Function Description

The transmitter is mainly composed of a laser driver part of the intelligent transceiver chip and a TOSA(light-emitting component), the TOSA includes a 850nm VCSEL laser and a backlight photo detection chip,When the module is working, the input signal is connected to the intelligent transceiver chip, at this time, the laser driver of the intelligent transceiver chip supplies the bias current and the modulation cur- rent to the laser.The intelligent transceiver chip simultaneously uses an automatic optical power control (APC) feedback loop to maintain a constant average optical power of the laser output. The purpose is to eliminate the change of the output optical signal due to temperature changes and aging of the lightsource device.When the transmitter enable pin (TX_Disable) is high (TTL logic “1”), the laser output isturned off. When TX_Disable is low (TTL logic “0”), the laser will turn on within 1ms.When the transmit-ter fault signal (TX_Fault) is reported as high,indicates a transmitter failure caused by the transmitter’s bias current or transmitted optical power or laser tube temperature exceeding a preset alarm threshold.Low indicates normal operation.

The receiver is mainly composed of a limiting amplifier part of the intelligent transceiver chip and a ROSA (light-receiving component),the ROSA includes a PIN photo detector and a trans impedance amplifier chip.When the ROSA detects the incident light signal, it will be converted into a photo-generated current by the PIN photo detector. The photo-generated current is converted into an electrical signal after passing through the trans impedance amplifier. The electrical signal is further amplified by the limiting amplifier of the intelligent transceiver chip, then outputs a fixed-amplitude electrical signal to the host.When the amplitude of the electrical signal received from the incident light conversion of the opposite optical transceiver module is lower than the set threshold,the module reports that the received signal is lost,the RX_LOS pin is high (logic “1”),which can be used to diagnose whether the physical signal is normal.The signal is operated in TTL level.The microprocessor inside the module monitors the module ’ s operating voltage, temperature, transmitted optical power, received optical power, and laser bias current value in real time. The host acquires this information over a 2-wire serial bus.

After the module is powered on, the read value of the security level access registers 7BH ∼ 7EH of A2H is replaced with 0x00. After the content of this group of registers is updated, the read value is the last written value. The security level 1 password of this module is 0x00001011. The method to enter the security level 1 working state is to convert and write the security level 1 password in the A2H 7BH ∼ 7EH registers of the module, namely 0x00, 0x00, 0x10, 0x11. After entering the security level 1 working state, the user can directly write to the content of the A0H device address, or modify the content of the A2H 7FH table selection register to write to the contents of Table 00 or Table 01.And this version of the module does not support users to modify the security level 1 password.