English 
Chinese 
German 
French 
Russian 
Arabic 
Panjabi Western Optronics application guide
Choose an ELSFP external laser source by matching its wavelength arrangement to your CPO optical engine. The CWDM4 and 1311 nm models below both supply eight channels of continuous-wave light, but they are separate configurations—not interchangeable replacements.
Choose the wavelength plan first
CWDM4 for 2×FR4 CPO
CY-ELSFP-8PMF-UHP1-CWDM4-B
Two sets of 1271, 1291, 1311 and 1331 nm wavelengths. Select this configuration when your optical engine requires two CWDM4 wavelength sets.
View the CWDM4 ELSFP module · Download CWDM4 datasheet (PDF)
1311 nm for CPO
CY-ELSFP-8PMF-UHP1-1311-B
Eight channels at a typical wavelength of 1311 nm, arranged in two banks of four. Select this configuration when your optical engine requires the corresponding 1311 nm wavelength plan.
View the 1311 nm ELSFP module · Download 1311 nm datasheet (PDF)
CWDM4 vs. 1311 nm: specification comparison
| Parameter | CWDM4 ELSFP | 1311 nm ELSFP |
|---|---|---|
| Optical channels | 8 continuous-wave channels | 8 continuous-wave channels |
| Wavelength arrangement | 2 × (1271 / 1291 / 1311 / 1331 nm) | 8 channels at 1311 nm typical |
| Optical output | ≥ +23 dBm per channel | ≥ +23 dBm per channel |
| Management | CMIS | CMIS |
| Nominal supply | 3.3 V | 3.3 V |
| Optical interface | Polarization-maintaining blind-mate interface | Polarization-maintaining blind-mate interface |
These values apply to the two Western Optronics models named above, not to all ELSFP products. Refer to each model’s datasheet for full specifications and operating conditions.
ELSFP selection questions
How is an ELSFP different from an optical transceiver?
An ELSFP supplies continuous-wave laser light to a compatible CPO optical engine for external modulation. It is not a complete optical transceiver. Select the laser source and host optical engine as a compatible system.
Does +23 dBm refer to each optical channel?
Yes. CY-ELSFP-8PMF-UHP1-CWDM4-B and CY-ELSFP-8PMF-UHP1-1311-B each specify a minimum optical output of +23 dBm per channel. This is not the combined output of all eight channels.
Are the CWDM4 and 1311 nm configurations interchangeable?
Not automatically. The CWDM4 model supplies two four-wavelength sets, while the 1311 nm model supplies eight channels at one typical wavelength. Confirm the optical-engine wavelength plan, optical connector, fiber assignment and host requirements before ordering.
What should be checked before selecting a model?
- Wavelength plan: confirm whether the optical engine requires two CWDM4 wavelength sets or eight 1311 nm channels.
- Optical interface: confirm the mating connector, fiber assignment and polarization requirements.
- Power and operating conditions: check the required optical output and the electrical and thermal limits against the model-specific datasheet.
- Host integration: confirm mechanical fit and management-interface compatibility with your platform.
- Evaluation: identify the evaluation kit and test-cable configuration needed for your setup.
Explore the ELSFP evaluation kit.
Request selection support
For a quotation, include the model, quantity, delivery schedule, optical connector, fiber assignment and host platform. If the model is not yet selected, provide the optical-engine wavelength plan and required optical power.
Email: sales@westernoptronics.com