Detail introduction of transceivers
Optical module classification
By package: 1*9, GBIC, SFF, SFP, XFP, SFP+, X2, XENPARK, QSFP+, 300pin, etc..
By rate: 155M, 622M, 1.25G, 2.5G, 4.25G, 10G, 25G, 40G, 100G, 120G etc..
By wavelength: conventional wavelength, CWDM, DWDM, etc..
By Mode: single mode fiber (yellow), multimode fiber (orange red).
By usability: hot pluggable (GBIC, SFP, XFP, XENPAK) and non hot pluggable (1*9, SFF).
Package form


Full name of different form factor:
GBIC: Gigabit Interface Converter
SFF: Small Form Factor
SFP: Small Form-factor Pluggable,
SFP+: Enhanced Small Form Factor Pluggable Module
XFP: 10G Small Form Factor Pluggable
QSFP+: Quad Small Form-factor Pluggable Plus
CXP: 120G 12x Small Form Factor Pluggable
CFP: 100G Small Form Factor Pluggable
AOC: Active optical cable
ACC: Active copper cable
PCC: Passive copper cable
Transmission distance:
SR: Multimode short range。62.5μm-275m,50μm-550m
LR: long range,standard distance 10Km
ER: standard distance 40Km
ZR: standard distance 80Km
The internal structure of transceiver
Different connectors:
Optical device
VCSEL
Vertical cavity surface emitting laser (Vertical Cavity Surface Emitting Laser), developed to GaAs semiconductor material, has the advantages of small size, circular output beam, single longitudinal mode, small threshold current, low price, easy to be set in large area array etc., widely used in optical communication, optical interconnection, optical storage and other fields. Mainly used in multimode 850 wave long short distance communication.
FP laser
FP laser is a semiconductor light-emitting device with FP cavity as resonant cavity and emitting multiple longitudinal mode coherent light. Characteristics of such devices, large output optical power, small divergence angle, narrow spectrum, high modulation rate, suitable for long-distance communications. Mainly for single mode 1310 wavelength long distance communication.
DFB laser
DFB laser is considered by grating optical device of the device is only one longitudinal mode based on FP laser on the characteristics of such devices, big output power, small divergence angle, narrow spectrum, high modulation rate, suitable for long distance communication. Mainly for 1310, 1550 wavelength long distance communication.
EML laser
Electro absorption modulated laser (EML) is an electro absorption modulator (EAM) and DFB laser (LD) integrated device, by using quantum confinement effect of Stark (QCSE) the electro absorption modulator and the grating coupling determine the high performance optical wavelength DFB laser integrated with small volume, low wavelength chirp
TEC
Semiconductor cooler (Thermoelectric Cooler), the use of semiconductor materials made of Perle effect.
The photoelectric detector is the device of optical signals into electrical signals, using two kinds of photoelectric detector in optical fiber communication system, namely the photodiode (PIN) tube and avalanche photodiode (APD).
PIN detector
PIN detector is a common layer photodiode based on the depletion layer of the device, it has a high quantum efficiency, low dark current, high response speed, low operating bias, no multiplication effect characteristics.
APD detector
Avalanche photodiode is a kind of electron hole pair excited by high bias voltage to accelerate the photon collision, and two electron hole pairs collide to form a photomultiplier. It has high quantum efficiency, high response and multiplication effect.
Is the working mechanism of APD photodiode: photogenerated hole electron of high electric field in high speed APD optical diode, through impact ionization effect in the process of movement, the number is the first electron hole pair two times, three times the new electron hole several times, thus forming a large current signal light. APD is widely used in large capacity and long distance optical fiber communication.
TIA
For converting external current to voltage. Typical applications include sensor measurements using optical diodes and other current outputs.
TOSA
Function: to realize the electro-optic conversion of the electrical signal to the optical signal. In optical fiber communication as light source and transmitter.
Appearance
Principle
From the products used in the optical communication field, its function is to convert the complete electrical signal to the optical signal. In this system, mainly including LD, PD chip, non spherical lens, optical isolator and single-mode fiber. From the input signal to drive the LD chip light emitting; optical signal by non spherical lens coupled to a single-mode fiber.
From the LD chip to realize the electro-optical conversion, PD chip LD chip to monitor the optical power, monitoring the operation. Non spherical lens as an optical component, play the role of optical focus. Ensure that the light isolator one-way transmission, eliminate light reflection.
ROSA
Function: photoelectric conversion function realization of optical signal to electrical signal. As detectors and receivers in optical fiber communications.
Appearance
Principle
The fiber output light signal through the lens cap TO to PD on the photosensitive surface, the current PD signal generated by the transimpedance amplifier (TIA) amplification of the output voltage signal to the external circuit.

BOSA
Function: to achieve a single fiber multiplexing downlink optical signal.
Appearance
*

Principle
By emitting a light signal provided by LD TO, the TO signal through the emission cap convergence, through WDM filter, coupled into optical fiber.
By receiving the optical signal from the optical fiber WDM filter, to reflection, after receiving the TO lens cap to the receiving chip on the photosensitive surface.
Application for P2P/EPON/GPON network
DWDM (sub L band and C band)
L band from 1610.06~1564.68 each septum 0.8nm, including 54
C band from 1563.86~1530.33 each septum 0.8nm, including 45
CWDM (1270-1610 each interval 20nm, including 18 bands)
The different wavelength has different loss
The 1380nm near the hydroxide particle absorption, fiber loss increased sharply, commonly known as water peak
The ITU-T band single-mode fiber over 1260nm E, divided O, S, C, L, U band
Easy to see that, in the 6 bands, C band and L band have minimum loss
Optical module protocol:
Form Factor
|
Data Rate
|
Protocol
|
SFP
|
125M-4G
|
SFP MSA,SFF-8472
|
SFP+
|
10G
|
SFF-8431,SFF-8432
|
XFP
|
10G
|
SFF-8077i
|
QSFP+
|
4*10G/4*25G
|
SFF-8436
|
CXP
|
12*10G
|
CXP MSA
|
CFP
|
4*10G/4*25G/10*10G
|
CFP-MSA-HW,CFP-MSA-MIS
|
CFP2
|
4*25G/10*10G
|
CFP2 MSA,CFP-MSA-MIS
|
CFP4
|
4*25G
|
CFP4 MSA,CFP-MSA-MIS
|
Digital Diagnostic Monitoring
Remote monitoring module to ensure the normal operation of modules, when abnormal, the system administrator can find some potential problems and fault location.
5 real-time measurement parameters for DDM monitoring are:
Project
|
Accuracy
|
Unit
|
TX-POWER
|
±3
|
dBm
|
RX-POWER
|
±3
|
dBm
|
LASER BIAS
|
10﹪
|
mA
|
Temp
|
±3
|
℃
|
VCC
|
±0.1
|
V
|
Eye Diagram
Where is the transceiver module used?
Optical modules are widely used in switches, routers, server network cards and other devices.
1) based on the algorithm set switch, router brand: CISCO, HP, H3C, LUCENT...
2 with special set of switches, router brands: EXTREME, NORTEL, ALCATEL, 3COM, BROCADE...
3) other switches: HUAWEI, ZTE, etc.


Application of optical module
Synchronous network (SDH/SONET): mainly used for backbone network transmission
SDH signal standard rate rating: STM-1 is 155.52M, STM-4 is 622.08M, STM-16 is 2488.32M, STM-64 is 9.953.28M, STM-256 is 40G. SONET rate rating: OC3, OC12, OC48, OC192, etc..SONET is used in North America and Japan, SDH is used in China and Europe. Main standard agreement: ITU-T series standard.
Fiber channel (Fibre Channel): primarily for optical storage networks.
1.0625G/2.125G/4.25G/8.5G/10.52G/14.025G/28.05G, the main standard agreement is: FC-PI-1, FC-PI-5, etc..
Ethernet (Ethernet): access network most commonly used network solutions, transmission rate Name: 100BASE-SX, 1000BASE-LX, 10GBASE-EX, etc.. Contains speed: 125M, 1.25G, 10.3125G, etc..