Fibre optic transmitter choices
Businesses of various aspects to any fiber optic transmitter. For just about any application, the various specifications need to be examined to make sure that the particular fibre optic transmitter will meet what’s needed.
One of the major aspects to any fiber optic transmitter, is its power level. There’s no question that the fiber optic transmitter must have a sufficiently high level of sunshine output for the light to be transmitted across the fiber optic cable towards the far end. Some fibre optic cable lengths many simply be several metres or many metres long, whereas others may extend for many kilometres. In the case of the long lengths, the strength of the fiber optic transmitter is of great importance.
The kind of light produced can also be important. Light could be split up into two classes, namely coherent and incoherent light. Essentially, coherent light includes a single frequency, whereas incoherent light contains a wide selection of light packets all containing different frequencies, i.e. there is no single frequency present. Although some emitters may appear to emit just one colour, they can be incoherent since the light output is centred around a given frequency or wavelength.
The regularity or wavelength from the light may also be important. Often fibre optic systems will operate around a given wavelength. Often the wavelength of operation is given.
It is also necessary to consider the rate where the transmitter can be modulated because this affects the data rate for that overall transmission. Sometimes low rate systems may only need to carry data for a price of some Mbps, whereas main telecommunications links have to transmit data at many Gbps.
How do Fiber Optic Transmitters Work?
Fiber optic transmitters contain an interface circuit, a source drive circuit, as well as an optical source. The interface circuit receives electrical signals. The source drive circuit converts these to optical signals and triggers the LED or laser diode that then sends the sunshine signals to the fiber optic cable, where they visit their destination.(see Figure 1.)
Figure 1. Optical Transmitter working process
Light Sources
There are two main types of fibre optic transmitter that are in use today. Both of them are based around semiconductor technology:
Light emitting diodes (LEDs)
LEDs are utilized mainly for short-to-moderate transmission distances because they have relatively large emitting areas. Shiny things cost less than laser diodes, but possess a limited bandwidth.
Laser diodes
Laser diodes can couple many times more power to optical fiber than LEDs. They are more expensive, but they are required for applications that must transmit signals over long distances.
We may see the comparison in Figure 2.
Figure 2. Chief Charactristics of LED and LASER DIODE
Cable Types
Fiber optic transmitters are designed for use with single mode and/or multi-mode cable.(see Figure 3.)
Figure 3. SMF&MMF
Single-mode fibers (SMF) have small cores and therefore are used withlaser sources for top speed, long-distance links. They transmit infrared (IR) laser light at wavelength from 1,300 to at least one,550 nm.
Multimode fibers (MMF) have larger cores and are used mainly with LED sources for lower speed, shorter distance links. The typical transmission speeds and distance limits are 100 Mbit/s for approximately 2km, 1Gbit/s to 220-550m, and 10Gbit/s to 300m.
Performance and Input Specifications
When selecting fiber optic transmitters, you will find five main performance specifications to think about: data rate, transmitter rise time, wavelength, spectral width, and maximum optical output power. Inputs include TTL, ECL, CMOS, RF, and video.
About Fiberstroe’ s fiber optic transmitters
Fiberstore’s Optical transmitters are special optical transmitting equipments in HFC broadband transmitting network. The product which use direct optical intension, low RF-signal input level, excellent airproof and fast-heating capability, make it possible work at any kind of bad environment. It can transmit analog TV signal, digital TV signal and INTERNET data signal in 860MHz frequency.(Figure 4.)
Applications:
- 1310 broadcast and narrowcast applications
- CATV forward path
- RF over fiber
«Figure 4. Fiberstore’s Optical transmitter
