Title: Cross-talk free, low-noise optical amplifier

Abstract

A low-noise optical amplifier solves crosstalk problems in optical amplifiers by using an optical cavity oriented off-axis (e.g. perpendicular) to the direction of a signal amplified by the gain medium of the optical amplifier. Several devices are used to suppress parasitic lasing of these types of structures. The parasitic lasing causes the gain of these structures to be practically unusable. The lasing cavity is operated above threshold and the gain of the laser is clamped to overcome the losses of the cavity. Any increase in pumping causes the lasing power to increase. The clamping action of the gain greatly reduces crosstalk due to gain saturation for the amplified signal beam. It also reduces other nonlinearities associated with the gain medium such as four-wave mixing induced crosstalk. This clamping action can occur for a bandwidth defined by the speed of the laser cavity. The lasing field also reduces the response time of the gain medium. By having the lasing field off-axis, no special coatings are needed. Other advantages are that the lasing field is easily separated from the amplified signal and the carrier grating fluctuations induced by four-wave mixing are decreased. Two related methods reduce the amplified spontaneous emission power withoutmore » sacrificing the gain of the optical amplifier. « less

Inventors:

Dijaili, Sol P ^[1]; Patterson, Frank G ^[2]; Deri, Robert J ^[3]

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1. Moraga, CA
2. Livermore, CA
3. Pleasanton, CA

Issue Date:

Sun Jan 01 00:00:00 EST 1995

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

OSTI Identifier:

870004

Patent Number(s):

5436759

Assignee:

Regents of University of California (Oakland, CA)

Patent Classifications (CPCs):

H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01S - DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT

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H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01S - DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT

H01S2301/02 - ASE
H01S5/10 - Construction or shape of the optical resonator {, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
H01S5/50 - Amplifier structures not provided for in groups H01S5/02 - H01S5/30
H01S5/5063 - {operating above threshold}
H01S5/5072 - {Gain clamping, i.e. stabilisation by saturation using a further mode or frequency}

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DOE Contract Number:  

W-7405-ENG-48

Resource Type:

Patent

Country of Publication:

United States

Language:

English

Subject:

cross-talk; free; low-noise; optical; amplifier; solves; crosstalk; amplifiers; cavity; oriented; off-axis; perpendicular; direction; signal; amplified; medium; devices; suppress; parasitic; lasing; types; structures; causes; practically; unusable; operated; threshold; laser; clamped; overcome; losses; increase; pumping; power; clamping; action; greatly; reduces; due; saturation; beam; nonlinearities; associated; four-wave; mixing; induced; occur; bandwidth; defined; speed; field; response; time; special; coatings; advantages; easily; separated; carrier; grating; fluctuations; decreased; related; methods; reduce; spontaneous; emission; sacrificing; related method; optical amplifier; four-wave mixing; greatly reduces; related methods; laser cavity; optical cavity; response time; signal beam; easily separated; spontaneous emission; signal amplified; optical amplifiers; greatly reduce; wave mixing; noise optical; low-noise optical; /359/