Annex
Introduction
Rofea's modulator bias controller is specially designed for Mach-Zehnder modulators to ensure a stable operation state in various operating environments. Based on its entirely digitized signal processing method, the controller can provide ultra-stable performance.
The controller injects a low frequency, low amplitude dither signal, and a bias voltage into the modulator. It keeps reading the modulator's output and determines the condition of the bias voltage and related error. A compensate bias voltage will be applied afterward according to the various pre- measurements. In this way, the modulator is ensured to work under a proper bias voltage.
The controller is very compact in volume with high performance. The maximum stable DC extinction ratio measured in Lab is 50.4dB. The highest carrier suppression ratio measured is 43dB.
Feature
• MZM bias control on Null and Peak modes
• Low profile: 37mm(W) × 25mm(D) × 8mm(H) High extinction ratio:
53dB Maximum1
50.4dB DC extinction ratio lab-verified 2
43dB carrier suppression lab-verified
• Low dither amplitude: 0.1% Vπ
• High stability: with fully digital implementation Easy to use:
Manual operation with mini jumper Flexible OEM operations through UART3
Two different modes to output bias voltage:
a. Automatic bias voltage
b. User-defined bias voltage
Application
• LiNbO3 and other MZ modulators
• Brillouin scattering system and other optical sensors
• Radio over Fiber systems
• Pulse Generation
• Carrier Suppression
Specifications
|
Parameter |
Min |
Typ |
Max |
Unit |
|
Control Performance |
||||
|
CSO1 |
−55 |
−65 |
−70 |
dBc |
|
Stabilization time |
|
10 |
|
s |
|
Electrical |
||||
|
Positive power voltage |
+14.5 |
+15 |
+15.5 |
V |
|
Positive power current |
15 |
|
30 |
mA |
|
Negarive power voltage |
-15.5 |
-15 |
-14.5 |
V |
|
Negative power current |
1.5 |
|
4 |
mA |
|
Output voltage range |
-11.34 |
|
+11.34 |
V |
|
Output voltage precision |
|
350 |
|
µV |
|
Dither frequency |
999.95 |
1000.00 |
1000.05 |
Hz |
|
Dither amplitude |
|
2%Vπ |
|
V |
|
Optical |
||||
|
Input optical power2 |
-30 |
|
-9 |
dBm |
|
Input wavelength |
1100 |
|
1650 |
nm |
1 CSO refers to composite second order. The linear quality of RF signal, modulators, and receivers shall be ensured. Besides, the system CSO readings may vary when running at different RF frequencies.
2 Please be noted that the input optical power does not correspond to the optical power at the selected bias point. It refers to the maximum optical power that the modulator can export to the controller when the bias voltage ranges from −Vπ to +Vπ.
