The excess density of electrons Δnand holes Δpin an LED is

Related MCQs

• A number of three-port single-mode fiber couplers are used in the fabrication of a ladder coupler with 16 output ports. The three-port couplers each have an excess loss of 0.2 dB along with a splice loss of 0.1 dB at the interconnection of each stage. Determine the excess loss.
• In a GaAs LED, compute the loss relative to internally generated optical power in the fiber when there is small air gap between LED and fiber core. (Fiber coupled = 5.5 * 10-4Pint)
• Calculate the radioactive minority carrier lifetime in gallium arsenide when the minority carriers are electrons injected into a p-type semiconductor region which has a hole concentration of 1018cm-3. The recombination coefficient for gallium arsenide is
• A BH can have anything from a single electron to several electrons. State whether the given statement is true or false.
• The phenomenon resulting in the electrons to jump from one state to another each time emitting of photon is known as :
• The periodic arrangement of cladding air holes in photonic band gap fibers provides for the formation of a photonic band gap in the
• In index-guided photonic crystal fiber structure, the dark areas are air holes. What does white areas suggests?
• Couplers insertion loss is same as that of excess loss. State whether the given statement is true or false.
• A four-port multimode fiber FBT coupler has 50 μWoptical power launched into port 1. The measured output power at ports 2,3 and 4 are 0.003, 23.0 and 24.5 μW respectively. Determine the excess loss.
• Determine the total carrier recombination lifetime of a double heterojunction LED where the radioactive and nonradioactive recombination lifetime of minority carriers in active region are 70 ns and 100 ns respectively.