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The cladding power stripper also referred to as the multimode optical power stripper is designed for amplifier applications and high power fiber laser. It is an ideal device  for ASE, residual pump power stripping, core modes that have escaped from double cladding fibers inner cladding while ensuring preservation of single power minimal degradation and beam quality (M2). Single power that is reflected into the inner cladding may also be stripped out too.  The handling capability of the stripping power goes to 800W or at times may be even higher

Stripping the Coating

The fibers that most reputable companies supply all come with a standard  acrylate single layer coating or, in some such as the high power products, a coating that is high temperature enduring. In comparison to dual layer coatings, the coatings that are single layer are more brittle and smooth. The coating can be removed readily using the conventional tools for fiber stripping such as the Fitel S-210 Clauss or CFS-1 for 125 μm cladding diameter fiber or for larger cladding diameters the Clauss No Nik stripper is used. For fibers whose outer diameter is non-standard, it is recommended that an adjustable stripper is used.  Thermal strippers such as those that are attached to the Schleuniger FiberStrip 7030 or the Vytran FFS-2000 can be used for all fiber in a safe way.

Alternatively, chemical stripping of fibers can be done using an appropriate solvent. For example, the coating can be exposed for one minute to sulfuric acid at 120°C sulfuric acid. Before the fiber is dipped into the liquid, the tip should be sealed with a drop of glue of 2 mm in diameter or through the end fiber hole collapsing using a fusion splicer.  It is worth noting that most glue types are dissolved in this acid, but epoxies that are two-component such as the Epotek ND353 tends to dissolve in a slower manner than the coating.

It is also possible to obtain chemical stripping through application on the fiber tip, of paint stripper. The paint stripper is usually in the form of a gel so as to reduce the occurrence of out-gassing and can be applied easily using a small brush. After a minute or so, the coating becomes soft and is removed easily using a lens tissue. It is worth noting that paint stripper typically contains dichloromethane (CH2Cl2) and as such there may be restrictions by local regulations to use it. For lower quality and faster stripping, another option would be to use a normal cigarette lighter to burn the coating off. However, the fiber may end up becoming brittle hence not the best choice for stripping.

Fiber Bragg Gratings for fiber laser

Laser Mirror Gratings

China, 21th July, 2016: Optical passive components available at DK Photonics are significant in a number of industries such as telecommunication applications, fiber laser, etc. In order to better give our fiber laser customers to do matching service, DK Photonics work with a Chinese optical research institute, after more than half a year’s efforts, and finally produced the FBG Mirrors used for fiber laser.

FBG Mirrors are based on the reflective properties of the Fiber Bragg Grating (FBG) written in the core of an optical fiber waveguide. FBG mirrors’ principal application is to use a high and low reflector to form a stable laser cavity having the lasing wavelength selected by the low reflector.

Fiber Bragg grating (FBG) is a distributed reflector constructed in an optical fiber short segment that allows reflecting particular wavelengths and transmitting the rest of them. The periodic variation of the fiber core refractive index generates a wavelength-specific dielectric mirror, which allows reflecting specific wavelengths. FBG can be used as a high reflector (HR) and output coupler (OC) to make a laser cavity in a fiber laser. Rare earth doped optical fiber increases the laser gain. The major advantage of all-fiber systems where free space mirrors are replaced with a pair of fiber Bragg gratings (FBG’s) is that the realignment process is no longer needed for the entire system functioning period, since FBG is spliced directly to the doped finer and never needs adjusting.

DK Photonics can provide varied wavelengths FBG, such as 1018nm, 1053nm, 1064nm, 1080nm, 1550nm, 1950nm, 2020nm, 2040nm; and can write in all common passive optical fibers, such as 6/125DCF,10/125DCF,15/130DCF,20/125DCF,25/250DCF,30/250DCF,20/400DC Fiber, PM or non-PM types are available. The Max. handling power up to 1000W. The following is main parameter or our FBG:

Parameters Values
Center Wavelength(nm) 1018nm, 1053nm, 1064nm, 1080nm, 1550nm, 1950nm, 2020nm, 2040nm
Wavelength accuracy 0.2nm
High Re­ector / Output Coupler HR OC
Reflectivity ≥99% 3%~20%
Bandwidth 1~3nm 0.2~1nm
Fiber Type 10/125 DCF,15/130DCF, 20/125 DCF,25/250 DCF,30/250 DCF,20/400 DC Fiber, PM or non-PM types are available
Power Handling(core) 20W, 50W, 100W, 500W,1000W.


FBGs offer multiple applications. It can replace conventional dielectric mirrors to provide optical feedback. It can be also used to create a multi-wavelength Raman fiber laser.

Fiber lasers offer a compact, electrically efficient alternative to Ar-Kr and Nd:YAG technologies. The FBG can be applied to fiber lasers of any type:

  • Single frequency fiber lasers;
  • Raman fiber laser;
  • Fixed frequency visible wavelength lasers;
  • Tunable frequency visible wavelength lasers;
  • Ytterbium doped fiber lasers;
  • Q-switched fiber lasers;
  • Pulsed fiber lasers;
  • Stabilized multi-mode emission sources;
  • Fine optical fiber responder, etc.

To obtain more information about the products, visit

About DK Photonics

The DK Photonics claims that they even provide customized solutions to their patrons. Those industries who wish their products to be distinctive can contact them for the same. The team mentions that they have passed the ISO9001 quality tests and hence, there is no compromise in this aspect.

Hi there,

Since the Chinese new year is coming,please arrange ahead of the issues in order to facilitate all the customers,suppliers and colleagues.And details list as below:

Holiday time:
Our factory will close from February 1, 2016 to February 14, 2016;
Our office will close from February 5, 2016 to February 14, 2016.
DK Photonics will resume normal work on February 15, 2016. Please make reasonable plan and arrange the schedule before the CNY.

If you have any inquiry or emergency,during our leave, please feel free to contact: [email protected] .We will try the best to comment back and keep you posted A.S.A.P.

We really appreciate your support for DK Photonics in the past whole year! We will try our best to provide you good products and services as we did before.

We wish you all the best!

DK Photonics Team
January 8, 2016

Technological parameter of laser welding:

(1) Power density

Power density is one of the key parameters in laser processing. When the power density is relatively high, the surface would be heated to boiling point in microseconds, thus generate mass vaporization. As a result, high power density is good for material removal processing such as punching, cutting and carving. When the power density is relatively low, it would take some microseconds to meet the boiling point, the bottom can reach the melting point before vaporization occurs, thus a good melt welding is successfully formed. So the power density ranges from 104~106W/cm2 in conductive laser welding.

(2) Laser pulse shape

Laser pulse shape is an important question in laser welding, especially for foil welding. When high strength laser beam reaches the material surface, 60~98% of the laser energy will be lost by reflection and the reflectivity is changeable by the temperature of the material surface. The reflectivity of metal can vary greatly in a laser pulse period.

(3) Laser pulse width

Laser pulse width is an important parameter to distinguish material removal and material melting; it is also a key parameter to decide the cost and volume of processing equipment.

(4) Influence of defocusing amount on weld quality

There are two ways of defocus: positive defocus and negative defocus. It is positive defocus when focal plane is above the workpieces, vise versa. According to geometry optical theory, when positive and negative defocusing plane equals to welding plane, the power densities are almost the same in the corresponding panels, but the actual laser pools have different forms. It can achieve larger depth of fusion when it is negative defocus.

Application field of laser welding

Laser welding machine has wide application in manufacturing industry, powder metallurgy field, automobile industry, electronics and some other fields.

fiber laser 3

Source : demarlaser

Application of laser welding in automobile industry

Volkswagen AG has adopted laser welding in car roof of brands like AudiA6, GolfA4 and Passat. BMW and GM have used laser welding in top of the car frame while Mercedes-Benz has applied laser welding in drive disk assembly. Except for laser welding, other laser technologies have be applied as well. Companies like Volkswagen GM, Benz and Nissan have used laser to cut covering parts while FIAT and Toyota have adopted laser for coating engine exhaust valve; Volkswagen has used laser for surface hardening on engine camshaft. Domestic vehicle models like Passat, Polo, Touran, Audi, Dongfeng Peugeot and Focus have adopted laser welding technology.

Independent automobile brands like Brilliance, Chery and Geely have adopted laser welding as well.

Improvement and development of new laser welding technology

Laser welding technology is continuously developing along with the progress of the time. The following three technologies can help expanding laser’s application scop and enhancing the automatic control level of laser welding.

  1. filler wire laser welding

Laser welding generally doesn’t fill wires but has high requirement on assembling clearance, which is hard to be guaranteed thus limits the application scope. Filler wire laser welding method has lower requirement on assembling clearance. For example, if the aluminum alloy plate is of 2 mm’s thickness, the clearance must be zero for a good shaping. When adopting φ1.6mm welding wire as filler metal, it can form good shape even the clearance is 1.0 mm. Besides, filler wire can be used for adjusting chemical components and multi-layer welding on thick board.

  1. Beam rotation laser welding

By the adoption of laser beam rotation laser welding methods, demands on welding assembly and beam centering are reduced greatly.

  1. On-line detection and control of laser welding quality

It is becoming a hot researching topic on detecting laser welding process by using plasma such as light, sound and electric charge; some researches have achieved closed-loop control.

DK Photonics –  specializes in designing and manufacturing of high quality optical passive components mainly for fiber laser applications such as 1064nm high power isolator, Cladding Power Stripper, Multimode High Power Isolator, pump combiner,1064nm Band-pass Filter,(6+1)X1 Pump and Signal Combiner, PM Circulator, PM Isolator, optical Coupler. More information, please contact us.

The key components in a WDM system are the optical wavelength multiplexer (MUX), and the de-multiplexer (DEMUX). In general, a CWDM (coarse WDM) MUX/DEMUX deals with small numbers of wavelengths, typically eight, but with large spans between wavelengths (spaced typically at around 20nm). A DWDM (dense WDM) MUX/DEMUX deals with narrower wavelength spans (as small as 0.8nm, 0.4nm or even 0.2nm), and can accommodate 40, 80, or even 160 wavelengths.

The one kind of DK Photonics LGX CWDM MUX/DEMUX modules are bi-directional passive optical multiplexers and de-multiplexers, allowing multiple optical signals at different wavelengths to pass through a single optical fiber strand.


The second DK Photonics ABS CWDM MUX/DEMUX modules are duplex fiber link bi-directional multiplexers and de-multiplexers, allowing multiple optical signals’ at different wavelengths to pass through duplex optical fiber.


The last one kind is simplex directional CWDM MUX only or CWDM DEMUX only. The kind of mux and demux must be used with each other.


CWDM MUX/DEMUX solution lets operators make full use of available fiber bandwidth in local loop and enterprise architectures. Our CWDM MUX/DEMUX modules split up to 18 channels (20 nm spaced) to a single fiber. The standard packages are ABS Plastic Box, 19″ Rack Mount Chassis CWDM Mux/Demux  and LGX Metal Box Mux/Demux. No matter what kinds of connectors (such as FC, ST, SC, LC, etc.) are all available and we can also mix connectors on one device.

CWDM MUX+DEMUX 8 Channels (Dual Fiber) Module

CWDM MUX+DEMUX 8 Channels (Dual Fiber) Module

DK Photonics offers a wide range of WDM (Wavelength Division Multiplexing) optical networking products that allow transport of any mix of services from 2Mbps up to 100Gbe over dark fiber and WDM networks providing for the entire set of the most demanding CWDM and DWDM network infrastructure needs.

Hi there,

Since the Chinese new year is coming,please arrange ahead of the issues in order to facilitate all the customers,suppliers and colleagues.And details list as below:

Holiday time:
Our factory will close from February 11, 2015 to February 24, 2015;
Our office will close from February 18, 2015 to February 24, 2015.
DK Photonics will resume normal work on February 25, 2015. Please make reasonable plan and arrange the schedule before the CNY.

If you have any inquiry or emergency,during our leave, please feel free to contact: [email protected] .We will try the best to comment back and keep you posted A.S.A.P.

We really appreciate your support for DK Photonics in the past whole year! We will try our best to provide you good products and services as we did before.

We wish you all the best!

DK Photonics Team
January 16, 2015

What’s the CWDM/DWDM Optical Add-drop Multiplexer?

The optical add-drop multiplexers (OADM) are used in wavelength-division multiplexing systems for multiplexing and routing different channels of light into or out of a single mode fiber. This is a type of optical node, which is generally used for the construction of optical telecommunications networks. An OADM may be considered to be a specific type of cross connect cabinet.

OADM ModuleApplication of OADM

A traditional OADM consists of three stages: an optical demultiplexer, and optical multiplexers, and between them a method of reconfiguring the paths between the optical demultiplexer, the optical multiplexer and a set of ports for adding and dropping signals. The optical demultiplexer separates wavelengths in an input fiber onto ports. The reconfiguration can be achieved by a fiber patch panel or by optical switches which direct the wavelengths to the optical multiplexer or to drop ports. The optical multiplexer multiplexes the wavelength channels that are to continue on from demultiplexer ports with those from the add ports, onto a single output fiber.

Principles of OADM technology

General OADM node can use four port model (Figure 1) to represent, includes three basic functions: Drop required wavelength signal, Add rumored signal to other wavelengths pass through unaffected. OADM specific network process is as follows: WDM signal coming from the line contains mangy wavelength signals into OADM’s “MainInput” side, according to business required, from many wavelength signals to selectively retrieved from the end (Drop) output desired wavelength signal, relative to the end from the Add the wavelength of the input signal to be transmitted. While the other has nothing to do with the local wavelength channels directly through the OADM, and rumored signals multiplexed together, the line output from the OADM (Main Output) Output.

OADM node technical classification

Optical drop multiplexer network technologies can be divided into two types, fixed optical drop multiplexer (Fixed OADM, FOADM) and reconfigurable optical drop multiplexer (Reconfigurable OADM, ROADM).

Fixed Optical Drop Multiplexer (FOADM)

FOADM to filter as the main component, and its function is fixed to join or retrieve certain light wavelengths. General common FOADM can be divided into three types, namely Thin Film Filter type (TFF type), Fiber Bragg Grating (FBG type) and integrated planar Arrayed Waveguide Gratings (AWG type).

* TFF FOADM using thin film between the filtering effect of the different refractive index.

* FBG FOADM use of fiber Bragg grating filtering effect, with two circulator can become FOADM.

* AWG FOADM gererally used in semiconductor fabrication processes, the integration of different refractive index material is formed on a flat substrate in a planar waveguide, when different wavelength light source is incident through the couping after the import side, due to take a different path length, while the different phase delay caused by different wavelengths and thus produce certain wavelengths in the export side to form a constructive or destructive interference, making waves in the export side, the different wavelengths will follow the design on a different channel to reach, and thus achieve FOADM function.

Reconfigurable Optical Add/Drop Multiplexer (ROADM)

ROADM can always be adjusted with the distribution network to add and drop wavelength, which reconstruct the network resource allocation, the flexibility to meet the requires of modern urban network, so a flexible ROADM features, plus optical switch substantial advantage, making the current fastest growing ROADM based optical switches based ROADM (switch based OADM). ROADM mainly be the optical switch, multiplexer and demultiplexer composed, Switch-based OADM, mainly divided into Wavelength independent switch array and wavelength selection switch.

OADM network applications

WDM ROADM optical fiber suitable for different network environments.

OADM in the metropolitan network development tendency

1. Arbitrary choice must be retrieved, adding wavelength, the wavelength can take advantage of the limited resources, the node can be retrieved with the need to do to join the adjustment of the signal wavelength, and has a remote control functions. This can provide dynamic reconfiguration of optical communications network capable ROADM will be connected to the backbone network critical devices. And FOADM is used for wavelength demand network access will be smaller parts to reduce costs. Furthermore, ROADM use to all kinds of Tunable Laser, unable Filter, or wavelength selective optical switches and other components.

2. Must be able to convert incompatible wavelength suitable for the backbone network will be transmitted wavelengths. Therefore, OADM be combined with wavelength conversioin Transponder or other functional components.

3. Must be able to compensate for the node to make acquisistion, adding such action energy loss. Therefore, OADM optical amplifiers must be combined with functional components.

4. Wavelength signals related specifications, such as: the signal to noise ratio (S/N), the energy balance between the signal wavelength, etc., are required to meet network requirements. Therefore must be combined OADM variable optical attenuators (VOA), dispersion compensation module (DCM) and other components.

Welcome to our new website & blog

A resource for entrepreneurs and a place for new ideas about optical communication

we are excited to introduce you to our new blog & website. This is where we plan to share our thoughts on the the world of the optical communication. We also plan to give you updates on DK Photonics’s activities, including the latest news on our startups, program events & partners around the world. Or, we may just share whatever is on our mind.

Take a tour of our new website.

This is just a taste. We have numerous other activities in the works – events, partnerships & opportunities for entrepreneurs to participate in our program in various ways.

So, I invite you to take a tour around our new blog, bookmark our website & connect with us on social media (Facebook, Twitter, LinkedIn & Google+) to stay up to date on our news. We will have a lot of updates to share in the coming weeks & months.

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( to explore a wide range of promising business opportunities.Image