Questions tagged [photonics]

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4answers
121 views

Laser scanning: Why are things like deflection and mirrors used instead of just a mount and servo?

In the Wikipedia article for laser scanning, it is said that laser scanning is the controlled deflection of laser beams, visible or invisible. It then lists some of the technologies used, such as ...
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2answers
28 views

Biasing network for phototubes and photomultipliers

I have some doubts about typical biasing network for vacuum phototubes and photomultipliers. Precisely, let's start by a simple photocathode. I have seen some biasing network like this one: In this ...
4
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1answer
48 views

Charge transfer in CCD

I have a basic doubt about charge transfer between pixels of a CCD. Let's consider this animation (picture taken from wikipedia): A precise time sequence of applied voltages between gates and bulk ...
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0answers
13 views

Q-value in APD photodetector

I try to calculate the Q value of APD photodetector with these parameters: $$R \hspace{0.1in} (response) = 1$$ $$M \hspace{0.1in} (magnification) = 10$$ $$k \hspace{0.1in} (ionization \hspace{0.1in} ...
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0answers
54 views

How to simulate a MMF fiber in COMSOL Multiphysics?

I am a complete newbie to COMSOL multiphysics, but I have to study and simulate the effects of temperature on multimode optical fibers (MMF) using COMSOL multiphysics for my Bachelor's thesis. I know ...
1
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1answer
59 views

Further Understanding Optical Parameter of Image Sensors for Use In Spectroscopy

I’m attempting to build a spectrometer and I’m having difficulty assessing the performance of a particular sensor. I am a novice and other posts on this forum have helped me greatly but I still haven’...
2
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2answers
112 views

Can linearity of photoreceptor be improved by calibration?

I am trying to determine if equipment I already have can be used to take a reading in mcd/m2, for a quality control test. I have a sensor which meets all the requirements listed in the standard test ...
1
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1answer
58 views

Control of large number of analog devices

For research that I work on we have photonic chips that have 100-200 analog devices on board. I wish to control these devices at a rate of ~-1 MHz from an fpga. Some require a current source and ...
5
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0answers
117 views

Photon count with ADC, am I doing it right?

I have this LED and I want to characterize this photodiode. The LED should produce light of 370 nm, but I measured it and it is around 358 nm, and at that wavelength the quantum efficiency (\$\eta\$) ...
1
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1answer
543 views

Influence of active area of photo diode on sensitivity

I am using a photodiode for detecting the laser. I have a question regarding the active area of the photodiode. Is less active area photodiode is less sensitive? Or it totally depends on the laser ...
0
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1answer
251 views

Importance of laser numerical aperture in selecting photo diode

I want to design a circuit in which the laser light will be detected by a photodiode. I just wanted to know how the laser numerical aperture will affect the photodiode selection. Am I have to ...
25
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3answers
7k views

How is 255 Tbit/s processed in optical fiber communication?

I have never understood how the new record breaking data transfer speeds are achieved in terms of converting from/to electrical and optical signals. Suppose we have 255 Tbits of data and we want to ...
9
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6answers
4k views

LED as power generator

As many of you probably know, a normal light emitting diode, while very handy as a cheap and ubiquitous indicator, can double as a power generator. The mechanism is the same that is exploited in ...
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1answer
215 views

What are the advantages of a photonic crystal versus a liquid crystal or piezoelectric grating tunable optic filter?

I want to design a tunable optical filter that can quickly change from being a red light filter to being a blue light filter. For this purpose, I am wondering about photonic crystal tunable optical ...
2
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2answers
5k views

Can we send multiple signals in same core at the same time in the fiber optics? If yes, how? [duplicate]

I am curious to know how exactly does the fiber optics works. I understand the basic concepts of the fiber optics communications but am curious to know if there is a way to send multiple signals in ...