Continuous Wave Radio-Frequency Gain » History » Version 17

GOMEZ, Ramon, 12/13/2015 06:05 PM

1 7 HAENNIG, Gerald
h1. Continuous Wave Radio-Frequency Gain for opitcal link (transmitter+fiber+receiver)
2 2 HAENNIG, Gerald
3 13 GOMEZ, Ramon
A Continuous Wave Radio-Frequency,CW RF, signal is generated with the Keysight N9310A Signal Generator. This signal is provided to the optical transmitter which converts it into an optical signal which intensity is modulated by RF carrier. The optical recevier converts the optical signal back to an CW RF signal. This signal is measured on the FSV spectrum Analyzer.
4 3 HAENNIG, Gerald
5 2 HAENNIG, Gerald
The gain is measured as : Gain = RF POWER [dBm] @ Optical Receiver Out - RF POWER [dBm] @ Optical Transmitter In. 
6 2 HAENNIG, Gerald
7 5 HAENNIG, Gerald
h2. Gain Linearity
8 5 HAENNIG, Gerald
9 13 GOMEZ, Ramon
Optical link overall response is linear within its operating input power dynamic : optical transmitter and receiver are both linear according to the specifications described on [[Elements and technical features]] between 0.7 and 2.1 GHz. Low signal distortion is expected.
10 6 HAENNIG, Gerald
11 1 GOMEZ, Ramon
p=. !{width:700px}RF_gain_linearity.png!
12 1 GOMEZ, Ramon
Figure 1. RF Gain Linearity of Optical Link.
13 13 GOMEZ, Ramon
14 16 GOMEZ, Ramon
For Figure 1 it has also been compared the gain for a monomode and a multimode fiber, concluding that the monomode fiber has a higher gain than the multimode.  
15 14 GOMEZ, Ramon
16 1 GOMEZ, Ramon
17 5 HAENNIG, Gerald
h2. Frequency Response
18 5 HAENNIG, Gerald
19 17 GOMEZ, Ramon
Optical link frequency response has a shape of a low path filter : the 3 dB cutoff frequency is above 2300 MHz. Thus, the optical link is meeting its specification and is able to support the total Inter Frequency, IF, band.
20 1 GOMEZ, Ramon
21 8 HAENNIG, Gerald
p=. !{width:700px}RF_frequency_respone.png!
22 9 HAENNIG, Gerald
Figure 2. RF frequency respone (for several RF input powers).
23 1 GOMEZ, Ramon
24 9 HAENNIG, Gerald
h2. RF Gain
25 10 HAENNIG, Gerald
26 4 HAENNIG, Gerald
As they are lossy coaxial cables to connect signal generator to the optical transceiver and optical receiver to spectrum analyzer, this losses have be to taken into account.
27 9 HAENNIG, Gerald
28 11 HAENNIG, Gerald
Optical link RF Gain has been measured with these corrections and the results are contained in the following figure.
29 10 HAENNIG, Gerald
30 12 HAENNIG, Gerald
p=. !{width:700px}RF_Gain_Corrected.png!
31 10 HAENNIG, Gerald
Figure 3. RF Gain (cable loss removed).