Application of photo diode

Photo diode generally used to convert the light into current or voltage based on the mode of operation of the device. So photo diode used in various industries. Now you can check the application of photo diode one by one below :

Application of photo diode :
  • Light detector. 
  • Used in demodulates.
  • Encoders.
  • Optical communication system.
  • High speed counting and switching circuits. 
  • Computer punching cards and tapes.
  • Light operated switches.
  • Sound track films.
  • Cameras.
  • Electronic control circuits. 
  • Used in cameras.
  • Medical devices.
  • Digital signal processing.
  • Safety equipment.
  • Position sensors. 
  • Bar code scanners.
  • Automotive devices.
  • Compact disk player.
  • Smoke detector.
  • Position sensor.
  • Surveying equipment.

PIN photo diode

What is the PIN diode?

 The PIN photodiode is a one type photodetector, it is used to convert an optical signal into an electrical signal. A photodiode in general and in this case PIN photodiode will respond to different light wavelength. It is generally the thickness of top p-type region one of the key parameters in determining the response sensitivity.

Basically, the PIN diode is a one types of a photodetector. This diode can be diagrammatical as being a PN junction. but in PIN diode intrinsic layer between the PN and layers. It converts an optical signal into an electrical signal. 

The PIN diode comprises three regions:
  1.  P - region
  2.  I - region
  3.  N-region 
In PIN diode both the P and N region are heavily doped and the region between the P and N layer where there are no majority carriers
Structure of  PIN diode
PIN diode operates in the exact same way as a normal diode. but the only difference is that depletion region, It normally exists between the P and N region in the reversed diode is larger. A region between the P and N region contains no charge carriers.

P and N region are heavily doped, P region has been doped holes and N region has been doped to contain excess electron. so the region between P and N region contain no charge carrier as any electrons or holes combine, so the depletion region has no charge carriers it acts as an insulator.

When the diode is forward biased, the carrier concentration, holes and electron is very much higher than the intrinsic level carrier concentration. 

This article also gives the various types of diode listed below:

Advantages and disadvantages of photodiode

A photodiode can convert light into either current or voltage depending upon the mode of operation. In general, a photodiode is designed to operate in reverse bias. It is one type of photodetector. In this article, you can check it out the advantages and disadvantages of knowing more about it. 

Advantages of photodiode :

  • The photodiode is linear
  • Low resistance
  • A very good spectral response
  • Better frequency response
  • Low dark current
  • Fastest photodetector
  • Long lifetime
  • Low noise
  • High quantum efficiency
  • It is highly sensitive to the light
  • Compact and lightweight
  • No high voltage requires
  • Ruggedized the mechanical stress
  • Using photodiode the speed of operation is very high

Disadvantages of photodiode :

  • Require increases in  the dark current 
  • It depends on the temperature
  • Small active area
  • Normal PN junction photodiode has a very high response time
  • It has very low sensitivity
  • Light sensitive device
  • Poor temperature stability
  • Change in current is very small,  hence may not be sufficient to drive the circuit
  • It need offset voltage 

Application of PIN diode

A PIN diode is used in a variety of different applications from low to high radiofrequency. PIN diodes are very good for RF switching and photodiode. Here is some application related to the PIN diode to know more details about PIN diode 

Application of Photodiode

  • A PIN diode is used as a photodetector for most fiber optic applications.
  • There are used as a variable resistor in at RF and microwave frequency.
  • They are used in electric Pre - Amplifier to boost sensitivity.
  • It used as a high voltage rectifier.
  • Audio CD players, Computer CD drive, DVD players.
  • In a phase shifter circuit considered as a lumped variable impedance microwave circuit element.
  • Nuclear radiation detector.
  • It can be also used limiter circuit and modulator.
  • PIN diodes are utilized as series or shunt connected switches in a phase shifter design.


Advantages and disadvantages of PIN diode

A PIN diode is used in a variety of different applications from low to high radiofrequency. PIN diodes are very good for RF switching and photodiode. So now check it out the advantages and disadvantages of PIN diode to know more details about PIN diode.


Advantages of PIN diode :

  • Low noise
  • Low dark current
  • Low bias voltage
  • Higher reverse voltages to be tolerated
  • High-speed response
  • Low junction capacitance 
  • Large depletion region 

Disadvantages of PIN diode :

Fiber optic cable advantages

A fiber optic cable is a flexible and transparent fiber made by drawing plastic or glass to a diameter slightly thicker than that of a human hair. Optical fiber cable is generally used most often as a means to transmit light between the two ends of the fiber and also find wide usage in the fiber optic communication system. So now let use check about the advantages and of fiber optical cable to know more details about fiber optic cable.

Advantages of fiber optic cable :

  • Fiber optic cable has a much greater bandwidth than metal cables
  • Optical fiber capability has a bandwidth capability of 400 MHz/km or greater
  • Longer lasting
  • Thinner 
  • Faster speed
  • Less signal degradation
  • Light signal
  • Long lifespan
  • Extremely high bandwidth
  • Crosstalk immunity
  • High carrying capacity
  • Reduced size and weight cable
  • An optical fiber can provide data transmission performance up to 10 Gbps
  • Resistance to corrosion and temperature variations.
  • High resistance ever-dropping
  • Immunity to electrical noise
  • Greater cable distance without a repeater
  • An industry standard for high-speed networking
  • Low power losses
  • an optical fiber is generally made of silica band, raw materials abundant compared with copper
  • Low-security risk
  • Less expensive than copper cable

Fiber optic cable disadvantages

The main features of fiber optic cable are that it is a flexible, transparent fiber made by drawing plastic or glass to a diameter as a means to transmit light between the two ends of the fiber and also find wide usage in fiber-optic communication. So now let use check about the disadvantages of optical fiber cable to know more details about fiber optic cable. 

Disadvantages of fiber optic cable :


  • Special training required to attach the connector to the cable
  • Difficult to splice
  • Can't be curved
  • Low power
  • The distance between the transmitter and receiver should keep short or repeater are needed to boost the signal
  • Difficult to work with and difficult to install
  • Higher initial cost installation
  • More expensive to repair or maintain
  • Interfacing cost
  • Connector problem
  • Highly susceptible
  • Expensive in comparison with conventional electrical cables
  • Limited application
  • More vulnerable damage compare to copper wires
  • Cost is higher than copper cable
  • Require specific skills
  • Affected by chemical

Fiber optic cable color code

Fiber color code:

In optical fiber terms inside the cable each tube in a loose tube cable, Individual fiber will be color-coded for different identification. So now in optical fiber communication, the fiber allows the convention created for telephone wire except fiber are identified individually, not pairs. Color fiber is spliced to ensure continuity of color codes throughout a cable run. The figure shows the color coding in optical fiber communication.


Fiber color codes

Connector color codes :


The earliest days of fiber optics cable like, orange, black or gray was multimode and yellow single mode. However, the advent of metallic connectors like the FC and ST mode connector color coding difficult, so colored strain relief boots were often used.

Fiber optic cable bandwidth

Introduction : 

In general, bandwidth is referred to as the range of a particular fiber optic cable. In reality, different cable has a different bandwidth capacity of transmitting data from one point to another. The bandwidth of fiber optic cable determines the maximum speed of the data pulses to the fiber cable can handle it. We know that the bandwidth is normally stated in terms of megahertz-kilometers.  For instance, there those which are most suitable is carrying large quantity data over long distances within a short time. Consequently, there are those most suited in transmitting a large quantity of data over short distances. In this case, the cable made to transmit data over very long distance cannot be used to transmit the same data over a short distance and if that is done, then the frequency will too much lower. For that reason, it is very important to study that bandwidth of particular fiber optic cable.

As the length of the fiber cable is increased, the bandwidth decreases in propagation. In general, a common 62.5/125 micrometer cable has a bandwidth in the 100 to 300 MHz-km range.

 The speed of optical fiber cable while in using a single mode fiber cable can run from a few meters to 40 kilometers Where a multimode fiber optic cable is used for much shorter ranges.

Fiber types and bandwidth  :


Single mode - 100 Ghz-km
Graded index - 560 MHz-km at 1300 nm, 160 MHz-km at 850 nm 
Step index - 20 MHz-km

 Conclusion :

 The cost of fiber cables with the bandwidth capacity of fiber optic cable. You can have also found that fiber cable with efficiently and faster bandwidth capacity is more expensive than others. The greater the frequency and larger the bandwidth of fiber optic cable the more efficient is the cable. So and we already know that different people have got different reasons to purchase a fiber cable, the variation of bandwidth has indeed been beneficial to many. Therefore, the bandwidth capacity of fiber optic cable before purchasing it.

Fiber optic cable definition

A fiber optic cable is a flexible, high-speed data transmission medium, transparent fiber made by drawing plastic or glass to a diameter slightly thicker than that of a human hair. It is a high-speed data transmission medium.

The optical fiber cable is generally used as a means to transmit light between the two ends of the fiber and find wide usage in fiber-optic communication. Digital data is transmitted through the cable via the rapid pulses of light. The receiving end of fiber optic transmission translates the light pulses into binary values, which can be read by a computer. Color fiber is spliced to ensure continuity of color codes throughout a cable run.

Since fiber optic cable provides fast transfer speed and large bandwidth, They are used for a large part of the internet backbone. For example, most transatlantic telecommunication cables between the U.S and Europe are fiber optic. In recent years, fiber optic technology has become increasingly popular for local internet connection as well. 
  • Fiber optic cable can be used as a medium for computer networking and telecommunication because it is flexible and can be bundled as cables
  • It also is used in telephone, military and space application
  • It can be used an easy, economical and attractive solution for a lighting project
  • It can be used to transmit power using a photovoltaic cell to convert the light into electricity. 

Fiber optic cable uses

A definition of fiber optic cable is a flexible, as well as transparent fiber made by drawing plastic or glass to a diameter slightly thicker than that of a human hair. Optical fiber cable can be generally used most often as a means to transmit light between the two ends of the fiber and find wide usage in the fiber optic communication system. So now let use check about where to uses of fiber optic to know more details about fiber optic cable.

Fiber optic cable can accommodate a variety of needs is given below :

  • It can be used in communication, fiber optic sensors, as well as illumination,
  • It is used a medical treatment like light guides, imaging tools and also as lasers for surgeries
  • It is used hydrophones seismic or SONAR application, submarines, like wiring in aircraft, and other vehicles and also for field networking
  • It used in computer networking, telephone, military as well as space application
  • It can provide an easy, economical and attractive solution for a lighting project
  • It is used for data transmission
  • It can be also used microscopy and biomedical research
  • It is used to transmit power using a photovoltaic cell to convert the light-electricity
  • It is used to connect in a variety of network settings 
  • And also help increase the speed and accuracy of data transmission
  • Broadcast/cable companies are using fiber optic cable for wirings like HDTV, CATV, internet, video on demand and other applications

Fiber optic cable speed

A fiber optic cable is a flexible, as well as transparent fiber made by drawing plastic or glass to a diameter as a means to transmit light between the two ends of the fiber and find wide usage in fiber optic communication system. allow data to be transmitted high speeds over a great distance.

There are two types of fiber :

  • Single mode fiber 
  • Multimode fiber.
The two types of fiber and speed from these two fibers are different. A single-mode fiber cable can run from a few meters to 40 kilometers While multimode fiber optic cable is used for too much shorter ranges. 

Speeds :

  
Fiber optic cable is generally in single mode fiber uses only (OS1) while in multimode uses different (OM1, OM2, OM3, OM4). Single mode fiber optic can reach speed up to 100GB whereas multimode fiber optic run at speed from 100 Mb to 10 GB.

In fiber optic cable transmit at different speed over varying length depending on the size is used.

OM1 - 275 m ,33 m (Gigabit range)
OM2  - 550 m, 82 m (Gigabit range)
OM3 - 800 m, 300 m, 100 m, 100 m (Gigabit range)
OM4 - 1100 m, 550 m, 150 m (Gigabit range)
OS1 - 40km (Gigabit range)

 Here we have to also compare the speed of Coaxial cable vs fiber optic cable. 

 Fiber optic cable is just flat out faster. Fiber optic cable speed up to 10 Gbps, symmetrical upload as well as download bandwidth.

While in cable internet speed vary by provider and range from 10 Mbps to 1Gbps download speed and upload speed from 3 Mbps to 50 Mbps.

Fiber optic cable types

The fiber optic cable is to be used a variety of situations such as underground, outdoor poles or submerged underwater. The structure of cable depends on the situation where it is to be used,  but the basic cable design principles remain the same.
The requirement of optical fiber material is to be transparent for the efficient transmission of light.

The mechanical property of cable is one of the most important factors for using any specific cable. The maximum allowable axial load on cable decides to the length of the cable can be reliably installed. That are several benefits of a fiber optic cable is a flexible, transparent fiber made by drawing plastic or glass to a diameter slightly thicker than that of human hair.

Fiber arrangements :

  • Several arrangements of fiber cables are done to use it for different application in a cable. The most basic form is two fiber cable is proper design. Shows basic two fiber cable design as given below. It is also known as a basic building block of fiber cable.
  • Multiple fiber cables can be combined together using some similar techniques. 
  • The basic fiber building blocks are used to form a large cable. These units are bound on a buffer material which acts as strength element along with an insulated copper conductor types of materials. The fiber building blocks are surrounded by paper tape, PVC jacket, yarn, and an outer sheath. 
Fiber optic  cable 

There are many types of fiber optic cable available in fiber optical communication. In general, there are two types of fiber optic cables are available :

1. Simplex cable
2. Duplex cable


1. Simplex cable :


In simplex cable single strand surrounded by around  900 um tight buffer then the aramid yarn and finally the outer jacket are available.

A jacket is used in 2 mm or 3 mm plenum or riser types of jacket.



2. Duplex cable:


 In duplex cable strands of fiber optic cable attached at the center point. Cable surrounded by a 900 um buffer then a layer of kevlar and finally the outer jacket there.

A jacket is used in 2 mm or 3 mm plenum or riser types of jacket.




A number of a core are bundled in a plastic type of ducts. In case, ease identification of individual fibers is color-coded types. Shows some example of the color coding in the optical cable used by manufactures.

1 - Blue
2 - Orange
3 - Green
4 - Brown
5 - Grey
6 - White
7 - Red
8 - Black
9 - Yellow
10 - Violet
11 - Pink or light blue
12 - Turquoise or netutral

Fiber optic cable material

Materials are used for optical fiber :


 The material requirement of fiber optic cable for glass and plastic. They offer widely different characteristics and therefore fibers made from the two different substances and find uses in very different applications.

The main requirement of fiber optic material to be given below :
  • Fiber material must be required with compatible the cladding material
  • It must be possible to draw long thin fiber from the material used
  • The material must be used to be transparent for efficient transmission of light

Glass and plastics materials have fulfilled this requirement:


 Most fiber consists of silica or silicate. Various types of low loss and high loss glass fiber are available to suit the requirement. Plastic fibers are not too much popular because of its high attenuation so they have better mechanical strength.

Glass fiber :

Glass fiber made by materials fusing mixtures of metal oxides having a refractive index of 1458 at 850 nm. For changing the refractive index different oxides like B2O3, GeO2 and P2O5 are added as dopants. 

One important criterion is that the refractive index of the core is greater than that of the cladding, hence some important composition is used such as given below :

Composition :

1 : Core type -  GeO2 - SiO2  Cladding type - SiO2 
2 : Core type  -  P2O5  - SiO2  Cladding type - SiO2 
3 : Core type - SiO2  Cladding - B2O3 - SiO2 
4 : Core type - GeO2 - B2O3 -  SiO2  Cladding type - B2O3  - SiO2 

The principal raw material for silica is sand and glass materials. The fiber materials composed of pure silica is called as silica glass. The desirable properties of silica glass are given below:
  • Resistance to deformation even at high temperatures.
  • Good chemical durability. 
  • Better transparency.
  • Resistance to breakage from chemical thermal shocks.
Other types of glass fibers are :
  • Halide glass fibers.
  • Active glass fiber.
  • Chalcogenide glass fiber.
  • plastic optical fibers. 

Function of MSC

MSC full form Mobile Switching Center is the centerpiece of an NSS full form network switching subsystem. 

MSC most commonly used with a communications switching function, such as call set-up, release, and routing. 

MSC is a telephone exchange that makes the connection between mobile users within the network, from mobile users to the public switched telephone network and also from mobile users to other mobile networks.

Function of BSC

BSC full form is Base Station Controller reserve radio frequency for communication and manages handovers between BTS. BCS connected to a single MSC. 

Some function of BSC are following below :

  • To control BTS.
  • Radio resource management. 
  • Handoff management and control.
  • It handles radio channel set up and frequency hopping. 
  • The BSC is physically connected through leased lines or microwave links to the MSC. 

Function of OMC

OMC full form is operations and maintenance center used in the switching system in GSM network architecture is connected to all equipment in the switching system and to the BSC. 


The implementation of ( operations and maintenance centers) OMC is called the operation and support system.

Now we can also check the function of OMC :

  • Used in security management. 
  • Used in maintenance tasks.
  • Used in network configuration, operation and performance management. 
  • Used in administration and commercial operations like subscriptions and terminals charging and in statistics. 

Full form of OMC

What is the full form of OMC?


 Answer :

  • Operations and Maintenance Center 


What does OMC mean?


OMC used in the switching system in a GSM network is connected to all equipment in the switching system and to the BSC. You can check the full form of BSC. 

The implementation of ( Operations and Maintenance Center ) OMC is called the operation and support system. 

Graded index fiber

Definition of Graded-index fiber :


 An optical fiber with a core having a refractive index that decreases with increases radial distance from the fiber axis. The most common refractive index for a graded index fiber is very nearly parabolic. The parabolic result in continual refocusing of the rays in the core, and compensates for multimode distortion.

 The graded index fiber has a core is made from many layers of glass. In the graded index fiber the refractive index is not uniform within the core, it is highest at the center and decreases smoothly and continuously with distance towards the cladding side. The refractive index profile across the core that takes place in the look like parabolic nature.

In graded-index fiber, the light waves are bent by refraction towards the core axis and they follow the curved path down the fiber length side. This result because of change in refractive index as moved away from the center of the core side.
Graded index fiber 

Multimode graded-index fiber :


The core size of multimode graded index fiber cable is varying from 50 to 100-micrometer range. 

In this fiber, the light ray enters the fiber at many different angles. So in graded index fiber, the light propagates across the core toward the center it is intersecting a less dense to more dense medium. This article gives some advantages of graded index fiber to know more details about it 

Therefore the light rays are being constantly being refracted and the ray is bending continuously. This cable is mostly used for long distance communication system.

Multimode graded index fiber

Some important point of graded index fiber :
  • Graded index fiber data rate is very high.
  • The path of light is helical in manner.
  • Graded index fiber is of only one types that is a multimode fiber.
  • Coupling efficiency is low.
  • In graded-index fiber, the diameter of the core is about 50 micrometer in the case of multimode fiber.
  • Attenuation is less.
  • Refractive index is non-uniform.
  • Graded index the bandwidth is high.  
  • It is mostly used in local and wide area networks.

Difference between step index fiber and graded index fiber

There are two types of fiber known as step index and graded index fiber.  step index fiber is fiber type cylindrical waveguide core with inner core has a uniform refractive index of n1 and the core is surrounded by an outer cladding with a uniform refractive index of n2. While the graded index fiber has a core made from many layers of glass and also have the graded index fiber, the refractive index is not uniform within the core. Here this article gives the difference between step index fiber and graded index fiber to know more details about this topic.

Step index fiber :

  • In this fiber data rate is very slow.
  • The ray path of light propagation is looked like Zig Zag manner. 
  • Step index fiber of two types of fiber known as mono-mode fiber and multimode fiber.
  • Coupling efficiency with fiber is very high.
  • In step-index fiber the diameter of the core is about 50 -200 micrometers in the case of multimode fiber while  In 10 micrometers in the case of single-mode fiber.
  • Attenuation is too much more. 
  • The refractive index of the core is high.
  • The bandwidth is low.
  • It is mostly used in the application of local network communication. 

Graded index fiber :

  • Graded index fiber data rate is very high.
  • The path of light is helical in manner.
  • Graded index fiber is of only one type that are called as multimode fiber.
  • Coupling efficiency is very low.
  • While graded-index fiber the diameter of the core is about 50 micrometer in the case of uses multimode fiber.
  • Attenuation is less.
  • The Refractive index is non-uniform.
  • The bandwidth is high.
  • It is most commonly used in local and wide area networks.

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