What is Optical Circulator? What is the application of Optical Circulator?

What is Optical Circulator?

An optical circulator is a special fiber-optic component that can be used to separate optical signals that travel in opposite directions in an optical fiber, analogous to the operation of an electronic circulator. An optical circulator is a three-port device designed such that light entering any port exits from the next. This means that if light enters port 1 it is emitted from port 2, but if some of the emitted light is reflected back to the circulator, it does not come out of port 1, but instead exits from port 3.

3 port Optical Circulator

The application of Optical Circulator

Fiber optic circulators are non-reciprocal optics, which means that changes in the properties of light passing through the device are not reversed when the light passes through in the opposite direction. This can only happen when the symmetry of the system is broken, for example by an external magnetic field. A Faraday rotator is another example of a non-reciprocal optical device.

The Configuration of optical circulator

As shown in Fig.2(a), an optical circulator typically has three input or output ports. The signal light input into the port 1 is output from the port 2. The signal light input into the port 2 is output from the port 3. The optical circulator is often used with adding an FBG at the port 2 as shown in Fig.2(b). For reference, a composition of optical circulator is shown in Fig.3.

Figure 2: Optical circulator. (a) Schematic of operation and (b) application.

Configuration of optical circulator

Figure 3: Configuration of optical circulator. 1: Poparization beam splitter (PBS), 2: reflection prism, 3 and 6: Birefringence crystal, 4: Faraday rotator, 5: half-wave plate

The application of Optical Circulator

An optical circulator is frequently used for an optical time domain reflectometer (OTDR), an optical add-drop multiplexer (OADM) and a dense wavelength devision multiplexing (DWDM) network using an FBG, and a pulse stretcher, a pulse compressor, and a disprersion compensator using a chirped FBG. Optical Circulators can be used to achieve bi-directional transmission over a single fiber. Because of its high isolation of the input and reflected optical powers and its low insertion loss, optical circulators are widely used in advanced communication systems and fiber-optic sensor applications.

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Optical Circulator

DWDM & CWDM Solutions

In today’s world of intensive communication needs and requirements, “fiber optic cabling” has become a very popular phrase.  In the field of telecommunications, data center connectivity and ,video transport, fiber optic cabling is highly desirable for today’s communication needs due to the enormous bandwidth availability, as well as reliability, minimal loss of data packets, low latency and increased security.  Since the physical fiber optic cabling is expensive to implement for each individual service, using a Wavelength Division Multiplexing (WDM) for expanding the capacity of the fiber to carry multiple client interfaces is a highly advisable.  WDM is a technology that combines several streams of data/storage/video or voice protocols on the same physical fiber-optic cable by using several wavelengths (frequencies) of light with each frequency carrying a different type of data. With the use of optical amplifiers and the development of the  OTN  (Optical Transport Network) layer equipped with FEC (Forward Error Corection), the distance of the fiber optical communication can reach thousands of Kilometers without the need for regeneration sites.

DWDM vs. CWDM

DWDM (Dense Wavelength Division Multiplexing) is a technology allowing high throughput capacity over longer distances commonly ranging between 44-88 channels/wavelengths and transferring data rates from 100Mbps up to 100Gbps per wavelength. Each wavelength can transparently carry wide range of services such as FE/1/10/40/100GBE, OTU2/OTU3/OTU4, 1/2/4/8/10/16GB FC,STM1/4/16/64, OC3/OC12/OC48/OC-192, HD/SD-SDI and CPRI.  The channel spacing of the DWDM solution is defined by the ITU.xxx (ask Omri) standard and can range from 25Ghz, 50GHz and 100GHz which is the most widely used today. Figure – 1 shows a DWDM spectral view of 88ch with 50GHz spacing.

Figure -1: Spectral view of 50GHz spacing 88 DWDM channels/wavelengths

DWDM systems can provide up to 96 wavelengths (at 50GHz) of mixed service types, and can transport to distances up to 3000km by deploying amplifiers, as demonstrated in figure 2) and dispersion compensators thus increasing the fiber capacity by a factor of x100.  Due to its more precise and stabilized lasers, the DWDM technology tends to be more expensive at the sub-10G rates, but is a more appropriate solution and is dominating for 10G service rates and above providing large capacity data transport and connectivity over long distances at affordable costs. The DWDM solution today is often embedded with ROADM (Reconfigurable Optical Add Drop Multiplexer) which enables the building of flexible remotely managed infrastructure in which any wavelength can be added or dropped at any site. An example of DWDM equipment is well demonstrated by PL-1000, PL-1000GM, PL-1000GT, PL-1000RO, PL-2000 and PL-1000TN by DK Photonics Networks.

Figure-2 Optical amplifier used in DWDM solution to overcome fiber attenuation and increase distance

CWDM (Coarse Wavelength Division Multiplexing) proves to be the initial entry point for many organizations due to its lower cost.  Each CWDM wavelength typically supports up to 2.5Gbps and can be expanded to 10Gbps support.  This transfer rate is sufficient to support GbE, Fast Ethernet or 1/2/4/8/10G FC, STM-1/STM-4/STM-16 / OC3/OC12/OC48, as well as other protocols.  The CWDM is limited to 16 wavelengths and is typically deployed at networks up to 80Km since optical amplifiers cannot be used due to the large spacing between channels. An example of this equipment is well demonstrated by PL-400, PL-1000E and PL-2000 by DK Photonics Networks.

It is important to note that the entire suite of DK Photonics’ equipment is designed to support both DWDM and CWDM technology by using standards based pluggable optical modules such as SFP, XFP and SFP+. The technology used is carefully calculated per project and according to customer requirements of distance, capacity, attenuation and future needs. DK Photonics also provides migration path from CWDM to DWDM enabling low entry cost and future expansion that can be viewed in the DWDM over CWDM technology page

WDM Installation

For designing and implementing a WDM network, there is a need to know some basic information regarding the infrastructure such as fiber type, attenuation of fiber, distance of fiber, network topology, service type, rate and connectivity. Based on this information, calculation of the optical link budget, OSNR (Optical Signal Noise Ratio) and dispersion can be performed in order to provide reliable, error free layer-1 optical solution.

DK Photonics’ WDM diversified equipment portfolio can provide either CWDM or DWDM solution for 4 wavelengths or 88 wavelengths ranging from few km to thousands of km and fit to the exact customer network needs. The network can be a point-to-point, linear add/Drop or ring Topology with passive Mux/DeMux or ROADM based infrastructure.

The WDM equipment serves as a demarcation point and is installed behind the Ethernet switch, router fiber channel SAN Fabric or SDH/SONET ADM coloring the fiber into different spectral wavelengths and multiplexing the rates fully isolated from each other over the same fiber to the remote site.  This allows transmission of multiple channels of different services and rates of data over the same fiber utilizing the fiber resources agnostically to the service type and rate.

The WDM technology can be applied to multiple applications such as connecting building service agnostic optical layer backbone,  data centers connectivity, Video broadcast, LTE fiber, cloud computing backbone, increasing existing fiber bandwidth and spectral efficiency.

Figure 3 shows the main traditional and emerging CWDM and DWDM technology applications which keep  growing along with the rise of the cloud computing and CSP (Content Service Providers) as well as Smart phones and video applications causing constant increase  to the WDM technology deployment and new capacities such as 100G.

Figure 3 – Main CWDM and DWDM technology applications

DK Photonics’ WDM products designed for easy and fast implementation take up minimal space and use least power, thus providing the highest integration level of CWDM and DWDM networks in the smallest 1U footprint, while providing high ROI. Additionally, the CWDM DWDM optical network is managed remotely with either DK Photonics’ Light Watch NMS/EMS or the imbedded web based management system as well as via any 3rd party SNMP tool.

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Filter-based WDM          CWDM            Mini CWDM Module       DWDM

Fiber Optic Sensors Global Market Forecast

According to ElectroniCast, the combined use of Continuous Distributed and Point fiber optics sensors will reach $3.98 Billion in 2017…

Shenzhen–September 20, 2013  -- ElectroniCast Consultants, a leading market/technology forecast consultancy, today announced the release of their market forecast and analysis of the global consumption Fiber Optic Point Sensors and Continuous Distributed Fiber Optics Sensor system links.

According to ElectroniCast, during the 2012-2017 timeline, the consumption value will grow at an impressive average annual rate of 20.3% from $1.58 billion to $3.98 billion.  Market forecast data refers to consumption (use) for a particular calendar year; therefore, this data is not cumulative data.

Monitoring and data transmission using fiber optic sensors and optical fiber in cabling is now commonplace in various applications, via intrinsic fiber optic sensors or extrinsic fiber optic sensors.  With an intrinsic sensor, one or more of the sensing/measuring quantity or physical properties (measurand) of the optical fiber passes through or inside the optical fiber and therefore experiences a change.  Extrinsic sensing takes place in a region outside of the optical fiber and the optical fiber acts as a transmission media of light to and from (linking) the sensing interface.

Fiber optic sensor technology has experienced impressive growth since ElectroniCast first started providing market and technology analysis of the subject since the early 1980s.  In fact their analysts were tracking the various advanced photonic technologies, since 1976.

DATA FIGURE

According to ElectroniCast, the consumption value of fiber optic sensors (Continuous Distributed + POINT) will grow at an impressive average annual rate of 20.3% from $1.58 billion to $3.98 billion.

Fiber Optic Sensor

DK Photonics – www.dkphotonics.com  specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as WDM, FWDM, CWDM, DWDM, OADM, Circulator, Isolator, PM Circulator, PM Isolator, Fused Coupler, Fused WDM, Collimator, and Polarization Maintaining Components, Pump Combiner, High power isolator, Patch Cord and all kinds of connectors.

DK Photonics Released Compact CWDM(Mini CWDM) Module

Shenzhen,China,September 10,2013 - DK Photonics recently released ompact CWDM(Mini CWDM) Module.

DK Photonics now can offers a Mini CWDM (compact CWDM) module that provides bandwidth capacity expansion for future network growth in one of the industry’s smallest packages.The compact CWDM modules are based on free space optics technology.It is available in 4-or 8-channel configurations.It have lower overall insertion loss and better uniformity across the channels.Its compact size and unique carrier tray set it apart, making it easier to deploy in a variety of field situations.

The Compact CWDM module comes with a carrier that allows for fast and easy snap-in mounting to splice tray or closure. Key benefits:

-Compact size: (L)53.8x(W)28x(H)8 mm.

-Free Space Optics design: Lower overall insertion loss and better uniformity across the channels.

-Simplified inventory management: The same component can be used in the head end or outside plant and as a Mux or Demux.

About DK Photonics

DK Photonics has been a well-established specialized fiber optic component supplier for fiber optic telecommunication,fiber lasers and fiber sensor applications in those years. We have excellent engineering capability, a well-established manufacturing process, and a high-quality standard.DK Photonics' promotion products including:1064nm High Power Isolator,1064nm Components, PM Components, (2+1)X1 Pump Combiner,Pump Laser Protector,Mini-size CWDM,100GHz DWDM,Optical Circulator,PM Circulator,PM Isolator,Fused Coupler,Mini Size Fused WDM. 

You are most welcome to contact DK Photonics(www.dkphotonics.com) to explore a wide range of promising business opportunities.

40/100GbE MPO FIBER OPTIC CONNECTOR – NORTH AMERICA MARKET FORECAST

According to ElectroniCast, 12-fiber single mode MPO connector consumption value will increase 141% per year through 2016…
ElectroniCast Consultants, a leading market research & technology forecast consultancy addressing the fiber optics communications industry, today announced the release of their annual market forecast of the North American consumption of MPO Fiber Optic Connectors used in 40 and 100GbE communication links.
In 2006, the IEEE 802.3 working group formed the Higher Speed Study Group (HSSG) and found that the growth in bandwidth for network aggregation applications was outpacing the capabilities of networks employing link aggregation with 10 Gigabit Ethernet. (The standard was announced in July 2007 and was ratified on June 17, 2010).
Applications such as video, virtualization (cloud computing), switching/routing and convergence are driving the need for bandwidth expansion. We continue on the path of gradually developing of growth (and change) from 1G to 10G to 40G and 100G. For data center (DC) environments operating at 40GbE or 100GbE, fiber optic cabling is generally recommended because its reach supports a wider range of deployment configurations compared to copper solutions.
The capability to choose increased speed will enable networks to play with the 10GbE resources to the access layer allowing 40/100GbE to handle traffic at the aggregation and core layers. In this market research report, ElectroniCast Consultants provides their 2011-2016 forecast and analysis of MPO fiber optic connectors used in North American 40/100GbE optical communication networks.
The 10GbE movement into the data centers will continue; however, “future-proofing” is continuing with an accent (40/100G), which is driven by significant broadband expansion demands, especially in regards to network productivity and operating expenses (OPEX costs).
According to ElectroniCast, 12-fiber multimode MPO patchcord dominate the North American (Mexico, Canada and the United States) 40/100GbE MPO connector marketplace in 2012; however, 12-fiber single mode MPO connector consumption value will increase at the fastest pace of 141% per year through 2016.
According to ElectroniCast, 12-fiber multimode MPO connectors currently dominate the North American 40/100GbE MPO connector marketplace, based on consumption value…

40 and 100 GbE MPO Connector Value

North America Market Share (%) in 2012, by Type

(Source: ElectroniCast Consultants)

DK Photonics – www.dkphotonics.com specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as PLC Splitter, WDM, FWDM, CWDM, DWDM, OADM, Circulator, Isolator, PM Circulator, PM Isolator, Fused Coupler, Fused WDM, Collimator, Optical Switch and Polarization Maintaining Components, Pump Combiner, High power isolator, Patch Cord and all kinds of connectors.