{"id":9391,"date":"2026-10-17T12:19:49","date_gmt":"2026-10-17T12:19:49","guid":{"rendered":"https:\/\/www.westernoptronics.com\/?page_id=9391"},"modified":"2026-10-17T12:24:38","modified_gmt":"2026-10-17T12:24:38","slug":"elsfp-selection-guide","status":"publish","type":"page","link":"https:\/\/www.westernoptronics.com\/fr\/elsfp-selection-guide\/","title":{"rendered":"ELSFP Selection Guide: CWDM4 vs. 1311 nm"},"content":{"rendered":"

Western Optronics application guide<\/strong><\/p>

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\u2014not interchangeable replacements.<\/p>

Choose the wavelength plan first<\/h2>

CWDM4 for 2\u00d7FR4 CPO<\/h3>

CY-ELSFP-8PMF-UHP1-CWDM4-B<\/strong><\/p>

Two sets of 1271, 1291, 1311 and 1331 nm wavelengths. Select this configuration when your optical engine requires two CWDM4 wavelength sets.<\/p>

View the CWDM4 ELSFP module<\/a> \u00b7 Download CWDM4 datasheet (PDF)<\/a><\/p><\/div>

1311 nm for CPO<\/h3>

CY-ELSFP-8PMF-UHP1-1311-B<\/strong><\/p>

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.<\/p>

View the 1311 nm ELSFP module<\/a> \u00b7 Download 1311 nm datasheet (PDF)<\/a><\/p><\/div><\/div>

CWDM4 vs. 1311 nm: specification comparison<\/h2>
Parameter<\/th>CWDM4 ELSFP<\/th>1311 nm ELSFP<\/th><\/tr><\/thead>
Optical channels<\/td>8 continuous-wave channels<\/td>8 continuous-wave channels<\/td><\/tr>
Wavelength arrangement<\/td>2 \u00d7 (1271 \/ 1291 \/ 1311 \/ 1331 nm)<\/td>8 channels at 1311 nm typical<\/td><\/tr>
Optical output<\/td>\u2265 +23 dBm per channel<\/td>\u2265 +23 dBm per channel<\/td><\/tr>
Management<\/td>CMIS<\/td>CMIS<\/td><\/tr>
Nominal supply<\/td>3.3 V<\/td>3.3 V<\/td><\/tr>
Optical interface<\/td>Polarization-maintaining blind-mate interface<\/td>Polarization-maintaining blind-mate interface<\/td><\/tr><\/tbody><\/table><\/figure>

These values apply to the two Western Optronics models named above, not to all ELSFP products. Refer to each model\u2019s datasheet for full specifications and operating conditions.<\/p>

ELSFP selection questions<\/h2>

How is an ELSFP different from an optical transceiver?<\/h3>

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.<\/p>

Does +23 dBm refer to each optical channel?<\/h3>

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.<\/p>

Are the CWDM4 and 1311 nm configurations interchangeable?<\/h3>

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.<\/p>

What should be checked before selecting a model?<\/h3>