Sdl Inc.

Spectra Diode Laboratories, Inc.

Amos A Hardy

David F Welch

Donald R Scifres

Robert G Waarts

David G Mehuys

Ross A Parke

Stephen O'Brien

Robert J Lang

Alexander Schoenfelder

An optical gain medium comprising, for example, an optical semiconductor device which is differentially pumped and a master oscillator power amplifier (MOPA) device employing such an amplifier. The gain medium may have a linear stripe region or a diverging stripe region that allows the light propagating therein to diverge along at least part of its length, such as a flared or tapered amplifier having a gain region that increases in width toward its output at a rate that equals or exceeds the divergence of the light. The amplifier is pumped with a current density at its input end which is smaller than the current density used to pump the output end for maintaining coherence of the beam to high power levels employing differential pumping. Differential pumping may be both longitudinal and lateral within the amplifier and may be patterned to reduce the peak modal gain observed longitudinally along and/or laterally across the pumped stripe region of the gain medium so that he experienced modal gain of the propagating light is more balanced along the length of the stripe region, i.e., rendered significantly more uniform in distribution, providing for higher diffraction limited performance without optical filamentation formation.

Differentially patterned pumped optical semiconductor gain media

An optical amplifier semiconductor device which is differentially pumped and a master oscillator power amplifier (MOPA) device employing such an amplifier. The amplifier allows the light propagating therein to diverge along at least part of its length, and may be a flared amplifier having a gain region that increases in width toward its output at a rate that equals or exceeds the divergence of the light. The amplifier is pumped with a current density at its input end which is smaller than the current density used to pump the output end for maintaining coherence of the beam to high power levels. Differential pumping may be both longitudinal and lateral within the amplifier. A single mode preamplifier section may be optically coupled to the input end of the amplifier. The amplifier input may have a width which is the same as or wider than that of the preamplifier output. The preamplifier may have a constant mode width or may be tapered to alter the divergence of the beams provided to the amplifier section. The laser oscillator in the MOPA device may be a single mode DBR laser diode monolithically integrated on the same substrate as the optical amplifier. Laser sources external to an amplifier chip may also be used. The input portion of the amplifier or the preamplifier section, if present, may be modulated. The laser oscillator might also be modulated if it has a high Q cavity. Tunable laser oscillators are also disclosed.

Differentially pumped optical amplifer and mopa device

An optical crossbar switch matrix for use in switching optical signals from a first set of optical fibers to a second set of optical fibers, in any order, which is characterized by having a matrix of rows and columns of diffraction gratings formed in a semiconductor heterostructure. Each grating is independently biased with either a forward or reverse bias voltage to switch the grating between a reflective state and a transmissive state. The gratings are oriented at an angle relative to the rows and columns so that when the Bragg condition for the light received from an optical film is met, a portion of the light is diffracted from the row in which it is propagating into a column toward another optical fiber. The heterostructure may include optical amplifiers to restore the optical signal to its original power level. Beam expanding, collimating and focussing optics may also be integrated into the heterostructure.

NxN Optical crossbar switch matrix

In a semiconductor laser array structure in which antiguided regions between high effective refractive index waveguide regions experience greater gain then the waveguide regions, structures introduced at the sides of the array, next to the edgemost waveguides and not on the array period, reflect laterally transmitted radiation back toward the center of the array. The edge reflecting structures may be waveguide regions having widths of (m'+1/2) half-wavelengths, where 'm'' is zero or a positive integer, compared to array waveguides with width m, where 'm' is an integer not necessarily equal to 'm''. The edge reflecting structures may also be stacks of such waveguides, where the regions between the edge waveguides are of a width substantially equal to (n'+1/2) half-wavelengths, compared to antiguide element widths of n half-wavelengths. The two integers n and n' may be, but are not necessarily, equal. Alternatively, the edge reflectors can be mirrors fabricated at the side edges of the array or by disordering the active region beyond the edgemost waveguides to form a refractive index step. The mirrors should be positioned a distance substantially a/2 from the edgemost emitters, where 'a' is the array period.

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Tel Aviv, Israel

Amos A Hardy