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Fiber Optics - Science topic
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Questions related to Fiber Optics
The fiber optic interferometer has effectively proven that Special Relativity is incorrect! The propagation of light requires the ether, and the ether is completely dragged by the Earth. We hope that our research will bring new perspectives to our peers and actively promote the research and application of optical theories.
Special Relativity has been erroneously in existence for 100 years, starting from MMX and ending at Sagnac. Although this is difficult to accept, we must confront it.
Preprint Investigating the Sagnac Effect
The spot diameter of the signal light is 1.3mm, and the collimating lens is a flat convex lens with a focal length of 11mm. The spot is measured by a spot quality analyzer, and the spot is measured 10cm away from the collimator. It is found that the spot is concentric circle type and the spot diameter is about 15μm after the collimating lens is focused. The large-mode optical fiber is liekki passive 30/250 dc pm with core NA of 0.07. Cut both ends of the optical fiber by 8°.
In the experiment, the collimated light beam is deflected through the half-wave plate and PBS, and then the optical fiber axis is used after passing through the second half-wave plate. The passive fiber is placed on the five-dimensional adjusting frame, and the output end of the passive fiber is collimated through a flat-convex lens with a focal length of 15mm. The output light spot can obviously see the panda eye spot, and there is no obvious bright spot in the center of the light spot, indicating that most of the signal light has entered the cladding, and the extinction ratio is only 1dB.
I have three questions:
1. If the signal is a fundamental mode Gaussian beam (actually a concentric ring type), it can be fully coupled into the core according to the formula, but the coupling effect is very poor at present, why?
2. How to measure the result of coupling? Is the output light spot periphery has entered the envelope of the diaphragm filter, and then measure the coupling efficiency, so that the extinction ratio is not taken into account. The goal of coupling is to get as much signal light into the core as possible with high coupling efficiency while maintaining a high extinction ratio for the output. The current experiments are sometimes more efficient, but the extinction ratio is worse.
3. If the passive fiber is replaced by a gain fiber, model liekki y1200 30/250 dc pm, how should the coupling result be measured? At this time, the signal light will have higher absorption in the core and less absorption in the cladding, and the coupling efficiency seems to be inappropriate.
I hope you can answer. If there are skills and experiences about spatial optical coupling into large mode field polarization-maintaining fibers, I also hope to share them.
I'm having a bubbling error while splicing 100/350 um optical fiber (core/cladding) on the Fujikura FSM100P+. I have tried some ways such as changing Prefuse power and Prefuse time but to no avail. Is there any way to handle this error? I put specific images in the file below.
a) Design a scalable and robust network architecture that can handle the increasing data traffic and support various communication technologies.
b) Recommend suitable transmission technologies, such as fiber optics, microwave of satellite, based on factors like bandwidth requirements, distance coverage and reliability.
c) Incorporate robust security measures to protect the network against cyber threats and ensure high reliability through redundancy and backup systems.
Hi all,
Recently I've been setting up Doric's ilFMC4 (3rd gen) cube for fiber photometry experiments. It says that in the cube itself there is an isobestic excitation (IE) port, a regular excitation (E) port of our wavelength needed, and a fluorescence (F) port that has a built in detector and amplifier. I had wired up the cube to a NI DAQ and everything was working fine two days ago. I removed the BNC cables connecting the E and F ports to the DAQ in order to use an oscilloscope to test for AC/DC current (maybe not the best idea?).
When I reconnected them and tested the system, I found that I had no light coming out of the the fiber optic patch cord that is connected to my sample port, where it's supposed to shine from. Usually I get about 40-50uW from the end of that cable that then goes into a fiber optic rotary joint (at this point I will get about 30-40uW) that is then used to shine light onto a mouse's implanted fiber (this final output has about 25-30uW of light at max). I could not get light to come out of even the first step, where it would usually be about 40-50uW.
I maxed out the LEDs to see if I got anything, and it looks like only the IE might be on. I saw absolutely no blue light at all. Any ideas what could have gone wrong? The cube was turned off between two days ago and when I switched it on today, and the only thing I fiddled around with was the E and F BNC cables to attempt to measure voltage on the oscilloscope. It runs on a power cord, not battery.
Dear community members,
I need to study the fluorescence of certain analytes in an aqueous solution. Currently, I am investigating fluorescence in a physiological solution. To conduct this study, I am using an Avantes spectrophotometer.
My goal is to obtain calibration curves for specific analytes in water at different concentrations.
The experimental setup consists of a peristaltic pump drawing the aqueous solution from a beaker containing the analyte. The solution flows through a plastic tubing. A small section of the plastic tubing consists of a circular plastic cuvette housed inside a light-shielded box. Inside this box, there are two LEDs and the entrance of the optical fiber that captures the light from the LEDs and the fluorescence of the solution excited by the LED light. Once crossed the box containing the LEDs, the liquid through the plastic tube returns to the beaker where the solution is recirculated for the experiment.
As mentioned, there is an optical fiber that captures the light from the LEDs and the fluorescence of the analytes dissolved in the water. The captured light travels through the fiber and goes into the box where the conversion of the light signal to an electrical signal takes place, along with all subsequent electronic processing. The spectrophotometer is connected via Ethernet to a Raspberry Pi, and I see the software interface on the screen to manage the spectrophotometer parameters. We have two LEDs: LED 1 emits light at 445 nm, and LED 2 emits light at 340 nm. One analyte absorbs at 445 nm and emits fluorescence between 500 and 600 nm, with a peak at 523 nm. Another analyte absorbs at 340 nm and emits fluorescence between 400 nm and 600 nm with a peak at 461 nm.
Now that I have explained the operation, let me describe the optical problem I am encountering.
In short, I observe a problem of "drift" in the light intensity detected by the light-to-electric signal converter. Let me explain it better. The LEDs (unless proven otherwise) always absorb the same amount of current (the voltage across the resistor is always the same over time, and they operate in the linear region), so they always emit the same light intensity. I observe that depending on how I bend the optical fiber and how it is touched and moved, the optical fiber affects the detected light signal, accentuating or attenuating a constant increase in detected light. If the optical fiber remains bent with very pronounced curves, I observe the drift phenomenon, i.e., a weak but constant linear increase over time in the light intensity of the LEDs or the fluorescence of the analytes, as shown in the plot attached. Let me explain it better. If the fluorescence peak of an analyte at 523 nm is, for example, 250 counts at a certain concentration, if no additional concentration of the analyte is added, and the circulating solution is always the same, then the fluorescence of the analyte at that constant concentration should remain constant. Instead, I observe a linear, weak but persistent increase in the fluorescence of the analytes at all emission wavelengths. So, if at time t, I observe fluorescence at 523 nm equal to 250 counts, after, for example, t + Dt, now the entire spectrum has grown, and, for example, the peak is at 1000 counts. Obviously, this "drift" in light intensity is not due to the LEDs because I believe their light intensity remains constant over time since the current they receive remains the same. At most, the LED intensity should decrease over time. It is not due to the auto-fluorescence of the analyte from ambient light because this phenomenon is observed even when the room is completely dark. There are no chemical reactions or degradation of the analytes (I would observe a decrease in fluorescence, not an increase because the degradation products of these substances do not absorb at 445 or 340 nm). Also, this positive drift phenomenon is observed even with plain water or air. It is not due to problems with the light-to-electric signal conversion electronics or due to bugs present in the source code.
I attribute it to the optical fiber, which, if it is straight, this problem is attenuated, but if it is very bent, this effect of increasing the detected light manifests. Attached, you will also find photo and plot files showing the abnormal trend over time of the fluorescence of the analytes or the light captured by the LEDs. I do not believe this anomalous trend depends on the light source.
I'm using a FT600EMT - 0.39 NA, Ø600 µm Core Multimode Optical Fiber
In your opinion, what could this uncommon phenomenon in the optical fiber be due to? And how could it be resolved?
I would appreciate any suggestions. Thank you for your patience and the time you've taken to read my question.
Best regards,
Lorenzo





+1
In one of our fiber photometry rigs, there is a pigtailed rotary joint connected to an FC-FC mating adapter (flange 11mm) that is then connected to our fiber optic patch cord. The problem is, the light transmission out of the pigtail is around 90 uW, and the adapter is pretty much the same, but then when we measure light transmission out of the fiber optic patch cord its around 20-30 uW. Is there any way to better optimize this region to get a higher light output?
Thanks!
Is the attenuation of light intensity at the outgoing end of a fiber related to the angle of the polarization plane after linearly polarized light has propagated within a single-mode fiber?
There are different approaches to diffuse reflectance modeling, most of them based on the solution of the radiative transport equation by the diffusion-based approximation. However, a set of fiber optic probes measure only a part of the diffuse reflectance leaving the tissue surface, and therefore there is inherent scale invariance in the measurement.
Then, how could I consider the numerical aperture and the refractive index of the fibers to remove scale invariance in the measurements?

By converting AC to DC then to light signals,then is it possible to transmit the light signals through optic fibre cables?
I am recently new in trying my hand at fiber photometry, but recently implanted fiber optics as well as viruses to monitor both dopamine and serotonin neurotransmission. I successfully implanted two fiber optics, injected the virus bilaterally, and added screws in the skull to reinforce their placement. The screws were placed deep enough to hold in the skull, but not so deep as to be flush against the surface of the skull. Three screws were put into place (one approximately 5 mm posterior from the injections), two screws ~1 mm anterior from the injections. After implanting the screws and optics, I briefly scoured the skull with a drill bit to provide a rough surface and applied the dental cement. These dental cement caps were secure 2 months following surgeries until I attempted to record from these animals.
My problem is, when I went to attach the optic cables to the implanted fibers, the caps popped off. It was also difficult to secure the plastic sleeves that are designed to cover half of the optic cable, and half of the fiber optic to prevent bleed-through of light onto the implanted optics. (I'm wondering if an excess build-up of dental cement surrounding the fiber optic made this difficult). However, the caps still should not have popped off as I attempted to attach these cables.
Does anyone have any advice for successfully ensuring that these "caps" remain attached to keep the fibers in place while attaching the optics?
Now i'm researching the size of photon....The silicon atoms size typical is 1.2 angstrom. is it possible can replaced the hardware by transfer current within transistor using photon instead of silicon atoms, If the photon size much smaller than silicon atom, it can minimize the IC feature size.
Generally, in coupler when light goes through one input port of Y coupler it divides into two output. But my doubt is that , will they produce entangled photons as well in the output.
I want to proceed the experiment using optical fiber. However, there is a problem. In one of the processes, the temperature reaches almost 600 degrees(Celsius). I know that the glass transition temperature of the soda lime glass is around 600 degrees.
In addition, the commercial glass optical fiber is consisting of 3 parts, core(pure silica) cladding(doped silica),and buffer layer(polyimide). The company says that this fiber can endure even at 400 degrees because of the polyimide, which is heat-resisting polymer. But, I think that it can endure up to 600 degrees if there is no polymer. Is it true? I will use the fiber as just a substrate, so I don't need any other layer except the core.
After I etch the polymer, what is the limit temperature for the glass optical fiber?
It is generally accepted that the fringe shift produced in a fiber optic Sagnac interferometer is independent of the refractive index of the fiber. In fact, the waveguide aspect of the fiber is not of any consequence, the counter propagating beams may propagate in any dielectric medium. Does anybody know a physical explanation for this effect, other than the special relativistic (M von Laue: On the Experiment of F. Harress) or general relativistic (Post, E.J: Sagnac Effect) explanations? It has been reported that(Wang, R: Modified Sagnac experiment for measuring travel-time difference between counter-propagating light beams in a uniformly moving fiber) the Sagnac effect is produced even when the moving path is effectively a straight line. This later configuration approximates an inertial frame, and with in an inertial frame one should not be able to measure one's state of motion!
For applications in visible and NIR ranges.

I am heating a tube to a very high temperature. i want to collect thermal radiation from the internal tube surface through a small hole I made. i have a fiber optics and various kinds of lens. Can anyone suggest a lens combination/arrangement so that I can collect maximum amount of radiation from the internal tube surface?

There are some interesting challenges for DAS systems in fields of agri-biophotonics and/or biophotonics - from vibration impact studies on the roots of growing plants to sea fauna acoustics monitoring, but researchers usually prefer array of single sensors or quasi-distributed sensors. Or maybe you know the examples with the DAS application? Thank you!
As we know, when we get a type of fiber from a company, we can get a few dispersion parameter D at corresponding wavelengths( lambda).so we can also get the dispersion slope dD/d_lambda.
Then how can we get the value of 4th disperison beta_4 with the value of D and dispersion slope dD/d_lambda?
I am simulating an Octagonal Photonic Crystal Fiber by Comsol. It is desired to extract some properties such as Dispersion, Confinement Loss and Effective Area vs. wavelength. For this purpose, I should obtain the Effective Refractive Index and Field Distribution for the Fundamental Mode. The Structure is a Solid-Core PCF (silica core n=1.45 and air holes n=1).
How I can reach to the Fundamental Mode?
I am wondering if it is possible to measure mode-locked laser stability (timing jitter, Noise) with an oscilloscope if the pulse duration is in the femtoseconds regime (lets say 150fs). If so, what type of measurement on an oscilloscope would quantify laser stability. What should be the bandwidth of the photodetector and oscilloscope?
Hi, I am looking forward for collaborators (academic and research work) who are interested to work in the following area:
Quantum Attacks
Quantum Computing
Quantum Artificial Intelligence
Post-quantum Cryptography
Internet of Drones
Blockchain and Quantum Computing
Can anyone recommend any papers/studies regarding the relationship of the core diameter of photonic bandgap (PBG) and/or inhibited coupling (IC)/Kagome fibers and signal propagation? I cannot seem to find a discussion in comparing core sizes and efficacy in transmission, although I imagine there must be some influence.
How would the spectrometer signal change if the target molecule was well dispersed in a solution and placed on the fiber optic SPR cable VS the target molecule concentrated at a specific region on the fiber optic cable?

I've been playing with a code for simulation of FBG properties. Code is using CMT and TMM implemented in matlab. Can anyone tell me why are there those sudden "drops/falls" in calculated dispersion? Am I missing something?

Can anyone tell what is the reason of these sharp frequency modulation in SPM broadened power spectrum. This is the spectrum of mode-locked laser with 0.4nm initial bandwidth at 1064nm. After amplification to 400mW (in YDF) and propagating through 6m length of PM-980, such spectrum appeared. I am wondering how to get rid of these modulations to enable efficient pulse compression.
Pls see the attached picture.

Two years ago, during my PhD defense one of the members of the committee asked me what diffuse reflectance is. I said diffuse reflectance is a type of surface reflectance (the other is specular reflectance) whose angle of reflection is independent on the angle of incident radiation. Diffuse reflectance is often observed with radiation incident on a mat or dull surface such as paper, tissues whereas specular reflectance is observed with radiation incident on a polished surface such as a mirror. This is a perfect text book definition
(ref Optical thermal response of laser irradiated tissue, A J Welch or Modern techniques in applied molecular spectroscopy by F. Mirabella)
However, my answer did not sit well with the committee, especially the “surface” part. They argued if diffuse reflectance is a surface reflectance than why diffuse reflectance spectroscopy (DRS) is used to detect tissue abnormality 300-400 micron underneath the surface? They came to agree that diffuse reflectance is “radiation that undergoes scattering and absorption events in tissue and comes back to the surface to be detected by detector”
I disagreed.
Just a few days ago, the same question is asked: what is diffuse reflectance? My answer is the same. Once again, there was lots of confusion.
Today, to put my mind to rest I am posting my explanation here. Again, diffuse reflectance is a type of surface reflectance (nobody can change that definition). The name diffuse reflectance spectroscopy (DRS) itself is quite confusing.
DRS collects not only the diffuse reflectance but also the remission. In clinical application of DRS, remission is frankly much more important because it tells us how light propagates within the tissue, and thus help us draw a picture of tissue components (scatterer, absorber). By the textbook, remission is the process in which light is scattered within the tissue, leaving tissue and propagating toward the detector. Therefore, remission is the result of complicated light propagation within the tissue.
This is, partially, why fiber optics DRS with fiber tip in contact with tissue plays an important role. The math is complicated. Principally, contact point of measurement DRS reduces chances to collect surface reflectance and increases chance to collect remission. DRS gave out-standing spectral resolution but not so much spatial information. So, there comes bundle of fibers in an optical probe that likely give enough spatial information to detect tumor margin.
Two tissue samples with different optical properties but same surface structure will have similar diffuse reflectance but different remission. As the results, different DRS signal is collected.
Next topic: Raw fluorescence signal that was not corrected for tissue attenuation is useless.
We are trying to run fiber photometry experiments for long time scales, but we get these sinusoidal artifacts that come up. We think they may be caused by twisting of the fiber optic subject cable. We tried using a rotatory joint to alleviate this, but the attenuation it causes is way too high (it attenuates the light coming back from the animal). Another rotatory joint we tried causes too much motion artifact and defeats the purpose of using it. Does anyone know a solution to minimize this type of artifact, or know of a good rotatory joint for photometry?

What is the reason of the received optical signal to be slimmed down in multi-mode fiber?
I have 4 km multi-mode fiber
Hello everyone, I would like some collective brainstorming on my setup.
I have a laser providing a collimated, randomly polarized beam at 1064 nm and I run it at about 150 mW of power. I focus the beam with an aspheric lens onto the SMF-28-100 fiber. The fiber is fixed in an FC/PC holder mounted on an XYZ translational stage with 2 rotational knobs. I struggle to obtain a stable Gaussian output.
1. Are there any fibers with cut-off wavelength close to 1064 nm? It looks like at least Throlabs and Newport have cut-off wavelengths at 970-980 nm and then at 1300-1500 nm.
2. How much effect would alignment have? The stage is a little bit unstable and may move when I turn one of the knob, so I have to use the rotational knobs until the power is maximized. I am even thinking of ordering a custom metal holder to mount both lens and the FC/PC connector ring on it.
3. The fiber is about 1 m long and mostly covered with the acrylate coating so I don't think I should worry about the cladding modes.
4. How efficient would be folding the fiber into '8's to achieve mode mixing and more of a flat beam profile?
Thank you in advance!
Hello! Colleagues, what resource do you use to monitor conferences on fiber optics and photonics?
Based on Faraday effect, If a piece of glass is exposed to a magnetic field, it optically activates.As the linearly polarized light passes parallel to the applied magnetic field, the plane of light polarization rotates.
1- can we pass light through fiber optic and fiber optic works as glass?
2- in some sources I see the linearly polarized light should be circularly polarized,because left and right circular polarized light waves have different speeds in magnetic field, I dont know to use linear or circular polarized light?
In recent research perspective this is very important field. Parity operation is reversal of co-ordinate (x->-x, p->-p)and time reversal operation is reversal of time (x->x,p->-p, i->-i).
But talking about this combined PT-symmetry in any field of science and engineering, what it implies?
I was wondering if anyone has looked into the use of Far UVC light as a way of treating Covid-19. Far UVC light has a strong antiviral effect but has minimal effect on mammalian cells compared to UVC light. By use of a Thoracosopy technique a fiber optic Far UVC light source could be introduced into a patients lungs and target the Covid-19 cells. Combining this with Ultraviolet Blood Irradiation (UBI) may be a therapeutic treatment that in some critical cases could be applied until such time as a true drug therapy can be applied.
Please let me know your thoughts
I'm interested in directing as much light as possible from the LED into the SMA-terminated optical fibre. What sort of adaptor or bushing would I need to be able to connect the LED to the fibre? I am using Osram SFH 4725S for the NIR LED and a lab-grade patch cord from Ocean Optics.
Can thin glass (thickness of 50μm or less) creep under high pressure and high temperature (754 mmHg, 80°C or 60°C) over long period of time (e.g. 40 days)? If the pressure on the thin glass is applied by submerging it in heated water (80°C or 60°C)?
If anyone knows about any research paper or literature on this topic, it will be really helpful.
Tight buffered fibers or bare fibers in a loose tube? If loose tube, with or without gel? Does a corrugated steel armor attenuate the accustic energy?
The perimeter length is 40Km and the required spatial resolution is 10 meters. Does the answer depend on the sensing method (e.g. Rayleigh coherent back scattering, Brillouin scattering etc.)?
For a single mode optical fiber having a step-index refractive index profile, the
relative refractive index difference Δ between the core (refractive index n1 )
and cladding (refractive index n2) is defined as Δ=( n1- n2)/n1.
What happens with the following parameters if Δ increases)s(n2 approaches n1) ?
1.The mode field radius
2The zero dispersion wavelength
3. The cut-off wavelength
Hi
Does someone know how we can calculate absorption coefficient in optical fiber at different wavelengths (such as 1117 nm).
I am trying to build a fiber laser based on multimode interference in SMF-GIMF-SMF (GIMF spliced between two SMFs) leading to saturable absorber phenomena in the design. I am using Er fiber as a gain median and pumping it by 980nm source. I observe Q-switching or sometimes unstable or weak mode-locking. What can I improve or add in this setup to achieve better modelocking.
Hello, i'm having a project where I must implement ofdm simulation with mmse estimator for the rayleigh channel. Although the estimation seems tolerant, i'm getting no improve with ber, even for simulation of 10000 symbols.
I have attached the paper i'm trying to implement, with the matlab code and some representative figures to see exactly what i'm doing
I can't understand if i'm missing something very important when estimating the channel or when using specific pilot symbols or in somewhere else..
Thanks in advance,
Anastasia
To change the path of Vehicle pushed at the speed of light by wavefront of Electromagnetic wave
What is the function of line traps other than communication?
I'am a specialist in fiber optic sensor development and already worked in a R&D project to detect and measure bacterial contamination on hospital environment using fiber optic properly modified.
Plastic core fiber optic sensor gives a sensing spectra with y axis variation i.e intensity variation with constant wavelength of 690 nm. Spectral shifting with x axis i.e. wavelength variation is not happening. Do i need to change the fiber or any spectroscopy setting can give x axis variations?
I am simulation one fiber optic liquid level sensor where I am taking 1cm long multimode fiber. The cladding of the multimode fiber is removed by chemical etching process. For, measuring the liquid level, some portion of the fiber is immersed in the liquid and the remaining portion in in the air. Thus, the guided mode beam profile in the air-cladding section and that in the fluid-cladding section should be different. So there should be mode conversion loss.
Is there any theoretical formula to calculate such mode conversion loss.
Iwould like to defined fiber optics in communication systems
When I cut the optical fiber, due to the large diameter of the fiber, cracks are formed on the surface.
By polishing the fiber, the fiber surface becomes angular.
This phenomenon greatly affects the scattering of photons.
Is there information about the best way to polish high-diameter optical fibers?
Dear All, I request the experts to provide me with some references about the use of nanotechnology to improve the fiber optics specifications in the Distributed Temperature Sensing DTS for temperature measuring and detection. I wish to study the effect of Nanomaterials (or nanoparticles) on the Raman Scattering in fiber optics ?
Q-factor= 20*log10(sqrt(2)*(erfcinv(2*(BER))));
I have searched a lot but unfortunately I only found the equation above that calculate the Q from BER ,but the Q will be infinity when the BER is 0. Also,when we need to calculate the Q for each individual subcarrier , the Q will be infinity for some of them.
In addition, is it applicable for all the M-size QAM and all the O-OFDM systems like DDO-OFDM or CO-OFDM?
So,is there any other way to find the Q-factor for optical QAM-OFDM ? may be for the Eb/No or others?
Thanks and best regards ....
how to measure DFB-LD frequency deviation per unit drive current change (in mA).
After amplification in optic fiber amplifier pulse autocorrelation (red line in the attached picture) width decrease as compared to initial pulse autocorrelation (black line). Fiber amplifier dispertion is normal, pulse chirp is positive. Pulse amplified spectrum width about 12 nm, output averaged power 2 W. What possible reason of pulse width shrinkage ?

I need this at wavelength 1550nm and 850nm. I have LED source already, but it is with SMA connector. I tried using SMA/FC converter, but it did not work.
How can be use the CW diode laser with sample from fiber optics part to obtained laser fiber?
How can I get the waveguide and material dispersion of a step-index single-mode fiber at the operating wavelength if I know its core size and NA?
In order to get highest coupling of the laser and fiber, who can promises the simple set up for this goal?
I was thinking about 2 m YB single mode-double clad
HR FBG 100%
OC FBG -Fresnel Loss 4%
Pump Power 6W
Can someone give me a little feedback on this design?
I am trying to couple NIR light from a high power LED to a multimode optical fiber. Ideally only a few (five) modes would be coupled but I am concerned about how it affects time coherence if compared to original time coherence (from LED).
The LED is 850nm/30nm and 1W power.
I am aware of power loss but I expect a few mW in the fiber output.
What is the best way of calculating or measuring the fraction of power from a seed leaser that is coupled into a semiconductor optical amplifier by a series of free space optics? Any help or references to relevant papers is much appreciated. Thanks.
If you have a B. Sc. student and if you like to do research in laser practices with fibers (laser application) it will be my pressure to work supervision together ?
regard
Raad
Hello,
We are looking for large core diameter graded-index silica MMF. Core diameter must be higher than standard 62.5 µm and cladding remaining at standard value of 125 µm. So far, we have found two providers : DrakaElite TM (100/125) and Leoni (85/125). The lengths we need is just a few meters.. Unfortunately Draka sells only 2.2 km minimum and is too expensive for our project. Furthermore they have a strict policy to not send samples.. Leoni they don't have it on stock..
So, is there anybody who use these fibers and could sell us a short piece ? Or maybe anyone knows alternative suppliers for that kind of fiber ?
Looking forward to your feedback.
Cheers,
Miguel
What are the expressions for the TM02 mode of an step index optical fiber for Z, r and ϕ components?
How do I determine which type of dispersion is important for step index optical fiber if the group index of HE11= group index core material?
For a single mode optical fiber having Δ= (n1- n2) /n1. What happens with the zero dispersion wavelength if Δ increases?
I merely fused two ports of the coupler together.
The coupling ratio is 99:1 and the port configuration is as below.
Besides, all the fibers are single mode fibers, no polarization-maintaining property. The whole optical system is placed into a vibration and thermo-isolator.
What can the reason be causing these non-periodic resonant dips?



Glass optical fiber is not suitable for my application and multimode plastic does not allow for the FBG inscription with required parameters. It can be done only if there are not more than several modes allowed in the fiber and that's why I'm looking for a SM POF or one, at least, close to it.
Nowadays, the structures of axial component are not enough to design all kinds of balance to meet different wind tunnel aerodynamic tests.
And some new strain sensors are used in balance, for example, fiber optic strain gage and semiconductor strain gage are gradually applied to strain balance.
So new concepts need to be used in the design of axial component.
I winded a few meters of optical fibers on a PZT tube which is driven by a signal generator, then made a fiber optical resonator with direction coupler. The source which I used is a 1550nm laser and the detecor is made of InGaAs, the signal is demonstrated on a oscilloscope.
What I observed is that the resonant curve on the oscilloscope is swinging, which means the resonant dip is drifting during the modulation process.
I wonder whether there's something wrong with my PZT tube or the phenomenon is normal while modulating with PZT. If it's normal, how should I remove or suppress the drift of resonant dip?