Tag Archives: tunable optics

10G DWDM Tunable XFP – Up to 80 km Reach

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With the spread of cloud computing and mobile broadband service, the volume of communications traffic has rapidly increased. In order to enable high-capacity optical networks, using a single optical fiber for optical signals of several different wavelengths in DWDM system is widely used. For this reason, tunable transceiver that enables ROADM functionality in next-generation networks is becoming more and more popular. In today’s market, there are mainly two kinds of tunable DWDM transceivers: tunable XFP and tunable SFP+. This article will take you to explore the DWDM C-band tunable XFP transceiver with 40 / 80 km transmission distance options.

10g-dwdm-tunable-xfp-transceiver

Figure 1: Cisco Compatible Tunable DWDM XFP Transceiver

Tunable XFP Transceiver

Tunable XFP transceiver is an integrated fiber optic transceiver that provides a high-speed serial link at signaling rates from 9.95 Gbps to 11.35 Gbps. It complies with the ITU-T G.698.1 S-D100S1-2D standard with 50GHz channel spacing for SONET/SDH, IEEE DWDM 10GBASE-ZR for 40 or 80 km reach (Ethernet), and DWDM 10G FC (Fibre Channel) for 40 or 80 km reach applications. Tunable DWDM XFP can be tuned from channel C17 (1563.86nm) to C61 (1528.38nm). The maximum distance of this transceiver on a single mode fiber is up to 80 km. As mentioned above, tunable XFP optical transceiver is a full-duplex serial electric, serial optical device with both transmit and receive functions contained in a single module. On the transmit side, the 10 Gbps serial data stream is recovered, retimed, and passed to a modulator driver. The modulator driver biases and modulates a C-band-tunable integrated laser Mach-Zehnder (ILMZ), enabling data transmission over singlemode fiber through an industry-standard LC connector. On the receive side, the 10 Gbps optical data stream is recovered from an APD/transimpedance amplifier, retimed, and passed to an output driver. This module features a hot-pluggable XFI-compliant electrical interface. Here is a simple picture showing its working process.

function diagram of tunable xfp

Figure 2: Working Process of Tunable Transceiver

Tunable XFP Optics Specifications:

  • 50 GHz ITU channel spacing with intergrated wavelength locker
  • Available in all C-Band Wavelengths on the DWDM ITU grid
  • Available distances 40 or 80 km
  • Supports 9.95Gb/s to 11.35Gb/s
  • Built-in Digital Diagnostic Functions
  • Tempereature Range: -5°C to 70°C

Two Transmission Distance Options: 40 km or 80 km

There are two transmission distance options for XFP tunable transceiver: 40 km or 80 km. Tunable XFP DWDM 80 km transceiver is designed for long distance optical communications up to 80 km with signaling rates up to 10Gbps. Obviously, the main difference is transmission distance. On account that 10G tunable DWDM XFP optical transceiver provides digital diagnostic functions via a 2-wire serial interface, which allows real-time access to the following operating parameters: transmitted optical power, received optical power, transceiver temperature, laser bias current and transceiver supply voltage. Therefore, the differences between 40 km tunable XFP and 80 km tunable XFP mainly lie on theses parameters. One thing to note is that 40 km tunable XFP optics is designed with high performance PIN receiver, while the 80 km tunable XFP transceiver is APD receiver. The APD (avalanche photodiode) receiver employed in these extended-reach optical transceivers has an enhanced sensitivity to allow for these extended distance fiber runs. However, it is to be noted that the input power is typically between -7 and -24 dBm. Therefore, the receiver sensitivity between these two distance has a big difference. Generally, the max receive dBm of 40 km tunable XFP transceiver is -15, while the 80 km tunable XFP transceiver is -24. And for power budget, 40 km tunable XFP is 14dB while a distance up to 80 km is up to 22dB power budget. The following table lists the main differences.

40km 80km tunable xfp

Table 1: 40 km Tunable XFP VS. 80 km Tunable XFP

Conclusion

In general, the channel switching of tunable switches can enable the service operators to turn up circuits faster and reduce their sparing costs dramatically in today’s DWDM systems. On the other hand, tunable optics are usually two or four times more expensive than the regular static DWDM optical module, because a special tunable laser is applied in it. Tunable XFP optical transceiver provides a full C-band window covering 1528nm to 1566nm for DWDM optical networks, which meets the need of rapid increase in the volume of communications traffic from telecom carrier and operator. The tunable DWDM XFP module can replace the fixed DWDM channel XFP transceivers that are currently used, while reduce the large stock since all wavelengths can now be covered with one transceiver module.

Model Frequency Wavelength Fiber Type Connector Price on FS.COM
ONS-XC-10G-C 50 GHz 1563.86~1528.3 SMF LC $1,400
XFP-10G-CBAND-T50-ZR 50 GHz 1563.86~1528.3 SMF LC $1,400
NTK583AAE6 50 GHz 1563.86~1528.3 SMF LC $1,400
TDXFP-10GHXXX-80 50 GHz 1563.86~1528.3 SMF LC $1,400
TDXFP-10GHXXX-40 50 GHz 1563.86~1528.3 SMF LC $1,400

Related Article: Wavelength Switching Solution: Tunable XFP Transceiver

Detail Introduction to 10G DWDM Tunable SFP+ Transceiver

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Optical transceivers play a key role in handling all storage, data, voice and video traffic whether linking rack to rack, bottom to top of rack, data center to data center or enterprise networks to network. A range of flexible fiber optic transceiver modules cover all of network needs, such as SFP, SFP+, QSFP, QSFP28, CFP, etc. But for 10G DWDM tunable SFP+, many people might find themselves in the mire. When I first heard about this tunable transceiver, I thought that it would definitely bring revolutionary change to future metro Ethernet and optical transport networks with its important practical value for flexibly selecting working wavelength. So this article will unveil all of the things about tunable SFP+ optical transceiver.

FS DWDM Tunable SFP+

About 10G DWDM Tunable SFP+

As the demand for great traffic capacity keeps growing, more optical transceivers of different wavelengths are needed. So tunable transceivers are recent innovations in DWDM transport systems. DWDM tunable transceivers are within the scope of DWDM transceivers, through which different DWDM wavelengths can be configured and output in the same optical module. But compare with conventional fixed-wavelength DWDM SFP+, the tunable SFP+ uses tunable laser as light sources in DWDM systems, which is tunable across the entire C-band with 96 channels on the ITU-T 50-GHz grid.

Cisco-tunable-SFP+

The tunable laser technology is firstly introduced by Oclaro, a leading supplier and and innovator of tunable laser and transceiver solutions. In 2013, it announced a standards-compliant, multi-rate tunable SFP+, which supports rates between 9.95 and 11.3 Gbps. But the first-generation tunable SFP+ optical transceivers were not widely adopted, because they did not meet the critical requirement of less than 1.5 W of power consumption at high operating temperatures. So in 2014, Oclaro demonstrated a new tunable SFP+ module based on a new Oclaro InP tunable laser platform. With the innovative new chip design and the use of next generation materials, the new module is fully compliant to the SFP MSA form factor and can operate at 1.5W at 70 degrees C with excellent OSNR tolerance. With the breakthrough of technology, the 10G tunable SFP+ transceivers become an important component for next generation data center, metro and regional optical network equipment. They meet the world’s growing bandwidth demands while reducing the size and power consumption for 10G connections.

Key Highlights of Tunable SFP+ Module:

(1) Fully compliant with MSA standard size based on SFF-8432 specification for Improved Pluggable Form Factor, rev. 5.1

(2) Tunable across the full C-band with 96 channels on the ITU-T 50GHz grid

(3) Multi-rate operation: 9.95 Gbit/s to 11.3 Gbit/s

(4) Operates at 1.5W at 70 degrees C with excellent OSNR tolerance

Advantages of Tunable SFP+

The tunable SFP+ transceivers are high-performance optics which can be tuned to the appropriate wavelength. The ability to operate on various wavelengths has set these optics apart from fixed-wavelength DWDM SFP+. Besides, These tunable optics will become popular among DWDM systems due to the several advantages.

  • Flexible network management

A tunable SFP+ transceiver will be remotely configured for a specific wavelength to support bandwidth changes as needed in Enterprise or Metro networks.

  • Reduced network inventory

One tunable SFP+ transceiver will support more than 80 different wavelengths. It will allow network operators to hold one tunable device code as opposed to 80+ fixed wavelength transceivers.

  • Reduced power consumption

It will provide a significant reduction in electrical power dissipation compared to other tunable solutions.

  • Compact and high-density form factor

The new tunable SFP+ transceiver will be about the size of a pack of gum, saving valuable real estate in data centers.

  • Increased network capacity

The tunable SFP+ will double the number of channels supported in this compact transceiver form factor. Upgrading to 50GHz channel spacing doubles the capacity potential in Enterprise and Metro networks.

Conclusion

The advent of 10G DWDM tunable SFP+ transceivers in the market will accelerate the trend for pace-, power-, and cost-efficient network solutions. Because tunability is critical for minimizing inventory and enabling flexible rapid service provisioning. Although now the market share for DWDM tunable SFP+ transceiver is not big enough, the huge potential will be demonstrated in the near future.