Semiconductor gain medium with multimode and single mode regions

a gain medium and semiconductor technology, applied in semiconductor lasers, instruments, optical elements, etc., can solve the problems of mw cw, associated higher output power, and generally low output power, and achieve the effect of high power amplification of forward propagating ligh

Inactive Publication Date: 2001-02-13
JDS UNIPHASE CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The above objects are met with a semiconductor active medium comprising an, at most, marginally stable resonant cavity with a single-spatial-mode filter therein. The semiconductor active medium is preferably an electrically pumped light amplifying diode heterostructure or "amplifier chip" that has a flared gain region with a narrow, single mode, optical aperture end and a broad light output end. The flared gain region permits the light to freely diverge as it propagates in the gain region, so the light has a diverging phase front. Only the central-most light rays of backward propagating light

Problems solved by technology

A problem with previously available external-cavity semiconductor lasers is their generally low output power (on the order of 10 mW cw and 2

Method used

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  • Semiconductor gain medium with multimode and single mode regions
  • Semiconductor gain medium with multimode and single mode regions
  • Semiconductor gain medium with multimode and single mode regions

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Embodiment Construction

With reference to FIG. 1, an external-cavity semiconductor laser, in accord with one embodiment of the present invention, has an active gain medium that is a light amplifying diode heterostructure or "amplifier chip" 11, and also has a light reflective, external, diffraction grating 15 and a lens 13. The amplifier chip 11 shown in FIG. 1 has a single mode waveguide section 17 incorporated on the grating side of the chip, opening into a flared gain section 19 on the output side of the chip. Preferably, the flared gain region 19 is linearly flared and increases in width toward the front output facet 21 of the amplifier chip 11 at a rate that is slightly greater than the divergence of light propagating within the flared gain region 19. The front output facet 21 is typically coated for low reflection. Though a facet reflectivity of 30% would likely be acceptable, typically the reflectivity of the coated facet 21 is less than 10%, with a 2 to 3% reflectivity being preferred. The rear fac...

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Abstract

A semiconductor gain medium has an optical cavity comprising a multimode region permitting propagation of light with a diverging phase front and a single mode region. An optical cavity is formed by optical feedback within the medium. Preferably, the feedback comprises a combination of a cleaved facet and a grating. The gain medium may be an amplifier or, in addition to the amplifier, may include a resonator cavity, or operate as an unstable resonator.

Description

BACKGROUND OF THE INVENTION1. Technical FieldThe present invention relates to semiconductor gain media, especially to those devices that include an integrated multimode region and single mode region and more particularly to laser devices with single spatial mode, diffraction-limited emission with flared gain regions.2. Background ArtExternal-cavity semiconductor lasers, including lasers with frequency selective tuning elements in the cavity, are well known and have been extensively studied. For example, T. Fujita, et al., in Applied Physics Letters 51(6), pages 392-394 (1987), describe a laser having a buried heterostructure laser that has been antireflection (AR) coated on the intracavity facet, a collimating lens, a polarization beamsplitter, external cavity mirrors in each of the TE and TM polarization light paths, and an electro-optic modulator in the TE polarization path between the beamsplitter and cavity mirror. The configuration allows selection of either the TE or TM mode o...

Claims

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Application Information

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IPC IPC(8): H01S5/10H01S5/00H01S5/20H01S5/12H01S3/081H01S3/23H01S5/026H01S5/042H01S5/0625H01S5/065H01S5/125H01S5/14H01S5/185H01S5/187H01S5/40H01S5/50
CPCG02B6/12004G02B6/305H01S3/0818H01S3/113H01S5/026H01S5/0286H01S5/0625H01S5/06256H01S5/0655H01S5/1003H01S5/1014H01S5/1064H01S5/1082H01S5/1085H01S5/1215H01S5/125H01S5/14H01S5/141H01S5/146H01S5/187H01S5/20H01S5/2036H01S5/2063H01S5/4025H01S5/4062H01S5/4087H01S5/50H01S2301/166H01S5/04256H01S5/185H01S5/065H01S5/10
Inventor WELCH, DAVID F.MEHUYS, DAVID G.SCIFRES, DONALD R.
Owner JDS UNIPHASE CORP
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