TRx Module Research Articles

Optical transceiver with in-chip temperature compensation module design and fabrication

An optical transceiver module with in-chip temperature compensation has been implemented using a 0.13 µm complementary metal oxide semiconductor technology to demonstrate stable light emission with temperature variations. The TRx module works up to 6.125 Gbps data rate and achieves a BER of <10−12 with received power of −11 dBm and input power of −8.2 dBm for Tx and Rx, respectively, at room temperature (25 °C). A measured 3-dB bandwidth of 4.05 and 4.75 GHz are obtained for the transmitter and receiver, respectively. For a temperature increase of 25–100 °C, the temperature compensation effectively works for the Tx module with an increased power of 1.2 dB, whereas temperature uncompensated Rx module input power increases to 3.5 dB at 6.125 Gbps and BER of <10−12.

10 Gbps/ch Full-Duplex Optical Link Using a Single-Fiber Channel for Signal Transmission

A 10 Gbps/ch full-duplex (simultaneous bidirectional) optical link utilizing two optical subassembly (OSA) transceiver (TRx) modules and two wavelengths, 850 and 1060 nm, for sending and receiving optical signals through a single fiber channel in a fiber array is demonstrated. Each of the OSA TRx modules consists of transmitter/receiver chips, optical fibers embedded in a V-grooved silicon substrate, two 45 ° mirrors formed in fibers, and three silicon optical benches for mounting vertical-cavity surface-emitting lasers, photodiodes (PDs), and monitoring PDs. Mirror-1 in the fiber is coated with a wavelength-filtering layer to reflect transmitted light and pass through received light. Mirror-2 deflects received light to the PD. Two OSA TRx modules were applied in an end-to-end quad small form-factor pluggable optical link for 40-Gbps operation. This optical link showed good performance with clear eye-diagrams and a BER of at <;10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> Gbps/ch with -8-dBm input power.

Biwavelength transceiver module for parallel simultaneous bidirectional optical interconnections

The design of a biwavelength transceiver (TRx) module for parallel simultaneous bidirectional optical interconnects is described. The TRx module has been implemented using two different wavelengths, 850 and 1060 nm, to send and receive signals simultaneously through a common optical interface while optimizing cost and performance. Filtering mirrors are formed in the optical fibers which are embedded on a V-grooved silicon substrate for reflecting and filtering optical signals from/to vertical-cavity surface-emitting laser (VCSEL)/photodiode (PD). The VCSEL and PD are flip-chip bonded on individual silicon optical benches, which are attached on the silicon substrate for optical signal coupling from the VCSEL to fiber and from fiber to the PD. A high-speed and low-loss ceramic printed circuit board, which has a compact size of 0.033 cc, has been designed to carry transmitter and receiver chips for easy packaging of the TRx module. Applied for quad small form-factor pluggable applications at 40-Gbps operation, the four-channel biwavelength TRx module showed clear eye diagrams with a bit error rate (BER) of 10 −12 at input powers of −5 and −5.8 dBm for 1060 and 850 nm operation modes, respectively.

Plant Thioredoxin CDSP32 Regenerates 1-Cys Methionine Sulfoxide Reductase B Activity through the Direct Reduction of Sulfenic Acid

Thioredoxins (Trxs) are ubiquitous enzymes catalyzing the reduction of disulfide bonds, thanks to a CXXC active site. Among their substrates, 2-Cys methionine sulfoxide reductases B (2-Cys MSRBs) reduce the R diastereoisomer of methionine sulfoxide (MetSO) and possess two redox-active Cys as follows: a catalytic Cys reducing MetSO and a resolving one, involved in disulfide bridge formation. The other MSRB type, 1-Cys MSRBs, possesses only the catalytic Cys, and their regeneration mechanisms by Trxs remain unclear. The plant plastidial Trx CDSP32 is able to provide 1-Cys MSRB with electrons. CDSP32 includes two Trx modules with one potential active site (219)CGPC(222) and three extra Cys. Here, we investigated the redox properties of recombinant Arabidopsis CDSP32 and delineated the biochemical mechanisms of MSRB regeneration by CDSP32. Free thiol titration and 4-acetamido-4'-maleimidyldistilbene-2,2'-disulfonic acid alkylation assays indicated that the Trx possesses only two redox-active Cys, very likely the Cys(219) and Cys(222). Protein electrophoresis analyses coupled to mass spectrometry revealed that CDSP32 forms a heterodimeric complex with MSRB1 via reduction of the sulfenic acid formed on MSRB1 catalytic Cys after MetSO reduction. MSR activity assays using variable CDSP32 amounts revealed that MSRB1 reduction proceeds with a 1:1 stoichiometry, and redox titrations indicated that CDSP32 and MSRB1 possess midpoints potentials of -337 and -328 mV at pH 7.9, respectively, indicating that regeneration of MSRB1 activity by the Trx through sulfenic acid reduction is thermodynamically feasible in physiological conditions.

A proposed reaction mechanism for rice NADPH thioredoxin reductase C, an enzyme with protein disulfide reductase activity

NADPH thioredoxin reductase C (NTRC) is an interesting NTR with a thioredoxin (Trx) domain at the C-terminus, able to conjugate both activities for 2-Cys peroxiredoxin (Prx) reduction. NTRC is dimeric in the presence of NADPH and interacted with dimeric 2-Cys Prx through the Trx module by a mixed disulfide between Cys377 of NTRC and Cys61 of the 2-Cys Prx. NTRC variants of both NTR and Trx active sites were inactive, but 1:1 mixtures of both variants allowed partial recovery of activity suggesting inter-subunit transfer of electrons during catalysis. Based on these results we propose a model for the reaction mechanism of NTRC. Structured summary MINT- 7017333: 2cys Prx (uniprotkb: Q6ER94) and 2cys Prx (uniprotkb: Q6ER94) bind (MI: 0407) by molecular sieving (MI: 0071) MINT- 7017101, MINT- 7017183: NTRC (uniprotkb: Q70G58) and 2cys Prx (uniprotkb: Q6ER94) bind (MI: 0407) by enzymatic studies (MI: 0415)

Chip-to-Chip Optical Link System Using an Optical Wiring Method

A practical optical link system was prepared with a transmitter (Tx) and receiver (Rx). The optical TRx module consisted of a metal optical bench, a module printed circuit board, a driver/receiver integrated circuit, a vertical-cavity surface-emitting laser/photodiode array, and an optical link block composed of plastic optical fiber (POF). For the optical interconnection between the light-sources and detectors, an optical wiring method has been proposed to enable easy assembly. The optical wiring link was constructed with POFs mounted on a v-grooved polymethylmethacrylate bench. The data transfer measurements were presented successfully.

Fabrication of a TFF-Attached WDM-Type Triplex Transceiver Module Using Silica PLC Hybrid Integration Technology

An optical triplex transceiver (TRx) module, which consists of thin-film filter (TFF)-attached wavelength-division multiplexer (WDM) and photodiode (PD) carriers, has been fabricated using a silica planar lightwave circuit (PLC) hybrid integration technology. Two types of TFFs were attached to a diced sidewall of a silica-terraced PLC platform to realize the TFF-attached WDM. The PD carriers with a 45deg mirror, on which receiving surface-illuminated PDs were bonded, were assembled with the PLC platform to form receiver (Rx) parts. As the main performances of the packaged TRx module, a very clear transmitter (Tx) eye pattern and minimum Rx sensitivity of -25.7 dBm were obtained under a 1.25-Gb/s Tx-Rx operation for digital applications. For an analog Rx application, a module responsivity of about 0.8 A/W was achieved, and a second-order intermodulation distortion value of less than -70 dBc at an optical modulation index of 40% was obtained under a two-tone test of 400 and 450 MHz