In recent years, along with fiber to the home , all-optical network applications , such as the rise of hot spots , the communications industry is facing a double challenge of bandwidth and speed , high-capacity , high-speed and high-quality optical fiber communication has become an inevitable trend of development of information industry . Optical transceiver module is an important part of the construction of optical networks , its core function is to provide optical transmission network between the various interfaces, optical or electro-optical conversion is completed , make sure to connect communication network . Currently wider application of miniaturized optical module types are hot-pluggable (SFP) module series. In the current mainstream of communication capacity and rate, which can satisfy the requirements of communication . But with the rise of a series of hot applications and low-cost optical modules , and further demand for high -capacity links , miniaturized compact hot-pluggable (CSFP) optical transceiver modules have come into being . In the now popular SFP on the basis of industrial packaging , through the use of dual or even quad-channel design , CSFP does not change the existing interface form, but will be reduced dimensions to the existing standard 1/ 2 or 1 /4 , also through a combination of The number of channels can be flexibly configured . Use of highly integrated optoelectronic circuits and packaging technology developed CSFP fiber optic transceiver module inherits all of the technical advantages , greatly reducing the optical modules and communication systems equipment dimensions, exponentially enhance information throughput and port density while also reducing the system cost , a huge commercial value . This paper aims to study and design of an integrated two traditional Bidirectional bidi sfp transceiver for CSFP , and its performance test results through further analysis of the data , verify product performance, demonstrated the feasibility of the design, for the CSFP the actual production of optical modules provide a theoretical basis
CSFP in the traditional optical module sfp transceiver module dimensions, integrates two BIDI SFP modules. The module consists of two PLC BOSA to achieve two-way transceiver under the original two channels of the same dimensions . Pin to define and monitor the amount of conventional SFP modules are quite different , the other basic functions , like the structure shown in Figure 3 , where the LOS alarm signals , IC chip is integrated , MCU for the microcontroller , EEPROM is electrically EEPROM , BOSA optical transceiver module .
CSFP completed the functions of the two traditional single fiber bidirectional SFP module integration , the structure contains two independent optical transmitting and receiving channels, each channel consists of a PLC BOSA device is responsible for the completion of the optical signal receiving and transmitting signals , is CSFP core component module .
BOSA emitting portion of the transmitter and the triple chip driver circuit, and is mainly composed of a laser diode transmitter (LD) and the monitor light emitting diode backlight power (PD) components. The effect is to provide a driving circuit required laser bias and modulation currents , the former is used to turn the laser operation, the latter is used to load the received modulated electrical signal to the output optical signal. The current drive circuit generally have automatic power control (APC) function, you can ensure that the whole laser light power is constant, the principle is based on the current size of the monitor diode backlight dynamically adjust the bias current.
Micro controller main block to the laser driver circuit, main amplifier, and EEPROM control.EEPROM basic unit is mainly used for storage of product model, series number, production date, such as fixed information related products, and CSFP module of digital diagnostic monitoring (DDM) should be added to the transfer of acquisition signal circuit.These circuits for module output optical power, the input optical power, working voltage, temperature and bias current parameters such as real-time monitoring and reporting.Acquisition circuit these parameters corresponding to the instantaneous voltage values to transform circuit, the output of digital signal block is stored in the EEPROM of the corresponding unit.
CSFP system interface between the modules and the upper machine adopts the I2C bus method, namely the clock line (SCL) and a data line (SDA), achieved by gold finger electric interface, complete PC optical module information, speaking, reading and writing.The data transmission between MCU and block storage device EEPROM is through the SPI bus, namely the clock line, data input and data output line.MCU through the I2C bus to monitor two way passage, once detected a channel abnormal changes of main parameters of MCU respectively to TX1 – Fault or TX2 – Fault, said error channel 1 or 2.MCU TX1 – Fault and TX2 – Fault output pins at the same time input terminal connected to an or gate, only when the two way passage all work, module goldfinger TX – don’t Fault pin up a machine alarm.The abnormal, otherwise, all the way to transport channel signals alarm module.
