M. Haji

Low divergence angle and low jitter 40 GHz AlGaInAs/InP 1.55 μm mode-locked lasers

We demonstrate a novel (to the best of our knowledge) 40 GHz passively mode-locked AlGaInAs/InP 1.55 μm laser with a low divergence angle (12.7°×26.3°), timing jitter of 1.2 ps (10 kHz-100 MHz), and a radio frequency linewidth of 25 kHz.

Monolithic 40-GHz Passively Mode-Locked AlGaInAs–InP 1.55-

We have fabricated 40-GHz passively mode-locked AlGaInAs-InP 1.55- lasers integrated with surface-etched distributed Bragg mirrors. Numerically optimized gratings provide low-scattering losses and accurate wavelength control. The lasers produce 4.46-ps Gaussian pulses with time-bandwidth product of 0.47.

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The first demonstration of harmonic mode-locked operation from a monolithic semiconductor laser comprising a compound cavity formed by twin deeply etched intracavity reflectors based on 1.55-μm AlGaInAs strained quantum-well material is presented. Nearly transform-limited Gaussian pulses are generated at 160-GHz repetition rate with a 1.67-ps pulse duration.

m MQW Laser With Surface-Etched Distributed Bragg Reflector

The monolithic integration of four 1.5 μm range AlGaInAs/InP distributed feedback lasers with a 4×1 multimode-interference optical combiner, a curved semiconductor optical amplifier, and an electro-absorption modulator using relatively simple technologies--sidewall grating and quantum well intermixing--has been demonstrated. The four channels span the wavelength range of 1530 to 1566 nm with a channel spacing of 12 nm. The epitaxial structure was designed to produce a far-field pattern as small as 21.2°×25.1°, producing a coupling efficiency with an angled-end single-mode fiber at twice that of a conventional device design.

160-GHz Passively Mode-Locked AlGaInAs 1.55-

We present a 10-GHz 1.55-μm passively mode-locked laser based on a novel AlGalnAs/InP epitaxial structure with a three-quantum-well active layer incorporating a passive far-field reduction layer. The device generated 1.06 ps pulses with a state-of-art timing jitter value of 194 fs (4-80 MHz), and a radio-frequency linewidth of 2 kHz, while demonstrating a low divergence angle (14.7° × 27.3°) with a twofold butt coupling efficiency to a flat cleaved single-mode fiber, compared to conventional five-quantum-well mode-locked lasers.

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The 45-GHz passively mode-locked AlGaInAs-InP 1.55- m lasers integrated with surface-etched distributed Bragg mirrors have been fabricated. Quantum-well intermixing was used to provide low absorption loss gratings with accurate wavelength control. The lasers produce 3.6-ps Gaussian pulses with time-bandwidth product of 0.57.

m Strained Quantum-Well Compound Cavity Laser

A 240 GHz, sixth-harmonic monolithic ~1.55 μm colliding-pulse mode-locked laser is reported using a three-quantum-well active layer design and a passive far-field reduction layer. The device emits 0.88 ps pulses with a peak power of 65 mW and intermediate longitudinal modes suppressed by >30 dB. The device demonstrates a wide operation range compared to the conventional five-quantum-well design as well as having a low divergence angle (12.7° × 26.3°), granting a twofold improvement in butt-coupling efficiency into a flat cleaved single-mode fibre.

CWDM source based on AlGaInAs/InP monolithically integrated DFB laser array.

We report femtosecond pulses from a passive C-band two-section AlGaInAs/InP mode-locked laser with a monolithically integrated passive waveguide made by quantum well intermixing. Without any external pulse compression, Lorentzian pulses are generated at a repetition frequency of ~38 GHz with 490 fs pulse duration, which is, to the best of our knowledge, the shortest pulse from any directly electrically pumped quantum well semiconductor mode-locked laser. The mode-locking range is relatively large and the ultranarrow pulse width is very stable over a broad range of driving conditions.

10-GHz AlGaInAs/InP 1.55-

Fast saturable absorber recovery times have been obtained in AlGaInAs/InP multiple quantum wells using the cross absorption modulation method for wavelength conversion. We report sub-picosecond pulse generation using a 40 GHz passively mode locked laser.

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A novel laser structure design was used in passive mode-locking. Devices exhibited output with low divergence angle (12.7° × 26.3°), timing jitter of 194 fs (4-80 MHz), and RF linewidth of 2 kHz.