Hello..

What must i consider when using laser and photodiode? What is the parameter that should i care for?

 

For an ordinary LED as well as a laser diode, current is the critical parameter.

For photodiodes, it is best to get the spec sheet on each device and use that as a guide to critical parameters.

 

Are you referring to matching them for operation? ie. The laser will trigger the photodiode?

If so, then you need to ensure that the wavelength of the laser matches with the peak sensitivity of the photodiode. This is called the diode's spectral response characteristic. Other considerations, especially for high speed communications, is photodiode terminal capacitance. This is a function of its construction and area of photodiode.

Steve