First of all, combined with working principle from the 40G QSFP LR4 transceiver, this paper gives its overall design plan. Next, based on different functions, the transceiver hardware is split into four sub transceivers: transmitting part, receiving part and control part, and they’re examined at length.
40G QSFP LR4 Transceiver Working Principle & Design
40G QSFP LR4 transceiver adopts a complete duplex working mode. It integrates the transmitting and receiving channels in a single transceiver. In the delivering finish, four 10Gbps serial data streams are delivered to the motive force nick. The driving nick controls the direct modulation laser (DML). The significant wavelengths from the laser are 1271nm, 1291nm, 1311nm and 1331nm. The optical signals output by four DMLS are loaded right into a single-mode fiber with an optical multiplexer as well as an LC connector. In the receiving finish, four 10Gbps optical signals flow with the optical demultiplexer to four channels. The optical signal flow of every funnel goes through the PIN photodetector / transimpedance amplifier and it is output with the restricting amplifier.
The transceiver supports hot plug, digital diagnosis and occasional power consumption mode. Based on the function division, the entire hardware part usually can be split into four parts, such as the electrical interface part, transmitting part, receiving part and control part. The general design plan is proven within the figure below.
40G QSFP LR4 Transceiver Working Diagram
The transmitting part includes 4 channels according to CWDM band ×10G TOSA as well as on-board driving circuit for loading driving signal to TOSA. It accounts for receiving four 10 Gbps data signals in the motherboard and loading the electrical signals in to the four bands of 1271nm, 1291nm, 1311nm and 1331nm of TOSA through direct modulation. Each gang of optical signal is packed with a 10G electrical signal.
The part from the receiving part would be to get the 40G optical signal in the optical fiber link and convert it into an identifiable digital signal through amplification, integer and regeneration. An entire receiving part usually includes photodetector, preamplifier and restricting amplifier (LA). The photoelectric monitor changes the optical signal in the link right into a weak current signal. The present signal is changed into current signal with a preamplifier. At the moment, the primary preamplifier is transimpedance amplifier (TIA). The signal amplified by TIA continues to be a continuously altering analog signal, which must be integer and regenerated into digital signal by LA.
The control area of the 40Gbase-lr4 transceiver studied within this paper adopts C8051F390 single nick microcomputer of Plastic Labs company. The nick adopts high-speed 8051µ The C core can execute 70% from the instructions in a couple of system clocks, includes a throughput of 25 MIPS in a clock frequency of 25 MH, and internally provides 768 bytes of ram and 16kb of space for storage. It offers 21 I/O ports, utilized by I2C bus, and it has one programmable 16 bit count/timer and 4 general 16 bit count/timers. The TIA configuration and 4 driver nick configuration information within the receiving Rosa is going to be kept in the MCU. Simultaneously, the storage about current, bias current, received optical power and a few related status bits needed within the QSFP multi-source protocol inf-8438i may also be configured within the MCU. The 21 I/O ports in C8051F339 are utilized to read the status from the corresponding functions from the nick and realize the use of specific ports. The detailed meaning of MCU I/O ports is proven within the figure below.
Control Part Interface Design Diagram
The paper above introduces the significant principle from the 40G QSFP LR4 transceiver and also the hardware style of transmitting, receiving and charge of the transceiver at length. QSFPTEK is definitely an original make of fiber optic transceiver factory outlet that serves SMB users. Aside from the 40G QSFP LR4 transceiver, QSFPTEK offers high-quality and-reliable 40G QSFP SR4, 40G QSFP ER4, and etc with industry-leading hardware optical components. Thanks for visiting consult via [email protected]