Continuously Tunable Modulator Bias Controllers
The iXblue MBC-DG-LAB is a family of automatic bias controllers specially designed to lock the operating point of LiNbO3 Mach-Zehnder modulators and to ensure a stable operation over time and environmental conditions.
The MBC-DG-LAB controllers are continuously tunable bias controllers, meaning they allow operation of the modulator at any point of its transfer function and thus can be used for a large variety of applications. They are easy to implement, and are available as bench top instruments and OEM boards. iXblue MBC-DG series controllers are especially well suited for digital and pulse applications.
The iXblue MBC-DG-LAB shows a very low noise sensitivity yielding a significant reduction of the required dither voltage amplitude. This new version is characterized by an enhanced stability. The electronic board benefits of an AUTOSET operation for the QUAD/MIN/MAX modes resulting in a simplified use. The user parameters are stored and can be recovered after switched off. An USB communication and a Graphical User Interface (GUI) are introduced for ease of use.
Principle
The iXblue MBC-DG-LAB controllers are dither signal based: a low amplitude, low frequency tone signal is superimposed to the modulation signal. The resulting optical modulation is then detected and a digital signal processing based on a FFT analysis principle allows to lock the operating point at the desired position.
FEATURES
• MIN, MAX, QUAD+ & QUAD-
• Any other operating point
• Continuous tuning of the bias point
• USB remote control
• High stability and sensitivity
• Autoset
APPLICATIONS
• LiNbO3, InP, GaAs modulators
• Digital NRZ, RZ, DPSK,...
• Pulse applications
• Analog applications
OPTIONS
• Internal photodiode and tap coupler
• Benchtop and board versions
• Ditherless version
Performance Highlights
Parameter
Min
Typ
Max
Unit
DC bias voltage
-10
-
+10
V
Autoset mode
MIN, MAX, QUAD-, QUAD+
-
Locking range
-
360
-
Degree
Locking accuracy at Quad±
-
90 ± 0.5
-
Degree
Extinction ratio at MIN mode
-
501 ± 0.05
-
dB
1 50 dB: from modulator nominal Extinction Ratio value
Electrical Characteristics
Parameter
Symbol
Condition
Min
Typ
Max
Unit
DC bias voltage
Vbias
-
-10
-
+10
V
Bias Voltage step
DVbias
Manual mode
0.001
-
0.1
mV
Automatic locking point
-
Transfer level
MIN (0%), MAX (100%),
QUAD-(-50%), QUAD+(+50%),
and other transfer level value
-
Dither frequency
fdither
by 40 Hz frequency step
400
-
1 400
Hz
Dither amplitude
Vdither
by 1 mV amplitude step
5
-
1 000
mV
Optical Characteristics
Parameter
Symbol
Condition
Min
Typ
Max
Unit
At Photodiode input port (MBC-DG-LAB version A0 & B0)
Wavelength
l
MBC-DG-LAB-A0
900
-
1 600
nm
MBC-DG-LAB-B0
600
-
900
Input optical power
OP
MBC-DG-LAB-A01 - Measured @1550 nm
-20
-10
-3
dBm
MBC-DG-LAB-A02 - Measured @1310 nm
-19
-10
-2
dBm
MBC-DG-LAB-A03 - Measured @1060 nm
-18
-8
-0.8
dBm
MBC-DG-LAB-B04 - Measured @850 nm
-17
-7
0.5
dBm
At Tap-Coupler input port (MBC-DG-LAB version A1, A2, A3, B1, B2)
Wavelength
l
-
760
-
1 600
nm
Input optical power
OP
MBC-DG-LAB-A11 - l range 1550nm±20nm
0
10
17
dBm
MBC-DG-LAB-A22 - l range 1310nm±20nm
0.5
13
18
dBm
MBC-DG-LAB-A33 - l range 1060nm±20nm
2.5
11.5
19
dBm
MBC-DG-LAB-B14 - l range 850nm±10nm
2.8
12.5
20
dBm
MBC-DG-LAB-B25 - l range 780nm±20nm
2.8
12.5
20
dBm
1 Measured @1550 nm - 2 Measured @1310 nm - 3 Measured at 1060 nm - 4 Measured at 850 nm - 5 Measured at 780 nm
Bias Control Characteristics
Parameter
Symbol
Condition
Min
Typ
Max
Unit
Timing
Autoset (MIN, MAX, QUAD±)
Auto
Automatic scan
25
30
40
s
Initialisation
-
After an autoset
-
10
-
s
Start up
-
-
10
-
30
s
QUAD+, QUAD-
Locking accuracy
-
at Quad±
89.5
90
90.5
Degree
Locking Stability
-
Standard deviation, over 2 hours,
and modulator temperature controlled
-0.1
-
+0.1
Degree
MIN & MAX Bias performances
Extinction Ratio
ER
Modulator with ER > 50 dB & tap coupler
-
-
50
dB
Locking stability
DER
-
-
±0.05
-
dB
MBC-DG-LAB
Different digital modulation formats (NRZ, RZ, DPSK) require specific operating points and bias control parameters. That is also true for pulse signals with different duty cycles. The MBC-LAB through its intuitive GUI offers pre-set (Autoset) bias setting for MIN, MAX, and QUAD for fast and easy modulator operation.
Dimensions
Dimensions (W x H x D) 220 mm x 220 m x 52 mm Power supply (rear panel)
100-120 V / 220-240 V automatic switch,
50-60 Hz
Interfaces
Photodiode Input /coupler input
FC/APC connector
Bias Output
BNC Female connector
Communication
USB
Remote Control
Minimum computer requirements
Windows XP SP3
Computer configuration
Recommended Windows XP-SP3, W7, W8
Ordering information
MBC-DG-LAB-A0: No coupler, 900nm to 1600nm
MBC-DG-LAB-B0: No coupler, 600nm to 900nm
MBC-DG-LAB-A1: Integrated coupler 1550nm ±20nm
MBC-DG-LAB-A2: Integrated coupler 1310nm ±20nm
MBC-DG-LAB-A3: Integrated coupler 1060nm ±20nm
MBC-DG-LAB-B1: Integrated coupler 850nm ±10nm
MBC-DG-LAB-B2: Integrated coupler 780nm ±20nm