adjust optical power in different spectral bands and dynamically compensate for the spectral non-uniformity of EDFA or Raman optical amplifiers. Since then it has extended its DGE from C to L band and introduced a dynamic gain equaliser module and a digital VOA.
Ultra-precise dynamic gain equaliser
Silicon Light Machines says that its Model 2200 dynamic gain equaliser is the first DGE to use diffractive MEMS technology with ultra-high spectral resolution.
Grating light valve technology combines standard CMOS with MEMS, forming movable, ribbon-like structures held in tension above an air gap over light-reflecting silicon. Electric current in the substructure bends the ribbons to reflect or diffract light, creating a spatial light modulator on the surface.
A 1D array of variable optical attenuators balances channels to ±0.1dB over a dynamic range of 15dB with <6dB of insertion loss and -40dB of return loss. Spectral power ripple is <0.1dB; equalisation time is <1.0ms; dissipation <5W.
First MEMS-based wavelength switch
Network Photonics Inc launched its first commercial MEMS-based wavelength switches, made by Fairchild Semiconductor.
The four-port CrossWave 1200 dynamically reconfigurable OADM and 2200 192x192 wavelength cross-connect (WXC) are for 50 and 100GHz DWDM with up to 96 wavelengths for linear and ring networks as well as emerging mesh topologies.
The 2200 is also designed for "Hybrid XC" switches - a WXC combined with a SONET/SDH digital cross-connect or OEO grooming optical cross-connect to optically route wavelengths and electronically groom sub-wavelength services.
Compared to combining DWDM terminals and OXCs, CrossWave has an all-optical wavelength routing element (WRE). This integrates 1D MEMS - a linear array of micro-mirrors with no need for complex closed-loop servo control for positioning - with a wavelength-dispersive grating for dynamic switching of wavelengths by integrating mux, demux and switching.
This eliminates external DWDM multiplexers and OEO conversions, and offers low insertion loss, wide flat-top passbands, low PDL, high extinction and fast switching times while consuming only 8W.
Foundry gears up for optical MEMS
Grenoble-based MEMS contract manufacturer Tronics Microsystems SA has received ISO 9001 certification.
Using surface micromachined silicon-on-insulator epiwafer technology transferred from LETI, optical telecoms application has included MEMS micro-mirror matrices and membrane components such as OXCs, switches and VOAs.
Last September Tronics started building a 6in wafer plant with a capacity of 20,000 wafers per year, for production from March 2003.
In November, Tronics established the MEMSOI consortium of eight European design houses within the EC's Europractice IST programme.
It offers a service from conception, design, simulation, prototyping and production of MEMS.
Switches and attenuators
Sercalo Microtechnology's 1x1, 1x2, 2x2 and 1x4 and 1x8 MEMS switches have a response time of <1ms as well as insertion loss <1dB.
The sl2x2-9N-12-16 and sl1x2-9N-12-16 latching switches are now available with a new internal driver, compatible with conventional relay-type switches and easing migration.
In April, Sercalo launched the first multimode MEMS-based components (with 50 or 62.5µm fibre pigtails).
In May, it launched MEMS-based single- and dual-channel attenuators with low polarisation-dependent loss characteristic for power manage-ment in DWDM networks or instruments. Matrix switches are also under development.
3D MEMS switches
In March, the S5200 three-dimensional (3D) MEMS optical switch module made Agere Systems Inc first to start volume production of a 3D MEMS optical switch, it claims.
Available in 64x64 and 32x32 configurations, Agere's S5200 is a small-form-factor scalable, low-loss solution for high-speed all-optical switching systems, cross-connects and add/drop multiplexers.
Fabricated using standard IC processing tools, it includes all control electronics needed to manipulate the micro-mirrors.
3D MEMS arrays are inherently non-blocking, reducing the path-dependent insertion losses of 2D and promoting lower loss and loss variations at larger port counts.
At this year's Optical Fiber Communications exhibition, Agere also demonstrated a MEMS-based 64-channel OADM, the first component in its B5100 series of OADM and 1xK wavelength-selectable switches.
The OADM can fully attenuate any of 64 channels for the drop function, as well as perform dynamic gain equalisation for non-blocked channels. The device can also passively add one or more channels back to an output fibre.
Racal Instruments has introduced a 96-channel laser-diode burn-in system which integrates an OSA, co-engineered by the Broadband/Photonics unit with ADC.
It also measures relative optical power, while evaluating monitor photodiode current, individual base-plate temperature control, TEC voltage, and TEC current, as well as device current, voltage, and thermistor temperature.
With 0.06-10nm OSA resolution and a range of 20-85°C, it provides accuracy of ±0.1°C, stability of ±0.25°C, and up to 5A drive current per device under test.
Optical layer monitoring
At March's OFC 2002, Proximion Fiber Optics AB, a supplier of optical layer monitoring, based in Kista, Sweden, showed its Wistom OSA for DWDM fault detection.
Wistom optical layer monitoring combines optical performance monitoring and channel monitoring. By opening up a narrow transmission window of an otherwise broadband, highly reflective fibre Bragg grating, Proximion's scanning filter enables both high detail and high scanning speed without moving parts.
Proximion says it scans the whole C-band in a "record" 0.1ms and reports channel-specific problems with a response time of <10ms while simultaneously measuring wavelength, power and OSNR.
Wistom optical layer monitoring provides a platform for applications including protection switching, fast dynamic gain equalization and long-term drift monitoring to secure the optical communication layer by proving and maintaining Quality of Service.
OSA for 600-1750nm range
Anritsu's MS9710C OSA covers wavelengths of 600-1750nm, has high power level accuracy, wide dynamic range and high reception sensitivity. The OSA can measure wavelength, power level and SNR for up to 300 DWDM channels, and be used for PMD and EDFA noise floor measurements.
An internal Tunable Laser Source Tracking function eliminates the external controller. Also, optional SLD, White light and Reference Wavelength light sources can be installed to simplify measurements.
In addition, the enhanced MS9710C*15 improves wavelength accuracy and resolution and power level flatness and linearity in the 1570-1620nm L band
At OFC 2002, NetTest showed its Walics-Reference benchtop DWDM OSA. Operating over 1250-1650nm with ±10pm accuracy, Walics is optimised for the S, C and L bands and potential monitoring wavelengths. It enables accurate optical signal-to-noise ratio (OSNR) measurements down to 12.5GHz channel spacing. Its flat-top filter mode can be used to isolate a specific channel for additional testing, such as BERT.
The 7520-792 Embedded OSA retrieves wavelength, optical power, OSNR, channel spacing and drift of transmission channels in both high- and coarse-resolution high-capacity DWDM systems in the C and L bands. Over 800 10GHz- spaced DWDM channels can be resolved, enabling integration in systems deploying channel spacings down to 12.5GHz.
The C- and L-band Model 4791 and 4792 OSA modules can be used in the CMA4000i Optical Test System, which has 10GHz channel spacing and 400 automatic channel display.
Acterna has launched a C- and L-band OSA module for its Media Test Set (MTSe) platform for fibre characterisation testing during installation, turn-up and maintenance on DWDM networks for channels from 1525 to 1610nm.
Due to the MTSe's dual-slot design, new modules also allow optical time domain reflectometry (OTDR), polarisation mode dispersion (PMD) and chromatic dispersion (CD) functions with a single unit, enabling full characterisation or qualification of fibre links for rates up to 10Gbit/s.
Last July, Acterna launched the first of a family of DWDM OSA plug-in modules for its portable Optical Network Tester (ONT), the first field instrument to combine optical and digital test in a single, modular unit. The modules, which cover C, L and S 1280-1650nm bands and take just 500ms per full scan, include:
- the single-port OSA 160; and
- the first dual-port analyser, OSA 200, for simultaneous testing of two multiplexed channels.
Measurements can be taken at the inputs and outputs of a network element simultaneously to analyse its effect on the signal, as well as over different paths at the same time for purposes of comparison.
The monitor port provides drop functionality for signal analysis of individual channels. Through its dual-channel principle the OSA-200 can verify optical network elements like OADMs and OAXC.
Benchtop and portable OSAs
Agilent Technologies' S, C, and L band OSAs have 10pm accuracy from 600-1700nm, built-in test applications, and a fast dual-sweep method.
- The 86142B benchtop and 86145B portable high-performance OSAs are suited for 50GHz+ WDM component and system test where power and wavelength accuracy, dynamic range and low polarisation dependency are critical.
- The 86140B benchtop and 86143B portable standard-performance OSAs maintain most of these characteristics but at value prices.
- The 86141B benchtop OSA with a monochromator output and photodiode input is a flexible platform with a tunable filter and broadband power meter. It can measure optical components, isolate WDM system channels, or measure total power of a source.
- The 86146B benchtop high-performance and 86144B portable standard OSAs both have a filter mode to simplify pre-selecting a DWDM channel. The external single-mode monochromator output allows isolation of 12.5GHz-spaced modulated signals, providing the accuracy and flexibility to drop a single channel with fast-tuning speed, low-insertion loss, and highly repeatable wavelength accuracy.
LighTech Fiberoptics Inc has launched the LT20 SFP (8.5x13x32mm small-form-factor pluggable) diplexer for mux/demux of 1310/1550nm broadband or narrow-band wavelengths.
The all-optical device delivers bit-rate- and protocol-independent operation across a wide range of applications with low insertion loss of 0.8dB and crosstalk of -60dB.
Data analysis for Ethernet, ATM and VoIP
At May's NetWorld+Interop exhibition, Acterna showed the DA-3400 Data Network Analyzer.
The analyser's features include:
- ATM analysis software for traffic from 1.5 to 622 Mbit/s and real-time voice-over-ATM (VoATM) and IP analysis. It verifies provisioning of new networks by offering IP and O.191 traffic generation to ensure end-to-end service with QoS measurements. The mainframe provides electrical test access for T1/E1 and DS3/E3 and supports OC-3c, STM-1, OC-12c and STM-4 rates.
- 10/100/1000 Mbit/s Ethernet analysis identifies complex problems at the Ethernet, virtual LAN, IP and application layers and automatically classifies VLAN or IP traffic for fast problem isolation. The mainframe interface provides test access for both 10/100/1000BaseT and 1000BaseSX/LX.
- VoIP software provides information and analysis for real-time protocols (RTP) and real-time control protocols (RTCP) to resolve call quality issues caused by jitter, packet loss and delay. Using it with Acterna Ethernet analysis software, real-time VoIP analysis on live Ethernet traffic eliminates the need for traffic simulators.
When combined with NetAnalyst Test Management Software the DA-3400 can be used for network operations centre (NOC)-based troubleshooting. The remote architecture enables integration into NOC-based operations support systems (OSS) including the NetAnalyst carrier-class, server-based software suite that manages users, test devices and test access.
WDM emulator and real-time component testing
Micron Optics Inc has introduced:
- The WDM Emulator (WDME), which replaces multiple, expensive arrays of lasers in multi-wavelength test-beds by producing a stable, accurately spaced comb signal. Internal phase-matched comb filters provide flexibility for emulating multiple channel-spacing plans. The ASE spectrum sliced signal and EDFA stage can be customised. The accurate ITU wavelength reference output enables efficient calibration for optical performance monitors, noise figure and gain flatness measurements in optical amplifiers, performance tests of DWDM multiplexers and de-multiplexers, and operational tests for optical cross connects and switches.
- The Real Time Component Test System (RT-CTS) for real-time measurements in the fabrication, assembly and testing of WDM components. Absolute wavelength accuracy is ±1pm and dynamic range is 70dB. Updates - including data acquisition, processing and display - take <0.2s. Internal NIST-traceable absolute wavelength references for automatic and continuous wavelength calibration. standard wavelength calibration is not required over its life. Tests can be distributed to multiple channels and remote stations via the Spyder Hub System expansion.
High-speed optical interface ICs
SiGe Semiconductor has entered the opto market by sampling the first three products in its LightCharger portfolio of eleven 155Mbit/s to 10Gbit/s optical interface ICs, which use silicon-germanium (SiGe) at the PHY layer to improve jitter and bandwidth response and cut noise.
The SE1030 and SE1031 fully integrated transimpedance amplifiers for low-noise front-end receiver systems up to 2.5Gbit/s have low power dissipations of 170 and 110mW, (suiting small-form-factor applications).
The 230mW SE1230 automatic gain control amplifier improves sensitivity for input signals up to 2.6mA peak and optimises noise performance with a sensitivity of -26dBm for 10-10 bit error rate of modules in 2.5Gbit/s cross connects, routers and modems.
40Gbit/s low-jitter physical layer solution
Multilink Technology Corp has launched its first 40Gbit/s chipset having demonstrated it at OFC 2002. The low-jitter, high-speed MTC1307 4:1 bit digital multiplexer (MUX) and MTC1308 1:4 bit digital demultiplexer (DMUX), employs silicon-germanium (SiGe) to handle data rates extended from 20 to 50Gbit/s.
The MTC1307 serialises four 10 (12.5) Gbit/s data channels into a single 40 (50) Gbit/s channel; the MTC1308 is the equivalent deserialiser. Operating at -3.6 V, these SiGe devices have low power consumption of less than 2.6 and 2.9W, respectively. Fast rise and fall times (<10ps) lead to low RMS-jitter (<0.7ps) and well-matched broadband output buffers. Main device attributes of the DMUX are high-sensitivity input buffer (<50mVpp), threshold adjust, flexible timing control, and error-free operation up to 50Gbit/s, maintained for long random bit sequences (PRBS, pattern length of 231-1).
Cisco Systems has 14 new platforms and several enhancements to its modular access routers, designed to extend network intelligence from the headquarters to full-service enterprise branch offices and remote workers. Cisco's IOS software allows remote configuration and troubleshooting.
The platforms support management tools, including CiscoWorks 2000, CiscoWorks for Windows and Cisco Easy VPN, a software enhancement based on Cisco's Unified Client Framework. This simplifies VPN deployment for enterprise branches, remote offices and corporate teleworkers.
The new 3700 Series Application Service Routers include the 3725 and 3745. Joining its 2600 and 1700 Series Modular Access Routers (MAR) are the 2691 MAR; the 2600XM MAR (models 2610XM, 2611XM, 2620XM, 2621XM, 2650XM and 2651XM); the 1760 and 1721 MAR; and the 827H, SOHO 71, and the SOHO 77H Broadband Routers.
Cisco also introduced a 36-port 10/100 EtherSwitch high-density service module (HDSM) for the 3700 and 3600 Series Routers.
Enhancements to the 7300, 7400, 7500 and 7600 Series multi-service routing platform for enterprise applications extend its broad routers from the single corporate teleworker and small office, to the enterprise branch and headquarters, through to the service provider's network edge.
High-capacity entrance splice cabinets
FONS Corp has launched a line of water- and dust-resistant Entrance Splice Cabinet - for mounting on a wall in a cable vault or in an alternative cable entrance facility. They are intended for transition splicing between outside plant cables to building cables at entrances, then routing to fibre distribution frames or equipment.
Splices are stored in modular slide-out splice trays, accommodating up to 864 individual splices or 2,592 mass fusion splices.
Any combination of up to 36 individual fusion trays and mass fusion trays can be accommodated. Key features include rugged steel splice enclosures, sealed doors and cable entry ports, and hinged doors and slide-out trays.
FTTU fibre and connectivity
Alcatel has launched the 6620 Fiber-To-The-User (FTTU) fibre cable and connectivity solution, which includes fibre cables, distribution cabinets, patch panels, closures and optical splitters, allowing bundling of voice, data and video onto a single medium. Platform-independent, it can accommodate solutions such as APON, BPON, Gigabit Ethernet, FDDI and others.
Also, Alcatel's 7340 FTTU solution - based on the ITU-T BPON (Broadband Access Passive Optical Networking) standard - is fully compliant with the Full Service Access Network PON standard. It delivers the final mile of connectivity, giving a fully managed, fully integrated core-to-user fibre solution.
All elements have been optimised for optical access, serving both businesses and residential deployments. It can be configured to accommodate both a point-to-multipoint or dedicated point-to-point system for Gigabit Ethernet.
High-performance fused couplers
Fujikura Europe's new range of fused couplers include:
- WDM couplers for 1550/980 erbium-doped fibre amplifiers with one of the lowest excess losses in a commercial capacity at 0.08dB and polarisation-dependant loss reduced to 0.04dB;
- tap couplers with typical excess loss of 0.05dB.
Dimensions are 3x50mm for the tap couplers and 55mm long for the WDM couplers.
Multimode cable for 10Gbit/s
Cable Design Technologies Corp subsidiary NORDX/CDT Inc has added a laser-optimised 50/125µm FiberExpress 2000 generation of TIA/EIA- and ISO/IEC-compliant multimode fibre cables to its family of IBDN FiberExpress Solutions.
The multimode fibre cables can be installed in lengths of up to 300m for 10 Gigabit Ethernet applications (10Gbase-SR/SW) using low- cost multimode 850nm vertical-cavity surface-emitting lasers (VCSELs).
"The key element of this new technology is its cost-effectiveness, which dramatically reduces the implementation expenses of new 10Gbit/s applications for premises wiring, data centres, and the SAN (Storage Area Network) market," says product line manager Richard Perron.
InGaAs PIN diodes
Hamamatsu Photonics' G8941 series of indium gallium arsenide (InGaAs) PIN photodiodes has a chip position tolerance of +0.075mm mounted on a ceramic package of just 2x2x1mm and low noise, good frequency response characteristics, and high-speed response, making it suitable for laser diode monitoring.
Photosensitivity is 0.9A/W at 1.31µm and 0.95A/W at 1.55µm. Detectivity is 5x1012 cmHz1/2/W.
The G8941-01, -02 and -03 have active area, dark current and terminal capacitance of f1mm, 1nA and 90pF, f0.5mm, 0.5nA and 12pF, and f0.3mm, 0.3nA and 5pF, respectively.
The G8925 InGaAs PIN + pre-amplifier receiver has sensitivity of 0 to -18dBm at 10Gbit/s. Photo-sensitivity is 0.85 A/W at 1.31µm and >0.9A/W at 1.55µm. Power supply voltage is only 5V.
The DIP-packaged G8050 512-element InGaAs linear image sensors use Hamamatsu's C-MOS read-out chip technology and have high sensitivity, low noise and low crosstalk for simultaneous optical channel monitor of hundreds of different DWDM wavebands at 1480-1640nm. Sensitivity is >0.9A/W and dark current per pixel just a few pA.
Network planning and design tools expanded
Sycamore Networks Inc has enhanced its SILVX InSight network planning and design software family (launched in October 2001) with:
- the new Silvx Circuit Spy Application, which gives real-time network capacity utilisation and service status through a secure web portal;
- the new InSight Design Services, which employs experienced network architects and SILVX software to provide customised, cost-optimised network designs, and quantify return on investment, cost savings and efficiency gains;
- the Enhanced Silvx Transport Design Application improvements produce least-cost transport designs for long-haul and ultra-long-haul routes, and reduce planning and deployment time by automating amplifier placement, circuit grooming, wavelength planning, node configuration, and dispersion management.
Radiall's Master Cord cable assemblies allow an eccentricity of a single-mode fibre core better than 0.3µm from the centre of the ferrule.
Pigtails and cable assemblies are available with different standard connectors such as SC, FC, LC etc (UPC and APC version).
Common applications are in:
- measuring insertion loss of cable assemblies (standard IEC 61300-3-4 method B, equivalent to CECC 86000 SS4.4.7 method 7 in front of the master plug);
- very low-loss interconnection (0.1dB) for patch panel dedicated to long-haul, terrestrial or submarine networks.
850nm single-mode fibre for LAN and FTTx
Pirelli Telecom Cables and Systems has launched FineLight Giga fibre and FineLight Base fibre - the first single-mode fibres for operation at 850nm - for fibre-to-the-business, premises and LAN applications.
A network can be built with a cable that meets requirements for multi-mode operation but can be upgraded to single-mode. The 850nm operation uses standard low-cost VCSELs, with upgrade by switching to single-mode equipment.
"FineLight fibres offer the first real opportunity to bring all three operating windows [multi-mode; 1310 and 1550nm single-mode] within the capability of a single optical fibre," says Sergio Antoci, Senior Product Manager, Fibre and Preforms.
Transmission capacity is 100Mbit/s up to 5km (base) and 1Gbit/s up to 1km (giga). Bandwidth is 600MHz.km (base) and 1,000MHz.km (giga). Attenuation is 2.2dB/km at 850nm.
Epoxy-free mini collimators
Koncent Communication Inc has launched a MinDCol epoxy-free collimator for smaller-footprint packages in next-generation WDM, Switch, VOA and collimator array applications.
It reduces the outside diameter dimension of conventional collimators from 2.8 to 1.0mm while maintaining high performance, typical insertion loss <0.25dB, working distance up to 200mm, and beam waist of 0.35mm.
Optical fibre arrays and V-grooves
Senko is offering a range of fibre arrays and V-grooves with cover plates in quartz, pyrex and silicon.
The arrays are available pre-assembled or in component form. Intended for the core of "next-generation" systems, the fibre array connectsPLC devices and between multiplexers.
Array applications include DWDM, waveguide packaging, MEMS and miniaturised fibre components. Arranged in sets of 1, 2, 4, 8, 16, and 32, the V-grooves and fibre arrays are standard designs, with pitches of 127 and 250µm. Excellent grinding technology ensures high degree of pitch accuracy. Custom configurations are available.