Optical/IP Testing

ECOC: It's All About the Network Upgrades

While the program of the European Conference on Optical Communication (ECOC) in Valencia, Spain, addresses high-concept technologies such as network architectures using flexible DSP-based transceivers, the use of optical components to build exascale data centers, and New IP technologies SDN and NFV, the companies attending are demonstrating more concern for simply guiding their customers safely from one network speed plateau to the next, from 10G to 40G or 100G, or from 100G to 200G and eventually 400G.

TeraXion Inc. is shooting for 100 Gbit/s and beyond with new InP-based modulators for single-wavelength transmission systems. TeraXion says its modulators offer Vpi drive voltage down to 1.5V, with bandwidth up to 40GHz.

Low drive voltages and high modulation bandwidth become increasingly critical as transmission rates climb to 100G and on through 200G and 400G, and port densities increase. Low drive voltages help minimize power dissipation, while high modulation bandwidth enables a higher symbol rate, thus increasing spectral efficiency, the company explains.

Ian Woods, TeraXion's VP of high-speed photonic components, says: "TeraXion has been sampling 400Gbit/s-ready IQ modulators since the beginning of this year and customers are actively advising us that their general performance is superior to lithium niobate modulators, particularly at higher symbol rates."

Finisar Corp. (Nasdaq: FNSR) is introducing what it claims is the first 100G QSFP28 SWDM4 module for systems using duplex multimode fiber.

Finisar explains that data centers typically have opted to use 10G duplex multimode fiber to keep initial costs down. That means an upgrade to 40G or 100G would probably have required upgrading their existing SWDM (single wavelength dual mode) fiber. Finisar said customers can avoid the expense of replacing their fiber by installing its transceiver modules instead.

The modules are based on Finisar's shortwave VCSEL (vertical cavity surface emitting laser) technology. The approach multiplexes different wavelengths on duplex multimode fiber. The company says it can run four wavelengths at either 10G or 25G to get to 40G or 100G, respectively.

Select customers are currently evaluating samples of the 100G QSFP28 SWDM4 module, the company says.

Polatis Inc. says the latest variation of its Series 6000 Optical Switching Modules (OSM) is now commercially available. The non-blocking, single-sided, all-optical 48-fiber matrix switch enables any-to-any port connectivity (in contrast to traditional symmetric NxN switch matrices).

The module supports up to 192x192 fiber ports, and features low loss and back reflection of typically less than 1dB and -50dB, respectively.

Polatis says the module is designed specifically for OEM integration with network equipment, fiber management systems and test and measurement tools.

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Inphi Corp. says it is sampling a new modulator driver designed for line cards, 4x5 modules, and CFP or CFP2 modules built for coherent optical systems used in 100G or 200G long-haul and metro networks.

Inphi describes its IN3217SZ as a quad linear differential to single-ended Mach-Zehnder (MZ) Modulator Driver. Available in a 14x9mm surface mount (SMT) package, the IN3217SZ directly interfaces to lithium niobate or indium phosphide MZ modulators.

A lot of this stuff is brand new, of course, and it is critical to have equipment to test it all.

Coherent Solutions has launched a laboratory optical transmitter with 40GHz of RF bandwidth. The IQTX-40 was designed to give R&D engineers the ability to generate coherent modulated signals at rates beyond 56GBaud.

The company says a new feature is an automatic bias control (ABC) that optimizes the performance of the modulator irrespective of the modulation format being used. The ABC also allows the user to control the bias locations of all biases of the modulator, which the company says is useful for generating a wide variety of signals beyond coherent modulation.

VeEX Inc. , meanwhile, is going big at ECOC, introducing several testers and tester upgrades.

The new products include the FX40 and FX45 low-cost, small-form-factor optical power meter, light source and loss test set series. Testers in the series feature result-saving, WaveID, bi-directional and ORL measurements, fixed or interchangeable optical connectors, alkaline or rechargeable NimH batteries.

The UX400 universal test platform supports four generations of 100G pluggable optics, including CFP, CFP2, CFP4 and QSFP28 modules for 100G networks.

The TX300s with OTDR is a portable dual-port 10G tester supporting simultaneous transmission and fiber testing and troubleshooting. The unit is aimed at helping technicians install, turn up and manage Ethernet, OTN and Fiberchannel networks operating over fiber.

The RXT-1200 test platform with RXT-100G module is equipped with SFP+, CFP2 and QSFP+ pluggable transceivers, which the company says makes it the industry's most compact and portable 1/10/40/100G tester.

VeEX also says it added a DWDM OTDR module to its platform. The RXT-4111 OTDR module features a highly stable, tunable laser for verifying ROADM channel routing in DWDM networks. The tunable laser covers all wavelengths from 1563.86 to 1528.77 (C-band), based on a 50GHz channel spacing according to the ITU-T wavelength grid. Optional features include a power meter, a light source and a visual fault locator.

— Brian Santo, Senior Editor, Components, T&M, Light Reading

kq4ym 10/9/2015 | 10:12:29 AM
Re: SWDM is shortwave wavelength division multiplexing over WBMMF!! Although the tecnology is way above my pay grade the possibility "customers can avoid the expense of replacing their fiber by installing its transceiver modules instead" seems like a fantastic wrinkle in getting those speeds. With the laser transmission mode and a reasonable cost for the hardware and installations a few years down the road I'd guess this is a real tech to study carefully.
toyama 9/30/2015 | 3:43:20 PM
SWDM is shortwave wavelength division multiplexing over WBMMF!! SWDM is not single wavelength dual mode. SWSM is shortwave wavelength division multiplexing. There is a recent announcement of SWDM Alliance (www.swdm.org). This uses four wavelengths between 850nm and 950nm. This is called shortwave in contrast with traditional wavelength division multiplexing which uses 1310nm or 1550nm ranges.

The Finisar's claim "customers can avoid the expense of replacing their fiber" is very dubious because SWDM requires a new MMF with a guaranteed bandwidth over wider wavelength range, called WBMMF (wideband MMF), while the current OM3 or OM4 MMF is specified only for 850nm operation. WBMMF is being announced by major fiber manufactures such as CommScope, Furukawa - OFS, Prysmian, but the spec must still be standardized by TIA and ITU.

If a data center does not have enough MMF fibers for 100G migration, the choices are (1) pulling more OM3 or OM4 MMF fibers, (2) replacing MMF by WBMMF, or (3) switching to SMF to use 100G-CLR4 (www.clr4-alliance.org), 100G-CWDM4 (cwdm4-msa.org), or 100G-LR4 (IEEE 10km spec).

A short-reach optical transceivers using VCSEL such as QSFP28 100G-SR4 or 100G-SWDM4 are chapter than a longer-reach SMF transceivers but MMF is actually more expensive than SMF. So a data center operator needs to look at the total cost and also future-proofness. 400GE is on the horizon and WBMMF may not help when we need to migrate to 400G. I would love to hear from data center operators if they are willing to upgrade to WBMMF or not.
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