Questions tagged [optics]
Anything related to optics applied to electronics. Optics is a branch of physics studying the properties of light and its interactions with physical media.
0
votes
1answer
53 views
Help me to build some devices for measuring LEDs optical power[mW] with range (1 -100)mW included [closed]
I have an application of photoactivation device with 10-20 LEDs for every color; with the following wavelengths : red 630-670nm ;yellow 575-595nm , green 510-540nm .
In order to obtain an uniform ...
0
votes
2answers
41 views
Specificity? “High-Contrast and spectroscopic-based specificity of optical imaging.”
I came across the following phrase:
High-Contrast and spectroscopic-based specificity of optical imaging.
I'm wondering what is meant by "specificity" in this context?
Thanks for any ...
-6
votes
1answer
62 views
speed of light measurement [closed]
u can video call one smartphone from another via wireless internet connection, ie: the signal travels from one device to a satellite and then to the other device. but i want to avoid network noise and ...
0
votes
1answer
66 views
Classification of LED type
Out of curiosity, I recently opened a damaged measurement device (it´s some kind of lab spectrometer, but I am not sure) that contains a LED with a package like I have not seen before (see picture).
...
0
votes
2answers
71 views
Measure laser with photoresistor (LDR)?
I want to make a simple setum, where I can measure the opacity of air. I want to use a simple laserbeam, which I shoot across the room, and on the other side I want to measure how much is blocked/...
1
vote
0answers
44 views
Generate ultrashort rise times with photoconductive switch or photodiode
I am trying to produce voltage pulses with very short rise time (<15 ps), medium width (20 ns) and amplitudes up to 15 V. As a promising candidate I selected photoconductive switches and ultrafast ...
1
vote
1answer
41 views
Material dispersion in fiber optics transmission
In plain English, why does material dispersion increase with wavelength in fiber optic transmission? I am aware that refraction index decreases with wavelength increase, i.e. pulse travels faster, but ...
1
vote
4answers
171 views
Fiber-optic transceiver ICs for applications other than fiber-optic Ethernet? [closed]
When we talk about fiber-optic transmission, we almost always talk about copper to fiber-optic Ethernet conversion using fiber-optic transceivers.
But since fiber-optic communication is just ...
2
votes
1answer
183 views
Reducing LED spread via pinhole
I am making an infrared break beam to detect insects, using an IR emitter LED and detector. The insects fall into a channel and then eventually cross the beam, which travels the length of the channel.
...
1
vote
1answer
88 views
wifi baseband access
I've got an unusual use case (optical communications) that would benefit from access to the wifi baseband signal before it is upconverted/modulated at 2.5Ghz. However most modern wifi chips combine ...
0
votes
0answers
93 views
concave conical lenses on 5050 SMD LEDs?
Is there any way to put plano-convex conical lenses, or something broadly equivalent, on 5050 SMD LEDs?
The lenses I'm talking about are the type commonly built into cheap christmas-tree lights:
As ...
1
vote
4answers
438 views
Method to determine angle of a rotating stage
I am currently working on a project that requires the rotation of polarizers to very specific angles. It is necessary that we are able to determine what angle the polariser is currently at so that we ...
1
vote
1answer
72 views
principle about SPAD for ToF ranging module from ST
My colleagues are using VL53L0 from ST which is one ToF ranging module. I am trying to understand the principle about the SPAD(single-photon avalanche diode) and have read many materials on it.
From ...
4
votes
2answers
187 views
How does a CD or DVD burner produce submicron lines separated by submicron distances?
What mechanism(s) are used to achieve repeatable submicron spacing between concentric tracks in a DVD, CD, or other optical writer? I want to understand the minimal set of hardware used to achieve ...
-2
votes
1answer
56 views
Is NeoPixel used in Amazon Echo series? [closed]
Is it true that NeoPixels are used in Amazon Echo series?
If so how many NeoPixel LED's are used?
If so what are the optics used to give a smooth streak of colours?
1
vote
4answers
248 views
When will electromagnetic waves reflect? What are the criteria for reflections?
When an EM Wave comes to a boundary of two different media (i.e different electrical permitivity and magnetic permeability media), the things below could be seen:
Reflections
Refractions (...
0
votes
1answer
54 views
Is the infrared sensor fabrication process(Using such materials HgCdTe, InSb, InGaAs) different from CMOS fabrication processes ?
I want to learn differences between Infrared sensor fabrication and standard CMOS IC fabrication. If I am not wrong, in standard CMOS fabrication Silicon is mostly used. But for infrared spectrum such ...
0
votes
1answer
137 views
What is the advantages of InGaAs infrared image sensors? [closed]
I am currently searching the InGaAs material for infrared imaging usage. I have read some papers about it. It seems a new one. But I can not get real advantages of it, yet. What is the basic reason(...
1
vote
1answer
50 views
Migration from multimode to single mode fiber
In my company we are using custom measurement systems with multimode fiber optic transmitters and receivers for synchronization between different devices. We are thinking of migrating our multimode ...
0
votes
3answers
274 views
Relationship between optical power and drive current/voltage?
For a project I'm working on I've got a laser diode whose spec sheet lists the optical power and operating voltage of the module. Unfortunately, the parameter I need most is the drive current. Can the ...
0
votes
0answers
54 views
Place of matched filter in fiber optic communication
In short-haul communication via optical fibers, we use photodiodes (PD) to detect the light. So if we want to use a matched filter, should we use it before the PD (optical domain) or after the PD (...
0
votes
1answer
511 views
Solid angle measurement conditions for radiant intensity specification in IR-LED's data-sheets
For some IR-LED's their data-sheets state Radiant Intensity and the conditions under which
that number was obtained, indicating also which solid angle was used for the measurement.
For example, this ...
0
votes
1answer
106 views
Symbol rate and optical bandwidth relation
I am quite new to the field of optical communication, so perhaps this question is so easy.
In reading some papers I have faced to the concept of optical bandwidth. For example, they say the symbol ...
1
vote
2answers
1k views
what is the span of an optical fiber?
I am new to the fiber-optic communication systems, and in reading some relevant papers, I faced to the term "span length" (such as long-span link) which I cannot distinguish it from the length of the ...
1
vote
1answer
165 views
Determining LED safety compliance
I have a compliance audit that has been foisted on me from on high - as part of what an external consultancy has highlighted, I now have to prove that the indicator LEDs on a board I designed a long ...
-2
votes
2answers
86 views
Is it guaranteed that fingerprint data taken by a scanner can be reused by another scanner? [closed]
I want to create a system that records employee attendance with optical finger scanner. Because the scanner has a limited lifetime, replacement with the same kind in the future might be impossible due ...
2
votes
6answers
3k views
Can camera sensors be damaged by light?
Suppose a 3.3 V white (or any colour) LED with a current draw of 20 mA is shone into the lens of a cheap webcam (or any budget camera) at close range (< 3 cm) for a long period of time (24 hrs) or ...
0
votes
1answer
107 views
How are the frequencies in 50 GHz channels in DWDM networks used?
In optical DWDM networks, the spectrum is classically divided into several 50 or 100 GHz channels.
So, let's assume some channel ranges from x to x+50 GHz. On which frequency/frequencies is the ...
3
votes
2answers
124 views
Optical Communication Two Sources One Receiver
I'm working on a project that requires me to wirelessly transmit analog information over a short range (few meters at maximum) to a receiving end from two transmitting ends. The tricky part is I can ...
0
votes
2answers
58 views
Low-cost way of shining a wide line of light, kind of like some bar code scanners do [closed]
What is a cost-effective way (say roughly $15) to shine a wide but thin beam of light, directly away from the source, so that it would project a line onto a nearby surface?
My particular beam would ...
1
vote
1answer
57 views
What is anti-reflection coating and in which application it is used?
I would like to know about anti-reflection coating and I am interested to know whether this can be used in antenna design also.
0
votes
3answers
74 views
detect optical transceiver transmit wavelength
Let's say there is a no-name SFP transceiver without a label and without DDM(allows to see manufacturer programmed wavelength data on EEPROM from network device) support. Is it technically possible to ...
4
votes
2answers
723 views
Atmospheric attenuation calculation for a 1550nm link budget
My apologies in advance if this is the wrong place to ask this question. I was told that there were some RF communications experts here, so i figured there might be some FSO experience here as well.
...
0
votes
1answer
381 views
How to measure air quality (especially PM2.5) from distance (scanning like a LiDAR)? [closed]
I have a bit of experience in measuring PM2.5 (fine particles in the (ambient) air 2.5 micrometres or less in size) using PMS5003 sensor. This sensor uses laser, photodiode and the fact that the air ...
0
votes
1answer
47 views
Group velocity dispersion for coupled waveguide system
I am an EE undergrad currently studying group velocity dispersion (GVD) for coupled waveguides, and am quite confused on the following question: how do you characterize group velocity dispersion for a ...
0
votes
2answers
128 views
Complete fiber optic transmitter and receiver with standard fiber optic connector and integrated power circuitry? [closed]
I am having a very difficult time trying to find a simple, completely self-contained module to convert digital signals (<2Mbps) to fiber optic, that uses a robust, standard fiber optic connector (...
0
votes
1answer
162 views
what dependence does the intensity of a normal LED(the one used for DIY projects) follow with respect to distance? [closed]
What is the dependence of my led's output with respect to distance.
I am guessing that since the LED inside the glass pane it is somewhat like a wire. Thus, it might follow inverse proportion with ...
2
votes
1answer
306 views
How can I estimate the readout time of an electronic camera shutter?
I would like your help in finding a way to estimate the readout time of a digital camera's rolling (electronic) shutter. Meaning, the time that it takes to scan a frame. I looked through the internet ...
-3
votes
1answer
92 views
What electronic component is this? - sensor part of particulate matter sensor [closed]
What electronic component is this?
This is a part of a laser sensor which measures particulates.
0
votes
1answer
147 views
Can I use sfp+ transceivers to interconnect PCIe x1 lane?
This is interesting because, sfp+ offers an inexpensive way to use optics to connect two PCIe x1 devices. But I do not know enough about sfp+ to know if I can simply connect up pcie lanes on a ...
0
votes
1answer
138 views
Dual layer DVD question
I'm curious how a laser knows which layer to read in a single side dual layer DVD. It seems like it could easily read data from the second layer while it's shining through scanning the first.
1
vote
2answers
500 views
Ultra low ripple constant-current LED driver design
I designed a LED driver(SMPS configuration) with ILD6150XUMA1 and below is the circuit. I used it with AC/DC adapter. The thing is, th optical system is ultra sensitive and ripple from the LED ...
0
votes
1answer
128 views
Phased array spectrophotometer for coherent and incoherent visible light
What is the principle of operation for a phased array spectrophotometer for coherent and incoherent visible light? I read this recent article about: http://www.laserfocusworld.com/articles/print/...
0
votes
1answer
100 views
Develop a system to differentiate laser pointers from the ambient light based on the information collected by two arrays of digital FPA detectors
I would like to develop a system to differentiate laser pointers from
the ambient light based on the information collected by two arrays of digital FPA detectors embedded inside the cavity of a ...
0
votes
3answers
201 views
detecting laser using solar cell and band pass filter
I need to detect a laser signal using a solar cell.
My first problem is that all I get is a current generated from the solar cell that will vary (as I understand and correct me if I'm wrong) in it's ...
3
votes
1answer
954 views
Is it possible that my UV LED is emitting white light? If so, how would I filter out the white light?
I recently purchased a 365 nm UV LED, and set up the proper circuit. When I turn the power on, the LED lights up very dimly. Is this white light (that's the color I saw) being emitted from the LED? ...
1
vote
0answers
162 views
How can we measure the coupling loss in a fused fiber Y coupler?
I'm trying to understand how the (power) loss in optical fibre works and I'm having some trouble.
This is a classic 50/50 fused fibre Y coupler. The output on port 2 is the same as port 3 (so half ...
0
votes
1answer
60 views
Optical Coupler
i have two modems, each modem Tx signal is converted to fiber optics.
can I combine the two Tx signals (signal A and signal B) with an optical coupler?
At each time data is transmitted by only on one ...
0
votes
1answer
385 views
Cheap options for a 2D position sensor
In March of 2003 Circuit Cellar published a feature article on using position sensing detectors (PSD). The project builds a 2D position sensor using a PIC16F873 as the microcontroller, an Aculux PCB ...
1
vote
2answers
498 views
RF to Fiber Optics Conversion
I have a RF signal at L-Band, 950-2150 MHz. with bandwidth up to 100 MHz.
this signal needs to be converted to optics.
Does single mode or multi mode fiber have frequency/bandwidth limitations after ...
