Reference no: EM132431684

All are different questions. Please answer them all.

1. Consider a single positive lens. Make a simple graph that shows the magnification as a function of the position of an object. Indicate when this imaging is real and when it is virtual.

Do the same for a single negative lens.

2. You shine a green laser pointer to the moon. The wavelength is 532 nm. The beam is perfectly Gaussian and has a 1/e radius of 1 mm. How large is the illuminated area on the moon.

Distance Moon to Earth: 384400 km.

3. Consider a thin layer of air in between two semi-infinite plates of silicon (n=3.5, no absorption). A plane wave with a (vacuum) wavelength of 1 micrometer is incident from the silicon under normal incidence. Make an approximate sketch of the power transmissivity as a function of the thickness of the air layer (over the range from 0 till 5 micrometer). For which thicknesses will there be a maximum or a minimum. Consider both s- and p-polarisation.

Do the same for light incident under 45 degrees.

4. What is the maximum thickness of a slab waveguide consisting of a core of silicon (n=3.5) and claddings of air, such that it is single-moded at a wavelength of 1.5 micrometers? What about the minimum thickness?

5. Which statement is more correct (and why):

a. the lens in a CD-player needs to have a small focal distance

b. the lens in a CD-player needs to have a large numerical aperture

6. A semiconductor laser with a length of 300 micron has facets formed between the semiconductor waveguide (n=3) and air. The scattering loss of the laser waveguide is 2/cm. The lasing wavelength is 1.55um. Make an estimate of the gain per unit length the lasing mode experiences. Express this value in 1/cm and dB/cm. Calculate the differential responsivity (in W/A) of this laser, assuming an injection efficiency of 100%.