# CWDM and DWDM Channel Wavelength Chart (ITU Grid)

> Source: https://netray.co/tools/cwdm-and-dwdm-channel-wavelength-reference
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Free Tools

## Short answer

Look up CWDM wavelengths and DWDM 100 GHz channel numbers, frequencies in THz and wavelengths in nm.

## Category

industry-templates

## Industry

Fiber Optics

## Audience

- Fiber engineer
- Optical network designer
- Test engineer

## Tool

**Kind:** worksheet

**Mode:** reference

**Columns:**

#### Grid

**Key:** grid

**Type:** text

#### Channel

**Key:** ch

**Type:** text

#### Frequency (THz)

**Key:** freq

**Type:** text

#### Wavelength (nm)

**Key:** wl

**Type:** text

#### Band

**Key:** band

**Type:** text

**Rows:**

**Grid:** CWDM 20 nm

**Ch:** 1270

**Freq:** 236.1

**Wl:** 1270

**Band:** O

**Grid:** CWDM 20 nm

**Ch:** 1290

**Freq:** 232.4

**Wl:** 1290

**Band:** O

**Grid:** CWDM 20 nm

**Ch:** 1310

**Freq:** 228.8

**Wl:** 1310

**Band:** O

**Grid:** CWDM 20 nm

**Ch:** 1330

**Freq:** 225.4

**Wl:** 1330

**Band:** O

**Grid:** CWDM 20 nm

**Ch:** 1350

**Freq:** 222.1

**Wl:** 1350

**Band:** O

**Grid:** CWDM 20 nm

**Ch:** 1370

**Freq:** 218.8

**Wl:** 1370

**Band:** E

**Grid:** CWDM 20 nm

**Ch:** 1390

**Freq:** 215.7

**Wl:** 1390

**Band:** E

**Grid:** CWDM 20 nm

**Ch:** 1410

**Freq:** 212.6

**Wl:** 1410

**Band:** E

**Grid:** CWDM 20 nm

**Ch:** 1430

**Freq:** 209.6

**Wl:** 1430

**Band:** E

**Grid:** CWDM 20 nm

**Ch:** 1450

**Freq:** 206.8

**Wl:** 1450

**Band:** E

**Grid:** CWDM 20 nm

**Ch:** 1470

**Freq:** 203.9

**Wl:** 1470

**Band:** S

**Grid:** CWDM 20 nm

**Ch:** 1490

**Freq:** 201.2

**Wl:** 1490

**Band:** S

**Grid:** CWDM 20 nm

**Ch:** 1510

**Freq:** 198.5

**Wl:** 1510

**Band:** S

**Grid:** CWDM 20 nm

**Ch:** 1530

**Freq:** 195.9

**Wl:** 1530

**Band:** C

**Grid:** CWDM 20 nm

**Ch:** 1550

**Freq:** 193.4

**Wl:** 1550

**Band:** C

**Grid:** CWDM 20 nm

**Ch:** 1570

**Freq:** 191.0

**Wl:** 1570

**Band:** L

**Grid:** CWDM 20 nm

**Ch:** 1590

**Freq:** 188.5

**Wl:** 1590

**Band:** L

**Grid:** CWDM 20 nm

**Ch:** 1610

**Freq:** 186.2

**Wl:** 1610

**Band:** L

**Grid:** DWDM 100 GHz

**Ch:** C21

**Freq:** 192.1

**Wl:** 1560.61

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C22

**Freq:** 192.2

**Wl:** 1559.79

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C23

**Freq:** 192.3

**Wl:** 1558.98

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C24

**Freq:** 192.4

**Wl:** 1558.17

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C25

**Freq:** 192.5

**Wl:** 1557.36

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C26

**Freq:** 192.6

**Wl:** 1556.55

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C27

**Freq:** 192.7

**Wl:** 1555.75

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C28

**Freq:** 192.8

**Wl:** 1554.94

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C29

**Freq:** 192.9

**Wl:** 1554.13

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C30

**Freq:** 193.0

**Wl:** 1553.33

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C31

**Freq:** 193.1

**Wl:** 1552.52

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C32

**Freq:** 193.2

**Wl:** 1551.72

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C33

**Freq:** 193.3

**Wl:** 1550.92

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C34

**Freq:** 193.4

**Wl:** 1550.12

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C35

**Freq:** 193.5

**Wl:** 1549.32

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C36

**Freq:** 193.6

**Wl:** 1548.51

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C37

**Freq:** 193.7

**Wl:** 1547.72

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C38

**Freq:** 193.8

**Wl:** 1546.92

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C39

**Freq:** 193.9

**Wl:** 1546.12

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C40

**Freq:** 194.0

**Wl:** 1545.32

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C41

**Freq:** 194.1

**Wl:** 1544.53

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C42

**Freq:** 194.2

**Wl:** 1543.73

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C43

**Freq:** 194.3

**Wl:** 1542.94

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C44

**Freq:** 194.4

**Wl:** 1542.14

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C45

**Freq:** 194.5

**Wl:** 1541.35

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C46

**Freq:** 194.6

**Wl:** 1540.56

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C47

**Freq:** 194.7

**Wl:** 1539.77

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C48

**Freq:** 194.8

**Wl:** 1538.98

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C49

**Freq:** 194.9

**Wl:** 1538.19

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C50

**Freq:** 195.0

**Wl:** 1537.40

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C51

**Freq:** 195.1

**Wl:** 1536.61

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C52

**Freq:** 195.2

**Wl:** 1535.82

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C53

**Freq:** 195.3

**Wl:** 1535.04

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C54

**Freq:** 195.4

**Wl:** 1534.25

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C55

**Freq:** 195.5

**Wl:** 1533.47

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C56

**Freq:** 195.6

**Wl:** 1532.68

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C57

**Freq:** 195.7

**Wl:** 1531.90

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C58

**Freq:** 195.8

**Wl:** 1531.12

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C59

**Freq:** 195.9

**Wl:** 1530.33

**Band:** C

**Grid:** DWDM 100 GHz

**Ch:** C60

**Freq:** 196.0

**Wl:** 1529.55

**Band:** C

**Notes:** CWDM channels are the ITU-T G.694.2 grid at 20 nm spacing; the Channel column shows the nominal wavelength. DWDM rows are the ITU-T G.694.1 100 GHz grid anchored at 193.1 THz, wavelength = 299792.458 / frequency in THz. Frequencies are rounded.

## Content

**Intro:** CWDM and DWDM multiplex several wavelengths onto one fiber pair. This chart lists the 18 CWDM wavelengths and the 40 DWDM C-band channels from C21 to C60 on the 100 GHz grid, so you can match mux ports, transceivers and filter modules.

**Sections:**

#### How to use the chart

**Body:** Search a wavelength or channel number to get the matching row. For CWDM, pick the wavelengths that your transceivers and mux support; many 8-channel muxes use 1470 to 1610 nm. For DWDM, match the C-number on the transceiver label to the mux port and check that the frequency is on the grid of your mux and amplifier.

#### The math behind the grid

**Body:** Wavelength in nanometers equals 299792.458 divided by frequency in terahertz. The DWDM 100 GHz grid is anchored at 193.1 THz (about 1552.52 nm), and channel numbers on this table count 100 GHz steps from 190.0 THz, so C31 is 193.1 THz. Higher frequency means shorter wavelength, so C60 sits at the short end of the C-band near 1529.55 nm.

**Bullets:**

- 100 GHz spacing is about 0.8 nm near 1550 nm.
- CWDM spacing is 20 nm, so uncooled lasers can drift without crosstalk.
- 50 GHz grids insert a channel between each 100 GHz pair.

#### Common mistakes

**Body:** Do not mix CWDM and DWDM filters on the same port, and do not use 1470 to 1610 nm CWDM optics through a mux that passes only the C-band. Confirm the O-band 1270 to 1330 nm CWDM channels are supported by your fiber; legacy fiber with a water peak near 1383 nm loses E-band channels. Note that channel-numbering conventions differ between vendors, so always confirm the wavelength.

**Cta:** Netray can map optical module part numbers and wavelengths to ERP item masters so planners see the right optics for each build.

**Faq:**

#### How many CWDM channels are there?

**Answer:** The ITU-T G.694.2 grid defines 18 channels from 1271 to 1611 nm at 20 nm spacing. In practice vendors label them 1270, 1290 and so on up to 1610 nm, and most muxes use 4, 8 or 16 of them.

#### What is the DWDM 100 GHz grid?

**Answer:** It is the ITU-T G.694.1 frequency plan where channels are 100 GHz apart, anchored at 193.1 THz. Near 1550 nm that is roughly 0.8 nm of wavelength spacing per channel.

#### How do I convert THz to nm?

**Answer:** Divide 299792.458 by the frequency in THz. For 193.1 THz the result is about 1552.52 nm. The relation is inverse, so higher frequency gives a shorter wavelength.

#### Can CWDM and DWDM run together?

**Answer:** Yes, with a CWDM mux that has a pass port in the C-band, DWDM channels can be added behind it. Plan the loss of both mux stages in the link power budget.

## Search terms

CWDM wavelengths, CWDM channel chart, DWDM channel plan, DWDM 100 GHz grid, ITU grid channel frequency wavelength, C21 to C60 DWDM, 1550 nm DWDM channel, CWDM 1470 1490 1510

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