Xiaolu Liao

All-optical flip-flop operation based on bistability in V-cavity laser.

We theoretically analyzed and experimentally demonstrated an injection-locking based all-optical flip-flop memory using a simple and compact tunable V-cavity laser (VCL). A bistable region in the tuning characteristics of the VCL is employed for the flip-flop operation. The state of the VCL can be set and reset by injecting signal pulses at two different wavelengths. The pulse power for both set and reset signal is only about 1 pJ. Short response times of about 150 ps are measured for storing and erasing.

Half-Wave-Coupled Ring-FP Laser With 50-Channel 100-GHz-Spaced Wavelength Tuning

We report our latest experimental results of the half-wave-coupled rectangular ring-FP laser. All the waveguides of the device are active, and the thermooptic effect is employed to extend the tuning range beyond the free-spectral-range limit. Singleelectrode tuning of 20 channels with 100-GHz spacing is obtained. By combining five single-electrode-controlled tuning curves with different bias currents on fixed electrodes and with the thermoelectric cooler fixed at 20 °C, wavelength tuning of 50 channels with 100-GHz spacing covering the L-band is achieved with a side-mode suppression ratio up to 41 dB. Direct modulation at 2.5 Gb/s is also demonstrated. The simple and compact ring-FP laser has great potential as a low-cost tunable laser for many applications.

Tunable V-coupled-cavity semiconductor laser monolithically integrated with monitoring photodiodes using deeply etched reflective trenches

We present a 1560-nm-band digitally wavelength tunable V-coupled-cavity semiconductor laser monolithically integrated with two waveguides based monitoring photodiodes (MPD) through deeply etched reflective trenches. The reflective trenches are designed to be 1.16μm wide, about three quarters of the wavelength, and are deeply etched through the waveguide with a depth larger than 4μm. Due to the high reflectivity of the etched trenches, a low threshold current of 19mA is achieved. Using a single electrode control, wavelength tuning of 22 channels at 100GHz spacing with SMSR above 35 dB is obtained. The relationship between the photocurrents of the two MPD at the two waveguide branches and the laser output power from the coupler side is investigated as a function of the wavelength. Since the integrated tunable laser with MPDs is very compact and does not involve any grating or epitaxial regrowth, it is suitable for low-cost multifunctional photonic applications for access and data center networks.

Narrow linewidth tunable V-cavity laser using self-injection method

A widely tunable V-cavity semiconductor laser with kilohertz linewidth is demonstrated using simple self-injection method. The tunable laser is packaged into a small-form-factor 9-pin TOSA and can be tuned over 22 channels at 100 GHz spacing with side mode suppression ratios over 36 dB. Self-injection method is used for linewidth reduction by applying optical feedback. Linewidth of the V-cavity laser can be compressed from several megahertz to tens of kilohertz. The linewidth reduction method is essentially channel independent and can be easily realized. It can meet the requirements of many applications such as high-order modulation, coherent communication and sensing.

All-optical wavelength conversion based on tunable V-cavity laser

We design and investigate a monolithically integrated wavelength converter based on a tunable V-cavity laser with a Mach-Zehnder interferometer with independent phase control. A 6.25 Gb/s non-return-to-zero conversion has been modeled using time-domain traveling-wave method.

Double half-wave-coupled rectangular ring-FP semiconductor laser with 19-nm quasi-continuous tuning range

We present our latest experimental results of the double half-wave-coupled rectangular ring-FP laser in a XMD TOSA package. A 19-nm quasi-continuous tuning range with over 30dB side mode suppression ratio is obtained.

All-optical flip-flop memory based on V-cavity laser

We experimentally demonstrate an all-optical flip-flop memory based on the bistability of tunable V-cavity laser with short storing and erasing response time of about 150ps and 159ps, respectively.

Simple and compact tunable semiconductor lasers based on novel half-wave coupler

Widely tunable semiconductor lasers based on a novel half-wave coupler are presented. They have been implemented in the form of half-wave coupled V-cavity and ring-FP cavities. By using the novel half-wave coupler, single-mode lasing with high side-mode-suppression-ratio is achieved. Single-electrode controlled wide-band wavelength tuning with Vernier effect is demonstrated. The full-band tuning of 50 channels with 100GHz spacing is realized by further employing temperature induced gain spectrum shift. The laser is packaged into a small-form-factor 9-pin box TOSA, and the electronic driver has been developed for the wavelength tuning and direct modulation. The advantages of compactness, fabrication simplicity, easy wavelength control and direct modulation allow the tunable lasers to be used in low-cost access and datacenter networks, as well as in portable devices for spectroscopic analysis.

Double Half-Wave-Coupled Rectangular Ring-FP Laser With

A widely wavelength tunable semiconductor laser based on two cascaded half-wave-coupled rectangular ring resonators is demonstrated. Vernier effect between two rectangular rings with perimeter of 281 and 305 μm is employed to enlarge the tuning range. Simple fabrication process is used with all active waveguides. No epitaxial regrowth, grating, or high-resolution lithography is needed. By adjusting the injection currents applied to the cascaded rectangular rings synchronously, wavelength tuning of 35 channels with 100 GHz spacing is achieved with side mode suppression ratio up to 40.5 dB.

35\times 100

We report our latest experimental results of a tunable semiconductor laser based on two cascaded half-wave-coupled rectangular ring resonators. Wavelength tuning of 28 channels with 100GHz spacing is demonstrated with side mode suppression ratio up to 41dB. The wavelength ranges from 1561.3nm to 1583.1nm.