Receiver sensitivity
The receiver sensitivity is the minimum
amount of optical power level that can be received by the detector. If the
sensitivity is high that detector can receive signals of having low strength
and it reduces the bit error rate. The sensitivity is decided by the
material used to manufacture the detector.
High fidelity
The detector must have the characteristic of receiving optical signal as it is.
And detector should have the capability of generate the optical signal into
electrical signal without destroying characteristic of the signal. Example -
signal wave lengths frequency and phase.
Short response time
Short response time means the time taken by detector to receive optical signal
generate the electrical signal. Better optical detector must have Short
response time because the bandwidth is depending on the time of conversion. If
the conversion time is high, we can get high bandwidth.
Small size
Detector must be compacted in size, in order to reduce the spare space it takes
during the installation. But small size detectors are required high cost of
manufacturing.
Minimum noise
Noise in the detector is caused due to photon to electrical conversion and the
thermal noise in the detector. To detect the weakest signal, detector should
maintain a high SNR. In order to do those detectors should have high quantum efficiency
and low noises.
Linearity
Linearity is another important characteristic of optical detectors .Detectors
are characterized by a response in which the output is linear with incident
intensity. The response may be linear over a broad range, perhaps many orders
of magnitude. If the output of the detector is plotted versus the input power,
there should be no change in the slope of the curve.
Low cost
This is the most important factor when we selecting optical detector of our
link. Most of detectors are highly cost because the technology and materials
are very much expensive. If we can choose low cost detector our whole project
will be successfully with low cost.
