Integrated photonic sub-systems

Example 1 – Microwave photonics link

An analogue optical link based on single mode fibre is operated at 1550 nm wavelength with fibre loss of 0.2 dB/km. If coupling losses from the transmitter (modulator) to fibre and to receiver (photodetector) are 3 dB each, what is the optical path loss for a link of the length of 20 km?

What is the equivalent electrical power loss for this optical transmission path?

What is the equivalent electrical power gain for this system if the laser is integrated with a modulator?

Example 2  – Optical frequency comb (OFC)

Let’s assume an OFC which is based on amplified circulating loop. What is the frequency of the supermode (resonance frequency) of the optical comb, if its fibre loop length is 20 m?

What is the relation between frequency fRF  and supermode frequency?