MT25EW Bookham Technology, MT25EW Datasheet - Page 2

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

www.bookham.com
www.bookham.com
Functional description
The module comprises an hermetically packaged 1550 nm BH Laser device with optical isolation and
Etalon wavelength feedback, laser drive, automatic laser power control, and monitoring circuitry.
The laser package uses a Thermo-Electric Cooler (TEC) to maintain the correct laser temperature to achieve
constant lasing wavelength based on true wavelength feedback from the Etalon filter. The microprocessor
based control circuit also provides temperature monitoring, alarm outputs and internal fault diagnostics.
The module features high speed complementary data inputs which are AC coupled and have internal 50
termination, transmitter disable input, modulation input for wavelength tagging, alarm and monitor
supervisory outputs, Etalon in lock output flag.
The optical output is via a single mode pigtail which can be fitted with a variety of single mode
optical connectors.
The module operates from a 5 V supply, with 3.3 V supply for the TEC to minimise power dissipation. The
module is very compact and incorporates an advanced integral heatsink.
Transmitter operation
Optical power control
The on board microprocessor provides fully automatic integrated power and wavelength control using
the Etalon output signals as feedback. This approach enables a controlled start and inter-channel
protection as well as normal constant power control.
Data input (DATA, DATA)
The inputs are AC coupled and terminated with 50 . This provides 100
recommended input signal must meet the required voltage swing for PECL/ECL. Due to the high speed
nature of this product it is vital that high speed design rules are followed in the design of the system board.
Follow the recommended user interfaces.
This transmitter is not suitable for burst mode operation and unbalanced data patterns may affect the
automatic constant power circuit.
Figure 1: Transmitter block diagram
ELECTRIC
THERMO-
COOLER
OPTICAL DEVICE
CONTROL
CIRCUIT
TEMP
AND CONTROL
LASER DRIVE
MONITORS
& ALARMS
CIRCUIT
CIRCUIT
differential impedance. The
EIL FLAG
TXSD
DATA
DATA
MODíN INPUT
LBC MONITOR
LASA (Laser alarm)
TEMP MONITOR
TEMP ALARM
Vcc
Vtec
Gnd
Thinking optical solutions
Thinking optical solutions