Abstract: A DC level detection circuit between high speed signal line connecting ports and a system using the same in optical communications is disclosed. Corresponding ports of a high speed signal line each have an additional resistor, where one additional resistor has a resistance significantly greater than that of the other resistor. The smaller resistor is grounded. The larger resistor is connected to a DC voltage source, a low pass filter, and a signal detection port. Thus, when both ports of the high speed signal line are connected, a status of the electrical level detected at the signal detection port changes. The circuit detects the connection state of the high speed signal line without negative effects on signal transmission and is applicable to various circuits, especially plug-in modules and corresponding slots. Thus, the circuit further enables signal port multifunctionality, increases module installation accuracy, and provides higher compatibility for plug-in modules.

Abstract: A gain-variable trans-impedance amplifier (TIA) in optical device is disclosed. The TIA has an improved dynamic range for receiving electrical signals and is configured to convert current signals from an avalanche photodiode (APD) to voltage signals. A resistor element is between the input and output terminals of the TIA, wherein the resistance of the resistor element can regulate the resistance and/or impedance value of the TIA, and a switch determines or controls the resistance of the resistor element. When the power of an optical signal received by the APD is higher than a predetermined value, the resistance becomes smaller and the gain of the TIA becomes greater. When the power of the optical signal is lower than the predetermined value, the resistance becomes greater. The gain of the TIA is automatically adjusted on the basis of the intensity of received optical signals to obtain a greater dynamic operational range.

Abstract: The present application discloses a method and circuitry that improves the monitoring and/or reporting accuracy and of a TOSA transmitter output power. In the method, the output power of an optical transmitter is measured at 25° C. and at N individual temperatures to obtain N tracking error (TE) values corresponding to the N individual temperature values, then a lookup table covering an operating temperature range of the transmitter is created based on a one-to-one mapping relationship between the TE values and the N individual temperatures and a line fitting process. The transmitter output power is reported at an interface of the transmitter according to the TE value at the transmitter operating temperature in the lookup table. The present application also discloses optical modules and optical communication systems. The present method and transmitter effectively improve the monitoring and/or reporting accuracy of the transmitter output power.

Abstract: A high speed optical module, and in particular, a multi-channel, single-mode, parallel transmission optical module in the field of optical communication is disclosed. The optical module includes a chassis, a first transmitter optical subassembly (TOSA), a second transmitter optical subassembly (TOSA), a third transmitter optical subassembly (TOSA), a fourth transmitter optical subassembly (TOSA) and a MT fiber connector. The TOSA may be a TO-38 TOSA of a 10 G DFB chip or FP chip. With single-mode communication, the optical module provides a transmission distance over 10 kilometers. In addition, to make coupling single-mode fibers easier, a twelve-core MT fiber connector is employed, wherein four fiber connectors are respectively connected to LC standard fiber stubs and the outputs of the TOSAs accordingly. Thus, the optical module further provides high speed and long-distance transmission, large capacity, small volume, and light weight and can be broadly applied to high speed optical communications.

Abstract: An N×N parallel optical transceiver includes a printed circuit board, a laser driving control chip, one or more lasers, two GRIN lenses, an optical band-pass filter, a multimode fiber array and a photodiode array. In the transmitter, laser beams of the same wavelength simultaneously output from the laser chip are first focused by the first GRIN lens, then the beams pass through a wavelength band-pass filter and are refocused by the second GRIN lens, and enter the channels in the multimode fiber array. In the receiver, laser beams of a different wavelength from the multimode fiber array are focused by the second GRIN lens, then reflected by the band-pass filter, refocused by the second GRIN lens, and received by the photodiode array. The multi-channel parallel transceiver has a small form, and can integrate a DFB or FP laser chip and GRIN lenses.

Abstract: An integrated lens with integrated functional optical surfaces for use in optical communication is disclosed. The integrated lens includes first and second cavities and a fiber adapter. The device also includes integrated first and second lenses. The first cavity houses one or more optical transmitting and/or receiving devices. The second cavity has a first optical surface and an optional second optical surface. The fiber adapter has the second lens. The integrated lens enables a small size, a light weight, high coupling and a high transmission efficiency, and can be produced by injection molding using a single mold. The integrated lens is applicable to optical signal coupling, fiber connections, optical modules, and optical or optoelectronic communication.

Abstract: An optical or free space isolator, and optical or optoelectronic transmitter and methods of transmitting an optical signal and making the transmitter are disclosed. The optical/free space isolator includes a first polarizer, configured to polarize light at a first polarization angle and block light at a second polarization angle; a Faraday rotator, configured to rotate the light polarized by the first polarizer by a predetermined number of degrees; and a half waveplate in the optical/light path, having a fixed or predetermined orientation angle. The first polarizer, Faraday rotator/isolator, and half waveplate have respective polarization, rotation and orientation values that allow light to pass through the optical isolator in a first direction, and block reflected light traveling through the optical isolator along a direction opposite to the first direction.

Abstract: A gain-variable trans-impedance amplifier (TIA) in optical device is disclosed. The TIA has an improved dynamic range for receiving electrical signals and is configured to convert current signals from an avalanche photodiode (APD) to voltage signals. A resistor element is between the input and output terminals of the TIA, wherein the resistance of the resistor element can regulate the resistance and/or impedance value of the TIA, and a switch determines or controls the resistance of the resistor element. When the power of an optical signal received by the APD is higher than a predetermined value, the resistance becomes smaller and the gain of the TIA becomes greater. When the power of the optical signal is lower than the predetermined value, the resistance becomes greater. The gain of the TIA is automatically adjusted on the basis of the intensity of received optical signals to obtain a greater dynamic operational range.

Abstract: An integrated lens with integrated functional optical surfaces for use in optical communication is disclosed. The integrated lens includes first and second cavities and a fiber adapter. The device also includes integrated first and second lenses. The first cavity houses one or more optical transmitting and/or receiving devices. The second cavity has a first optical surface and an optional second optical surface. The fiber adapter has the second lens. The integrated lens enables a small size, a light weight, high coupling and a high transmission efficiency, and can be produced by injection molding using a single mold. The integrated lens is applicable to optical signal coupling, fiber connections, optical modules, and optical or optoelectronic communication.

Abstract: The present application discloses a method and circuitry that improves the monitoring and/or reporting accuracy and of a TOSA transmitter output power. In the method, the output power of an optical transmitter is measured at 25° C. and at N individual temperatures to obtain N tracking error (TE) values corresponding to the N individual temperature values, then a lookup table covering an operating temperature range of the transmitter is created based on a one-to-one mapping relationship between the TE values and the N individual temperatures and a line fitting process. The transmitter output power is reported at an interface of the transmitter according to the TE value at the transmitter operating temperature in the lookup table. The present application also discloses optical modules and optical communication systems. The present method and transmitter effectively improve the monitoring and/or reporting accuracy of the transmitter output power.

Abstract: A dual-rate power point compensating circuit, comprising a microprocessor and a transmitter optical subsystem assembly (TOSA), wherein the TOSA includes a laser connected to a laser driver, a monitor photodiode (MPD) connected to the laser driver, and a current divider connected to the microprocessor and the MPD. When a feedback current from the MPD exceeds the adjustable and/or operating range of the laser driver, the feedback current is reduced so that it is kept in the adjustable and/or operating range of the laser driver. The laser driver determines the optical output power of the laser from the value of the reduced feedback current. The circuit and method extend the adjustable and/or operating range of a laser driver and enable it to regulate a target optical output power of the laser with a broad testing range and high accuracy when the feedback current is relatively high.

Abstract: A DC level detection circuit between high speed signal line connecting ports and a system using the same in optical communications is disclosed. Corresponding ports of a high speed signal line each have an additional resistor, where one additional resistor has a resistance significantly greater than that of the other resistor. The smaller resistor is grounded. The larger resistor is connected to a DC voltage source, a low pass filter, and a signal detection port. Thus, when both ports of the high speed signal line are connected, a status of the electrical level detected at the signal detection port changes. The circuit detects the connection state of the high speed signal line without negative effects on signal transmission and is applicable to various circuits, especially plug-in modules and corresponding slots. Thus, the circuit further enables signal port multifunctionality, increases module installation accuracy, and provides higher compatibility for plug-in modules.

Abstract: A burst-mode laser control circuit and related methods thereof are disclosed. Using an APC loop with an additional burst-mode control circuit, and a switch in series with a diode and in parallel with the laser, a continuous-mode laser driver is enabled to operate in burst-mode by turning the switch on or off via external logic. Burst-mode control manages the switch, and a bandwidth-select circuit using a high or low logic level input, wherein the laser is disabled and the bandwidth-select circuit enters a fast-track mode when the external logic signal has a first level. The laser provides regular optical signals, and the bandwidth-select circuit enters a slow-track mode, thereby enabling the APC loop to operate normally, when the external logic signal has a second level. In addition to a low cost and simple implementation, the control circuit and method provide lasers with a fast response capability using one or more externally-controlled switch circuits to meet demands of PON systems for burst-mode ONUs.

Abstract: A burst-mode laser control circuit and related methods thereof are disclosed. Using an APC loop with an additional burst-mode control circuit, and a switch in series with a diode and in parallel with the laser, a continuous-mode laser driver is enabled to operate in burst-mode by turning the switch on or off via external logic. Burst-mode control manages the switch, and a bandwidth-select circuit using a high or low logic level input, wherein the laser is disabled and the bandwidth-select circuit enters a fast-track mode when the external logic signal has a first level. The laser provides regular optical signals, and the bandwidth-select circuit enters a slow-track mode, thereby enabling the APC loop to operate normally, when the external logic signal has a second level. In addition to a low cost and simple implementation, the control circuit and method provide lasers with a fast response capability using one or more externally-controlled switch circuits to meet demands of PON systems for burst-mode ONUs.

Abstract: A multi-channel optical device and method of making the same are disclosed. The optical device includes a plurality of detectors on a detector mounting substrate, and a corresponding plurality of lenses on an interior surface of the optical device. Each detector detects light having a unique center wavelength. Each center wavelength corresponds to a channel of the optical device. Each lens focuses light towards a corresponding detector. Each detector has a location corresponding to a focal point of the light focused by a corresponding lens. The method of making the optical device includes placing lenses on a surface of the optical device housing, transmitting light having a plurality of center wavelengths through the lenses, determining locations on a detector mounting substrate where each light beam is focused by a lens, and placing a detector at each location.

Abstract: A small form-factor pluggable (SFP) optical transceiver includes a casing configured to accommodate optical and electrical devices. During normal operation, the casing is connected to a switchboard via a connector in the switchboard, and the optical devices are outside the switchboard, thereby exposing optical devices sensitive to high temperature to the outside air, reducing the operational temperature of the optical device portion relative to the heated portion inside the switchboard. Thus, the present SFP optical transceiver advantageously improves operational performance and extends the life of the device. Also, the present SFP optical transceiver having the optical device portion outside the switchboard advantageously improves the cooling performance for the optical device portion.

Abstract: A multi-channel optical transmitter generally includes a first light source configured to emit light of a first wavelength, a second light source configured to emit light of a second wavelength, a first modulator configured to modulate the light of the first wavelength, and a second modulator configured to modulate the light of the second wavelength. The first modulator has a first anode and a first cathode, and the second modulator has a second anode and a second cathode electrically isolated from the first anode and the first cathode. The modulators (and optionally the light sources) are on a common substrate. A method of transmitting optical signals generally includes modulating light emitted from a first light source using a first modulator, and modulating light emitted from a second light source using a second modulator, where the first modulator receives a first modulation signal, and the second modulator receives a second modulation signal electrically isolated from the first modulation signal.

Abstract: A modulated laser system generally includes a light emission region, a modulation region having a plurality of semiconductive layers, at least one of which includes a quantum well layer having a variable energy bandgap, and an isolation region separating the light emission region and the modulation region. The laser may be an electro-absorption modulated laser, the light emission region may include a distributed feedback laser, and the modulation region may include an electro-absorption modulator. The laser may be manufactured by forming a lower semiconductive buffer layer on a substrate, an active layer including one or more quantum well layers having the variable energy bandgap on or above the lower semiconductive buffer layer, an upper semiconductive buffer layer on or above the active layer, a contact layer on or above the upper semiconductive buffer layer, and an isolation region separating the light emission region and the modulation region.