Mach-Zehnder Interferometer Wavelength Converter Research Articles

Silicon Photonics towards Disaggregation of Resources in Data Centers

In this paper, we demonstrate two subsystems based on Silicon Photonics, towards meeting the network requirements imposed by disaggregation of resources in Data Centers. The first one utilizes a 4 × 4 Silicon photonics switching matrix, employing Mach Zehnder Interferometers (MZIs) with Electro-Optical phase shifters, directly controlled by a high speed Field Programmable Gate Array (FPGA) board for the successful implementation of a Bloom-Filter (BF)-label forwarding scheme. The FPGA is responsible for extracting the BF-label from the incoming optical packets, carrying out the BF-based forwarding function, determining the appropriate switching state and generating the corresponding control signals towards conveying incoming packets to the desired output port of the matrix. The BF-label based packet forwarding scheme allows rapid reconfiguration of the optical switch, while at the same time reduces the memory requirements of the node’s lookup table. Successful operation for 10 Gb/s data packets is reported for a 1 × 4 routing layout. The second subsystem utilizes three integrated spiral waveguides, with record-high 2.6 ns/mm2, delay versus footprint efficiency, along with two Semiconductor Optical Amplifier Mach-Zehnder Interferometer (SOA-MZI) wavelength converters, to construct a variable optical buffer and a Time Slot Interchange module. Error-free on-chip variable delay buffering from 6.5 ns up to 17.2 ns and successful timeslot interchanging for 10 Gb/s optical packets are presented.

On-Chip SOI Delay Line Bank for Optical Buffers and Time Slot Interchangers

We demonstrate integrated silicon-on-insulator (SOI) spiral waveguides with record-high 2.6-ns/mm2 on-chip delay efficiency performing as delay bank stage in variable optical delay buffering and time-slot interchanger applications with 10-Gb/s optical packets. The micro-scale SOI chip comprises three integrated waveguide delay elements of different lengths, providing variable delays of 6.5, 11.3, and 17.2 ns, respectively. Utilizing two semiconductor optical amplifier Mach-Zehnder interferometer wavelength converters and on-chip packet delay, error-free on-chip variable delay buffering from 6.5 to 17.2 ns and successful time-slot interchanging for 10-Gb/s optical packets are presented.

Input-Power and Polarization Insensitive All-Optical Wavelength Converter With Monolithically Integrated Monitor PD and Gain-Controlled SOA

This paper presents a polarization-insensitive semiconductor optical amplifier Mach-Zehnder Interferometer (SOA-MZI) wavelength converter with a wide dynamic range. Direct detection of the wavelength-converted output signal power and feedback control of the signal power input to the SOA-MZI are proposed and are confirmed to be able to reduce the variation with input signal power and polarization. The gain-controlled SOA (GC-SOA) and monitor PD used to implement the feedback control are monolithically integrated into the SOA-MZI wavelength converter. A dynamic range of over 8 dB is obtained for TE and TM polarized input signals NRZ modulated at 43 Gb/s under feedback control, 7 dB better than with no feedback.

Study of the OCDMA Transmission Characteristics in FSO-FTTH at Various Distances, Outdoor

Abstract It is important to apply the field Programmable Gate Array (FPGA), and Optical Switch technology as an encoder and decoder for Spectral Amplitude Coding Optical Code Division Multiple Access (SAC-OCDMA) Free Space Optic Fiber to the Home (FSO-FTTH) transmitter and receiver system design. The encoder and decoder module will be using FPGA as a code generator, optical switch using as encode and decode of optical source. This module was tested by using the Modified Double Weight (MDW) code, which is selected as an excellent candidate because it had shown superior performance were by the total noise is reduced. It is also easy to construct and can reduce the number of filters required at a receiver by a newly proposed detection scheme known as AND Subtraction technique. MDW code is presented here to support Fiber-To-The-Home (FTTH) access network in Point-To-Multi-Point (P2MP) application. The conversion used a Mach-Zehnder interferometer (MZI) wavelength converter. The performances are characterized through BER and bit rate (BR), also, the received power at a variety of bit rates.

Performance Analysis of OCDMA Based on AND Detection in FTTH Access Network Using PIN & APD Photodiodes

Abstract In order to comprise between PIN photo detector and avalanche photodiodes in a system used double weight (DW) code to be a performance of the optical spectrum CDMA in FTTH network with point-to-multi-point (P2MP) application. The performance of PIN against APD is compared through simulation by using opt system software version 7. In this paper we used two networks designed as follows one used PIN photo detector and the second using APD photo diode, both two system using with and without erbium doped fiber amplifier (EDFA). It is found that APD photo diode in this system is better than PIN photo detector for all simulation results. The conversion used a Mach-Zehnder interferometer (MZI) wavelength converter. Also we are study, the proposing a detection scheme known as AND subtraction detection technique implemented with fiber Bragg Grating (FBG) act as encoder and decoder. This FBG is used to encode and decode the spectral amplitude coding namely double weight (DW) code in Optical Code Division Multiple Access (OCDMA). The performances are characterized through bit error rate (BER) and bit rate (BR) also the received power at various bit rate.

The “OPORON” Project: Demonstration of a Fully Functional End-to-End Asynchronous Optical Packet-Switched Network

This paper presents the outcomes of the optical packet switching over wavelength routed network (OPORON) project, which demonstrated an asynchronous end-to-end optical packet switched network. Several novel techniques and subsystems for optical packet-switched network are analyzed and described in details, and their functionalities are validated through a demonstrator. The demonstrated network comprises two wavelength agile edge routers with traffic-shaping capabilities, a fully controlled core router with wavelength conversion (WC) capability, and a control plane. The OPORON edge router incorporates a novel traffic aggregation method, asynchronous optical packet transceiver, and agile wavelength allocation mechanism. The OPORON core router is based on the WC and selection architecture. It utilizes a semiconductor optical-amplifier-based Mach-Zehnder interferometer wavelength converter, in combination with an agile tunable wavelength source and an arrayed waveguide grating, for performing packet switching. The core router also utilizes an advanced and fully controllable mechanism for the packet switch control, which is implemented on field programmable gate array technology. Finally, the integration of the aforementioned subsystems is discussed, and the results of a complete and end-to-end asynchronous and variable length optical packet-switched demonstrator are presented.

40 Gbps All-Optical 3R Regeneration and Format Conversion with Related InP-Based Semiconductor Devices

We report an experimental demonstration of 40 Gbps all-optical 3R regeneration with all-optical clock recovery based on InP semiconductor devices. We also obtain alloptical non-return-to-zero to return-to-zero (NRZ-to-RZ) format conversion using the recovered clock signal at 10 Gbps and 40 Gbps. It leads to a good performance using a Mach-Zehnder interferometric wavelength converter and a self-pulsating laser diode (LD). The self-pulsating LD serves a recovered clock, which has an rms timing jitter as low as sub-picosecond. In the case of 3R regeneration of RZ data, we achieve a 1.0 dB power penalty at 10 -9 BER after demultiplexing 40 Gbps to 10 Gbps with an eletroabsorption modulator. The regenerated 3R data shows stable error-free operation with no BER floor for all channels. The combination of these functional devices provides all-optical 3R regeneration with NRZ-to-RZ conversion.

Optical Burst Switching Router With 40-,10-Gb/s Bit-Rate Transparent Contention Resolution

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> We report a bit-rate transparent optical burst switching (OBS) router prototype using a fast 5 <formula formulatype="inline"><tex>$\times$</tex> </formula> 5 PLZT [(Pb,La)(Zr,Ti)O<formula><tex>$_3$</tex></formula>] optical matrix switch. Dynamic switching in a two-wavelength, 2 <formula formulatype="inline"> <tex>$\times$</tex></formula> 2 OBS switch is demonstrated. Contention resolution using a tunable Mach–Zehnder interferometer wavelength converter for both 40- and 10-Gb/s bursts is demonstrated for the first time. Error-free operation was achieved for both bit rates under the same settings, as required in autonomous networks. </para>

Bidirectional Data Injection Operation of Hybrid Integrated SOA–MZI All-Optical Wavelength Converter

A bidirectional data signal input scheme of a semiconductor optical amplifier--Mach-Zehnder interferometer (SOA-MZI) wavelength converter was proposed and experimentally verified for a nonreturn-to-zero (NRZ)-format signal. Theoretical analyses reveal that it is possible to mitigate the patterning effect induced by cross-gain modulation (XGM) by utilizing the difference of the ratio between the XGM and cross-phase modulation on the injection directions of data signals. A hybrid integrated SOA-MZI all-optical wavelength converter, in which the coupling loss between the SOA and the silica waveguide was as small as 1 dB owing to a unique active alignment technique, was used for the experiment. We have verified the superior characteristics of the proposed operation scheme for the first time. Error-free wavelength-conversion operation for an NRZ signal at 40 Gb/s was confirmed

Polarization-Insensitive Monolithic 40-Gbps SOA–MZI Wavelength Converter With Narrow Active Waveguides

A polarization-insensitive monolithic 40-Gbps semiconductor optical amplifier (SOA)-Mach-Zehnder interferometer wavelength converter has been developed. Based on the photon-electron rate equation, we optimized the dimensions of the waveguide structure to maximize the field confinement in the active layer. An InGaAsP active layer with narrow SOA waveguide effectively enables polarization-insensitive high-speed wavelength conversion. High-precision wafer processing technique enabled the fabrication of submicrometer-wide active waveguides with low current leakage. Input waveguide arrays were fabricated at intervals of 25 mum and mounted in a module with two-lens aspherical lens optics. The 40-Gbps nonreturn-to-zero wavelength conversion experiment demonstrates a clear eye opening over full C-band operation

Cascadability of Optical 3R Regeneration for NRZ Format Investigated in Recirculating Loop Transmission Over Field Fibers

This letter demonstrates optical 3R regeneration in 10-Gb/s nonreturn-to-zero field transmission. The 3R regenerator utilizes semiconductor-optical-amplifier-based Mach-Zehnder interferometer wavelength converters, a synchronous modulator, and a Fabry-Perot filter to realize optical 3R regeneration including all-optical clock recovery. The cascadability of the 3R regenerator is investigated in recirculating loop transmission experiments with various regeneration spacings up to 462 km (corresponding to an input optical signal-to-noise ratio (OSNR) of 22 dB). Transmission with the 3R regenerator shows significant performance improvement over that without 3R regeneration. A 66-km-spaced 3R regeneration with a 33-dB input OSNR achieves 1000-hop cascaded error-free transmission (66 000 km in distance) with no hop-to-hop power penalties. A 264-km-spaced 3R regeneration with a 25-dB input OSNR also achieves 100-hop cascaded transmission (26 400km in distance) with a bit-error-rate error floor at ~1times10-8

NRZ-OOK-to-RZ-BPSK modulation-format conversion using SOA-MZI wavelength converter

A novel all-optical modulation-format conversion from nonreturn-to-zero on-off keying (NRZ-OOK) to return-to-zero binary phase-shift keying (RZ-BPSK) is proposed. A Mach-Zehnder interferometric (MZI) wavelength converter consisting of integrated semiconductor optical amplifiers (SOAs) is utilized to implement the proposed format conversion. Error-free operation at a bit rate of 10.7 Gb/s is experimentally demonstrated in order to show the feasibility of the proposed scheme. The received sensitivity of the converted signal is improved by 2.9 dB compared with a back-to-back NRZ-OOK signal at BER=10/sup -9/. In addition, a reasonable dispersion tolerance of the converted signal up to /spl plusmn/500 ps/nm is observed. The numerical simulation based upon the carrier-rate equation verifies the experimental results.

Improvement of the dynamic input power range in a 10 Gb s−1 all-optical Mach–Zehnder interferometric wavelength converter module with monolithically integrated SOA preamplifiers and tapered-edge multimode interference couplers

All-optical wavelength conversion at 10 Gb s−1 is demonstrated in a Mach–Zehnder interferometric wavelength converter (MZI-WC) module with monolithically integrated SOA preamplifiers and tapered-edge multimode interference couplers (TMMIs). A conventional buried-type 1 × 2 MMI coupler exhibits a minimal excess loss of 0.43 dB and a reflectivity of 5.1 × 10−4 (LMMI = 172 µm, WMMI = 12 µm). We adapt the 1 × 2 TMMI in the MZI-WC to improve back-reflection and poor uniformity, which is a major problem of conventional MMI and Y-branch. A good performance of the MZI-WC monolithically integrated with TMMI and SOA preamplifiers at 10 Gb s−1 is obtained with clear eye patterns, and a power penalty below 1.5 dB at a 10−9 bit error rate over the whole C band (45 nm span) is obtained. The dynamic input power range is enhanced up to 11.3 dB by adjusting only the injection current of the SOA preamplifier.

101-hop cascaded operation of an optical-label switching router with all-optical clock recovery and 3R regeneration

This paper experimentally demonstrates the cascaded operation of an optical-label switching router for up to 101hops with 3R regeneration (reamplification, reshaping, and retiming). A semiconductor optical amplifier-based Mach-Zehnder interferometer wavelength converter performs the reshaping. A Fabry-Peacuterot filter all-optically recovers the clock from the incoming packets. Synchronous modulation by a LiNbO3 modulator using the recovered clock performs the retiming. The 3R regeneration maintains good signal quality in the cascaded operation, which is important for scalable optical networking

The characterization of all-optical 3R regeneration based on InP-related semiconductor optical devices

We report characterization and experimental realization of recent InP-related semiconductor optical devices for all-optical 3R regeneration. A Mach-Zehnder interferometric wavelength converter (MZ IWC) with preamplifiers gives an extinction ratio (ER) improvement and a negative power penalty for all-optical reamplification and reshaping (2R) of pseudorandom bit sequence (PRBS) nonreturn-to-zero (NRZ) data at 10 Gb/s. In addition, we briefly describe the mechanism for injection locking of the multisection laser diode with a distributed feedback (DFB) reflector. Using this device, we demonstrate clock recovery from PRBS return-to-zero (RZ) and NRZ data. The achieved rms timing jitter is less than 1 ps for the input of 11.727 Gb/s PRBS RZ and NRZ. All-optical 3R regeneration leads to a good performance using the MZ IWC and multisection DFB LD. The combination of these functions provides all-optical 3R regeneration with NRZ to RZ conversion. For the realization of a small and compact 3R regeneration module, we propose the hybrid module packaging process, which is composed of 2R and 1R semiconductor chip in single butterfly-type module

Performance optimization of an InP-based widely tunable all-optical wavelength converter operating at 40 Gb/s

We report on the design and performance optimization of a quantum-well active region-based semiconductor optical amplifier Mach-Zehnder interferometer wavelength converter monolithically integrated with a widely tunable sampled-grating distributed Bragg reflector laser, operating differentially at 40 Gb/s. The device is fabricated using an offset quantum-well platform, requiring a single regrowth. We show error-free operation, with a less than 3-dB power penalty at the optimal differential delay, and open eyes across a 25-nm output tuning range.

All-optical FSK-WDM to intensity modulation-OTDM transmultiplexing for access passive optical networks

All-optical frequency shift keying (FSK)-WDM to intensity modulation (IM)-optical TDM (OTDM) transmultiplexing conversion by using a Mach-Zehnder interferometer wavelength converter is reported for an integrated access-metro network scenario. The WDM tributary signals are generated by direct FSK modulation on a grating coupler sampled reflector tunable laser. The resultant IM-OTDM signal is up to 20 times faster than with the tributary channels and is stable and tolerant to channel interference. All-optical demultiplexing has also been validated.

Demonstration of an optical-label switching router with multicast and contention resolution at mixed data rates

This letter experimentally demonstrates a scalable optical-label switching router architecture that supports a limited multicast function. A semiconductor-optical-amplifier-based Mach-Zehnder interferometer wavelength converter performs multiwavelength conversion for multicast at 10 Gb/s by cross-phase modulation. With a 2.5-Gb/s unicast channel, the experiment also demonstrates contention resolution in the wavelength domain at mixed data rates.

Novel automatic control for the optimum optical gain and phase differences in SOA–MZI wavelength converter: Theory and experiment

We have proposed, simulated, and experimentally verified the novel automatic control method and apparatus to automatically adjust and constantly maintain the optimum optical gain and phase differences in order to achieve the automatically optimized semiconductor optical amplifier (SOA)–Mach-Zehnder interferometer (MZI) wavelength converter (WC) with wide input power dynamic range (IPDR) and maximum extinction ratio (ER). Our automatic control algorithm is proposed through the results of simulation and its validity is confirmed through the experiment.

Extinction Ratio Improvement and Negative Bit-Error-Rate Penalty in Mach–Zehnder Interferometric Wavelength Converter for Optical 2R Regeneration

We have fabricated a semiconductor optical amplifier-based Mach–Zehnder interferometric wavelength converter with preamplifiers. For 2R regeneration, we have measured the extinction ratio (ER) and the bit-error-rate (BER) penalty of the wavelength-converted signal by optimizing the applied currents to the preamplifiers in varying the ER of a non-return-to-zero input signal at 10 Gbit/s. The ER was more improved and the BER showed a larger negative power penalty for an input with a smaller ER. For a typical input signal with a 5 dB ER, the ER improvement was 5.5 dB and the power penalty was -2.6 dB.