Allied Telesis, Inc.

Allied Telesyn, Inc.

Other

Vitali Tikhonov

Shinkyo Kaku

Severino Tolentino

Vladimir Pugach

Svetlana Tikhonova

Nikolai Fediakine

A method for automated calibration of an avalanche photodiode receiver includes measuring two values of avalanche photodiode biases at two successive times, measuring and comparing a bit error rate corresponding to each value. When the bit error rate of the second value is equal to or greater than the bit error rate of the first value, then a third value and a fourth value of avalanche photodiode bias closer together are measured. When the bit error rate of the fourth value is smaller than the bit error rate of the third value, two subsequent values as third value and fourth value are measured, and an optimum avalanche photodiode bias when the bit error rate of the fourth value is equal to the bit error rate of the third value is measured.

Apparatus and method for automated adjustment and setting of APD optical receiver operation point

A system and method for an Avalanche photo-diode ('APD') optical receiver and laser system to adjust its performance during system operation without disturbing network traffic. Very small changes may be adaptively applied to some key portions of the system by controlling a set of main system parameters including Q-factor; Bit Error Rate (BER); histograms of '1' and &#x201c;0&#x201d; levels; input optical power; and laser output power. This adaptive routine may be performed during operation of the system to keep the main system parameters close to their optimum value. During adjustment, the system may be divided into separate portions. The adjustment of each portion may be independent of the other portions of the system. For the optical network system, optimization and priority of different portions may be assigned based on network channel architecture.

Apparatus and method for adaptive adjustment and performance monitoring of avalanche photo-diode optical receiver and laser transmitter for fiber link long haul applications

Disclosed are an in-line monitoring apparatus, an optical receiver and a method for monitoring an input power of an optical signal in which one or more power monitoring stages, for example can measure the input power over an extended input power range. In one embodiment, an apparatus includes an avalanche photodiode ('APD') configured to receive the optical signal and an input configured to bias the APD. It also includes one or more power monitoring stages coupled to the input in parallel with the APD for generating one or more measurement signals in-situ. In one embodiment, a range selector selects which one of the one or more power monitoring stages is to provide a measurement signal indicative of the input optical power. The power monitoring stages can provide for a wide range of linear current measurements as well as a range of measurable currents to monitor low-powered optical signals.

In-situ power monitor providing an extended range for monitoring input optical power incident on avalanche photodiodes

Disclosed are an in-line monitoring apparatus with a temperature compensator, an optical receiver and a method for stabilizing gain of an avalanche photodiode ('APD') over an extended range of input power values and across temperature variations. The apparatus can include one or more power monitoring stages coupled in parallel to the APD for generating one or more measurement signals in-situ. The apparatus also includes a temperature compensator configured to adjust an operational parameter for the APD as a function of temperature and the measurement signal. The temperature compensator adjusts the bias to maintain a substantially uniform gain across temperature variations to facilitate an increased sensitivity with which to monitor the input power at lower levels than if the temperature compensator did not adjust the bias in response to the temperature. One of the power monitoring stages can be configured to monitor the low-powered optical signals.

In-situ power monitor having an extended range to stabilize gain of avalanche photodiodes across temperature variations

An apparatus for detecting abnormalities in spatial perception that consists of a first transparent screen in a close-vision field and a second screen seen through the first one and located in a far-vision field of a person being tested. The apparatus is provided with devices for forming images selectively on the first or second screen and with a device for tracking trajectories of the eye pupils while following the images. The method is based on detecting specific irregularities in trajectories of the eye pupils, such as nystagmuses, cut-offs, sudden drops of the gaze, etc., when a person follows the smooth trajectory of a moving image on a selected screen, or when the size and position of the eye pupil change with certain irregularity in response to instantaneous switching of images between the screens without changing the position of the person's head.

Growing community of inventors

Mountain View, CA, United States of America

Vitali Tikhonov