Operation Instruction for Micro MBC Plus (0002)
(06/05/2015 Rev.1.0)
Micro MBC plus 0002 is a dual channel LN modulator bias controller which can perform excellent bias control for two modulators simultaneously. Each channel can be configured to work in one of the four control modes: Peak/Null control and Quad+/- control. Furthermore, 0002 has a special methods for modulator applied with PRBS-signal applications so the controller can work without applying dither signal on the Gain Control of RF driver .
Figure 1. Modulator working function
Features of Micro MBC Plus (0002)
- Two modulators can be controlled with one controller
- Four selectable working points for every channel(Peak/Null/+Quad/-Quad);
- Special locking method for Modulator with PRBS-signal applications
- All settings are remote controllable through USB computer interface, or UART.
- User can select automation mode or manual mode
- Pilot amplitude tone is adjustable
- Low profile (2.65” * 1.40”* 0.65”)
Figure 2. 0002 MBC Board
Table 1. 0002 MBC Specifications
PARAMETERS / MIN / TYP / MAX / UNITSOptical Performance
Detector Input Power1 / -30 / -10 / dBm
Optical wavelength / 1000 / 1650 / nm
Electrical Performance
Bias voltage / -10 / 10 / V
Null Mode Extinction Ratio2 / 25 / 40 / dB
Locking Slope / Positive or Negative
Pilot tone
Modulation Depth 3 / 0.1 / %
Pilot Tone Frequency / 9K / Hz
Power Supplies
Positive Power Voltage / 11.5 / 12 / 12.5 / V(DC)
Negative Power Voltage / -11.5 / 12 / -11.5 / V(DC)
Positive Power Current / 180 / mA(DC)
Negative Power Current / 30 / mA(DC)
General
Operating temperature / 0 / 70 / Degree C
Storage Temperature / -40 / +85 / Degree C
Dimension / 2.65x1.40x0.65 inch
Weight / 0.2 lb
- For a given input, detection power refers to the coupled optical power to the photodiode of DPMZ-MBC when the modulator output is at its minimum attenuation (The detection power does not describe the detected power at locking status). In this case, if the modulator output power is 0 dBm, 1% coupler was used, the detection power should be –20 dBm.
- The distinction ratio will be close but not exceed the distinction ratio of the modulator.
- Optical Modulation Index = amplitude of modulation/V.
1.Dual Channel MBC0002 Layout
Figure 3. Layout of 0002 MBC
Connectors and Jumpers on 0002 Board:
J1 ---- 3-pin terminal for power supply, GND,-15V and +15V
J2 ----3-pin Bias Output,GND, Bias1 and Bias2
J3 ---- 3-pin VC Output, GND, VC1 and VC2
JP1 ---- USB connector for communication. The USB connector is used for remotecontrol through USB serial interface. Please connect this port with the computer to use GUI.
JP2----UART port. They are LVTTL signals of Microprocessor.Baud rate: 9600bps, data bits: 8, stop bit:1, parity bit : None, please note there should be no any termination after the command.
JP4----PD Select, short pin1 and pin2 when using PD1, short pin2 and pin3 when using PD2.
JP5----PD input test terminal, the current of PD = the voltage on JP5/30 (mA).
JP3 and JP6---- Factory use only
Reset Button --- for board reset.
LED ---To indicate working status.
Green LED : normal working
Red LED :PD input power istoo high (>-8dBm) or too low(<-30dBm)
P1----ForQuad control, Channel1VC voltage adjustment.
P2----For Quad control,Channel 2VC voltage adjustment.
PD1 and PD2--- If RF Driver has Amplitude Gain Control (AGC) terminal, PD1 should be used to lock the modulator at Peak, Null or Quad point. In this case, short Pin1 and pin2 of Jump4 and Select PD1 on the GUI first. If locking point is Quad, first connect AGC of RF driver with adjustable power supply and tune the voltage of AGC to make the amplitude of RF signal about Vpi, then tuneP1 or P2 to make the voltage of VC1 or VC2 equal to the AGC voltage. Then disconnect AGC with power supply and connect VC with the AGC and connectthe bias output on the board with modulator. If locking point is Peak/Null, just connectthe bias output on the board with modulator, leave VC terminal alone.
If the RF signal to Modulator is PRBS and there is no Gain Control terminal on the RF Driver, PD2 can be used to lock the Bias. In this case, short Pin3 and pin4 of Jump4 and Select PD2 on the GUI first.If PD2 is used, the input power to PD2 must be higher than -30dB even locking at Null point, or the board will not work.
If only Peak/Null points are needed to lock (never need to lock at Quad point), then always select PD1 and leave VC terminal alone.
For locking at Peak/Null mode, the RF signal on modulator can be from 0 to 120%Vpi, For locking at Quad Mode, the RF signal must be from 80% Vpi to 120% Vpi.
2.Communication with the Board
There is GUI which can be used to communicate with the board. In addition, User can send commands through UART port or USB port to the board.
Commands to change working Mode and check Status
The user may change the working mode and the slope setting through USB.
Table 2. Commands to set working Mode and check status
Commands / Commands Return / FunctionSSA / SA:Ch1 at positive slope / Set Ch1 Modulator At positive slope
SSa / Sa: Ch1 at negative slope / Set Ch1 Modulator At negative slope
SSB / SB: Ch2 at positive slope / Set Ch2 Modulator At positive slope
SSb / Sb: Ch2 at negative slope / Set Ch2 Modulator At negative slope
SSC / SC: Ch1 signal is PD1 / Tell the board CH1 signal is PD1
SSc / Sc: Ch1 signal is PD2 / Tell the board CH1 signal is PD2
SSD / SD: Ch2 signal is PD1 / Tell the board CH2 signal is PD1
SSd / Sd: Ch2 signal is PD2 / Tell the board CH2 signal is PD2
SSE / SE: Ch1 atPeak/Null Mode / SetCh1 Modulator At Peak/Null
SSe / Se: Ch1 at +Quad/-Quad / Set Ch1 Modulator At +Quad/-Quad
SSF / SE: Ch2 atPeak/Null Mode / Set Ch2 Modulator At Peak/Null
SSf / Se: Ch2 at +Quad/-Quad / Set Ch2 Modulator At +Quad/-Quad
SSG / SE: Ch1 atCalibration Mode / Ch1 Modulator will calibrate every time when power on
SSg / Se: Ch1 at No calibration Mode / Ch1 Modulator will not calibrate every time when power on
SSI / SE: Ch2 atCalibration Mode / Ch2 Modulator will calibrate every time when power on
SSi / Se: Ch2 at No calibration Mode / Ch2 Modulator will not calibrate every time when power on
SSR / SR: Reset / Soft Reset Board
SSU / UA#### / Read PD input Power
For example, if the commands return shown as UA2256,It means: PD Current 0.2256mA
SSV / SV1.0 / Read software version.
For example, if the commands return shown as SV1.0
It means: the version is V1.0
SSN / S##### / Read serial number.
For example, if the commands return shown as S61679
It means: the SN is 61679.
SKK / VVAA262BB171 / Read the voltages of the two channels. VV is the start words. The first letter ‘A’ or ‘B’stands for the first or second channel. The letter ‘A’ or ‘B’just before the digits show negative or positive. A: Positive; B: negative. The digits is the corresponding bias voltage which timed by 100. Like the commands return: VVAA262BB171
It means: Ch1Bias is +2.62V
Ch2 Bias is -1.71V
Commands to inputor read Modulator Parameters including Peak/Null positions and Pilot values.
During Calibration, the board will look for the Null and Peak point of the modulator, and then calculate the Quad point and the value of pilot tone. But the error will get bigger when the light to PD gets smaller. User can set these parameters using commands.
First send “SSP” or “SSX” ,“SSY”“SSZ”command to MBC Board, and the board will return “SP”，or “SX” ,“SY”“SZ”. “SSP” means “set Ch1 modulator parameters”, “SSX” means “set Ch1 Pilot tone”, “SSY” means “set Ch2 modulator parameters”, “SSZ” means “set Ch2 Pilot tone”.
Then send the modulator parameters or Pilot tone value after the first command. The delay should be no more than 5s. The modulator parameters have the following format:
A( or B)# # # # A(or B) # # # #
A means the value is positive, B means the value is negative. The digits is the corresponding voltage which timed by 100.
For Example, send A0222B0333, it means Null is 2.22V, Peak is -3.33v
The Pilot tone value has the following format:
# # # #
This is the pilot tone value, the unit is mV. For Example, send “0055”, it will set pilot tone at 55mV.
Send “SSp” or “SSx” ,“SSy”“SSz”command to MBC Board, and the board will return “ZZ” and the modulator parameters or pilot tone value which has been stored in the board. “SSp” means “read Ch1 modulator parameters”, “SSx” means “read Ch1 Pilot tone”, “SSy” means “read Ch2 modulator parameters”, “SSz” means “read Ch2 Pilot tone”
Commands for settingBias offset.
Sometimes, there is necessity to tune the locking point. This can be done in the automatic mode by setting the bias offset. For example, first the 0002board locks the bias at Null point of the modulator,then 0002 will lock the Bias at other point near the Null when the user adjust the Bias offset value. The offset between the setting point and null is decided by the Bias Offset Value.
First send “O # #” command to the Board, and the board will return “# # : Set Bias Offset”. Then send the Bias offset Value after the command and the delay should be no more than 5s. .
The command format is : O + channel + A(positive) or B(negative)
Channel value has two values : A means Ch1, B means Ch2.
The Bias offset value format is # # # #
For example, send command “OAB”, it means send Ch1 bias offset and the value is negative. The board will return “AB: set Ch1 offset”. Then Send Bias offset value as “0100”. It means the offset value is -100.
Note: The offset value is not equal to offset voltage. The offset value is ranged from
-2000 to 2000. The actual bias offset voltage may vary under different condition, for example, different optical power, different RF signal, etc.For example, the bias voltage offset is about 0.6V when Bias offset value is set to 200 and the PD Received Power is about -18dBm. But when the RD received power is different, 200 may not represent 0.6V offset. The user needs to try different offset values to set needed offset voltage.
Command for checking the working status.
Send "SSH" to check the status,the board will send back " P # # # S # # # A(or B) # # # #A(or B) # # # #
P# # # is decimal value which has 8 bits:
Bit 0: Ch1 Slope: 1 Positive, 0 Negative
Bit 1: Ch2 Slope:1 Positive, 0 Negative
Bit 2: Ch1Signal: 0 PD1, 1 PD2
Bit 3: Ch2Signal: 0 PD1, 1 PD2
Bit 4: Ch1 Mode: 0 Peak/Null, 1 +Quad/-Quad
Bit 5: Ch2 Mode: 0 Peak/Null, 1 +Quad/-Quad
Bit 6:Ch1 Pilot: 0:ON, 1:OFF
Bit 7:Ch2 Pilot: 0:ON, 1:OFF
S # # # is decimal value which has 8 bits:
Bit 0 : Ch1 Calibration: 0:ON; 1,OFF
Bit 1 : Ch2 Calibration: 0:ON; 1,OFF
Bit 2: No meaning
Bit3: No meaning
Bit4: Ch1 pilot tone applied at: 0:Bias, 1:VC
Bit5: Ch2 pilot tone applied at: 0:Bias, 1:VC
A means the following value is positive, B means the value is negative.
The last two values are the offset value of Ch1 and Ch2 modulators.
Special functions (manual mode):
For user’s convenience, the pilot tones can be stopped to any one modulators; the user then can manually set the bias voltage of that modulator through USB interface.
Command to disable pilot tone.The commands are listed in the following table.
Table 3. Commands to enable or disable Pilot tone
Commands / Commands Return / FunctionSMA / MA: Bias Ch1 without Pilot tone / Set Bias of Ch1 Modulator at current voltage
SMa / Ma: Bias Ch1 with Pilot tone / Enable the pilot tone on Ch1
SMB / MB: Bias Ch2 without Pilot tone / Set Bias of Ch2 Modulator at current voltage
SMb / Mb: Bias Ch2 with Pilot tone / Enable the pilot tone on Ch2
Commands to set voltage
This should be done in the manual mode (disable the pilot tone).
First send “S # #” command to MBC Board, and the board will return “# # : Set Bias Value”. Then send the Bias Value after the command and the delay should be no more than 5s.
The command format is : S + channel + A(positive) or B(negative)
Channel value has two values :A means Ch1, B means Ch2.
The Bias value format is: # # # #. The digits is the corresponding voltage which timed by 100.
For example, send command “SAB”, it means send Ch1 bias and the value is negative. The board will return “AB: set Ch1 Bias”. Then Send Bias value as “0100”. It means the Bias value is -1.00V.
Note: The above commands only work in the manual mode. First send the command to disable the pilot tone first, then set the voltage. Otherwise, it won’t work. The command to read bias voltage can also work in the manual mode.
3.Major Application
Figure 4.1. Only working in Peak/Null Mode(no matter what kinds of RF signal)
Figure 4.2.There is AGC on RF driver and Quad point also needs to be locked for sin wave signal
Figure 4.3. There is no AGC on RF driver and RF signal is PRBS
Figure 4.4. Two Channel are all used to control two modulators( PD1 or PD2 is decided by the RF signal, Whether VC is needed is decided by the locking point of every modulator)
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