OPTI 380A Lab 1 Semiconductor Light Sources - Procedures-1

OPTI 380A Lab 1 Semiconductor Light Sources - Procedures-1...

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!"!#$! & ’()*+,- . /012 3"!4 567 $ . 8,9(:;<=>:+;- 5(?@+ 8;>-:,* 06?, $ OPTI 380A—LAB #1 Semiconductor Light Sources WARNING: In all experiments, stay below the maximum current rated for the LD (35mA)! (1) Physical and power characteristics a. LED i. Observe a reference marker under the microscope in order to scale dimensions in the images. ii. Look at the device under the microscope with the camera. Measure significant dimensions and make a sketch. Make a sketch of the emission area. iii. Turn on device at low power and observe where light is emitted. USE THE CAMERA. DO NOT LOOK DIRECTLY INTO THE MICROSCOPE. Note on sketch from (i) where light is emitted. iv. Use black tape to mount the LED on the integrating sphere. Use a black cloth to block any stray light from the room from entering the integrating sphere. v. Measure output power versus drive current in the integrating sphere. Do not exceed 15V drive voltage (about 130mA drive current). Use the lowest amplification setting on the transimpedance amplifier in order to avoid amplifier saturation. vi. Graph your data from (v), using both the raw data from the detector voltage and the conversion (supplied by your TA) to optical power. b. Repeat (1a) for the LD. In part (i), determine the location of the laser output facet and determine cavity length and width. In part (ii), do not exceed 35mA drive current. Estimate laser diode mode separation. c. Compare your results with LED and LD specifications. d. Which source emits more total optical power? (2) Beam characteristics of light output a. LED i. Divergence Bench 1. Estimate the collection solid angle of the detector. 2. Use an ~1kHz square wave to modulate the LED (~0-10V square wave from a function generator.) Measure divergence by rotating the LED and measuring the peak-to- peak voltage as a function of rotation angle on the oscilloscope. Be careful to avoid reflected light striking the detector. You might need to turn off room lights and use
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This document was uploaded on 10/30/2010.

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OPTI 380A Lab 1 Semiconductor Light Sources - Procedures-1...

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