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Category: CWDM/DWDM Transceivers

Tunable Laser – the Core of Tunable Transceiver Modules

Tunable Laser – the Core of Tunable Transceiver Modules

tunable-XFPOver the last 10 years the adoption of tunable based solutions has grown significantly. Particularly in the recent years, tunable transceivers are becoming more and more widely used in DWDM transmission systems. The most significant difference between tunable transceivers and ordinary transceivers are the laser. As we know, the early DWDM systems used fixed-wavelength lasers as light sources, which meant that many kinds of optical transceivers were needed for the wavelength channels. However, the use of tunable lasers, which can operate at any channel wavelength, means that only one kind of transceiver is needed, so the inventory cost can be reduced. As the core of tunable transceiver modules, tunable laser plays an very important role in tunable transceivers. Today, we are going to learn and further understand the tunable laser.

A tunable laser is a laser the output wavelength of which can be tuned or adjusted, i.e. wavelength tuning. Lasers that are tunable over multiple wavelengths, and progressively over the whole C-band appeared at the beginning of the last decade. They soon became widely used in DWDM systems since they allowed the reduction of different line card or transceiver, which was needed for every different wavelength. Together with ROADM (reconfigurable add drop multiplexers), they became the core of the optical transport systems.

Various kinds of tunable lasers have been developed in the last 10 years, and their performance has been greatly improved. A tunable laser consists of a semiconductor gain region and a wavelength-tunable optical filter. The wavelength is tuned by changing the filter wavelength. Tunable lasers are classified into three structural types: distributed feedback (DFB) laser array, distributed Bragg reflector (DBR) laser and external cavity laser. All of these laser structures provide a tuning range of more than 35 nm, which is required for DWDM systems.

comparison of wavelength tunable laser

DFB and DBR lasers can be considered as first-generation tunable lasers, because they can be configured to two or possibly four different wavelengths. However, tunable laser modules can transmit many wavelengths across a wide spectrum as compared to the DFB and DBR lasers widely used today. DFB arrayed lasers have their tuning range limited by the number of elements in the array and require 1 to 10 milliseconds (ms) of tuning time. Nowadays, people have reduced the spectral linewidth of DFB laser to make it applicable to 100G systems.

External cavity tunable lasers include collimating optics, mirrors, and an external grating. Commercial external cavity tunable laser modules also include an integrated thermal tuner, a gain chip, an isolator, and a number of flexures that precisely align the laser to the fiber before it is mounted in the package. For example, external cavity lasers with thermally tunable silicon etalon filters have been commercialized for use in tunable transceivers. External cavity tunable lasers have a typical output power in excess of 20 milliwatts (mW). Generally, the more widely tunable the laser, the less its transmit power. Newer DWDM systems are being designed with external cavity tunable lasers. External cavity tunable lasers can switch from one wavelength to another in the order of nanoseconds, and this makes them potential candidates for building optical switched that could route traffic on a wavelength basis.

At present, the market of 10G tunable transceivers, e.g. tunable DWDM XFP and SFP+ have already been very mature. The next step is to develop a higher-performance tunable transceiver to satisfy the 100G systems. As the core of tunable transceivers, tunable laser requires higher power, a wider tuning range, and lower power consumption. In addition, the package of the next generation tunable transceivers must be more and more compact to meet the aggregation switches. In all, research and development will continue with the aim of obtaining tunable lasers and tunable transceivers with even better performance.

How Much Do You Know About CWDM SFPs?

How Much Do You Know About CWDM SFPs?

You must be very interested in some SFP modules which are with colorful markings, such as color arrow on label and color coded bale clasp. But do you know what are these colorful SFPs used for? And why are they designed as several color? This paper is going to introduce one type of these colorful SFP transceiver modules.

These SFPs with color arrow on label and color coded bale clasp are called WDM(Wavelength Divison Multiplexing) SFPs. WDM SFPs are devided into two basic types. One is CWDM(Coarse Wavelength Divison Multiplexing) SFPs, and the other one is DWDM(Dense Wavelength Division Multiplexing) SFPs. This paper is mainly about the CWDM SFPs. The different colors represent different wavelength.

What’s CWDM SFP?
CWDM SFP is a kind of optical transceiver which combines the CWDM technology. Similar with the traditional SFPs, CWDM SFP is also a hot-swappable input/output device that plugs into an SFP port or slot of a switch or router, and links the port with the fiber-optic network. It is a convenient and cost-effective solution for the adoption of Gigabit Ethernet and Fibre Channel (FC) in campus, data-center, and metropolitan-area access networks.


CWDM SFPs With Different Wavelengths
In general, CWDM SFPs come in eight wavelengths that range from 1470 nm to 1610nm. In order to better identify the wavelength to which the Gigabit Ethernet channel is mapped when using these CWDM SFPs, we use the color markings on the devices, such as color arrow on label and color coded bale clasp to achieve it. This is why there are many SFPs with different colors for applications. Here, we take Cisco for example. Here, we take Cisco for example. The following table lists the CWDM SFPs with their wavelength and color codes.

cisco cwdm sfp information

Standards and Regulatory Compliance

  • RoHS compliant
  • IEEE Std 802.3 (Gigabit Ethernet 802.3z,802.3ah, FastE 802.3u)
  • Fibre Channel Draft Physical Interface Specification FC-PI-2
  • Compliant with SONET/SDH optical standards
  • SFP MSA (multi-source agreement)

Protocols and Data Rates

  • Fast Ethernet (125Mbps)
  • Gigabit Ethernet (1.25Gbps)
  • 1G and 2G Fibre Channel
  • SONET OC-3 (155Mbps), OC-12 (622Mbps), and OC-48 (2.488Gbps)

Fiberstore CWDM SFPs Solution
Fiberstore offers a cost-effective CWDM SFPs solution which is 100% compatible with many devices of major brands, e.g. Cisco, HP or Juniper etc. Compatible CWDM SFPs with multi-rate transceiver for data rates from 100 Mbps up to 4 Gbps, transfer distance at 20 to 40km, 40 to 80km and 80 to 120km as well as different color marking options are available in Fiberstore which can better satisfy the different requirements on parameters of our clients. CWDM SFP transceivers also feature digital diagnostics, also known as digital optical monitoring (DOM), which is supported by the majority of switch and router OEMs in their operating system software.


For Cisco users, we highly recommend our CWDM SFP products, such as CSFP-1G47-80-CO, CSFP-1G49-80-CO, CSFP-1G51-80-CO, CSFP-1G53-80-CO, CSFP-1G55-80-CO, CSFP-1G57-80-CO, CSFP-1G59-80-CO, CSFP-1G61-80-CO that are the corresponding compatible CWDM SFPs of Cisco’s. Additionally, we can offer other products which are the custom version for Cisco compatible. Actually, more products are waiting for you. If you want to order other brand compatible or get more information about these products, we welcome you to visit our website or contact us over E-mail directly.

Learn Some about CWDM SFP Transceivers

Learn Some about CWDM SFP Transceivers

As we know, CWDM SFP (CWDM) is on the SFP transceivers or socket switch or router port, it is a kind of technology of hybrid protocols and data rate, allow the multi-channel, combination, and through the optical fiber cable transmission.

CWDM SFP use SFP interfaces to connect devices, at the same time, double LC/PC type optical fiber connector software, optical network connection.CWDM SFP for port connected to the optical fiber network, the typical CWDM SFP as cisco can support gigabit Ethernet and fiber channel at the same time. It is compatible SFP with fast Ethernet, SONET OC – 3 and OC – 12, and STM and SDH STM – 1-4 standard.

The purpose of CWDM SFP transceivers basic characteristics are hot pluggable and double LC interface, and compliant with IEC60825-. The transmitter center wavelength ranges from 1270nm to 1610nm and the receiver PIN or APD is single +3.3V power supply, PECL data interface; Operating temperature range s from -5 to + 70 degrees;

CWDM SFP transceivers consists of three parts: an uncooled CWDM DFB laser, PIN photodiode integrates a trans resistance preamplifier (TIA) and single-chip microcomputer control unit. This optical transceiver integration in a module to send and receive channel. In the sender, serial data stream is transmitted to the the laser driver. Laser driver bias and modulation of refrigeration directly modulated laser (DML), according to the LC connector industry standard, make the data transmission of single-mode fiber. At the receiving end, the data flow from a PIN or restore the avalanche photodetector (APD), transmitted to trans resistance amplifiers, rear and then passed to the amplifier.The module has to be hot-swappable SFI standards for electrical interfaces. This integrated optical transceiver to provide signal transmission rate from 100 Mbps to 3.1 Gbps of high-speed serial link and the module in line with the small pluggable (SFP) multi-source agreement (MSA).

We know that typical CWDM SFP transceivers including CWDM-SFP-1470, CWDM-SFP-1490, CWDM-SFP-1510, CWDM-SFP-1530, CWDM-SFP-1550, CWDM-SFP-1570, CWDM-SFP-1590, CWDM-SFP-1610. Cisco CWDM SFP is a series of single-mode transceiver covers from 1470nm to 1610 nm wavelength applications, they are different colors to identify them, these CWDM SFP to gigabit Ethernet and 1/2 GBPS fiber channel applications. And another brand is Juniper CWDM SFP, it includis SFP-1GE-LH-CWDM-1270, SFP-1GE-LH-CWDM-1290, SFP-1GE-LH-CWDM-1310, SFP-1GE-LH-CWDM-1330, SFP-1GE-LH-CWDM-1350. The Cisco SFP transceiver and Juniper CWDM SFP transceivers are with excellent quality. Casting CWDM SFP transceivers work on the 80 km, with different wavelengths from 1470 nm to 1610 nm. It is fully compatible with and in its intended functions casting router or switch, and complete the MSA compatible.

CWDM SFP Transceiver

Cisco’s may possibly aim at either Gigabit Ethernet or Fiber Channel. Fiberstore supply original CWDM SFP, along with other CWDM SFP transceivers, impressive company like cisco, HP, huawei, juniper networks and etc. Fiberstore, as a famous optical fiber manufacturers, provide many other kinds of fiber optic transceivers like SFP transceivers, GBIC transceiver, CWDM SFP transceivers, DWDM SFP transceivers, SGMII SFP transceivers, SFP+ transceivers, XFP transceiver, X2 transceiver, Xenpak transceiver, and so on. In addition, Fiberstore is making with 30% of the price including all SFP transceivers. So if you want to know more and take action for it immediately. The website is