MT25EW Bookham Technology, MT25EW Datasheet - Page 3

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

www.bookham.com
www.bookham.com
Transmitter operation (continued)
Transmitter disable (TXSD)
Transmitter operation can be disabled by applying a CMOS Logic 1 level to the TxSD pin. The laser can
be disabled by the module microprocessor in the event of gross failure. When disabled the output power
is < -40 dBm. In event of the microprocessor sets the Laser Alarm and the Temperature Alarm and
maintains the transmitter disable until a power on reset.
Laser Bias Current Monitor (LBCM)
The LBCM provides an analog voltage output corresponding to the laser bias current. The LBCM output
is referenced to ground and indicates the change of laser threshold as the laser ages. The LBCM output
is buffered; use with high impedance loads to reduce errors and dissipation.
Laser alarm (LASA)
The Laser Alarm is an Active High CMOS level output. The Laser Alarm is active when the optical
output power is outside of operations limits.
Temperature alarm
The temperature alarm is an active high CMOS level output. The temperature alarm is activated when
the laser temperature is approximately 1°C above or below normal laser operating temperature for
Etalon lock. This is a high current output and can drive alarms directly.
Etalon in lock flag (EILF)
This output provides an indication of when the wavelength is locked to the reference wavelength under
Etalon control.
Modulation input (MODN)
The modulation input allows for the use of a low frequency tone (10-500 kHz) for modulation of
the “1”s level. This input must be driven from a 50
exceed the maximum drive level. Over driving this input can cause waveform distortion; limit
modulation depth to 5-10%. If unused, connect this input to 0 V to prevent noise pickup.
Two-wire interface (TWCK, TWDA)
The module can be configured using a two-wire communication interface. TWCK carries the clock
signal generated by the external master. TWDA carries the serial data stream.
Power supplies
The module operates from a single rail power supply of +5.0 V nominal. The Thermo-Electric Cooler is
supplied from a separate pin (Pin 11 Vtec). The TEC operates with a 3.3 V supply for a wide operating
temperature range. This low voltage ability is used to reduce the power dissipation of the module.
Ensure the supply to the module is well filtered and as noise free as possible to prevent any possible
interference with the module (see the recommended system interface). The supply feeds to the module and
TEC must be of low DC impedance with minimal voltage drop at the maximum module and TEC currents. For
maximum EMI screening, the case is electrically connected to the Gnd pins.
source, and is AC coupled internally. Do not
Thinking optical solutions
Thinking optical solutions