March 22, 2016 at 3:25 am #33527
IS IT POSSIBLE TO CREATE THE REFRACTIVE INDEX IN THE RANGE OF 1.4 TO 1.7 USING THE GLASS MATERIAL(1.4).
FURTHER MORE ARE THERE ANY MATERIAL HAVING REFRACTIVE INDEX UPTO 1.7 THAT IS BEING USED IN OPTICAL FIBER COMMUNICATION.
March 23, 2016 at 9:31 am #33607
i got the refractive index range;
solid Refractive Index
Crown glass 1.5 – 1.62
Flint glass 1.57 – 1.75
looks like flint glass is the range which i need;
a hard grey rock consisting of nearly pure silica (chert), occurring chiefly as nodules in chalk.
Flint glass is optical glass that has relatively high refractive index and low Abbe number (high dispersion). Flint glasses are arbitrarily defined as having an Abbe number of 50 to 55 or less. The currently known flint glasses have refractive indices ranging between 1.45 and 2.00.
In the optical glass industry, flint glass is any highly refractive lead-containing glass ( Flint glasses contain 45-65% lead oxide)used to make lenses and prisms. Because it absorbs most ultraviolet light but comparatively little visible light, it is also used for telescope lenses. The light-dispersive power of flint glass can be made twice as high as that of crown glass (of conventional soda-lime composition), and the two complementary types of glass are cemented together to make lenses corrected for chromatic aberration. In the container glass industry, flint glass is any clear glass free of colouring.
March 23, 2016 at 9:54 am #33611SAHIL SINGHParticipant
Hi Aasif Bashir,
Thank you for such valuable information and detailed explanation of the concept… Highly appreciate your efforts…. I also agree that flint glass will suffice your need…
March 23, 2016 at 1:09 pm #33619Ranjeet KumarParticipant
Index profile is the refractive index distribution across the core and the cladding of a fiber. Some optical fiber has a step index profile, in which the core has one uniformly distributed index and the cladding has a lower uniformly distributed index. Other optical fiber has a graded index profile, in which refractive index varies gradually as a function of radial distance from the fiber center. Graded-index profiles include power-law index profiles and parabolic index profiles.
Glass optical fibers are almost always made from silica, but some other materials, such as fluorozirconate, fluoroaluminate, and chalcogenide glasses as well as crystalline materials like sapphire, are used for longer-wavelength infrared or other specialized applications. Silica and fluoride glasses usually have refractive indices of about 1.5, but some materials such as the chalcogenides can have indices as high as 3. Typically the index difference between core and cladding is less than one percent.
Silica exhibits fairly good optical transmission over a wide range of wavelengths. In the near-infrared (near IR) portion of the spectrum, particularly around 1.5 μm
A high transparency in the 1.4-μm region is achieved by maintaining a low concentration of hydroxyl groups (OH).
March 23, 2016 at 1:14 pm #33621Ranjeet KumarParticipant
Three types of material make up fiber-optic cables:
Plastic-clad silica (PCS)
These three cable types differ with respect to attenuation.
The attenuation of PCS fiber-optic cable falls between that of glass and plastic. PCS fiber-optic cable has a glass core, which is often vitreous silica, and the cladding is plastic, usually a silicone elastomer with a lower refractive index.
March 23, 2016 at 1:22 pm #33623
i got the answer
please do not reply any body
i request admin to close the topic for further reply
March 23, 2016 at 4:04 pm #33635Dr. Dhiman KakatiParticipant
Hi aasif bashir dar,
I need to mention one more factor that most widely used optical fiber has refractive index of around 1.4 to 1.5 but most importantly you should maintain the core and cladding refractive index difference as low as possible otherwise the dispersion effect a major concern in that case. moreover going for much higher refractive index material the velocity of light will become lesser and lesser. Thanking you.
March 24, 2016 at 12:41 am #33644
hi dhiman kakati;
very well said by you that higher refractive index materials are more dispersive in nature and core and cladding refractive index difference should be very small…
but in my query i had not mentioned that what i have to do with the refractive index material of 1.4-1.7.
i am not designing optical fiber as thought by you.
still a very valuable comment in the discussion.
March 24, 2016 at 2:36 am #33655umer syedParticipant
hi aasif bashir dar,
can you explain what are upto.. instead of designinig the fiber.
despite the flint glass , crown glass aborb the UV rays and do not aborb the vissible part of light so must ,they are extremely dispersive.
it is bit confusing, what can be the application of such material ..
please provide so application here
March 24, 2016 at 6:47 am #33674
hi umer syed;
i am desgning PCF which is hidhly dispersive in nature,for dispersion compensation.
March 24, 2016 at 7:02 am #33675FAYIQA NAQSHBANDISpectator
Here i would like to ask you one question.. it is obvious that you are not working on physical or fabrication part of the fiber so can you please tell me which the tool are you using for designing of PCF and is it possible there that you can choose the refractive indices of the fiber components on your own..
Thanks & regards+7
March 24, 2016 at 11:54 pm #33761
hi fayiqa naqshbandi
i am using optiFTDT and BPM for fabrication of photonic crytal fibers
i am designing a pCF or holey fiber so as to mitigate the dispersion effects in the channel.
more over optigrating also provides such option to have high refractive indexs..
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