Analog optical fiber communication system, and laser adapted for use in such a system
US5111475A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 1991 |
| Grant date | May 5, 1992 |
| Priority date | — |
| Expiry date | Mar 20, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/1243
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Lasers for use in multichannel analog optical fiber communication systems (e.g., of the type contemplated for CATV) have to meet very stringent requirements, including high linearity. DFB lasers are advantageously used in such communication systems. Typically only a relatively small percentage of the nominally identical DFB lasers on a wafer meet the specifications. It has now been discovered that the likelihood that a given DFB laser will meet the requirements is substantially increased if the laser comprises means that are adapted for producing a non-uniform photon density in the laser cavity, with the density of photons being larger in the rear portion of the cavity than in the front portion, such that during operation of the laser the gain in the back portion is substantially independent of the laser current, whereas the gain in the front portion is a function of the laser current. A particular embodiment of the invention is a "bare patch" DFB laser having a grating that extends only part way from the front facet towards the back facet, such that a portion of the laser cavity does not have the grating associated therewith. The design ensures that the proper photon density is es…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.