All-optical routing using a 12×12 passive InP wavelength selective router and tuneable wavelength conversion

All-optical routing of 2.5Gbit/s WDM signals across two cascaded Optical Cross Connects(OXCs) with a penalty of only 0.6dB has been demonstrated using tuneable wavelength converters and a passive WDM router.

Demonstration of multi wavelength picosecond pulse generation with resonant RF drive using an monolithically integrated multi-grating cavity (MGC) laser

Multiwavelength pulses were generated using a monolithically integrated device. The device used is an integrated InGaAs/InGaAsP/InP multi-wavelength laser fabricated by selective area regrowth. The device self pulsated on all of the four wavelength channels. 48 ps pulses were obtained which were measured by a 50GHz oscilloscope and 32GHz photodiode which was not bandwidth limited. Simultaneous multi-wavelength pulse generation was also achieved.

Fabrication of test structures for 4×4 InP/InGaAsP integrated optical matrix

A novel optical switching matrix measuring 1×2 mm2 in size is fabricated. The switching matrix is composed of waveguides, four 1×4 multimode interference (MMI) splitters, 32 total internal refraction mirrors and four 4×1 MMI combiners with the extremely compact size of 1×2 mm2. This integrated device are assessed and loss contribution measured from test structure is presented.

Technique for wavelength converting a 2.488 Gb/s signal whilst simultaneously monitoring and replacing a wavelength identifying pilot tone

A wavelength conversion device was demonstrated at the bit rate of 2.488 Gb/s with 2R (reamplification and reshaping) regenerative properties. A low frequency pilot tone was removed during the conversion process and a new one added. The wavelength converter is shown to operate well at 10 Gb/s, and tone identification/replacement should also be possible at this data rate.

All optical wavelength conversion at 2.488 Gbits/s using the integrated multi grating cavity (MGC) laser

A novel integrated Multi-Wavelength Grating Cavity (MGC) laser has been used for multi-channel wavelength conversion at 2.488 Gbits/s. Functions demonstrated include conversion to multiple wavelengths, WDM multiplexing and 1×4 space switching.

Multi-wavelength picosecond pulse generation using a monolithically integrated Multi-wavelength Grating Cavity (MGC) laser

Multi-wavelength picosecond pulses are demonstrated using a single monolithically integrated Multi-wavelength Grating Cavity (MGC) laser. This is achieved on two WDM wavelength channels at a repetition rate of 7.63 GHz.

Three band-gap QW intermixing in InP/InGaAs/InGaAsP system for monolithically integrated optical switch

Quantum well intermixing is a key technique for photonic integration. The intermixing of InP/InGaAs/InGaAsP material involving the deposition of a layer of sputtered SiO2 on the semiconductor surface, followed by thermal annealing has allowed good control of the intermixing process and has been used to fabricate extended cavity lasers. This will be used for optimization of the performance of optical switches consisting of passive components, modulators and amplifiers.

1 × 4 space switching and simultaneous all-optical wavelength conversion at 2.488Gbit/s using a single monolithically integrated multiwavelength laser

A novel InGaAs/InGaAsP/InP integrated multiwavelength grating cavity laser is presented, which has been used to demonstrate space switching and simultaneous all-optical wavelength conversion at bit rates of 2.488 Gbit/s. This has been achieved using a single monolithically integrated device without the need for post-filtering to separate the converted signal from the input.

Process development on the monolithic fabrication of an ultra-compact 4×4 optical switch matrix on InP/InGaAsP material

We have fabricated an ultra-compact 4×4 optical matrix on InP/InGaAsP material. 1×4 MMI couplers and TIR mirrors are employed to produce a compact 1×2 mm2 device. A CH4/H2/O2 RIE dry etch process has been used to realize two-level dry etching: deep-etch for both the MMI couplers and the mirrors and shallow-etch for the rest of the routing waveguides. It was found that a metal/dielectric bilayer mask is essential for multi-dry-etch processes and high profile verticality. We have found a Ti intermediate mask for the deep-etch process which is removable by SF6 dry-etch before the following shallow process. Dry-etch removal of the intermediate mask is necessary to protect the deep-etched mirror sidewall.

All-optical 3R regeneration and format conversion in an integrated SOA/DFB laser

Using a compact, integrated device at 2.488Gb/s, simultaneous NRZ to RZ format conversion and regeneration was achieved. The regenerated signal has a negative BER sensitivity of -1.5dB compared with a data signal transmitted down 101km of standard fiber.

All-optical 3R regeneration and wavelength conversion in an integrated SOA/DFB laser: Experiment and simulation

The simultaneous all optical 3R regeneration and format conversion in a simple, single integrated device was examined. The integrated device consisted of a semiconductor optical fiber (SOA) monolithically integrated with a distributed feedback (DFB) laser. Gain saturation was employed for the transmission of a data signal regenerated all-optically in the laser/amplifier device. The regeneration of the electrically filtered eye diagrams was observed by noise removal and extinction ratio-improvement by the device.

10-Gbits/s all-optical 3R regeneration and format conversion using a gain-switched DFB laser

A strain-compensated multiple quantum well device is used as a DFB laser, this has been optimized for low jitter gain switched operation at 10 GHz. The signal is transmitted down 80 km of standard fiber then amplified, filtered and polarization controlled before being injected into a DFB laser. The purpose of this regeneration process is to gain switch the DFB with the extracted clock signal in order to retime the converted signal. This process also simultaneously converts the input NRZ format to an output RZ data to format and results in a signal whose optical power and extinction ratio are considerably improved by the regeneration process.

All-optical switching in a vertical coupler space switch employing photocarrier-induced nonlinearity

A novel compact integrated nonlinear optical switch is demonstrated. Using a high-power picosecond pulse of 5-ps pulsewidth and 250-MHz repetition rate, all-optical switching with a contrast ratio of 23 dB has been achieved using an in-fiber input power < 14 dBm (100 pJ/pulse). The switch speed depends on the carrier sweep-out time, which can be reduced to the 10 ps range by either applying a reverse bias or by introduction of carrier recombination centers in the active layer.

All optical wavelength conversion at 2.488GBits/s using the integrated multi grating cavity (MGC) laser

A novel integrated Multi-Wavelength Grating Cavity (MGC) laser has been used for multi-channel wavelength conversion at 2.488Gbits/s. Functions demonstrated include conversion to multiple wavelengths, WDM multiplexing and 1×4 space switching.