Thermo-optic Variable Optical Attenuator Research Articles

Polymer/Silica Hybrid Waveguide Thermo-Optic VOA Covering O-Band.

In this paper, a polymer/silica hybrid waveguide thermo-optic variable optical attenuator (VOA), covering the O-band, is demonstrated. The switch is fabricated by simple and low-cost direct ultraviolet (UV) lithography. The multimode interferences (MMIs) used in the Mach–Zehnder interferometer (MZI)-VOA are well optimized to realize low loss and large bandwidth. The VOA shows an extinction ratio (ER) of 18.64 dB at 1310 nm, with a power consumption of 8.72 mW. The attenuation is larger than 6.99 dB over the O-band. The rise and fall time of the VOA are 184 μs and 180 μs, respectively.

Design and fabrication of all-polymer thermo-optic variable optical attenuator with low power consumption

In this paper, an all-polymer thermo-optic variable optical attenuator (VOA) based on Mach–Zehnder interferometer (MZI) waveguide structure was designed and fabricated on PMMA substrate. To improve the performance of the VOA device, the air trench structure was employed. The improved device presents a low power consumption of 2.8 mW and a high optical attenuation of −40.2 dB. The variation of attenuation was ±2.45 dB within the wavelength ranging from 1530 nm to 1610 nm. Under 1550 nm operating wavelength, the insertion loss of the VOA was measured to be 9.3 dB, and the response time was about 600.0 μs.

Cross-cascaded AWG-based wavelength selective switching integrated module using polymer optical waveguide circuits

100-GHz cross-cascaded arrayed waveguide gratings (AWGs)-based wavelength selective optical switching optical cross-connects (OXCs) modules with Mach-Zehnder interferometer (MZI) thermo-optic (TO) variable optical attenuator (VOA) arrays and optical true-time-delay (TTD) line arrays is successfully designed and fabricated using polymer photonic lightwave circuit. Highly fluorinated photopolymer and grafting modified organic-inorganic hybrid material were synthesized as the waveguide core and cladding, respectively. The one-chip transmission loss is ~6 dB and the crosstalk is less than ~30 dB for the transverse-magnetic (TM) mode. The actual maximum modulation depths of different thermo-optic switches are similar, ~15.5 dB with 1.9 V bias. The maximum power consumption of a single switch is less than 10mW. The delay time basic increments are measured from 140 to 20 ps. Proposed novel module is flexible and scalable for the dense wavelength division multiplexing network.

Variable optical attenuator based on photonic crystal waveguide with low-group-index tapers

We demonstrate a compact thermo-optic variable optical attenuator (VOA) based on the cutoff effect of W1 photonic crystal waveguide (PCW). In experiment, a variable attenuation range of 29 dB is achieved with a device length of only 16.8 μm. The coupling loss is also reduced by 7.5±2.5 dB through introducing low-group-index tapers between the W1 PCW and strip waveguide. This VOA provides the largest variable attenuation range in the reported tunable PCW device to our knowledge.

Design of Thermo-Optic Variable Optical Attenuator Based on Quartz Substrate

In this paper, we designed a thermo-optic variable optical attenuator (VOA) based on quartz substrate, which consists of a Mach-Zehnder interferometer (MZI) and a thin film heater above the phase-modulation arm. The transmission properties of the waveguide and attenuation characteristics of the device have been simulated by beam propagation method (BPM), and the simulated results illustrated that the designed VOA had good performance.

Silicon-on-insulator thermo-optic variable attenuator module with fast response

A thermo-optic variable optical attenuator module composed of a silicon-on-insulator attenuator chip and driving circuit was designed and fabricated. The module exhibited a maximum attenuation of 21.8 dB and a response time of 10 mu s. (c) 2005 Society of Photo-Optical Instrumentation Engineers.

Variable optical attenuator based on ion-exchange technology in glass

A thermooptic variable optical attenuator (VOA) based on the Mach-Zehnder interferometer principle was fabricated in glass by an ion-exchange technique. The thermooptical effect was reached via heating electrodes on the side of the Mach-Zehnder arms. The insertion loss of the device was 1 dB, the dynamic range was 38 dB, maximal power consumption was 138 mW, and the polarization-dependent loss (PDL) was 0.2 dB/0.6 dB at 10 dB/20-dB attenuations, respectively.

New type of multimode-interference-type thermo-optic variable optical attenuator

A thermo-optic variable optical attenuator (VOA) based on a Mach-Zehnder interferometer and multimode-interference coupler is fabricated. Not a single-mode but a multimode waveguide is used as the input and output structures of the optical field, which greatly reduces the coupling loss of the VOA with a normal single-mode fiber. The insertion loss of the fabricated VOA is 2.52 to 2.82 dB at the wavelength of 1520 to 1570 nm. The polarization dependent loss is 0.28 to 0.45 dB at the same wavelength range. Its maximum attenuation range is up to 26.3 dB when its power consumption is 369 mW. The response frequency of the fabricated VOA is about 10 kHz.

Thermo-optic variable optical attenuator with low power consumption fabricated on silicon-on-insulator by anisotropic chemical etching

A thermo-optic Mach-Zehnder (MZ) variable optical attenuator based on silicon waveguides with a large cross section was designed and fabricated on silicon-on-insulator (SOI) wafer. Multimode interferometers were used as power splitters and combiners in the MZ structure. In order to achieve a smooth interface, anisotropic chemical etching of silicon was used to fabricate the waveguides. Isolating grooves were introduced to reduce power consumption and device length. The device has a low power consumption of 210 mW and a response time of 50 mus. (C) 2004 Society of Photo-Optical Instrumentation Engineers.

New design for a variable optical attenuator based on a bent channel waveguide

We present a new method for bend loss control in a curved channel optical waveguide and employ it in a novel design of a thermo-optic variable optical attenuator. We show that the introduced asymmetric refractive index profile of the waveguide structure, combined with the optimal placement of the heating electrodes, leads to a significant increase of the dynamic range of the attenuator.

Multimode-interference-type thermo-optic variable optical attenuator with a response frequency of 10 kHz

A thermo-optic variable optical attenuator based on a multimode interference coupler principle is fabricated. The propagation loss of the fabricated device is 1.6 to 3.8 dB at the wavelength range 1510 to 1610 nm, which is very near the calculated value (1.2 dB) by the finite difference beam propagation method. The maximum power consumption is 363 mW and the dynamic attenuation range is 0 to 26 dB. The response frequency of the fabricated attenuator is about 10 kHz. (C) 2003 Society of Photo-Optical Instrumentation Engineers.

SIMULATION AND FABRICATION OF THERMO-OPTIC VARIABLE OPTICAL ATTENUATORS BASED ON MULTIMODE INTERFERENCE COUPLER

A type of thermo-optic variable optical attenuator based on multimode interference coupler is proposed. The optical field propagation properties of the devices are simulated using finite difference beam propagation method. The propagation loss of the fabricated device is 2-4.2 dB at the wavelength range 1510-1610 nm. The total power consumption is 370 mW and the maximum attenuation is more than 25 dB, which almost can meet the requirements of optical fiber communication systems.

Variable optical attenuator for large-scale integration

A polymer thermooptic variable optical attenuator (VOA) was designed and demonstrated for dense waveguide device integration. The waveguide bend design is compatible with photolithography fabrication techniques and operates by controlling waveguide bend radiation loss. The design optimizes the compromise between integration capability, integration cost, and attenuation efficiency. For a 5 mm bend length, optical attenuation of >40 dB has been achieved with an applied electrical power of 250 mW. The fiber-to-fiber insertion loss was 1.5 dB for a 20-mm total waveguide length. The design's compact size makes it practical for both VOA arrays and dense integrated optical circuits.

Low-power consumption polymeric attenuator using a micromachined membrane-type waveguide

We have proposed and demonstrated a low-power consumption thermooptic variable optical attenuator incorporating a membrane-type asymmetric branch waveguide in polymers. The membrane structure has been introduced by partially removing the silicon substrate with a bulk micromachining technique of backside etching. As a result, the heat flow in the polymer layers has been appropriately adjusted to increase the temperature gradient between the two arms of the branch and thus to enhance the attenuation efficiency. The measured electrical power consumption of the proposed attenuator was as small as 25 mW at 1550 nm, which was reduced by about 50% compared to that of the conventional device. Further improvement is achieved by a more optimized design of the area to be etched away.