Hi
There are different type of GBICs available in market which basically differs based on the distance it supports or upto the max distance it can carry the signals..
GBIC-SX WS-G5484 1000BASE-SX short-wavelength GBIC (Multimode only)
GBIC-LX/LH WS-G5486 1000BASE-LX/LH long-haul GBIC (single mode or multimode)
GBIC-ZX WS-G5487 1000BASE-ZX extended-reach GBIC (single mode)
Also refer ths link which throws more lite on the wavelength it operates and the max distance it can go up..
http://www.cisco.com/en/US/products/hw/modules/ps5455/products_data_sheet09186a008014cb5e.html
you have to take care of patch (fiber)cables which you use to connect them up.
Again there are 2 different modes one is single mode and the other one is multimode.
The above mentioned does contains the details of fiber patch cords which can be used to connect them up..
regds