MT25EW Bookham Technology, MT25EW Datasheet - Page 11

• Manufacturer Part Number: MT25EW
• Description: 2.5 Gb/s Transmitter Module - Dwdm, 50 & 100GHz
• Manufacturer: Bookham Technology

www.bookham.com
www.bookham.com
SBT (05h)
Return the laser submount temperature in units of 1/10ths of a degree C, e.g. 345 = 34.5C. Result is
returned as an unsigned 16-bit value, MSB first followed by the LSB. Command is read-only.
SBF (06h)
Return the current in uA of the short wavelength back-facet monitor (BFM). Result is returned as an
unsigned 16-bit value, MSB first followed by the LSB. Command is read-only.
LBF (07h)
Return the current in uA of the long wavelength BFM. Result is returned as an unsigned 16-bit value,
MSB first followed by the LSB. Command is read-only.
The sum of the short and long BFM currents can be used to monitor relative optical power.
The difference between the two gives an relative indication of wavelength.STA (08h)
Return the module status. Module returns one byte that is divided into several bit fields as shown.
Command is read-only.
The following table describes the Control loop state bits
4
0
0
0
0
0
0
0
0
7
Etalon In Lock
If set, all parameters
are within tolerance
Status bit
3
0
0
0
0
1
1
1
1
2
0
0
1
1
0
0
1
1
1
0
1
0
1
0
1
0
1
THERMISTOR_STATE.
Submount temperature is being stabilised under thermistor control
DUAL_BFM_ACQ_STATE.
Submount temperature stabilised. Laser drive increased until a valid response is obtained from BFM’s
DUAL_BFM_RAMP_STATE
Submount temperature now under Etalon control. Optical power and extinction are ramping to their final values.
DUAL_BFM_LOCK_LASER
Wavelength, optical power and extinction ratio have stabilised at their pre-set values. Module is ready for use.
DISABLE
The processor has disabled the laser.
POWER_UP
First state after power up. Laser is disabled while the microcontroler initialises peripherals.
EXTERNAL_LASER_DISABLE
User has disabled the laser via the module disable input.
SYSTEM_CONFIG
Module is initialising all calibration parameters after a power on.
Alarm. If set,
6
Temperature
submount tem-
perature is out-
side tolerance
Description
5
Laser Alarm
If set, optical
power and/or ER
are outside tolerance
Status bits
4
Control loop state, see
Control State table
below for details
3
2
1
0
1
Thinking optical solutions
Thinking optical solutions