Optical test innovations debut at ECOC
Courtesy of Teledyne LeCroy
ECOC 2015, the 41st European Conference on Optical Communication, took place this fall in Valencia, Spain, and companies including Anritsu EMEA, Coherent Solutions, Keysight Technologies, Oclaro, Tektronix, and Teledyne LeCroy have all reported on innovations they demonstrated at the event.
First, at the show Teledyne LeCroy introduced the IQS series of Coherent Optical Receivers, which, the company said, feature the industry’s highest bandwidth and extend Teledyne LeCroy’s Optical Modulation Analysis (OMA) portfolio, enabling the creation of flexible, modular systems (Figure 1). When combined with Teledyne LeCroy’s 10Zi-A oscilloscopes and integrated Optical-LinQ analysis software, the IQS receivers test DP-QPSK and DP-16QAM optical signals at speeds up to 130 Gbaud.
Teledyne LeCroy said the 70-GHz IQS70 Coherent Optical Receiver is the result of several years of collaboration with the optical specialists at Coherent Solutions. The IQS70 pairs with the 10-65Zi-A oscilloscope to provide a system bandwidth of 65 GHz, delivering a solution for characterizing leading-edge 56-Gbaud communications systems and enabling detection up to 130 Gbaud. For lower-rate applications, the 42-GHz IQS42 Coherent Optical Receiver provides a test platform for up to 32-Gbaud DP-16QAM or DP-QPSK when used with the 36-GHz 10-36Zi-A.
Completing the company’s OMA solution, Optical-LinQ is an intuitive and fully integrated software package for measurement and visualization of optically modulated signals. It runs entirely within the user interface of the 10Zi-A. Optical-LinQ provides fully automated control of the IQS receiver, phase recovery algorithms, and polarization demultiplexing as well as an exhaustive number of modulation analysis displays and parameters.
R&D platform
At ECOC, the IQS70 and Optical-LinQ played a key role as Teledyne LeCroy, Coherent Solutions, Oclaro, and Anritsu teamed up to demonstrate what they say is the industry’s first commercially available R&D platform for testing single-carrier coherent optical communication systems and components operating at 56 Gbaud and beyond. This development platform is available now and features what the companies believe to be the highest baud-rate single-channel optical communications test and measurement system achievable today using commercial instrumentation.
Teledyne LeCroy explained that as research and development groups worldwide strive to achieve higher optical data transmission rates, they will require high bandwidth signal generation and analysis tools to develop the new technologies, components, and higher-order modulation formats necessary to support the insatiable global demand for bandwidth. The companies’ demonstration showcased how high baud-rate optical signals can be reliably generated, optimized, and analyzed through the integration of leading-edge equipment from multiple suppliers.
In the platform demonstrated at ECOC, Anritsu’s MP1800A signal quality analyzer used in combination with its MP1861A MUX generated 56-Gbaud electrical signals. The 40-GHz IQTransmitter from Coherent Solutions translates these signals into an emulated dual-polarization optical signal, enabled by the integration of Oclaro’s 400G single-carrier LiNbO3 modulator. Teledyne LeCroy’s 10-65Zi-A OMA system incorporating the new IQS70 70-GHz coherent optical receiver and OpticalLinQ software then analyzed the performance of the optical transmission system.
Anritsu’s MP1800A signal quality analyzer is a bit error rate tester offering a comprehensive suite of testing capabilities to support complete signal and transmission integrity analysis. Key features include superior signal waveform quality, extremely low intrinsic jitter and fast transition times, multichannel generation and analysis, and integrated full jitter tolerance stress generation. Anritsu also has announced another evolution for this platform to cover signal generation, analysis, and jitter tolerance testing up to 64.2 Gb/s as a worldwide solution for R&D on signal transmission up to 1 Tb/s.
Coherent Solutions’ new IQTransmitter offers 40 GHz of RF bandwidth and incorporates new modulator automatic bias control circuitry, which provides fully pattern-independent bias control—a critical capability for the investigation of higher order modulation formats such as 16-QAM. The 40-GHz IQTransmitter supports research, development, and production environments with a stable, coherently modulated optical signal for component and system characterization. “We are very pleased to be able to showcase our new release of the IQTX-40 in this system which sets a new standard for high baud-rate optical signal generation and analysis instrumentation,” stated Andy Stevens, CEO of Coherent Solutions, in a press release.
The Oclaro 400G LiNbO3 external modulator has been explicitly designed to enable 400G and beyond speeds on a single wavelength or carrier. “By eliminating the need to use two wavelengths with the 16-QAM modulation format, Oclaro’s new modulator will enable customers to accelerate the design and test of next-generation, high-speed 400-Gb/s networks,” said Adam Carter, chief commercial officer at Oclaro. “We are pleased to see our modulator being used in this industry-first development platform as this represents a major milestone in the design, test, and delivery of higher-speed networks that carriers are demanding.”
Teledyne LeCroy said its OMA solution combines high bandwidth with flexible analysis. The 70-GHz bandwidth IQS70 coherent optical receiver integrates seamlessly with the 10Zi-A oscilloscope and OpticalLinQ software. “Consistent bandwidth leadership means Teledyne LeCroy oscilloscopes have become crucial tools for those pushing the boundaries of optical communications technology,” said Patrick Connally, product manager for high-performance oscilloscopes at Teledyne LeCroy. “Our complete OMA solution, including our new IQS receivers, enables us to continue that trend in this leading-edge development platform.”
TDEC measurement
As for Tektronix, the company noted that publication of the IEEE 802.3bm specification is enabling broad market acceptance of lower cost 100G optical products. At ECOC, Tektronix demonstrated that it is responding to this new spec with what it calls the industry’s first fully automated transmitter dispersion eye closure (TDEC) measurement and 100GBASE-SR4 conformance test solution that will make the complex process of ensuring that new product designs conform to this optical specification faster and easier. With the addition of TDEC measurement as well as the full 100GBASE-SR4 conformance test support, Tektronix said it now offers a turnkey and fully automated optical solution. This solution is based on a DSA8300 equivalent-time oscilloscope equipped with an 80C15 optical module, which supports full clock recovery and TDEC automation beyond 25.781 Gb/s.
“As 100G networking becomes mainstream, Tektronix is playing a key role by providing validation tools that reduce the need to be an insider on the complex set of IEEE product conformance requirements,” said Brian Reich, general manager, Performance Oscilloscopes, Tektronix, in a press release. “Our turnkey tools for TDEC and 100GBASE-SR4 bridge this knowledge gap and let designers tackle conformance testing with a high degree of confidence.”
Tektronix also announced the expansion of its Performance Oscilloscope Series to include 50-GHz and 23-GHz models at ECOC. By extending the flagship 70-GHz model, the new 50-GHz product is suitable for engineers and researchers who want to take advantage of the low-noise performance of the patented asynchronous time interleaving architecture for technologies such as 28-GBaud PAM4 and K-band frequency testing. The 23-GHz instrument joins the existing 33-GHz models, which feature compact dimensions and built-in scalability using the UltraSync synchronization technology.
“The DPO70000SX Series is setting the new standard for performance leadership. We are quickly expanding the family in direct response to customer demand,” said Reich. “With our flagship model offering 10% more bandwidth, 25% higher sample rate, and 30% lower noise than the nearest major competitor, we wanted to extend our portfolio to cover more engineers and researchers who are serious about signal integrity.”
Tektronix also announced the implementation of SignalVu software on its family of DPO70000SX scopes. SignalVu will allow researchers and others engaged in developing next-generation wide- and ultra-wide bandwidth technologies such as 5G, cellular backhaul, and radar to perform RF modulation measurements with unprecedented margins of error.
“The integration of SignalVu software with the DPO70000SX platform is a very compelling solution for customers who need to demodulate and analyze signals with extremely wide bandwidth up to 70 GHz,” said Jim McGillivary, general manager RF and Component Solutions, Tektronix. “For RF applications, we’re essentially delivering the widest bandwidth signal analyzer on the market with great signal fidelity and comprehensive analysis capabilities, including modulation and pulse analysis along with support for advanced commercial wireless standards such as 802.11ac and LTE. What’s more, it not only can be used as a spectrum analyzer, but also is an oscilloscope.”
In addition, Tektronix announced a comprehensive set of analysis tools for emerging PAM4 modulation measurement needs with full support for both optical and electrical interfaces. The new tools operate on both DPO70000SX 70-GHz real-time and DSA8300 equivalent-time oscilloscopes. PAM4 is being adopted in the latest 400 Gigabit Ethernet standard by the IEEE P802.3bs working group for 400G (typically 8 x 50G) electrical and optical interfaces. Compared with traditional NRZ that uses two-level signaling, the four-level scheme used in PAM4 significantly increases signal complexity and places new demands on test equipment for performance and noise sensitivity, the company said.
Tunable laser sources
And finally at ECOC, Keysight Technologies demonstrated its new 81607A, 81608A, and 81609A tunable laser sources, a range of modules for the Keysight 8164B lightwave measurement system. The new modules extend the product family that debuted in March 2015 with the Keysight 81606A tunable laser source.
The value and basic line models share the 81606A’s new design with low spontaneous emission and narrow line width as well as power repeatability and long-term stability. The new modules offer additional price-performance options based on output power, tuning speed, wavelength accuracy, and repeatability. Whether engineers need to verify the design of demanding optical components or adjust more wavelength-selective switches per hour or they simply need a stable, tunable optical source, the 8160xx family of tunable lasers offers a suitable model. The new 81607A value-line tunable laser source complements the top line 81606A model at a more moderate output power. With a typical wavelength repeatability of ±1 pm, even during 200-nm/s two-way sweeps, it can be used for high-throughput test and automated adjustment of passive optical components.
The new 81608A, another member of the value line of tunable laser sources, offers more than +12-dBm peak output power, at least 75 dB/nm above its spontaneous emission level. The 81608A provides ±1.5-pm typical wavelength repeatability at two-way sweeps up to 200 nm/s. The laser’s balance of features, performance, and price makes it suitable for both coherent transmission experiments and cost-efficient manufacturing-floor component testing.
The new 81609A basic-line module (Figure 2) can step within 300 ms to discrete wavelengths with 0.1-pm resolution and ±3-pm typical wavelength repeatability, making it suitable for cost-effective testing of broadband optical devices. Like the other modules in the family, the 81609A delivers more than +12-dBm peak output power with low spontaneous emission levels. At ±0.01-dB power stability over an hour, it also can serve as a static local oscillator with a wide tuning range for receiver testing or transmission experiments.
Courtesy of Keysight Technologies
All members of the new tunable laser family are compatible with the current 81600B laser commands and the N7700A photonic application suite, a collection of advanced software tools for making fast and accurate optical measurements, controlling fiber-optic instruments, and analyzing measurement results. This commonality makes it easy for engineers to transition smoothly to the new modules.
“For production managers, higher throughput and lower cost of ownership of test equipment are keys to optimize their organization’s cost efficiency,” said Juergen Beck, vice president and general manager of Keysight’s Digital and Photonic Test Division, in a press release. “We designed the new tunable laser family to ensure the highest long-term stability and cost-efficient servicing. A range of performance classes allows our customers to scale their investment without compromising manufacturing efficiency.”
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