Things You May Feel Curious About CWDM Transceiver

WDM is a new technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths of laser light. And in fiber-optic communications, Coarse Wavelength-Division Multiplexing (CWDM) is a convenient and cost-effective solution for the adoption of Gigabit Ethernet and Fiber Channel in campus, data-center, and metropolitan-area access networks, which has greater potential compared with DWDM (Dense wavelength division multiplexing). There are some things you may feel curious about CWDM transceiver, after going through this passage, you might have a clear understanding of CWDM transceiver.

 

1. What is the difference between CWDM transceiver and DWDM transceiver? The main difference between CWDM transceiver and DWDM transceiver lies in the wavelength interval. The DWDM system’s wavelength interval is 0.2nm to 1.2nm, while CWDM possesses a much broader wavelength interval, and each wavelength band covers the five wave bands—O, E, S, C, L of single-mode fiber system. CWDM transceivers’s wavelength is 1270 nm, 1290 nm, 1310 nm, 1330 nm, 1350 nm, 1370 nm, 1390 nm, 1410 nm, 1430 nm, 1450 nm, 1470 nm, 1490 nm, 1510 nm, 1530 nm, 1550 nm, 1570 nm, 1590 nm, 1610 nm.

2. If my equipment doesn’t support CWDM or DWDM transceivers, how can I transport the signal over a WDM network? The connector type is generally a function of the density of the transceiver. CWDM transceiver supports FC/APC, FC/UPC, SC/APC, SC/UPC, LC/UPC, LC/APC, etc. GBIC transceiver is larger than an SFP transceiver, the GBIC uses the larger “SC" style of connecter while the SFP/SFP+ transceiver uses the smaller “LC" style of optical connector. Many times the optical patch cables will need to have different connector styles at each end, and example is having a SFP (LC connector) installed in a router connected to a SC port on a patch panel.

3. Can you describe the basic capabilities of CWDM transceiver? CWDM transceiver supports DFB Laser transmitter and its compliant receiver is PIN or APD. CWDM transceiver’s data rate is up to 2.7Gbps. And its operating temperature is between 0℃ and +70℃ with a distance up to 80km, which is compliant with SFP MSA SFF-8074i, digital diagnostic SFF-8472, Telcordia GR-468 and RoHS.

4. You might be curious about how to test CWDM transceiver since the coverage range of CWDM transceiver’s wavelength is very wide. To be honest, it is relatively complicated to test it, but to put it simple you can use the following methods. One is that using the white light as testing light, and then using the scan spectrometer to test it. The other is that using the 1550 nm LED light as a testing light, and then using scan spectrometer, or you could use tunable laser light source as testing light, then use the PM detection. There are some merits and demerits in the above methods. You should use them flexibly and subject to availability.

5. Since the CWDM transceiver is a new product, it might encounter some problems during its development. What are they? First, with respect to DWDM transceiver, the price advantages of DWDM transceiver is not competitive. DWDM transceiver also put great pressure on CWDM transceiver because it will form a complete metro DWDM network by using DWDM technology with good scalability. Besides, there are technical problems about the higher speed and longer transmission distance of CWDM transceiver.